Weaning and Withdrawal of Mechanical Ventilation

#### **Chapter 6**

## Weaning from Mechanical Ventilation

*Liran Statlender and Pierre Singer*

#### **Abstract**

Weaning off mechanical ventilation (MV) is a process that ultimately ends with a patient's liberation from the ventilator. As extubation failure worsens prognosis, every effort should be made to safely extubate the patient when the clinical condition allows it. There are several methods and techniques to assess whether a patient is ready for weaning. The clinician should choose the proper method for each patient to minimalize the risk of extubation failure. When liberation from MV is not possible, tracheostomy and transferring the patient to a long-term rehabilitation ward may be required. If this is not feasible, palliative care should be considered.

**Keywords:** weaning, extubation, spontaneous breathing trial (SBT), rapid shallow breathing index (RSBI)

#### **1. Introduction**

Weaning from mechanical ventilation (MV) is the process by which a patient is liberated from a ventilator. It begins with a readiness assessment and ends with liberation, usually by extubation. A successful weaning process should discriminate patients who might fail in the extubation and need reintubation from those who might be successful and maintain spontaneous breathing without mechanical support. This is important, as extubation failure and reintubation worsen prognosis and increase risk of mortality, length of stay, length of ventilation, and ventilationassociated events [1].

Ventilation duration affects the weaning process. If a patient was ventilated for a short time (e.g., during a surgical procedure, trauma patient emergency work-up and treatment), it is usually possible to liberate the patient from MV immediately at the end of the procedure without any special difficulties. Of course, patient characteristics matter in these cases (more caution is mandated in a fragile patient than in a young patient). However, longer time of ventilation due to severe respiratory failure or other severe injury or inflammatory process usually mandates a more structured weaning process, which this chapter describes [2, 3].

#### **2. Readiness for weaning**

A daily assessment of readiness for extubation should be performed in every ventilated patient. This screening is important to identify patients who might be successfully weaned and to avoid premature extubation in patients who are not ready yet.

The first consideration when weaning a patient from MV is whether the disease that necessitated MV is controlled and in recovery phase. If the disease process is active and not controlled, the patient should not be considered ready for extubation [4].

The second consideration is respiratory function, both oxygenation and ventilation [5]:

1.Oxygenation

a.paO2/FiO2 > ~260

b.FiO2 < 0.4

c.Positive end expiratory pressure (PEEP) < 5 cmH2O

If these criteria are not met, it is likely that the patient needs considerable oxygen supplementation.

2.Ventilation

a.pH > 7.25

A lower pH represents a great load on the respiratory system.

These criteria are considered conservative. For example, early works considered paO2/FiO2 of 150 as satisfactory for extubation consideration. Later works suggested a higher cutoff of 260–290 [6–8]. Nevertheless, in specific subgroups of patients, these criteria should be slightly adapted. For example, in patients who suffer interstitial lung disease (or other chronic hypoxic diseases), a paO2/FiO2 > 120 can be used. In patients who suffers from obstructive lung disease, pH and pCO2 should be close to the patient's baseline level.

The third consideration is cardiovascular function. Initiation of MV unloads the work of breathing from the patient. Cessation of MV imposes this work on the patient again and adds work to the cardiac output. Moreover, as positive endexpiratory pressure (PEEP) decreases afterload, discontinuation of MV increases afterload, potentially worsening heart failure. Therefore, it is necessary that a patient be hemodynamically stable before weaning (no more than a small and stable rate of vasopressors) [9].

The fourth consideration is neurological status. A patient can be considered ready for extubation if they are alert and cooperative. It is necessary that the patient not be under the effect of IV sedation drugs [4], which might cause respiratory depression (opiates, benzodiazepines, propofol). A small dose of IV sedatives that do not cause respiratory depression (dexmedetomidine, ketamine) is acceptable. Enteral or transdermal analgesia and sedation are possible, as long as the doses are stable and the patient is cooperative.

It is worth emphasizing the importance of patient cooperation. After extubation, the patient will usually have to promote cough, cooperate with respiratory therapy, and might need some support in the form of non-invasive ventilation (NIV) or supplementary oxygen. Failure to cooperate with any of these might lead to re-intubation and thus it is important to achieve the patient's cooperation.

Another issue of neurological status is muscle power, especially the ability to cough [10]. Although specific maneuvers to assess respiratory muscle strength are not superior to current maneuvers to assess weaning probability success, it is important to evaluate the patient's ability to cough, as coughing evacuates secretions and

#### *Weaning from Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.99257*

prevents aspiration. Whenever a patient seems too weak or not able to perform cough mechanics, the risk of aspiration and re-intubation increases.

Other factors to consider are hemoglobin [11] and temperature [12]. Although both are not mandatory and critical to be completely normal before extubation, it is worth confirming that the patient being assessed for weaning is not developing a new problem such as sepsis, bleeding, or hemolysis (any of which might impose further load on the respiratory system and mandate intubation by itself). If so, it might be better to hold off on the weaning process.

#### **2.1 Weaning predictors**

When a patient seems ready for extubation, it is possible to perform some measurements as predictors of successful weaning. As no predictor is 100% sensitive and specific, and as some are cumbersome to perform, it is not mandatory to use any of these predictors. Some use weaning predictors in a structured fashion, while others use them only in cases of doubt whether the patient is ready or not [13–15].

The best studied predictor is the Rapid Shallow Breathing Index (RSBI), which is calculated by dividing the tidal volume (in liters) by the respiratory rate (Vt/f). To calculate this predictor, the patient has to breath spontaneously, without any support, for 1 minute, during which the tidal volume and the respiratory rate are measured. Though this measurement is sometimes performed while disconnecting the patient from the ventilator (measurement by external spirometer), it is acceptable to measure RSBI 1 minute after setting the ventilator on zero pressure support and zero PEEP. An RSBI of 105 is considered the cutoff for extubation failure. RSBI >105 has good correlation with extubation failure (negative predictive value 95%), and thus it is advised to delay extubation. However, RSBI <105 does not guarantee successful weaning, as its positive predictive value is about 80%. Interestingly, using automatic tube compensation increases RSBI sensitivity for successful extubation [13, 16, 17].

Other predictors include p/F ratio, dead space measurement, minute ventilation, compliance of respiratory system, work of breathing, P0.1 (inspiratory effort at 0.1 seconds inspirium), maximal inspiratory pressure (MIP), P0.1/MIP, diaphragmatic sonography, tension-time index (TTI), CROP index, CORE index, Weaning Index (WI), and Integrative Weaning Index (IWI). **Table 1** provides more detail about these predictors [13, 18–24]. Although some of these have been shown to better predict successful or unsuccessful extubation than RSBI, there is only slight improvement in prediction, and all these slightly better predictions are more cumbersome to perform than RSBI.

#### **2.2 Spontaneous breathing trial (SBT)**

Whether any weaning predictor is used or not, assessing a patient for extubation requires a spontaneous breathing trial. Several techniques are possible, but the basic principle is the same. The spontaneous breathing trial (SBT) is a short period of time in which the patient is breathing spontaneously, with support as minimal as necessary to overcome the endotracheal tube or without support at all. Among the different techniques are using a T-piece device and ventilating using pressure support mode with pressure support (PS) of 0 cmH2O and PEEP 0 cmH2O, or PS 0 cmH2O and PEEP 5 cmH2O (CPAP), or PS 7–8 cmH2O and PEEP 5 cmH2O. There are controversial results from several studies regarding the superiority of specific techniques. Some studies found no difference, while others have shown better success rates with PSV 8 cmH2O and PEEP 0 cmH2O compared to T-piece [25]. In any case, FiO2 during SBT should be 0.4 or lower.


*\*Dead space and TTI predict failed extubation.*

*Sens, sensitivity; Spec, specificity; PPV, positive predictive value; NPV, negative predictive value; RSBI, rapid shallow breathing index; RR, respiratory rate; Vt, tidal volume;* <sup>2</sup> , *PaCO arterial partial pressure of carbon dioxide;*  2 , *PeCO end tidal partial pressure of carbon dioxide; PIP, peak inspiratory pressure; PEEP, positive end expiratory pressure; PTP, transthoracic pressure; MIP, maximal inspiratory pressure; TTI, tension time index; MAP, mean airway pressure; Ti, inspirium time;* , *TTOT total time of inspirium + expirium; Cdyn, dynamic compliance of lung;* <sup>2</sup> , *PaO arterial pressure of oxygen;* <sup>2</sup> , *PAO alverolar pressure of oxygen; RR, respiratory rate.*

#### **Table 1.**

*Weaning predictors and their diagnostic value.*

From a historical point of view, SBT was found to shorten weaning time more than previously used methods of weaning such as PSV gradual decrease, IMV gradual decrease, or no SBT at all [4, 26]. In recent years, an automated mode of SBT has been possible due to the development of closed-loop ventilators. These ventilation modes are mainly pressure controlled/pressure supported, but their settings are changed automatically by the ventilator based on oxygen saturation and end tidal monitoring. Upon activation of automated SBT modes, the ventilator decreases support and monitors physiological parameters including heart rate (from saturation pulse), oxygen saturation, respiratory rate, tidal volume, compliance, end tidal CO2, and RSBI. After completing SBT for a predefined time, the ventilator alerts whether the patient is ready for extubation or not. There is paucity

#### *Weaning from Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.99257*

of data comparing automated SBT to manual SBT, but results seem promising, with a possibility of automated SBT shortening MV duration [27].

When first introduced, the recommendation was to perform SBT for 2 hours. Later studies showed no difference in outcomes with SBT lasting only 30 minutes. When there is a suspicion regarding patient strength, it seems logical to perform longer SBT [28].

As SBT is somewhat challenging for the patient, its endpoint is mainly clinical [5]. To successfully pass the SBT, the patient should remain calm during the test, without any stress signs such as tachycardia, tachypnea, elevated/decreased blood pressure, desaturation, restlessness, feeling uncomfortable, increased effort in breathing, diaphoresis, or new complaints such as chest pain. If any of these occur, the patient has failed the SBT and should remain ventilated. In case of doubt, it is possible to obtain an arterial blood gas (ABG) sample to assess adequacy of oxygenation and ventilation. An ABG sample is also warranted in the case of chronic obstructive pulmonary disease (COPD).

If a patient passes the SBT successfully, extubation should be performed. If a patient fails the SBT, the ventilator should be set to the pre-SBT settings and a workup should be done to determine cause of failure reason and proper treatment. In this case, a daily SBT should take place.

#### **3. Extubation**

Once the patient has successfully passed an SBT, extubation should be performed. However, one must pay attention to the patient's ability to remove secretions on their own. Nursing staff should be asked about amounts of secretions and frequency of secretion suctions. Also, patient cough mechanics should be assessed clinically. It is possible that a patient will be screened successfully for extubation and pass an SBT but still suffer from a large amount of secretions or muscle weakness. Suction frequency greater than once every 2 hours is considered unsafe for extubation. Peak expiratory flow during cough <60 L/min is also considered unsafe for extubation. If this is the case, postponing extubation is advised [29].

In select groups of patients who are considered to have risk factors for postextubation stridor, usually due to laryngeal edema, a cuff leak test is necessary before extubation. This test is not mandatory in all patients, as without any risk factors the leak test is not sensitive nor specific. Risk factors for laryngeal edema include age older than 80 years, female gender, prolonged ventilation (more than 1 week), large-diameter endotracheal tube (more than 8 mm for males and 7 mm for females; smaller diameters are appropriate if the patient is short), CT imaging with endotracheal tube diameter >0.45 than tracheal diameter, Glasgow Coma Scale (GCS) < 8, traumatic intubation, and history of asthma. Any one of these endanger the patient for stridor and therefore mandate performing a cuff leak test. The cuff leak test is performed by deflating the endotracheal tube cuff and measuring the difference between the inspired tidal volume to the expired tidal volume (during volume-controlled ventilation). Generally, when a patient suffers from laryngeal edema, there will be small air leak, if any. Usual cutoffs that support this diagnosis are leak of <110–130 ml or <12–24% of the inhaled tidal volume. If the cuff leak test is positive (i.e., the patient suffers from laryngeal edema), a course of steroids should be given (methylprednisolone 20 mg every 6 hours) before next evaluation [30].

When the patient is ready for extubation, all necessary arrangements should be made to perform the procedure safely. The physician who performs the extubation

must keep in mind that despite taking all precautions, the patient might fail immediately and be prepared for reintubation. This is the main theme of the extubation.

Once the decision to extubate the patient is made, FiO2 of the ventilator should be set to 1. This is the preoxygenation for possible reintubation. All the equipment needed to intubate must be within grasp, including sedation drugs, laryngoscope, endotracheal tube (usually half the size of the current tube), suction tube, and resuscitation cart. If prior intubation of the patient was difficult, then the method that was finally used should be available. Before extubation, a suction is performed within the tube and oral cavity to prevent aspiration. The patient is placed in the upright position and a short explanation about the procedure is given. Extubation itself is performed either with a bag valve mask (e.g., Ambu bag) without one. With an Ambu bag the cuff is deflated, and small positive pressure is constantly applied with the bag while pulling the tube out. Without a bag, the patient is asked to take a deep breath and hold. In that time the cuff is deflated, and the tube is quickly removed. The purpose of both techniques is to set exhalation by the patient as the first movement without the tube to decrease the chance of aspiration.

#### **3.1 Post extubation management**

Usually, immediately after extubation the patient is supported by oxygen. Respiratory therapies are advised shortly after the extubation to support secretion removal. Closed monitoring for any sign of respiratory distress is mandatory to allow intervention and reintubation, if necessary, as soon as possible after respiratory distress appears.

About 85% of patients are at low risk of reintubation. Usually, these patients are managed with low-flow oxygen (nasal prongs, simple mask). Occasionally, a patient will be more comfortable with a high-flow nasal canula (HFNC), even without overt hypoxemia. Patients in this group should be monitored closely for 12–24 hours, and if there are no alarming events, they can be discharged from the ICU afterwards (considering no other active ICU problems) [2, 31].

About 15% of patients are at high risk of reintubation within 48 hours of extubation. These patients should be closely monitored and treated accordingly to avoid reintubation. High-risk patients are considered those whose cough is ineffective, who need secretion suction at a frequency greater than one suction every 2 hours, who are in positive fluid balance, who were intubated because of pneumonia. Who are not fully conscious, and who suffer from congestive heart failure (CHF) or COPD. Treatment should be focused with the etiology of deterioration (frequent secretion suction, diuretics, etc.) [1].

Applying HFNC or NIV to these patients seems beneficial in some instances, but this has not been proven. Applying NIV to all extubated patients was not found efficient in all studies performed. In select patients, immediate use of HFNC or NIV might be beneficial, especially in those patients who suffer from COPD or CHF. Both of these patient populations have specific indications for PEEP and therefore have better outcomes when extubated directly to bilevel positive airway pressure (BiPAP). HFNC was found to be non-inferior to NIV, in that instance [32, 33].

When a patient develops respiratory failure after extubation, applying NIV or HFNC might be harmful, as usually it does not prevent reintubation, but rather only postpones it. As such, when the patient finally goes to reintubation, their muscle fatigue is greater than before the NIV/HFNC challenge [4, 34]. Therefore, when a patient starts to deteriorate after extubation, careful monitoring should be performed. If an etiology of deterioration is evident, it must be treated aggressively (suction of secretions, CHF treatment, etc.). If no such reason is apparent, or if treatment response is not sufficient, it is better to reintubate the patient than to challenge with NIV/HFNC.

Reintubation is a bad prognostic factor. Usually, reintubated patients are hospitalized for a longer time (both in ICU and in hospital), suffer from more infections, and have higher mortality rates [1].

### **4. Management of SBT failure and the difficult-to-wean patient**

Approximately 60% of patients manage to pass their first SBT and are extubated successfully. These patients are classified as having simple extubation. About 40% of patients do not pass their first SBT and thus will be classified (initially) as difficult to wean (**Table 2**). These patients should undergo workup to determine why SBT failure occurred. While determining reasons for failure, daily SBT should take place. Most patients who are difficult to wean will require up to three SBTs or 7 days to pass an SBT [2].

Several pathophysiological processes might cause SBT failure. These are classified according to the main system that compromises the patient.


Usually, a careful patient examination involving history review, physical examination, ventilator graph analysis, basic laboratory examination, and imaging studies might reveal the reason and aid treatment.

During the time between SBTs the patient should be ventilated in settings that will maintain oxygenation and ventilation targets, in accordance with lung protective ventilation principles. Usually, PSV mode would apply. However, the patient must be comfortable with PSV settings. In addition, to allow respiratory muscles to rest, some patients may require mandatory ventilation.

Once the process that is suspected to have failed the previous SBT is treated, the patient can undergo another SBT. Usually, this SBT should be longer than the previous one, about 2 hours. The SBT technique should be the same as the previous attempt. However, if CHF is suspected as the reason for SBT failure, it might be better to perform an SBT with a T-piece. This will allow to examine whether the patient can tolerate absence of PEEP.

If the patient successfully passes the SBT, an extubation should be performed. However, if the patient fails, the SBT should be halted at the first signs of failure to decrease fatigue of respiratory muscles.

#### **4.1 Prolonged weaning/prolonged mechanical ventilation**

Patients who are not able to pass an SBT in three consecutive attempts or who take more than a week to pass are considered to be going through prolonged weaning. Although they represent the minority (about 10%), these patients are at increased risk of death and are likely to need tracheostomy [3].


**Table 2.**

*Weaning process classification.*

Assuming the acute illness has already recovered, and those pathologies that might cause SBT failure were also treated, the most prominent reason for prolonged MV is imbalance between respiratory system load and capacitance. In other words, patients who need prolonged MV are patients whose respiratory systems cannot meet the physiological demands of the body, whether because of lung pathology (abnormal lung mechanics), respiratory muscle weakness, or neurological dysfunction [31].

Medically, a patient who needs prolonged MV should undergo tracheostomy. This is done to improve patient communication, decrease sedation, ease nursing treatment, and allow for transfer to a long-term weaning facility. With coordination of physicians, nurses, physical therapists, clinical dietitians, and social workers, long-term weaning facilities focus on weaning and rehabilitation. As reasons of prolonged MV are multifactorial, there is no accepted strategy to liberate a patient from the ventilator, and a tailored approach to each patient is feasible.

Outcomes of long-term rehabilitation wards are as follows:


One-year survival is variable among different studies, in the range of 25–75%. Most likely, this represents variability in patients' baseline characteristics [35].

Upon diagnosing a patient as one who needs prolonged MV, it is important to discuss this with the patient (or the patient's next of kin/primary caregiver/legal guardian) and explain the chances of remaining ventilator dependent and possible quality of life. If patient expectations are not possible to meet, it seems appropriate to discuss the option of palliative care.

#### **5. Conclusion**

Weaning is the process of liberating a patient from MV. Whenever a patient is ventilated for more than 24 hours, the weaning process should be a structured process. **Figure 1** presents the weaning process as performed in our unit. This allows for patient safety and avoids unnecessary extubation failures, which worsen prognosis.

*Weaning from Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.99257*

In most cases, the patient will be extubated without complications. In a minority of cases, special attention should be given to pathological processes that might endanger the patient to extubation failure. In severe cases, weaning will be a long process performed in dedicated ward.

*Mechanical Ventilation*

#### **Author details**

Liran Statlender\* and Pierre Singer Rabin Medical Center, Petach Tikwa, Israel

\*Address all correspondence to: liranst1@clalit.org.il

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Weaning from Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.99257*

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#### **Chapter 7**

## How Medical Conditions Affect the Weaning of Mechanical Ventilation

*Iuri Christmann Wawrzeniak, Karolinny Borinelli de Aquino Moura and Eder Chaves Pacheco*

#### **Abstract**

Weaning from mechanical ventilation is a common process in critically ill patients and its failure is related to worsening outcomes. A better understanding of the subject is necessary to change these unfavorable results. This chapter will review the approach to weaning from mechanical ventilation in special groups of critically ill patients. The chapter will also review the causes of failure to wean from MV along with strategies for improving evaluation and approach of the patient with difficult and prolonged weaning from mechanical ventilation. Therefore, the presence of this topic in a book on mechanical ventilation is fundamental and relevant.

**Keywords:** critical illness, intensive care unit, respiratory failure, mechanical ventilation, mechanical ventilator weaning

#### **1. Introduction**

Mechanical ventilation (MV) is a lifesaving intervention in critically ill patients. MV is commonly used for postoperative respiratory failure, trauma, pneumonia, sepsis, heart failure (HF), chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS) [1, 2]. After the condition that caused the use of MV improves, the process of removing invasive ventilatory support begins, which is called weaning from MV [3, 4]. The MV weaning process is crucial and frequent in the critically ill patient's recovery. Almost 50% of the total duration of MV is dedicated to weaning patients [3]. However, some patients may fail to wean from MV despite all criteria in a planned extubation. This extubation failure is reported in around 10–20% of critically ill patients and, consequently, this weaning failure group has a high mortality when compared to patients who successfully weaned from MV [5–9].

The MV weaning and failure process have been studied since the 70s and 80s [10–13]. Milic-Emili questioned that the MV weaning performed in this period was more based on art than science because there were few scientific studies on the topic [14]. Studies in subsequent decades evaluated the best ventilatory mode to perform weaning from MV as well as predictors of weaning from MV [15–19]. After advances in the study of MV weaning, guidelines were formulated establishing

better criteria for evaluating the weaning process [20, 21]. Despite this, there are still different ways to practice MV weaning among intensive care units (ICU) in different countries, suggesting the need for more studies on the topic [4].

This chapter aims to review the weaning from MV in special subgroups. How to evaluate and to manage MV weaning will be discussed.

#### **2. Weaning from mechanical ventilation in special groups**

The cause of weaning failure may be related to individual or associated dysfunctions (respiratory, muscular, cardiac, neurological, endocrine, metabolic and iatrogenic). However, understanding the pathophysiology of MV weaning failure can be complex in some cases and it is not always fully understood, making its treatment difficult (**Figure 1**). When a patient does not pass a weaning trial, structural evaluation could help to identify factors that played a role in that specific patient. Moreover, it is important to know and to understand peculiarities of some critical patient subgroups in order to achieve more successful weaning. The **Table 1** summarizes the main characteristics, assessment and management of the main groups of patients in the process of weaning from mechanical ventilation admitted to an ICU.

#### **2.1 Chronic obstructive pulmonary disease**

In COPD patients, the weaning process is more difficult, prolonged and has higher failure rates than general populations. The higher failure rates in COPD patients can be attributed, at least in part, to the underlying pathophysiology of the disease. In COPD patients with acute respiratory failure, dynamic hyperinflation and the generation of intrinsic PEEP are the main factors that causes increased intrathoracic pressure, which lead to increased work of breathing, MV-induced injury, asynchrony, dyspnea, hemodynamic worsening, in addition to MV dependence and weaning failure [22]. In this population, the use of prophylactic non-invasive ventilation (NIV) after extubation is also recommended, considering this group of patients is at high risk of failure. The use can be extended to immediate extubation for NIV of COPD patients who have failed T-tube spontaneous

**Figure 1.** *Aspects of mechanical ventilation weaning failure.*


*How Medical Conditions Affect the Weaning of Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.100332*

*Legend: MV, mechanical ventilation; NIV, non-invasive ventilation; CAM, confusion assessment method; HFNC, High-flow nasal cannula; COPD, chronic obstructive pulmonary disease; PEEP, positive end-expiratory pressure; ARDS, acute respiratory distress syndrome.*

#### **Table 1.**

*Weaning from mechanical ventilation in special groups.*

breathing trial (SBT), with evidence of reduced length of stay in the ICU, nosocomial pneumonia and 60-day mortality, when compared to those weaned through invasive pressure support ventilation. These findings were corroborated by a recent meta-analysis [22, 23].

#### **2.2 Heart failure**

SBT causes spontaneous respiratory movements, which generate negative pressures and consequently hemodynamic repercussions. Negative intrathoracic pressures cause increased left ventricular (LV) preload which increases LV afterload and, ultimately, reduces left ventricular ejection fraction. This reduction in ejection fraction during an SBT can precipitate or worsen heart failure. Thus, if there are volume overload or systolic or diastolic left ventricular dysfunction, SBT can cause cardiorespiratory decompensation with pulmonary edema, reduced oxygen transport and insufficient cardiac output [24]. Furthermore, SBT can cause or worsen myocardial ischemia as a result of reduced left ventricular compliance, pulmonary edema and/or increased respiratory effort. To assess a possible cardiac dysfunction as a cause of weaning failure, it is suggested to perform an electrocardiogram and an echocardiography, in addition to collecting a pro-brain N-terminal natriuretic peptide and a central venous blood gas measuring SvO2.

An accurate diagnosis of the mechanism of cardiac dysfunction is needed to better guide therapy. In difficult-to-wean patients, additional medications can also be used to optimize ventricular function [24, 25].

Volume overload should be adjusted before performing a SBT because it has been associated with worse weaning outcomes [24]. It can be treated with diuretics or hemodialysis and after that, direct extubation for NIV can be used in order to maintain a positive end-expiratory pressure. When there is evidence of heart pump failure, reduction in afterload and/or use of inotropic agents (such as dobutamine or milrinone) may be considered. Furthermore, the improvement in pulmonary mechanics itself will improve cardiac performance by reducing the afterload of the left ventricle [24].

#### **2.3 Neurological dysfunction**

The decision to extubate comatose neurocritical patients is complicated. Previous studies have shown that the reduction in the level of consciousness is a good predictor of extubation failure [26]. Coplin et al. have challenged common sense showing that patients with a Glasgow Coma Scale (GCS) 8 did not impede successful extubation [27]. Moreover, the delayed extubation in this population was related to more ventilator-associated pneumonia (VAP) and longer intensive care unit and hospital stays [28, 29]. Also, according to the study by Coplin et al., the professional should avoid prolonged intubation when the level of consciousness is the only reason to maintain MV. Navalesi et al. demonstrated that a daily screening to assess MV weaning is recommended for patients with neurological diseases to reduce the duration of MV [30]. Strategies that include protective ventilation, early enteral nutrition, standardization of antibiotic therapy for nosocomial pneumonia, and systematic testing to assess readiness for extubation showed an association with a reduction in MV time in brain injured patients [31].

There are still other concerns about the neurological status of patients able to wean from MV. A study has shown that the change in cognitive function had been associated with a four times greater risk of unsuccessful extubation [32]. The ability to handle secretions and airway protection is also a relevant issue. In addition, the causes of acute brain dysfunction in difficult-to-wean patients should be

#### *How Medical Conditions Affect the Weaning of Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.100332*

considered, such as delirium, which is very common. The CAM-ICU can be a good tool to assess delirium in intubated ICU patients and performing non-pharmacological and pharmacological measures can help in symptomatic management. Improving hospital environments, for example, with poor noise and ICU-beds near to windows, besides frequent reassurance, touch, verbal orientation and family members presence can improve delirium symptoms [33]. Furthermore, it is important treating potential causal factors such as pain, constipation, infection and withdrawal of precipitating medications such as benzodiazepines and others [25]. In case of hyperactive delirium unresponsive to non-pharmacological measures, antipsychotics can be used for symptomatic management. Although there are no clinically significant differences between the classes of antipsychotics, haloperidol is one of the most used and studied.

#### **2.4 Neuromuscular diseases**

Weaning from MV requires adequate neuromuscular activity to overcome the impedance of the respiratory system and maintain adequate alveolar ventilation to eliminate carbon dioxide and ensure a metabolic balance. For this to happen, a generation of the stimulus by the central nervous system, adequate transmission via spinal respiratory motor neurons, respiratory muscles and neuromuscular junctions are necessary. Modifications anywhere of this complex system can contribute to MV weaning failure. Peripheral neurological alterations can also be the cause of weaning failure. Neuromuscular alterations are relatively common, being reported in up to 62% of patients in some studies [34]. Primary neuromuscular disturbance, such as Guillain-Barré syndrome, myasthenia gravis and motor neuron diseases, are usually diagnosed prior to intubation. Occasionally new diagnoses will occur as the difficulty of weaning from MV develops and is investigated.

In the ICU, the most common is secondary neuromuscular diseases, especially muscle weakness acquired in the ICU. It is a pure axonal disease, affecting mainly the peripheral nerves and muscles, symmetrical and bilateral and predominantly proximal. Prevalence between 50 and 100% is estimated in studies and is associated with disease severity, multiorgan dysfunction, exposure to corticosteroids, hyperglycemia and prolonged ICU stay [35–38]. Diaphragmatic muscle weakness can also impair weaning and its assessment can be challenging at the bedside, as the tests are either invasive and/or depend on the patient's ability to understand and to cooperate. There are studies that demonstrate an association between ICU-acquired muscle weakness and longer weaning duration or failure [34, 39–41]. Diaphragmatic muscle weakness can also impair weaning and its assessment can be challenging at the bedside, as the tests are either invasive and/or depend on the patient's ability to understand and to cooperate. There are studies that demonstrate an association between ICU-acquired muscle weakness and longer weaning duration or failure.

#### **2.5 ARDS**

In the early stages of MV in patients with acute respiratory distress syndrome (ARDS), the use of protective-ventilation strategies is recommended, as well as the use of neuromuscular blockers, prone position and extracorporeal membrane oxygenation (ECMO) in more severe cases [42]. However, during weaning from MV in patients with ARDS, this protective-ventilation strategy may be lost, mainly due to the influence of spontaneous ventilation with higher respiratory demands [43]. The increased lung volumes, higher respiratory drive, breath stacking, pendelluft and patient-ventilator asynchrony besides to delirium and ICU-acquired paresis may influence weaning from MV and should be considered in the assessment of patients with ARDS [44].

In addition, the use of the arterial-to-inspired oxygen (PaO2/FiO2) ratio to demonstrate improvement in hypoxemia, does not always translate into improvement in inflammatory response and weaning success [45]. Then, the premise for the beginning of weaning from MV based on PaO2/FiO2 ratio (resolution or improvement of the cause that led the patient to MV) is not always a good predictor to weaning success. Moreover, the management of MV weaning in these patients through consensus on weaning from MV generally does not include this specific group of patients [20, 21, 46]. Studies have shown that a greater proportion of patients have difficult and prolonged weaning when compared to the general ICU population [29, 47]. Therefore, regarding current knowledge, the evaluation of MV weaning does not differ in general from other patients. However, this subgroup has a particular pathophysiology that can influence and delay the evolution of the withdrawal of invasive ventilatory support.

#### **2.6 Obesity**

Obese patients, with a body mass index (BMI) > 30, have specific problems during MV. The large weight on the rib cage can cause alveolar collapse in some conditions and gravity can influence pulmonary mechanics [48]. In a study of obese patients with ARF, mortality was reduced by 50% when the choice of PEEP was guided with an esophageal catheter (EsoC) and electrical impedance tomography (EIT) [49]. During the process of weaning of MV is crucial to pay attention to the work of breathing, because the increased negative pleural pressure in these patients can led to a compression of the diaphragm in to the rib cage and can induce atelectasis in patients with muscle weakness [49]. Therefore, obese patients may benefit from higher PEEP during the pre-extubation period, making pleural pressure more positive and preventing alveolar collapse [50]. After extubation, positive pressure in the smaller airways can be maintained through by NIV, preferably in a sitting position, to avoid abdominal cavity compression of the diaphragm and inducing collapse by undermining the mechanics of the rib cage [51].

#### **3. Prolonged weaning and some considerations**

Prolonged weaning concerns about 10% of critically ill intubated patients and is associated with a high mortality [19, 27, 52]. Patients with prolonged weaning are associated with chronic critical illness [53]. The multidisciplinary rehabilitation group is very important to treatment [54]. Physical therapy will be very important to assess the patient's tolerance and exercise. Swallowing dysfunction can complicate the extubation process and its evaluation is essential for the return to normal eating habits [55]. Short daily cuff down trials with a speaking valve are performed to induce vocal cords to exert their original function during expiration. Tracheostomy may be considered as a useful adjunct for easier care of the patient, especially for mobilization and better comfort [56, 57]. A randomized controlled trial suggested that tracheostomized patients were more rapidly separated from the ventilator by repetitive T-tube trials than with a gradual reduction of PSV without influencing survival at 12 months [58]. Assessment with the patient and family should address explicit discussion of realistic versus futile treatment goals [59].

#### **4. Future perspectives**

More recently, tools such as ultrasound, EsoC and EIT have helped to predict MV weaning. The EsoC can be useful in the objective assessment of respiratory

*How Medical Conditions Affect the Weaning of Mechanical Ventilation DOI: http://dx.doi.org/10.5772/intechopen.100332*

effort, estimating transpulmonary pressure and autoPEEP [60]. On the other hand, ultrasound can be useful in providing information through visual assessment and in obtaining objective measurements of cardiorespiratory variables at different stages of weaning. A study by Haji et al. showed that loss of pulmonary aeration and left ventricular diastolic dysfunction are more frequent in patients who fail extubation [61]. Additionally, several studies have shown that the use of the EIT can help to evaluate weaning from MV. Bickenbach et al. and Lima et al. showed loss of recruitment and lung homogeneity during SBT [62, 63]. Studies in specific populations, such as patients with COPD, are ongoing and partial results indicate that those who fail the SBT ventilate more the anterior lung regions [64].

#### **5. Conclusions**

The weaning from MV in critically ill patients is a common and fundamental process in the ICU. The understanding the withdrawal of invasive ventilatory support and identifying possible causes of weaning failure are essential. The use of SBT trial and predictors guide weaning from MV. Some subgroups should be better valued to better individualize MV weaning and avoid reintubation associated with worse outcomes.

#### **Conflict of interest**

"The authors declare no conflict of interest."

#### **Author details**

Iuri Christmann Wawrzeniak1 \*, Karolinny Borinelli de Aquino Moura1,2 and Eder Chaves Pacheco3

1 Centro de Terapia Intensiva do Hospital de Clínicas de Porto Alegre, Brazil

2 Programa de Pós-Graduação em Cardiologia da Universidade Federal do Rio Grande do Sul, Brazil

3 Laboratório de Pneumologia LIM-09, Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo, Brazil

\*Address all correspondence to: iwawrzeniak@hcpa.edu.br

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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#### **Chapter 8**

## Palliative Withdrawal of Mechanical Ventilation and Other Life Supports

*Lauren F. Goodman*

#### **Abstract**

Palliative or compassionate withdrawal of mechanical ventilator support at the end of life aims to optimize comfort, alleviate suffering, and allow a natural death in patients for whom life supports are not achieving desired goals. Palliative withdrawal is a medical procedure and must be treated as such. Appropriate planning and preparations are required to optimize patient comfort, which is the goal of the procedure. Many institutions have a "one size fits all" approach to this process, but individual patient factors require consideration to meet the patient's needs. Some of these factors include patient pathophysiology (airway edema, airway trauma, hemoptysis, secretions), current treatment modalities (ventilator settings, medications including sedatives, vasopressors, inotropes, inhaled agents, neuromuscular blockade agents), and patient and family values and preferences. This chapter will discuss the implications of each of these factors and propose methods for successful transitions to comfort-focused care. Case vignettes will demonstrate the thought processes involved and model optimal management. Common ethical considerations and questions regarding palliative withdrawal of life support will also be discussed.

**Keywords:** Palliative, terminal, Withdrawal, comfort care, end of life

#### **1. Introduction**

Palliative or compassionate withdrawal of mechanical ventilator support at the end of life aims to optimize comfort, alleviate suffering, and allow a natural death in patients for whom life supports are not achieving desired goals. Medical ethics discussions have shifted significantly over the decades since critical care was first developed. It is now generally, though not universally, accepted that withdrawal of life support is equivalent to withholding of life support. Some now argue that withdrawal may be ethically superior to withholding life support, as withholding assumes the life support will not achieve the patient's goal, while withdrawal occurs only after this assumption has been proven true [1].

#### **2. Decision-making process**

A patient with capacity must be given the opportunity to participate in decision-making. This can be challenging when medical interventions limit audible speech, as with an oroendotracheal or nasoendotracheal tube. While sometimes

time-consuming, solutions such as computers or tablets with keyboards, phones with texting capabilities, sign language, letter boards, or simply pen and paper, can allow a patient to ask questions and express their own values, goals, and preferences. Some patients with a tracheostomy tube in place can generate audible fricative speech, even when the cuff must remain inflated for respiratory support. Some patients with either tube can mouth words clearly enough to be understood, though this can be difficult for both patient and medical team. The powers of the Power of Attorney may be limited by the patient, or by local laws, but generally allow the surrogate to make medical decisions on the patient's behalf when the patient is unable or chooses to defer. Capacity for medical decision-making is a complex construct and can vary over time, and with the decision to be made. Some patients are unable to process any significant medical information. Some are able to process and express clear and consistent preferences about simpler matters but not complex ones. As with language interpretation, these interpretations must be made by a member of the medical team and not exclusively by family or friends of the patient, and must be confirmed with the patient in other ways, such as nodding or shaking their head to confirm or refute accuracy.

A patient with capacity can also choose to defer to their legal surrogate, and in many jurisdictions can select and assign Power of Attorney for Health Care to one or more people to speak for them.

Still others are able to understand, manipulate, and ask questions about the medical information presented to them, and to express clear, consistent decisions on their own behalf.

#### **3. When to discuss withdrawal of life supports**

Ideally, physicians discuss with each patient their prior experiences, values, preferences, goals, and minimal acceptable outcomes prior to onset of critical illness, and prior to initiation of life supports. This is often not possible, sometimes due to the acute nature of some critical illnesses, and sometimes due to patient factors such as unwillingness to discuss these issues. Unfortunately, this is also sometimes due to physicians' and medical teams' discomfort with, inadequate time for, or failure to recognize the necessity of such discussions.

Regardless of whether routine or baseline discussions of experiences, values, preferences, and goals have occurred, the onset of critical illness is an important prompt to discuss or rediscuss these thoughts. Ideally, at the beginning of a patient's critical illness, their physician discusses with the patient or surrogate, or with both, the presumed diagnosis, the treatment options, and the likely outcomes of each and how soon the outcomes are anticipated. The patient or surrogate ideally understands and integrates this information and selects the treatment that gives them the best chance of recovery within the parameters of acceptable risk and acceptable burdens or suffering defined by that individual patient. After learning the patient's risk and burden tolerance, the physician confirms and documents the treatment plan, including any limits set by agreement with the patient or surrogate. The physician should then schedule a date to discuss progress, or lack of improvement, and further options with the patient or surrogate, unless new findings or changes require significant discussions sooner. This constitutes a time-limited trial, which is a useful framework for acknowledging the uncertainty of outcomes of critical illness [2].

If the patient is not improving to the extent they themselves would require to make continuing current life supports acceptable, or if the patient, or surrogate acting in the patient's best interest, finds the current life supports too burdensome despite good efforts at symptom management by the medical team, it is important to discuss the option of palliative withdrawal of life supports.

When multiple life supports are present, and the patient or surrogate and team are considering withdrawing one form of life support, it is necessary to consider whether or not the other forms of life support present are contributing to achievable medical goals. If any form of life support is not helping the patient progress toward achievable goals, potential withdrawal should be considered and discussed.

#### **4. How to withdraw mechanical ventilation**

Palliative withdrawal is a medical procedure and must be treated as such. Appropriate planning and preparations are required to optimize patient comfort, which is the goal of the procedure. Many previously published works, and many institutions have a "one size fits all" approach to this process, but individual patient factors require consideration to meet the patient's needs. Unfortunately, for understandable reasons, at this time there are exceedingly few studies of how to perform any part of this procedure. Therefore, many aspects require logical consideration and expert opinion to guide practice, as well as consideration of the individual patient's condition, needs, preferences, and goals.

Evidence suggests family satisfaction is increased when a step-wise approach to withdrawal of life support is used [3].

#### **4.1 Ventilator weaning vs. immediate discontinuation**

Older literature regarding palliative withdrawal of life supports generally describes either universal weaning or universal immediate discontinuation. More recent literature and guidelines take a more patient-centered, case-specific approach and recommend consideration of the patient's current ventilator support requirements and level of symptoms [4]. For patients on moderate or high ventilator support, it is recommended to wean ventilator support - specifically positive end inspiratory pressure (PEEP), potentially pressure support, and fraction of inspired oxygen (FiO2) - in a step-wise approach, titrating opioids and benzodiazepines especially to control dyspnea and anxiety respectively.

For example, for a patient who is on assist control volume control with a set rate of 14, tidal volume 6 mL/kg ideal body weight, PEEP of 14 cmH2O, and FiO2 60%, it would be advisable to achieve comfort with medications before initiating weaning, then reduce PEEP and FIO2 to 10–12 and 40% respectively, titrate medication boluses to achieve and maintain comfort, and continue to wean ventilator support every 15-30 minutes as tolerated.

#### *4.1.1 Mode*

Modern ventilators allow for a wide variety of mandatory, intermittent mandatory, assisted breath, and entirely spontaneous modes. Each mode has potential benefits and potential burdens to the patient.

When transitioning to comfort measures, patient condition and clinician comfort with managing the various modes will determine optimal mode for weaning or continued support. A patient who is awake, alert, and requires little ventilator support may be most comfortable right away with low levels of pressure support and PEEP. A patient with poor lung compliance or with neurologic or myopathic limitations to breathing may require a more sensitive trigger or a more controlled mode that ensures volume delivery, and for some, having a minimum breath frequency is necessary for comfort.

#### *4.1.2 Rate*

In modes with a set minimum rate, reducing a rapid set rate may unmask intrinsic tachypnea, which may be physiologic, or may be due to pain or anxiety. In synchronized intermittent mandatory ventilation settings, reducing the set rate may increase the frequency of spontaneous breaths; depending on the level of support provided with these spontaneous breaths, patients may feel more dyspnea if undersupported, or less dyspnea if their respiratory efforts are sufficiently supported.

#### *4.1.3 Peep*

Reducing PEEP can allow pulmonary edema, alveolar secretions, or pulmonary hemorrhage to become more prominent. Some patients may experience increased cough and may have difficulty expectorating the secretions. A stepwise approach, reducing PEEP by 2–4 cmH2O per step, may allow for titration of symptom control medications. Most ventilators have backup apnea settings that cannot be discontinued. For patients who are maintained on ventilator support throughout the comfort care process, it is important to remind families and team members that the ventilator will continue to deliver breaths even after the patient has died.

#### *4.1.4 Oxygen*

Some patients are asymptomatic or relatively asymptomatic with hypoxemia, while others note symptoms with even relatively small reductions in oxygenation. Again a stepwise approach, reducing by approximately 20% per step, allows for symptom management with medication titration. Supplemental oxygen through the ventilator can be weaned to as low as 21%, especially if the plan is for discontinuation of ventilator support without supplemental oxygen.

#### *4.1.5 Tidal volume*

Since the first ARDSnet trial publication [5], when tidal volumes are set on the ventilator, they are commonly set to a low tidal volume, lung protective strategy of 8 mL or less per kilogram of ideal body weight. Some patients find this strategy uncomfortable, as it forces small, limited volume breaths. If ventilator support is to be continued, especially if awaiting arrival of family members, or another significant event, continuing the current set volume is typical, but liberalizing the set volume somewhat may improve comfort.

#### *4.1.6 Drive pressure, inspiratory pressure, or pressure support*

These terms all refer to pressure added by the ventilator for the inspiratory phase of each breath to inflate the lungs and generate a tidal volume. The size of the tidal volume depends on the pressure administered and on the patient's lung and airway compliance. For patients with acute lung injury or acute respiratory distress syndrome, the pressure is generally set to target lung protective low tidal volumes. For patients without lung injury, the pressure requirement may be fairly low, or may be set to allow more liberal breath sizes for comfort.

#### **4.2 Extubating vs. maintaining oro- or nasoendotracheal tube**

Many institutions, and some older articles written about the process of palliative withdrawal of life supports, have a near-universal practice of removing the patient's

#### *Palliative Withdrawal of Mechanical Ventilation and Other Life Supports DOI: http://dx.doi.org/10.5772/intechopen.99579*

oral (or nasal) endotracheal tube. It is generally assumed that patients and families prefer extubation and will be more comfortable after removal of the tube. However, there are some important considerations that may limit or worsen patient comfort after removal of these tubes. Airway compromise caused by edema, trauma, masses, or other lesions may make removal of the oro- or nasoendotracheal tube risky for causing or allowing burdensome symptoms to occur. Similarly, significant hemoptysis or secretions, whether purulent or edematous, may require excessive effort by the patient to clear, and may limit comfort after extubation.

Decades ago, some institutions also routinely removed tracheostomy tubes at end of life. Unless there are specific patient-centered reasons to do so, this is no longer recommended.

#### **4.3 Sedatives, analgesics, anxiolytics**

#### *4.3.1 Basal rate titration vs. bolus dose administration*

As with enteric opioid medication administration, as needed bolus dose administration and titration should be the mainstay of symptom management. Anecdotally, ICU physicians and nurses often treat opioid and benzodiazepine infusions as though they have the pharmacokinetic and pharmacodynamic properties of vasopressors in terms of time to peak effect and time to steady state. This is not consistent with the actual activity of these medications, and can cause both ineffective symptom management initially, and excessive dosing later in the patient's course.

Pharmacologic principles must be remembered and utilized in the management of infusions of opioids and benzodiazepines. When a patient has significant symptoms, bolus doses can and should be administered as often as the time to peak effect for the drug in question. If the bolus dose is effective in controlling symptoms, the dose can be repeated after time to peak effect when it is needed again. If the dose is only moderately helpful for symptom control, the dose can be increased by 50% at the next administration to improve efficacy. And if the dose is minimally or ineffective, the dose can be doubled at the next dosing interval, or an alternative medication can be considered.

#### *4.3.2 Propofol*

Propofol is an anesthetic and sedative without analgesic properties. Some institutions restrict use without a secured airway. However, it can have benefits, including control of seizures, and may occasionally be a helpful adjunct to symptom control for those with severe anxiety, for example, where the patient prefers deep sedation over the possibility of experiencing their severe symptoms at end of life.

#### **4.4 Inhaled vasodilator agents**

There are no significant studies to inform best practices on withdrawal of inhaled pulmonary vasodilators. Generally it is probably reasonable to discontinue the agent at the start of transition to comfort measures, before weaning any ventilator settings. Based on half life, symptoms may become significant or severe approximately 15 minutes after discontinuing nitric oxide, or 25 minutes after discontinuing inhaled epoprostenol. Opioid administration as needed for dyspnea or chest pain, and benzodiazepine administration as needed for anxiety after discontinuation are the mainstays of management.

#### **4.5 Neuromuscular blockade agents**

Medication must be stopped and effect must be absent prior to withdrawal of life support to ensure ability to demonstrate any discomfort they are experiencing, and to avoid active euthanasia by this mechanism. Even if practicing in a jurisdiction where active euthanasia is legal, withdrawing life support in the presence of neuromuscular blockade is not acceptable because of the temporary and avoidable inability to actively monitor for symptoms and address them during the process.

Ethically, this differs from palliative withdrawal of life support in a neurologically devastated person who is intrinsically unable to demonstrate discomfort during end of life care because their inability to demonstrate discomfort is permanent and irreversible. In this case, for a patient whose surrogate feels the patient would not wish to continue life sustaining treatments, best practice is to aggressively treat for potential symptoms, using changes in vital signs as markers for possible distress and treating accordingly.

Ideally, neuromuscular blockade infusion can be stopped at the initiation of the transition to comfort measures and the effect allowed to wear off gradually as the drug is metabolized. Cessation of neuromuscular blockade allows patients to physically express whether symptoms such as pain, anxiety, dyspnea, or other forms of distress are present.

However, in some instances, patients may have such severe hypoxemia that oxygenation may start to falter before the drug effect is entirely resolved, sometimes to the point that the patient could die before physical symptoms can be fully assessed. In such situations, reversal of neuromuscular blockade may be considered, with neostigmine and glycopyrrolate for any agent, or with sugammadex for rocuronium or vecuronium only.

#### **4.6 Dialysis**

When to discontinue dialysis is highly dependent on the patient's situation. For patients with volume overload who are on continuous dialysis, continuing volume removal at least until the time of ventilator withdrawal or extubation may improve comfort by reducing pulmonary edema and whole body anasarca.

For patients with end-stage renal disease, some patients tolerate dialysis well and feel better with continuing it. In the United States, patients who enroll in hospice for a terminal diagnosis not related to their end-stage renal disease may be able to continue outpatient dialysis for a time; this is generally situation-dependent.

#### **4.7 Vasopressors and inotropes**

Optimal timing of withdrawal of vasopressors and inotropes is dependent on the situation. For less responsive patients, some physicians recommend discontinuing these early in the course of withdrawal of life supports, to induce a hypotensive or hypoperfusion-related encephalopathy, with the hope of reducing experience of symptoms through this mechanism. Other physicians elect to continue pressors until symptoms are noted to be well controlled after completion of palliative ventilator weaning or withdrawal to ensure medications can be circulated through the body to maximize their effect. Still other physicians discontinue vasopressors and inotropes concurrent with early palliative ventilator withdrawal. To date, there are no studies examining optimal timing; clinical judgment regarding which strategy will most likely meet the individual patient's values, goals, and preferences in light of their condition is needed.

#### **4.8 Pacemakers and implanted cardiac defibrillators**

Implanted Cardiac Defibrillators (ICDs) should be deactivated as soon as transition to comfort measures is started, if not already deactivated with DNR order. Implanted pacemakers are typically not deactivated unless the pacemaker function is felt to be significantly prolonging the dying process. Temporary pacemakers are typically deactivated at some point during the withdrawal process; timing can be considered similar to vasopressors.

#### **4.9 Lines, drains, and tubes**

At the time of transition to comfort care, the medical team should discuss all lines, drains, and tubes in place and decide whether to maintain or remove each. Urinary catheters may be maintained or removed depending on patient preference and perceived comfort. Temporary central venous catheters and tunneled central venous catheters can generally be maintained unless causing discomfort; temporary catheters may be considered for removal if the patient will be discharged to a setting where use of the catheter may not be feasible.

Nasogastric and orogastric tubes can generally be removed unless continued gastric decompression is necessary or unless there are medications that absolutely must be continued for comfort after extubation. Orogastric tubes should almost always be discontinued if extubation is planned due to significant risk of gagging and oropharyngeal discomfort. Surgical drains and wound vacuum systems should be discussed with the surgical or wound care team.

Pulmonary arterial catheters and arterial lines generally do not improve comfort and should be removed at initiation of transition to comfort measures.

Chest tube management depends on the indication for placement. If a chest tube was initially placed for pneumothorax and maintained in place only because of continued positive pressure ventilation, clamping and removal can be considered, especially if ventilator support will be discontinued. Chest tubes placed for significant, symptomatic pleural effusions likely should be continued to allow continued pleural drainage, unless pleurodesis has occurred. Those placed for pneumothorax that has not resolved likely should also be maintained and kept to suction to avoid symptomatic expansion of the pneumothorax. In all cases, the patient's condition should be the driving factor in decision-making.

#### **4.10 Artificial hydration and nutrition**

The limited benefits and significant risks, harms, and symptoms induced by artificial hydration and nutrition should be discussed with the patient or surrogate prior to the palliative withdrawal process. Ideally these should be discontinued hours before initiation of the withdrawal process to avoid full stomachs or fluid overload. Patients who are able to express desire to eat or drink after extubation should be allowed to do so with caution and support, with a focus on comfort and quality of life.

#### **5. Other consideration**

#### **5.1 Brain death**

Jurisdictions may vary in their laws regarding management of patients diagnosed as brain dead. In some, the local organ procurement organization must be notified and allowed to assess the patient for donation before withdrawal of life supports can be considered.

#### **5.2 Organ and tissue donation**

Depending on local or national laws regarding organ and tissue donation, the local organ procurement organization may be required to be notified prior to initiation of the withdrawal process. It may also be required to allow the agency to assess the patient and discuss potential for donation with the patient or surrogate.

Ethically, clinicians involved in the patient's care should not be involved in discussing organ or tissue donation. Perceived or real pressures to procure organs for other patients can adversely affect both decision-making processes of the patient or family and of the medical team. This can also erode the patient's trust in the medical team to prioritize their needs and care. Discussions regarding organ and tissue donation should occur between the patient or family and procurement specialists not involved in the patient's care.

### **6. Process of palliative ventilator withdrawal**

#### **6.1 Time out**

Prior to the initiation of palliative withdrawal of life supports, the care team should convene to discuss the patient's condition and formulate a plan consistent with the patient's and family's goals, values, and wishes, and making every effort to minimize or at least control symptoms. This process should be a formal, focused discussion and should occur before initiation in every case. The discussion should include the physician, bedside nurse, and respiratory therapist (RT) at least, ideally should include the chaplain, and the clinical pharmacist when needed.

Topics for discussion during the time out must include plans regarding timing of and method for withdrawing each form of life support, symptoms anticipated due to withdrawal of each life support, and plans for managing these symptoms. The team should also clarify which team member is to be the first point of contact if initial symptom management strategies are insufficient, or if other issues arise.

Where required, the local organ procurement organization must be notified of the plan for palliative withdrawal of life supports and anticipated or possible patient death prior to initiation of the process.

The bedside nurse in particular must be given support and time to focus exclusively or nearly exclusively on the patient undergoing transition to comfort measures, to ensure a smooth transition with excellent symptom management.

Prior to initiation of any steps in the process of withdrawal, the appropriate Do Not Resuscitate order must be signed by the appropriate medical team member. Remaining full code while undergoing palliative withdrawal of life supports is completely counter to the goals of the process; it is absolutely predictable that at some point after withdrawal, cardiopulmonary arrest will occur and require either cessation of efforts based on futility, or require re-initiation of some forms of life support. At best, life supports required at this point might be the same as those in use prior to withdrawal, but more likely would include additional supports to sustain a condition that would at best be equal to the patient's condition at the initiation of withdrawal. If the patient or surrogate desires resuscitative efforts at time of death, current management should be continued. This can include agreed-upon plans to limit escalation (e.g., not adding additional pressors, dialysis, or other new therapies), or to plan to discuss progress, or lack thereof, at a specified date and time, typically a few days.

#### *Palliative Withdrawal of Mechanical Ventilation and Other Life Supports DOI: http://dx.doi.org/10.5772/intechopen.99579*

The patient, surrogate, and family should be asked about what cultural or spiritual practices related to death and dying are meaningful to them, and efforts should be made to support these needs and wishes. These can include Last Rites or specific prayers to be said prior to death, creating memorial items before or after death, and rituals regarding cleaning and care of the patient's body after death. Some memorial items such as handprints, hand casts, recordings, and ECG tracings, can be made fairly easily and inexpensively. Some family members may wish to preserve locks of hair. It is essential to ask open ended questions and not project what the patient or family 'should' or 'should not' want at this point.

Once the plan is created and agreed upon, it should be reviewed with the patient as able, and with the family, to their desired level of detail. Anecdotally, many families and most patients are satisfied hearing that the plan for transition and withdrawal has been discussed and agreed upon by everyone participating, and has been designed to maximize the patient's comfort.

Once transition has started, the bedside nurse should update the designated point of contact for the medical team to discuss any inadequately controlled symptoms or changes in clinical status.

After the patient's death, family should be allowed and encouraged, but never forced, to assist in caring for the patient's body after death. Specific cultural or religious practices regarding care and monitoring of the body after death should be elicited and respected.

#### **7. Case examples**

#### **7.1 Case 1: a 'simple' case**

Mrs. A is a 78 year-old woman with chronic obstructive lung disease with chronic hypoxic and hypercarbic respiratory failure, and pulmonary cachexia. Her baseline oxygen requirement is 3 liters of oxygen by nasal cannula around the clock. She has been in the intensive care unit (ICU) for three weeks with acute on chronic respiratory failure due to chronic obstructive pulmonary disease (COPD) exacerbation and pneumonia, which have been fully treated. She has failed noninvasive ventilation repeatedly and was reintubated for the third time four days ago. She has spent a total of 16 days on the ventilator thus far. She has mild to moderate secretions and is able to expectorate them without distress. She is on assist control volume control with a tidal volume set at 6 mL/kg ideal body weight, requiring peak inspiratory pressure of 20, rate set at 12, PEEP of 5, and FiO2 35%.

She has a good cuff leak, but failed her spontaneous breathing trial this morning for dyspnea and tachypnea. She requests palliative extubation as she is not amenable to tracheostomy or prolonged ventilatory support.

She is awake, alert, able to write long coherent paragraphs about her understanding of the situation and about her wishes regarding her further care. Her spouse and children are understandably sad but supportive of her wishes, agreeing that this request is consistent with her long-stated wishes regarding prolonged life support. She is on no sedation and reports feeling comfortable on assist control.

After confirming the patient has capacity and is expressing a consistent choice with internally consistent logic based on good understanding of her medical condition, and answering any questions she or her legal surrogate or family have, the physician should discuss with the bedside nurse, RT, and when needed, the ICU charge nurse, to ensure the nurse and RT will have time to properly devote to this patient as the transition to comfort measures occurs. They should discuss what as-needed medications she has been given over her ICU stay, and what her response has been to each, to determine what she is likely to need during the withdrawal process, and orders for these medications should be placed.

The physician or nurse should ask the patient and family if they wish to visit with a chaplain and when. If a chaplain visit is desired prior to transition to comfort measures, the chaplain should ensure they ask about any specific spiritual or cultural practices they wish to observe. If the chaplain's visit is declined, the physician and nurse should coordinate to explore culture or spiritual needs and wishes related to the transition process.

After the appropriate Do Not Resuscitate order is signed, and preparations for symptom management are made, and the patient and family are ready, as she is already on minimal ventilator settings, a spontaneous breathing trial should be initiated again, and comfort medications titrated to maintain her comfort with minimal ventilator support. Once she is comfortable on minimal ventilator support, she can be extubated when she and her family are ready, placed on oxygen via supplemental nasal cannula as is her baseline, and treated with the minimal effective dose of an opioid as needed for pain or dyspnea, or benzodiazepine as needed for primary anxiety, and supported until death or transition to another location for further care.

#### **7.2 Case 2: a more challenging case**

Mr. B is a 57 year-old with a remote mid-thoracic spinal cord injury with paraplegia but no known chronic respiratory insufficiency who was admitted to the intensive care unit 2 weeks ago for septic shock due to urinary tract infection with secondary bacteremia. He was initially intubated for respiratory fatigue after hours of working to compensate for lactic acidosis, but developed acute respiratory distress syndrome (ARDS) requiring PEEP of 18 cmH2O at most, FiO2 80–100%, with a set respiratory rate of 34. He has required pressors for the past two weeks, and developed renal failure requiring continuous renal replacement therapy for the past week. He requires deep sedation to maintain ventilator synchrony, and is encephalopathic and agitated when sedation is lightened. When updated at a meeting to discuss his clinical condition and values, preferences, and goals, his legal surrogate states he would not accept prolonged life support measures, including a tracheostomy, a longer-term feeding tube, or more than a few weeks of ventilator support or dialysis. The surrogate feels he has 'had enough' and would not want to continue current management; he feels the patient would wish to have Last Rites administered by a priest, and has no other specific requests for rituals surrounding death.

His code status is changed to Do Not Resuscitate. As soon as is feasible, family and friends are allowed a few hours to visit and say goodbyes. The patient's priest comes to the hospital and administers Last Rites. The patient's nurse and respiratory therapist are relieved of some of their other duties for a time, to be allowed to provide dedicated care to this patient. As discussed in the time out prior to withdrawal, first medications and therapies that do not improve his comfort are discontinued. Renal replacement therapy is then stopped and the machine is removed from the room. Vasopressors are then stopped. Blood pressure falls to a MAP of 50 mmHg but stabilizes, and heart rate increases from 90 to 110 and stabilizes.

His face appears calm and he is synchronous with the ventilator. His current opioid and benzodiazepine infusion rates are continued. Ventilator weaning is initiated; rate is reduced by 4–6 breaths per minute, FiO2 is reduced by 10%, and PEEP by 2 cmH2O simultaneously. Tidal volume is not changed, or may be increased slightly to improve comfort. Any respiratory distress or apparent anxiety are treated *Palliative Withdrawal of Mechanical Ventilation and Other Life Supports DOI: http://dx.doi.org/10.5772/intechopen.99579*

with boluses of opioids or benzodiazepines or both, and once controlled, rate, FiO2, and PEEP are weaned again with ongoing boluses and titration of bolus doses as warranted by his symptoms. His SpO2 falls to 60%, but his vital signs remain fairly unchanged. Once he is weaned to 30% with a PEEP of 6, and a set rate of 14 with a total rate of 18, and he appears comfortable based on lack of grimacing and lack of restlessness, the oroendotracheal tube is removed. Additional doses of opioids are given as needed for respiratory discomfort, and benzodiazepines are given as needed for evidence of anxiety. Family remains at the bedside until he dies.

#### **7.3 Case 3: an unusual circumstance**

Mr. C is a 30 year-old man with relapsed acute myeloblastic leukemia who develops severe tumor lysis syndrome after induction chemotherapy and is transferred to the ICU for management. He is started on a bicarbonate infusion and IV fluids. He is placed on BiPAP to support his respiratory compensation for acidemia while arrangements are made to start continuous renal replacement therapy, but is unable to maintain respiratory compensation for acidemia and is intubated. His respiratory rate is moderate, with minimal pressure and oxygen requirements. He remains remarkably alert, calm, and coherent after medications given for intubation wear off. After discussion of his overall condition, in which he has fully participated, he writes out clearly that he wants to transition to comfort care. The medical team discusses his physiologic derangements and recalls his extremely high respiratory rate prior to initiation of bicarbonate infusion. After a short spontaneous breathing trial in which he remains somewhat tachypneic but does not feel distressed.

He requests his code status be changed to Do Not Resuscitate and Do Not Intubate; these orders are completed. He is extubated to allow him to speak with his family. Continuous renal replacement therapy is continued for a few more hours until the cassette requires changing, at which time the set-up is taken down and not restarted. Bicarbonate infusion is continued to ameliorate his acidemia in hope of preventing dyspnea due to tachypnea. He is offered opioids for dyspnea when he appears to have respiratory distress and allowed to choose whether or not he feels he needs them, as well as being allowed to request them when needed. After several hours of good conversations with his family, he feels his breathing is tiring out and requests more frequent opioids, even if this means he may be too sleepy to interact with family. Opioids are given to relieve his dyspnea and respiratory distress. When the bicarbonate infusion bag is nearly empty, the rate is reduced and opioids are titrated to comfort before the bag is completed and the infusion stopped. His breathing pattern becomes irregula as he is no longer able to maintain compensation, and he appears comfortable until and through his death.

#### **7.4 Case 4: a very challenging case**

Mx. D is a 37 year-old person with antiphospholipid antibody syndrome and patent foramen ovale, with multiple deep venous thromboses and pulmonary emboli in the past, on therapeutic anticoagulation, develops diffuse alveolar hemorrhage and acute hypoxic respiratory failure requiring intubation and mechanical ventilation. They are treated with steroids and inhaled tranexamic acid, and chronic anticoagulation is held. They unfortunately have several seizures and are found to have multiple embolic strokes with severe hemorrhagic conversion, including several of the cerebellum and visual cortex. On meeting with their family including parents who are their legal surrogate, they feel that the likely longterm impairments caused by the strokes would be unacceptable given their career as a dancer, and that they would not want to continue disease-directed therapies.

Given the continued moderate and occasionally large volume hemoptysis requiring suctioning through the oroendotracheal tube, the patient's sibling, who is a respiratory therapist, expresses concern about the patient's ability to breathe comfortably if extubated. Code status is changed to Do Not Resuscitate prior to transition to comfort care. Ventilator support is weaned down to the lowest PEEP level at which the patient appears comfortable. Pressure support, SIMV-PSV, and APRV with only a small difference between high and low PEEP. The medical team advises their family that the ventilator will continue to trigger after the patient's death, as the ventilator's apnea backup settings can be minimized but not completely discontinued. Their comfort is maintained with opioid and benzodiazepines as needed until death.

#### **7.5 Case 5: organ procurement**

Ms. E is a 25 year-old woman with a long-standing history of opioid abuse including ingestion and injection- both subcutaneous and intravenous- of prescription opioid pills, and injection of heroin and fentanyl. She has suffered several overdoses requiring hospitalization and brief periods of intubation and mechanical ventilation in the past, has undergone rehab including some periods of abstinence, but has unfortunately suffered multiple relapses. Five days ago she was found unresponsive with agonal breathing at home after last speaking to family by phone hours earlier. MRI of the brain and serial head CT scans over several days in the ICU showed diffuse anoxic injury with severe edema and progressive herniation. Her clinical exam with normal electrolytes, normal temperature, and normal pCO2 and pH progresses to demonstrate no brainstem reflexes.

Several forms of testing clearly demonstrate brain death. The medical team informs and consoles her family, and requests the chaplain and social worker to further assist in supporting the family. The bedside nurse contacts the local organ procurement organization, whose representative comes to the hospital and reviews Ms. E's case. She is noted to be a self-registered organ donor, and is deemed to be a candidate for donation of multiple organs. The representative from the organ procurement organization discusses with her family the process of assessing her and preparing for potential organ donation. She is maintained on mechanical ventilation via oroendotracheal tube. Pituitary failure is managed with IV levothyroxine, DDAVP, and hydrocortisone. Blood pressure is maintained with vasopressors. When assessment is complete and the organ procurement organization and explant surgeons are available, she is taken to the operating room with a solemn procession in her honor, where life supports are withdrawn simultaneously. Cardiac death occurs 20 minutes later, and all viable organs are harvested for transplantation.

#### **8. Conclusions**

The above discussions, and the case examples, are not exhaustive of the situations clinicians may find themselves facing in the course of caring for patients. They are examples of some of the more common conditions that require consideration and flexibility for patient-centered management. Far from a simple, 'one size fits all' process, they illustrate that palliative withdrawal of life supports is a medical procedure that requires thoughtful collaboration and consideration to provide each patient with the most comfortable transition to end of life care possible.

*Palliative Withdrawal of Mechanical Ventilation and Other Life Supports DOI: http://dx.doi.org/10.5772/intechopen.99579*

### **Author details**

Lauren F. Goodman Department of Internal Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, The Ohio State University College of Medicine, Columbus, Ohio, USA

\*Address all correspondence to: lauren.goodman@osumc.edu

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[3] Gerstel E, Engelberg RA, Koepsell T, Curtis JR. Duration of withdrawal of life support in the intensive care unit and association with family satisfaction. Am J Respir Crit Care Med. 2008 Oct 15;178(8):798-804. doi: 10.1164/ rccm.200711-1617OC. Epub 2008 Aug 14.

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### *Edited by Jessica Lovich-Sapola, Jonathan A. Alter and Maureen Harders*

Mechanical ventilation, ventilator management, and weaning from mechanical ventilation vary based on location within the hospital, type of lung injury, and medical condition of the patient. Understanding the types of lung injury and various methods of achieving ventilation expand the armamentarium of the practitioner and allow for the best management decisions. This book begins with the use of a high-flow nasal cannula (HFNC) and a detailed description of the advanced modes of ventilation. The information on the types of ventilation can then be applied to the ventilation approaches in different populations of patients: the trauma patients, the obese patients, and the patients under neurocritical care. The conclusion contains a discussion of the mechanisms on how to wean from mechanical ventilation and how certain medical conditions affect the weaning process.

Published in London, UK © 2022 IntechOpen © sudok1 / iStock

Mechanical Ventilation

Mechanical Ventilation

*Edited by Jessica Lovich-Sapola,* 

*Jonathan A. Alter and Maureen Harders*