**5. Postoperatively not complicated**

At present, the cardiovascular monitoring is noninvasive and invasive integral part of the intensive care critically ill cardiac patient.

### **Cardiovascular monitoring**

The proper outcome after cardiac surgery depends on preoperative and postoperative status of the myocardium rather than coronary anatomy in the postoperative period is uniformly diminished contractility compared to the preoperative magnitude and duration of this depression depends on the severity of chronic dysfunction, the presence of recent ischemic events, efficacy and complications of operative procedures and the intraoperative course. All intraoperative events play a significant role in recovery processes are the most important anesthetic management, cardioplegia and cardiopulmonary bypass duration. Events and preoperative and intraoperative interventions vary in magnitude and duration but in characteristic result in reduced myocardial contractility and compliance, which affects the postoperative management and eventual evolution. Ejection fraction in the preoperative less than 35%, the presence of ischemia or infarction in the immediate preoperative have substantial postoperative management, patients with outflow tract obstruction by a disease associated with hypertrophic chronic hypertension or stenosis aortic present particular difficulties postoperatively. It is always important to optimize left ventricular preload in TiPQ evaluated through filling pressures but not always filling pressures adequately reflect preload, defined as ventricular end-diastolic volume, so that ideally should be monitored with end-diastolic volume index and cardiac index continued, ie in real time. Patients with chronic volume overload, as in those with mitral regurgitation are dependent on adequate volume resuscitation in these patients the response of blood pressure and heart rate are usually a better guide to the proper preload because pulmonary occlusion pressure and pulmonary artery pressure are insensitive, except at the ends of hypovolemia and fluid overload in this situation, blood pressure and cardiac index can significantly change before filling pressures. 36.37

Ventricular work is a crucial element in the postoperative management of heart surgery, the hypertrophic ventricular pressure overload or are intolerant to significant changes in heart rate when the heart rate is high, the filling time can be shortened enough to compromise the volume of end-diastolic volume and thus cardiac output, in contrast, when heart rate is below the time needed to develop the maximum end-diastole, cardiac output may decline relative to the low frequency. Assuming that the preload is adequate, a heart rate between 90 and 100 beats per minute is optimal for a hypertrophic myocardium, where compliance is significantly diminished synchronized atrioventricular contraction plays a significant role in ensuring optimal preload, so these patients require sinus rhythm or a dual-chamber pacemaker. The ventricle with volume overload in contrast, is more tolerant of tachycardia and loss of atrioventricular synchrony. When ventricular compliance at the end of diastole decrease as a result of increased heart rate, systolic emptying may be better in these patients,

electrolytes, coagulation, time Ivy, myocardial enzymes, prealbumin, liver function tests (LFT), nitrogenous, Cystatin C, urine sediment and start of urine collection for urinary urea nitrogen (NUU), subsequent tests are given in the next 6 hours or before be

At present, the cardiovascular monitoring is noninvasive and invasive integral part of the

The proper outcome after cardiac surgery depends on preoperative and postoperative status of the myocardium rather than coronary anatomy in the postoperative period is uniformly diminished contractility compared to the preoperative magnitude and duration of this depression depends on the severity of chronic dysfunction, the presence of recent ischemic events, efficacy and complications of operative procedures and the intraoperative course. All intraoperative events play a significant role in recovery processes are the most important anesthetic management, cardioplegia and cardiopulmonary bypass duration. Events and preoperative and intraoperative interventions vary in magnitude and duration but in characteristic result in reduced myocardial contractility and compliance, which affects the postoperative management and eventual evolution. Ejection fraction in the preoperative less than 35%, the presence of ischemia or infarction in the immediate preoperative have substantial postoperative management, patients with outflow tract obstruction by a disease associated with hypertrophic chronic hypertension or stenosis aortic present particular difficulties postoperatively. It is always important to optimize left ventricular preload in TiPQ evaluated through filling pressures but not always filling pressures adequately reflect preload, defined as ventricular end-diastolic volume, so that ideally should be monitored with end-diastolic volume index and cardiac index continued, ie in real time. Patients with chronic volume overload, as in those with mitral regurgitation are dependent on adequate volume resuscitation in these patients the response of blood pressure and heart rate are usually a better guide to the proper preload because pulmonary occlusion pressure and pulmonary artery pressure are insensitive, except at the ends of hypovolemia and fluid overload in this situation, blood pressure and cardiac index can

Ventricular work is a crucial element in the postoperative management of heart surgery, the hypertrophic ventricular pressure overload or are intolerant to significant changes in heart rate when the heart rate is high, the filling time can be shortened enough to compromise the volume of end-diastolic volume and thus cardiac output, in contrast, when heart rate is below the time needed to develop the maximum end-diastole, cardiac output may decline relative to the low frequency. Assuming that the preload is adequate, a heart rate between 90 and 100 beats per minute is optimal for a hypertrophic myocardium, where compliance is significantly diminished synchronized atrioventricular contraction plays a significant role in ensuring optimal preload, so these patients require sinus rhythm or a dual-chamber pacemaker. The ventricle with volume overload in contrast, is more tolerant of tachycardia and loss of atrioventricular synchrony. When ventricular compliance at the end of diastole decrease as a result of increased heart rate, systolic emptying may be better in these patients,

necesario.31, 32,33,34,35

**5. Postoperatively not complicated** 

intensive care critically ill cardiac patient.

significantly change before filling pressures. 36.37

**Cardiovascular monitoring** 

sinus rhythm below 75 beats per minute tends to be more deleterious to an abnormal rhythm frequencies above 90 per minute, with low heart rates, prolonging the diastolic filling time committed ventricular ejection fraction because the ventricle is more dilated. Ultimately in ventricles with volume overload tachycardia and loss of atrioventricular synchrony can be better tolerated than sinus bradycardia. Determining the degree of reduction in contractility admission to TiPQ is problematic, the main contributors to the decrease in postoperative contractility including ejection fraction before surgery less than 35%, CPB time, especially if the duration exceeds 120 minutes. In patients undergoing valve procedures, it is advisable to perform intraoperative transesophageal echocardiography at the end of CPB as this is useful to assess valve function and ventricular dynamics. If the preoperative ejection fraction is greater than 35% and the operative course was satisfactory, decrease myocardial compliance in the first 4-6 hours in the unit and then quickly returns TiPQ values similar to or better than the preoperative values. Patients with an ejection fraction before surgery less than 35%, presence of perioperative ischemia or complicated operative course may require a longer time to recover or make permanent dysfunction, myocardial depression may persist for an extended period of time. These factors may affect the withdrawal of ventilatory support and necessitate the use of oxygen in prolonged, the tachypnea may be a reflection of compromised perfusion rather than primary respiratory failure.

Maintaining normal blood pressure is critical in the early hours of postoperative necessarily invasive measurement must be continued for at least 24 hours for analysis beat to beat but if it is non-invasive measurement must be measured regularly every 5 minutes but the objectivity of plethysmographic measurements are reliable non-invasive automatic in the absence of intense vasoconstriction and a very high frequency. Class I recommendation, level of evidence C. The optimal MAP in the first 6 postoperative hours especially in revascularized patients should be 65 to 80mmHg, maintaining adequate tissue perfusion to all organs and prevent bleeding at the sites of anastomosis of the bypass. The goal of hemodynamic monitoring of critically ill patients is to assess the adequate perfusion and tissue oxygenation, using intermittent or continuous measurement of oxygen saturation both considered acceptable, although the measurement of lactate may be useful lacks precision as a measure of status tissue metabolism in patients with mechanical ventilation is recommended central venous pressure of 12-14 mm Hg to offset the increase in intrathoracic pressure especially those with PEEP> 5mmHg. A similar consideration is the elevation of intra-abdominal pressure (IAP is approximately normal. 5-7 mmHg in critically ill patients) as it is inversely proportional to tissue perfusion pressure (PPP) and dependent on the mean arterial pressure (MAP) ie: PPA = MAP - IAP.

The good use in the immediate postoperative period of Swan-Ganz implies a broad knowledge of hemodynamics by the doctor for a proper training and constant use of the device, much of the value of this catheter for monitoring the hemodynamic status is based on their ability adequate to measure pulmonary capillary pressure which we take as a measure of left ventricular preload. The subsequent interpretation of a good wedge pressure curve are not simple things, implies among other things, the tip of the catheter has been placed in a part of the lung that the condition of zone 3, the ball was not over-inflated or default, the catheter is floating in the right place and has not migrated back, there is no strong auto-PEEP and various other things. However there are many more and more data, which indicate that the use of postoperative pulmonary catheter in heart depends on many

Intensive Care Management of Patients in the First 24 Hours After Cardiac Surgery 13

Over 90% of postoperative patients reach TiPQ Units with mechanical assistance in breathing, so the generally invasive respiratory monitoring, however, is always important clinical evaluation since joining our service to have an initial assessment and observe its evolution in the first 24 hours. Not established the need for routine use of PEEP in patients without complications due to decreased functional residual capacity (FRC) in these patients and atelectasis appear 5 minutes after the onset of anesthesia are not important and no impact on arterial oxygenation postoperatively. However, in the first hour is important to evaluate the relationship and consider PaO2/FiO2 lung history to give an appropriate value, it is also important to rule out existence of residual pleural effusion or pneumothorax because both entities are also involved in lowering the ratio PaO2/FiO 2, and evaluated these considerations and having a stable hemodynamic status can be performed alveolar recruitment maneuver (ARM) is a technique that uses a sustained increase in airway pressure with the aim of recruiting collapsed alveolar units, increasing lung area available for gas exchange and consequently arterial oxygenation. Recent studies concern the use of MRA after cardiac surgery, during which the authors believe that lung function and oxygenation are decreased> 20% with the use of cardiopulmonary bypass and the inflammatory response with the exponential growth atelectasis. Cardiac surgery with cardiopulmonary bypass includes the complete collapse of the lungs, thus, the move will improve oxygenation by opening collapsed lung regions. The results of current work suggest that alveolar recruitment maneuvers are safe procedure in patients with

cardiovascular surgery and reduces the frequency of postoperative atelectasis.

who are able to adequately of extubated successfully.

(BiLevel) or that pressure release ventilation (APRV).

postoperative heart patient.

The decline of ventilatory support should generally be within 24 hours, ideally Fast-track implementation of the ventilation is the goal in most patients (Fast-track cardiac anesthesia-FTCA-). The importance of predicting the timing of weaning is that both the early weaning as the unnecessary prolongation of mechanical ventilation is deleterious to the patient. In addition only with the clinical trial is difficult to predict how successful disconnection accurate (50% positive predictive value and 67% negative predictive value) because these results justify the implementation of objectives and accurate methods to identify patients

Early extubation is associated with a significant reduction in costs associated with mechanical ventilation, there is now several modalities to a quick and safe extubation, spontaneous ventilation with pressure support (VPS) with 2 dual ventilation PEEP levels

Patients extubated within 24 hrs it has decreased PaO2/FiO2 ratio <200 is recommended the use of noninvasive mechanical ventilation for 24 hrs demonstrated by Yoshiyuki Takami et al, as it must be part of primary treatment strategy in patients with acute pulmonary edema in this group of patients and reduces the need for endotracheal reintubation and lower mortality when compared against conventional treatment with oxygen therapy in

Pulse oximetry has been used to transfer the patient to the operating room TiPQ unit and required at all times to monitor the state of oxygenation does not replace the determination of arterial blood gases, however the devices currently are more sensitive and less margin for

Mode: Assist-control (volume or pressure)

Respiratory rate = 10-15 L / min; Tidal volume = 6-8 ml / kg; FiO2 = to maintain SaO2> 90%.

factors that have little to do with their true indications or the severity of the patient also has serious complications observed in studies presented to the placement of a Swan-Ganz pulmonary artery in this group of patients where metabolic changes, hypothermia, cardioplegia, ischemia or myocardial stunning favor residual arrhythmias, thromboembolic events, infections, pulmonary infarction or to knotting of the catheter, not to mention does not improve cardiovascular survival in critically ill patients.

You must have a central venous line and periodically monitor the central venous saturation (SvO2) and good availability in the administration of appropriate fluids for resuscitation in the first six hours following the early goals of Rivers and colleagues, as therapy guided by objectives has been shown to improve survival in critically ill patients susceptible to revival under the supervision of personnel in these areas.

During the first hours must meet the physiological parameters already discussed, however those who do not meet these criteria should be reassessed therapeutic conduct, analyze ECG, diuresis, PVC, the need to correct up to 30% hematocrit and evaluate the need for inotropic or increase in dosage especially if the central venous saturation is <70%, or GCinvasive measurements have decreased their acceptable ranges. The SvO 2 is a determinant and with greater sensitivity in the postoperative monitoring of oxygenation, perfusion, oxygen consumption and microcirculatory level, now has shown that goal-directed resuscitation, in which this has been a decisive objectives in the first six hours significantly decreased cardiopulmonary morbidity and mortality in patients to assess critical to tissue oxygenation indirectly: this is defined as adequate oxygen supply to demand, the supply is always greater than consumption (VO2), in cases of circulatory shock and severe hypoxemia there is a significant fall in DO2 but the VO2 is maintained by the compensation determined by the EO2%, which explains a security mechanism that ensures the proper use until it descends DO2 a critical point where consumption becomes dependent on the contribution anaeróbico initiating cellular metabolism. 38,39

The use of PiCCO (press contour cardiac output) can continuously monitor cardiac output, the variability of pulse pressure and stroke volume. Likewise, estimates of the severity of intermittent pulmonary edema, intravascular volume and intrathoracic cardiac chambers, two measures related to ventricular preload.

Electrocardiographic monitoring or driving is important in the first six hours after a stroke thoroughly evaluated on admission electrocardiogram to TiPQ, you need continuous monitoring of electrical activity and identify arrhythmias or morphological changes that warrant immediate management. You also have to periodically assess the proper functioning of epicardial pacemaker generator. Management should be initiated when the ventricular rate is above 110lat/min.

#### **Respiratory monitoring**

First of all clinical assessment remains the mainstay in respiratory monitoring, inspection of the chest is important from the patient's arrival to TiPQ is important to assess that there is synchrony in movements of both amplexación amplexión and thorax as well as observation of permeability each of chest drains and their exact position placed by the surgical team must verify proper endotracheal tube position, surely the next step is auscultation of lung regions in search of clinical syndromes or abnormal sounds that suggest some clinical suspicion is necessary to assess respiratory mechanics measurements in our patient by the ventilator as well as scheduling parameters. Sets the following startup parameters:

Mode: Assist-control (volume or pressure) Respiratory rate = 10-15 L / min; Tidal volume = 6-8 ml / kg;

12 Special Topics in Cardiac Surgery

factors that have little to do with their true indications or the severity of the patient also has serious complications observed in studies presented to the placement of a Swan-Ganz pulmonary artery in this group of patients where metabolic changes, hypothermia, cardioplegia, ischemia or myocardial stunning favor residual arrhythmias, thromboembolic events, infections, pulmonary infarction or to knotting of the catheter, not to mention does

You must have a central venous line and periodically monitor the central venous saturation (SvO2) and good availability in the administration of appropriate fluids for resuscitation in the first six hours following the early goals of Rivers and colleagues, as therapy guided by objectives has been shown to improve survival in critically ill patients susceptible to revival

During the first hours must meet the physiological parameters already discussed, however those who do not meet these criteria should be reassessed therapeutic conduct, analyze ECG, diuresis, PVC, the need to correct up to 30% hematocrit and evaluate the need for inotropic or increase in dosage especially if the central venous saturation is <70%, or GCinvasive measurements have decreased their acceptable ranges. The SvO 2 is a determinant and with greater sensitivity in the postoperative monitoring of oxygenation, perfusion, oxygen consumption and microcirculatory level, now has shown that goal-directed resuscitation, in which this has been a decisive objectives in the first six hours significantly decreased cardiopulmonary morbidity and mortality in patients to assess critical to tissue oxygenation indirectly: this is defined as adequate oxygen supply to demand, the supply is always greater than consumption (VO2), in cases of circulatory shock and severe hypoxemia there is a significant fall in DO2 but the VO2 is maintained by the compensation determined by the EO2%, which explains a security mechanism that ensures the proper use until it descends DO2 a critical point where consumption becomes dependent on the contribution

The use of PiCCO (press contour cardiac output) can continuously monitor cardiac output, the variability of pulse pressure and stroke volume. Likewise, estimates of the severity of intermittent pulmonary edema, intravascular volume and intrathoracic cardiac chambers,

Electrocardiographic monitoring or driving is important in the first six hours after a stroke thoroughly evaluated on admission electrocardiogram to TiPQ, you need continuous monitoring of electrical activity and identify arrhythmias or morphological changes that warrant immediate management. You also have to periodically assess the proper functioning of epicardial pacemaker generator. Management should be initiated when the

First of all clinical assessment remains the mainstay in respiratory monitoring, inspection of the chest is important from the patient's arrival to TiPQ is important to assess that there is synchrony in movements of both amplexación amplexión and thorax as well as observation of permeability each of chest drains and their exact position placed by the surgical team must verify proper endotracheal tube position, surely the next step is auscultation of lung regions in search of clinical syndromes or abnormal sounds that suggest some clinical suspicion is necessary to assess respiratory mechanics measurements in our patient by the

ventilator as well as scheduling parameters. Sets the following startup parameters:

not improve cardiovascular survival in critically ill patients.

under the supervision of personnel in these areas.

anaeróbico initiating cellular metabolism. 38,39

two measures related to ventricular preload.

ventricular rate is above 110lat/min.

**Respiratory monitoring** 

FiO2 = to maintain SaO2> 90%. Over 90% of postoperative patients reach TiPQ Units with mechanical assistance in breathing, so the generally invasive respiratory monitoring, however, is always important clinical evaluation since joining our service to have an initial assessment and observe its evolution in the first 24 hours. Not established the need for routine use of PEEP in patients without complications due to decreased functional residual capacity (FRC) in these patients and atelectasis appear 5 minutes after the onset of anesthesia are not important and no impact on arterial oxygenation postoperatively. However, in the first hour is important to evaluate the relationship and consider PaO2/FiO2 lung history to give an appropriate value, it is also important to rule out existence of residual pleural effusion or pneumothorax because both entities are also involved in lowering the ratio PaO2/FiO 2, and evaluated these considerations and having a stable hemodynamic status can be performed alveolar recruitment maneuver (ARM) is a technique that uses a sustained increase in airway pressure with the aim of recruiting collapsed alveolar units, increasing lung area available for gas exchange and consequently arterial oxygenation. Recent studies concern the use of MRA after cardiac surgery, during which the authors believe that lung function and oxygenation are decreased> 20% with the use of cardiopulmonary bypass and the inflammatory response with the exponential growth atelectasis. Cardiac surgery with cardiopulmonary bypass includes the complete collapse of the lungs, thus, the move will improve oxygenation by opening collapsed lung regions. The results of current work suggest that alveolar recruitment maneuvers are safe procedure in patients with cardiovascular surgery and reduces the frequency of postoperative atelectasis.

The decline of ventilatory support should generally be within 24 hours, ideally Fast-track implementation of the ventilation is the goal in most patients (Fast-track cardiac anesthesia-FTCA-). The importance of predicting the timing of weaning is that both the early weaning as the unnecessary prolongation of mechanical ventilation is deleterious to the patient. In addition only with the clinical trial is difficult to predict how successful disconnection accurate (50% positive predictive value and 67% negative predictive value) because these results justify the implementation of objectives and accurate methods to identify patients who are able to adequately of extubated successfully.

Early extubation is associated with a significant reduction in costs associated with mechanical ventilation, there is now several modalities to a quick and safe extubation, spontaneous ventilation with pressure support (VPS) with 2 dual ventilation PEEP levels (BiLevel) or that pressure release ventilation (APRV).

Patients extubated within 24 hrs it has decreased PaO2/FiO2 ratio <200 is recommended the use of noninvasive mechanical ventilation for 24 hrs demonstrated by Yoshiyuki Takami et al, as it must be part of primary treatment strategy in patients with acute pulmonary edema in this group of patients and reduces the need for endotracheal reintubation and lower mortality when compared against conventional treatment with oxygen therapy in postoperative heart patient.

Pulse oximetry has been used to transfer the patient to the operating room TiPQ unit and required at all times to monitor the state of oxygenation does not replace the determination of arterial blood gases, however the devices currently are more sensitive and less margin for

Intensive Care Management of Patients in the First 24 Hours After Cardiac Surgery 15

surgery is also necessary to know the values of venous blood gases. The determination of arterial and venous blood gases provides three basic values through direct measurement of

The PaO2 is the rate of oxygenation of the blood an indicator of the intensity of the presence of molecular oxygen dissolved in plasma, is the expression of the efficiency of alveolar ventilation-perfusion and alveolar capillary diffusion normal to achieve the transfer oxygen from inside the alveolus to pulmonary capillary blood. The PaCO2 is a ventilation parameter also reflects the respiratory component of acid-base and is a highly reliable method that reflects without confusion or error, unless you have a fan failure or bad programming environment with respect to individual clinical Patient postoperados.40,

The clinical value in the immediate postoperative period is important because the simple quantification of urine schedule can objectively evaluate renal function, however there are several circumstances where the patient usually attends with minimal deterioration and time indicated by decreased urine output, factors are multi-age, prior renal impairment, intravascular volume cash cytokines by CBP, controlled hypotension, bleeding, and so on. The incidence of acute renal failure (ARF) in cardiac surgery with cardiopulmonary bypass, between 1% and 45%, and in most schools in a 1% to 15%. The incidence of severe ARF that required renal replacement therapy techniques, the work varies between 1% and 11.1%, thanks to a study by Charujas and colleagues demonstrate and validate a "ARF score" in patients undergoing heart surgery and determine the risk of postoperative renal failure in taking a score: 1 to 17 than to predict the risk of acute renal failure expressed in

The CBP has also been involved for many years in the genesis of renal damage associated with cardiac surgery, initially manifested by microscopic or gross hematuria depending on the severity, though studies of the last fifteen years, using sensitive techniques to identify kidney damage have suggested greater importance of perioperative generator impairment and acute renal failure, as opposed to possible damage of CPB. Most of these studies have been performed in elective postoperative patients with normal preoperative renal function, recent studies comparing off-pump coronary surgery versus conventional coronary surgery, show no differences in postoperative renal damage, however the valve patients have been considered within the group at high risk of kidney damage. So today in the early hours 24 hours urine volume remains the most reliable parameter of renal impairment and prayers

whatever their origin (hypovolemia, nephrotoxicity, ischemia, contrast, etc). 44,45,46,47

Hyperglycemia in the perioperative period is associated with increased morbidity, decreased survival and increased costs. A number of observational studies have shown that improved control of glucose levels in diabetic patients undergoing coronary revascularization improves the outcome. Van den Berghe et al demonstrated in surgical ICU patients, 63% of whom were postoperative cardiac surgery, the control of glucose concentrations of 80-100 mg / dl was associated with a relative decrease in mortality over

the respective electrodes:

41,42,43

**Renal monitoring** 

percentage.

**Metabolic monitoring** 

1. Partial pressure of oxygen dissolved in plasma, PaO2.

3. The degree of acidity or alkalinity of the plasma pH.

2. Partial pressure of carbon dioxide dissolved in the plasma, PaCO2.

error, which has gained considerable ground in noninvasive respiratory monitoring. The most common cause of inaccurate readings of SpO2 is movement, affects the ability of light to travel from the light-emitting diodes (LED) to the photodetector, parkinsonism, seizures, tremors, cause problems with detecting saturation with falsely high measurements in low perfusion states, such as low cardiac output, vasoconstriction, hypothermia, hypovolemia, severe hypotension, particularly in cardiac surgery, the oximeter reading is difficult, however, this noninvasive method provides reliable early the decrease in oxygen saturation before they show clinical signs of hypoxemia.

Capnometry capnography and monitoring is a noninvasive method useful in the postoperative cardiovascular since it is constantly evaluating the level of carbon dioxide (CO2) exhaled and its graphical representation is undoubtedly an important tool in the management of mechanical ventilation in the first hours after surgery. Carbon dioxide the patient is transported from the cells into the lungs through the venous blood, mostly in the form of bicarbonate (HCO3) and dissolved in small amounts in plasma and bound to hemoglobin, the amount of CO2 that comes the alveoli is determined by its production and flow of venous blood that is, its perfusion (Q), on the other hand, their removal is an almost direct function of alveolar ventilation (V). Therefore, the PaCO2 is the result of the relationship between ventilation and perfusion: the ratio = V / Q


As evaluated in the above three points the lungs are not physiologically homogeneous and therefore carbon dioxide at the end of expiration (ETCO2) is the average of the mixture of all different types PaCO2 alveoli. It's called PaCO2-ETCO2 gradient to the difference between arterial CO2 pressure and the pressure of CO2 in the alveoli (ETCO2), which normally is 1-5 mmHg. This small difference is due to the small dead space that exists in normal conditions. But knowing the physiological concepts, translation in the immediate postoperative clinic may be:


Arterial blood gases are essential to making the postoperative management of blood gases were performed on all patients from their initial arrival and subsequent to any adjustment or correction fan electrolyte and acid-base status, interpretation of blood gases is sometimes difficult; laboratory results must always be studied in light of the clinical picture, by the systematic approach to each of the values. In the critically ill patient post-operative heart surgery is also necessary to know the values of venous blood gases. The determination of arterial and venous blood gases provides three basic values through direct measurement of the respective electrodes:


The PaO2 is the rate of oxygenation of the blood an indicator of the intensity of the presence of molecular oxygen dissolved in plasma, is the expression of the efficiency of alveolar ventilation-perfusion and alveolar capillary diffusion normal to achieve the transfer oxygen from inside the alveolus to pulmonary capillary blood. The PaCO2 is a ventilation parameter also reflects the respiratory component of acid-base and is a highly reliable method that reflects without confusion or error, unless you have a fan failure or bad programming environment with respect to individual clinical Patient postoperados.40, 41,42,43

### **Renal monitoring**

14 Special Topics in Cardiac Surgery

error, which has gained considerable ground in noninvasive respiratory monitoring. The most common cause of inaccurate readings of SpO2 is movement, affects the ability of light to travel from the light-emitting diodes (LED) to the photodetector, parkinsonism, seizures, tremors, cause problems with detecting saturation with falsely high measurements in low perfusion states, such as low cardiac output, vasoconstriction, hypothermia, hypovolemia, severe hypotension, particularly in cardiac surgery, the oximeter reading is difficult, however, this noninvasive method provides reliable early the decrease in oxygen saturation

Capnometry capnography and monitoring is a noninvasive method useful in the postoperative cardiovascular since it is constantly evaluating the level of carbon dioxide (CO2) exhaled and its graphical representation is undoubtedly an important tool in the management of mechanical ventilation in the first hours after surgery. Carbon dioxide the patient is transported from the cells into the lungs through the venous blood, mostly in the form of bicarbonate (HCO3) and dissolved in small amounts in plasma and bound to hemoglobin, the amount of CO2 that comes the alveoli is determined by its production and flow of venous blood that is, its perfusion (Q), on the other hand, their removal is an almost direct function of alveolar ventilation (V). Therefore, the PaCO2 is the result of the

1. In the case where the alveolar ventilation equals pulmonary blood perfusion, PaCO2 is very similar to PaCO2 in these cases changes in the PaCO2 almost exactly reflect those

2. In cases where ventilation is inappropriately high with respect to the infusion, ie there is a high degree of "dead space" (VD), PaCO2 is considerably lower than PaCO2. 3. In cases where the ventilation is decreased in relation to infusion, PaCO2 is close to the values of PCO2 in venous blood, ie the PvCO2, and results in a V / Q low. This occurs in those clinical situations in which the airways or alveolar sick or increased pulmonary

As evaluated in the above three points the lungs are not physiologically homogeneous and therefore carbon dioxide at the end of expiration (ETCO2) is the average of the mixture of all different types PaCO2 alveoli. It's called PaCO2-ETCO2 gradient to the difference between arterial CO2 pressure and the pressure of CO2 in the alveoli (ETCO2), which normally is 1-5 mmHg. This small difference is due to the small dead space that exists in normal conditions. But knowing the physiological concepts, translation in the immediate postoperative clinic

A ETCO2 of 0 usually means the patient is not breathing, however, can also be the

 The decrease in ETCO2 suggests a decreased production of CO2, hypothermia or a fall in transport, low cardiac output, excessive alveolar ventilation, hyperventilation or a

Increased ETCO2 may be the result of excessive production of CO2, hyperthermia or

Arterial blood gases are essential to making the postoperative management of blood gases were performed on all patients from their initial arrival and subsequent to any adjustment or correction fan electrolyte and acid-base status, interpretation of blood gases is sometimes difficult; laboratory results must always be studied in light of the clinical picture, by the systematic approach to each of the values. In the critically ill patient post-operative heart

before they show clinical signs of hypoxemia.

observed in PaCO2.

blood perfusion.

malfunctioning fan. fig 6

may be:

relationship between ventilation and perfusion: the ratio = V / Q

result of a malfunctioning fan or a disconnect from it.

sepsis or a decrease in alveolar ventilation

The clinical value in the immediate postoperative period is important because the simple quantification of urine schedule can objectively evaluate renal function, however there are several circumstances where the patient usually attends with minimal deterioration and time indicated by decreased urine output, factors are multi-age, prior renal impairment, intravascular volume cash cytokines by CBP, controlled hypotension, bleeding, and so on. The incidence of acute renal failure (ARF) in cardiac surgery with cardiopulmonary bypass, between 1% and 45%, and in most schools in a 1% to 15%. The incidence of severe ARF that required renal replacement therapy techniques, the work varies between 1% and 11.1%, thanks to a study by Charujas and colleagues demonstrate and validate a "ARF score" in patients undergoing heart surgery and determine the risk of postoperative renal failure in taking a score: 1 to 17 than to predict the risk of acute renal failure expressed in percentage.

The CBP has also been involved for many years in the genesis of renal damage associated with cardiac surgery, initially manifested by microscopic or gross hematuria depending on the severity, though studies of the last fifteen years, using sensitive techniques to identify kidney damage have suggested greater importance of perioperative generator impairment and acute renal failure, as opposed to possible damage of CPB. Most of these studies have been performed in elective postoperative patients with normal preoperative renal function, recent studies comparing off-pump coronary surgery versus conventional coronary surgery, show no differences in postoperative renal damage, however the valve patients have been considered within the group at high risk of kidney damage. So today in the early hours 24 hours urine volume remains the most reliable parameter of renal impairment and prayers whatever their origin (hypovolemia, nephrotoxicity, ischemia, contrast, etc). 44,45,46,47

### **Metabolic monitoring**

Hyperglycemia in the perioperative period is associated with increased morbidity, decreased survival and increased costs. A number of observational studies have shown that improved control of glucose levels in diabetic patients undergoing coronary revascularization improves the outcome. Van den Berghe et al demonstrated in surgical ICU patients, 63% of whom were postoperative cardiac surgery, the control of glucose concentrations of 80-100 mg / dl was associated with a relative decrease in mortality over

Intensive Care Management of Patients in the First 24 Hours After Cardiac Surgery 17

and mortality in recent years. This consideration has resulted from recent meta-analysis and evidence-based medicine, evidence shows the association of adverse effects such as increased costs, morbidity and mortality especially in the group <65 years so even 7.5gr hemoglobin can be well tolerated and no increased risk increase in elderly patients without ischemic but the minimum allowed is 8.5 grams, although a large number of scientific publications are those who prefer to have an algorithm in relation to individual patient characteristics as shown in the table below . The indications for transfusion in patients with coronary disease are valid when hypovolemia has been corrected, optimized hemodynamics

It is common in the postoperative cardiac surgery hours uncomplicated run smoothly. At approximately 36 hours the patient can be transferred to a general room with telemetric

Hypotension and hypoperfusion injury may condition not directly related to the surgical procedure and include cardiac tamponade, a new myocardial ischemia, tension pneumothorax, hemothorax or significant bleeding related to arterial cannulation. Rarely produce acute thrombosis of a graft or coronary embolization. The electrocardiogram (ECG) may be of diagnostic aid because it is expected that the initial postoperative ECG changes does not show or reveal abnormalities preoperatively limited ST-T. If there are significant changes in ECG repeated, should be thought of an occlusive lesion of one of

In the presence of suspected acute ischemia should indicate intravenous nitroglycerin, the risk of a perioperative myocardial infarction is present from the preoperative to the hospital and even after the diagnosis of acute myocardial infarction (AMI) presents difficulties in the perioperative You must have a combination of ECG, cardiac enzymes and echocardiography can occasionally make the diagnosis. Frequently observed nonspecific ECG changes a large percentage of patients have an increased enzyme and troponin I (TnI) generally exceeds the levels observed in AMI unrelated to cardiac surgery. The loss of graft thrombosis has been reported in up to 10% of grafts in the first week in the hours following the surgery, aspirin and possibly clopidogrel appears to reduce the prevalence of AMI diagnosis although postoperative postoperative AMI is difficult itself has a significant effect on morbidity and

The low cardiac output syndrome (LCOS), is characterized by decreased performance of cardiac function where the cause may damage myocardial and cardiogenic shock condition corresponds to a failure in the balance between central cardiac pump and control components peripherals, including: a) the tone of the peripheral circulation and b) neurohumoral regulators of vascular tone, with the arrival insufficient oxygenated blood to peripheral tissues to meet metabolic needs, their presence is associated with high mortality at that requires immediate diagnosis and treatment. The multiple causes can produce or aggravate this syndrome can be grouped, for descriptive purposes, the following pathogenic

and oxygenation after correction tachycardia. 55,56,57

**6. Complicated postoperative** 

control.

**Cardiovascular** 

the grafts.

mortality in the long term.

Low cardiac output syndrome

**Arrhythmias** 

mechanisms:

40% when compared with controls. This study has been criticized for lack of blind control, administration of high doses of glucose control and high incidence of hypoglycemia. The current recommendation is to try to keep blood glucose below 150 mg / dl, this was secondary to a study called normoglycemia in Intensive Care Evaluation Survival Using Glucose Algorithm-Regulation (NICE-SUGAR) used to test the hypothesis that intensive of blood sugar reduces mortality 90 days in this study showed higher mortality from severe hypoglycemia. Because polyuria in the early hours, the release of antidiuretic hormone and hyperaldosteronism that characterizes the patient operated on with CPB, it is common the presence of hypokalaemia which must be corrected for values greater than 4.0 mEq / L, just as occurs hypomagnesemia should be corrected usually there is usually no changes in serum calcium or other ions that require correction.

The dilutional hyponatremia type being increased total body sodium, the use of mannitol and / or furosemide during CPB produces a polyuria in the first two to three hours postoperatively INSTANT that can reach 1000 ml / hour, with a tendency to normalize within hours, the usual consequence is the need to infuse fluids resulting hypovolemia. 48.49

### **Neurological monitoring**

It is essential in the first 24 hours because it is not uncommon to find deficits in different degrees and which are generally grouped into cognitive dysfunction, which is the most common disorder and unnoticed, and that their identification will be necessary to carry out mini-mental and demonstrate an early deficit and time of their higher mental functions. All patients coming to the unit with residual sedation TiPQ so within the next 6 hours there is a 95% elimination of sedatives, since coming patients should be evaluated clinically to assess the integrity of the stem bark and well-get a first impression to rule out diagnoses and cerebral ischemic event or bleeding. In patients who quickly integrates a focus fasciocorporal study should be completed image and a more detailed review to have an early management and prevent secondary damage. 50.51

Moreover, patients with prolonged CPB tend to have greater involvement of cardiorespiratory function and hemodynamic instability preoperatively intraoperative surgery more complicated, hence the increased incidence of neurological disorders may be related to these factors rather than the CPB time, now happens with hypotension and cerebral hypoperfusion which is another postulated mechanism of neurological damage. The CBP is under hypothermia and anesthesia, both of which lower the cerebral metabolism and thus cerebral blood flow as there is less demand on the other hand, hemodilution decreases blood viscosity by decreasing its resistance to move, so lower blood pressure can keep the same cerebral blood flow. Thus, it alters the autoregulation curve of cerebral blood flow may keep it even with blood pressures of 50 to 60 mm Hg, studies measuring regional cerebral blood flow in patients during CPB have shown that blood pressure can reach 50 mm Hg without altered cerebral blood flow. Moreover, the flow can reach 19 cm 3 per 100 grams of tissue per minute without psychometric alterations detected between pre and post operative. Glasgow is interpreted evaluation at baseline and 6 hours by issuing a neurological assessment, monitoring with bispectral index (BIS) in patients who have to initiate a secondary sedation is necessary to identify a level of sedation adecuado.52, 53 , 54

### **Hematologic monitoring**

Hematologic monitoring after surgery is associated with anemia hemodilution and blood loss, the minimum necessary use of blood products has shown improvement in morbidity and mortality in recent years. This consideration has resulted from recent meta-analysis and evidence-based medicine, evidence shows the association of adverse effects such as increased costs, morbidity and mortality especially in the group <65 years so even 7.5gr hemoglobin can be well tolerated and no increased risk increase in elderly patients without ischemic but the minimum allowed is 8.5 grams, although a large number of scientific publications are those who prefer to have an algorithm in relation to individual patient characteristics as shown in the table below . The indications for transfusion in patients with coronary disease are valid when hypovolemia has been corrected, optimized hemodynamics and oxygenation after correction tachycardia. 55,56,57

It is common in the postoperative cardiac surgery hours uncomplicated run smoothly. At approximately 36 hours the patient can be transferred to a general room with telemetric control.
