**1. Introduction**

Airway patency is crucial and vital for maintenance of life occurs naturally in the awake and conscious individuals or can be accomplished artificially in those becoming unable to maintain it. Incapacity of this might be intentional; as in medical procedures requiring deep sedation and/or general anesthesia or in pathological conditions; where there is an alteration in sensorium or elective airway protection needed.

Airway management is defined as an intervention using a technique, maneuver or a device to keep its patency, consequently its normal physiological functions have been achieved; providing oxygen and removing carbon dioxide.

Critical illness is a clinical condition belong to a group of medical situations sharing the need of intensive care unit (ICU) admission and have either single or multiple organ dysfunction. Critically ill patients showing different gradations of snags to maintain the airway and subsequently derangement of aerobic metabolism exists. Optimization of oxygen supply is needed, as dramatic rise of both work of breathing and oxygen demand exist.

Hypoxemia is a medical condition where the partial pressure of oxygen in the arterial blood (PaO2) is lower than normal. A PaO2 value of less than 60 mmHg in normal individuals with healthy lungs; corresponds to arterial oxygen saturation (SpO2) of 90%, is used as a cut point for hypoxemia treatment initiation. There are many causes and mechanisms of hypoxemia which required management via oxygen administration. Critically ill patients commonly showing hypoxemic status on the time of admission and oxygen supplementation should be considered in all with high flow delivery system (15 L/min) until becoming stable then reduction of inspired oxygen concentration (FIO2) to achieve a target of SpO2 of 94–98% or 88–92% for patients with risk of hypercapnic respiratory failure [1].

#### **1.1 Physiological consideration**

Airway is the natural passages of the airflow, inaugurated by nose and mouth downwards to the alveoli in the lungs, where the gas exchange takes place involuntary. Airway patency is mandatory for life and it's the responsibility of pharyngeallaryngeal muscles tonic control and muco-ciliary system's clearance of mucus and foreign particles.

The airflow via the airway is intermittent and biphasic; inwards during inspiration and outwards during expiration. The work of breathing is a potential energy stored in the lung tissues during inspiration that exists by the work of overcoming the elastic forces and resistance in the airway to be enough for subsequent expiration. In compliant, healthy lung this work of breathing does not consume a portion of the body's energy needs and its daily fraction is less than 3% of total body energy requirement [2].

Impaired consciousness, associated cervical spine trauma, burns and pulmonary shunt causing rapid desaturation and impedes preoxygenation. Besides, limited time for airway management before life-threatening hypoxia, hemodynamically (HD) unstable, imminent risk of collapse before intubation, tricky standard induction drugs effects provoke time pressure environment.

Cessation of the desirable airflow in critically ill patients could be due to a variety of reasons, foremost of those is the airway obstruction. Airway obstruction might occur at any, upper parts; due to foreign body, mucus, secretions, blood and decreased sensorium or lower parts; due to aspiration, infection and spasm of bronchial muscles. Different maneuvers and devices used to eliminate the airway obstruction thus maintenance of airflow will be gained.

Airway management in critically ill patient aimed for:


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**Table 1.**

*Airway Management in Critical Settings DOI: http://dx.doi.org/10.5772/intechopen.93923*

5.Reduce the work of breathing.

7.Altered sensorium, required airway protection.

Critical illness and its management protocols might hinder the airway anatomy, fluid resuscitation and capillary leak makes the airway edematous and distorted. Furthermore, the patient demography, body mass index (BMI), associated neurological and cardiopulmonary comorbidities, and the indication of ICU admission

Oxygen (O2); is an inert gas essential for life, being inspired through the airway

All critically ill patients must have high-flow oxygen delivery device (15 L/min), until stable status achieved, then oxygen requirement could be individually determined depending on the existing pathology. Patient's breathing effort is the primary determinant for the oxygen delivery device selection. Critically ill patients might be one of two groups; spontaneous breathing group or assisted ventilation one and

Patients with breathing effort requiring O2 delivering device matched for their

2 - 15 Unknown; depend on

patient's effort and O2 flow rate

High, up to 45 Well-known, fixed. All obey a principle of high

**FIO2 Example**

Simple face mask, face mask with reservoir bag, nasal cannula. (**Figure 1**)

> airflow O2 enrichment (HAFOE). (**Figure 2**)

each group has a preference in oxygen delivery system [4].

**O2 flow rate (L/min)**

and transported via the lungs towards the blood to be used in cellular respiration and delivery of energy needed for body metabolism. Human body uptake of oxygen in concentration of 20.95% from air by natural airways; nose and mouth, transported down along the conductive airways to be resting in the alveoli where the gas exchange happening. Physiological and pathological conditions required an increased FIO2 to meet the body oxygen requirement and its high demand. Devices are designed to facilitate oxygen delivery from artificial oxygen sources in correspond to the target of FIO2, patient's breathing effort and patient's device

6.Improve CO2 clearance.

**1.2 Anatomical consideration**

contribute to anatomical difficulties.

**1.3 Devices of oxygen delivery**

*1.3.1 Spontaneous- breathing group*

breathing power (**Table 1**).

**Fixed-Performance** 

*Oxygen delivery devices [3].*

**Devices**

**Variable-Performance Devices**

compliance [3].

8.Others in ICU.

4.Relieve the distress of dyspnea.


*Special Considerations in Human Airway Management*

breathing and oxygen demand exist.

**1.1 Physiological consideration**

foreign particles.

requirement [2].

Critical illness is a clinical condition belong to a group of medical situations sharing the need of intensive care unit (ICU) admission and have either single or multiple organ dysfunction. Critically ill patients showing different gradations of snags to maintain the airway and subsequently derangement of aerobic metabolism exists. Optimization of oxygen supply is needed, as dramatic rise of both work of

Hypoxemia is a medical condition where the partial pressure of oxygen in the arterial blood (PaO2) is lower than normal. A PaO2 value of less than 60 mmHg in normal individuals with healthy lungs; corresponds to arterial oxygen saturation (SpO2) of 90%, is used as a cut point for hypoxemia treatment initiation. There are many causes and mechanisms of hypoxemia which required management via oxygen administration. Critically ill patients commonly showing hypoxemic status on the time of admission and oxygen supplementation should be considered in all with high flow delivery system (15 L/min) until becoming stable then reduction of inspired oxygen concentration (FIO2) to achieve a target of SpO2 of 94–98% or

Airway is the natural passages of the airflow, inaugurated by nose and mouth downwards to the alveoli in the lungs, where the gas exchange takes place involuntary. Airway patency is mandatory for life and it's the responsibility of pharyngeallaryngeal muscles tonic control and muco-ciliary system's clearance of mucus and

The airflow via the airway is intermittent and biphasic; inwards during inspiration and outwards during expiration. The work of breathing is a potential energy stored in the lung tissues during inspiration that exists by the work of overcoming the elastic forces and resistance in the airway to be enough for subsequent expiration. In compliant, healthy lung this work of breathing does not consume a portion of the body's energy needs and its daily fraction is less than 3% of total body energy

Impaired consciousness, associated cervical spine trauma, burns and pulmonary

shunt causing rapid desaturation and impedes preoxygenation. Besides, limited time for airway management before life-threatening hypoxia, hemodynamically (HD) unstable, imminent risk of collapse before intubation, tricky standard induc-

Cessation of the desirable airflow in critically ill patients could be due to a variety of reasons, foremost of those is the airway obstruction. Airway obstruction might occur at any, upper parts; due to foreign body, mucus, secretions, blood and decreased sensorium or lower parts; due to aspiration, infection and spasm of bronchial muscles. Different maneuvers and devices used to eliminate the airway

3.Adjunct for procedures; diagnostic e.g. bronchoscopy or therapeutic e.g. band-

tion drugs effects provoke time pressure environment.

obstruction thus maintenance of airflow will be gained. Airway management in critically ill patient aimed for:

2.Airway protection and prevention of pulmonary aspiration.

1.Improving the oxygenation.

ing of bleeding esophageal varices.

4.Relieve the distress of dyspnea.

88–92% for patients with risk of hypercapnic respiratory failure [1].

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