**3. Special consideration in anesthesia and airway management in space and microgravity conditions**

The first vehicles carrier used to carry humans to the stratosphere atmosphere, was the Balloons in 1783, the first round across the Earth had been achieved by the hybrid balloon. The increasing advancement of advanced life support programs and control systems progress had allowed to transport humans higher for more plans and the preparation to colonize the Moon and the trip to Mars [19].

Now recently aerospace companies are aiming to give scientists the chance to develop their clinical experience by arranging near space trips [20]. A great progress in Human spaceflight has expanded over the last 40 years leading to a larger, more sophisticated, and more distant journeys. As a result of this continuous advancement, space flight crews might require medical procedures, that mandates anesthesia, so the medical personnel on board should be well experienced to perform surgery and anesthesia during flights in deep space. So anesthesia strategies and techniques have to be adjusted to deal with specific problems and dangers that may rise while patients are under the effects of microgravity [10].

Airway management requires adequate training to maintain excellent medical care during aviation, our knowledge about airway management in microgravity is progressing and numbers of trials that examine the difference between different airway management methods is increasing. This justifies the importance of reviewing

this topic to so that a better understanding of all the challenges in microgravity environment is achieved.

The most common indications for advanced airway management in aviation are acute respiratory failure, hypoxemia or inadequate ventilation and protection of the airway in a patient with impaired alertness.

#### **4. Challenges in airway management during space exploration missions**

Challenges during space mission are very numerous, it can be classified into: patient related, environmental, and caregivers related. Medical emergency during aviation will more likely to have high risk of morbidity or mortality.

The patient factors are discussed in the physiological changes in microgravity.

The environment during aviation is characterized by the loss of gravity which may make very important simple adjuncts as fluids unavailable, it also affects the actual force that the body control, this render the caregiver with a totally new circumstances while doing intubation. Any practicing Anesthesiologist will be able to appreciate the importance of the ability to create the same effect while holding the laryngoscope with the usual power that the operator tends to use in normal conditions. The weightlessness also creates a big difference in patient positioning, the patient will be in free floating position and precision will be difficult without adequate training as tracheal intubation will be a single-handed technique.

Multiple factors in space are expected to create a challenging environment for airway management and by so affecting patient safety. Stress and cognitive factors, environmental hazards, deficiency in equipment, lack of intubation skills and suboptimal working conditions are not all but most of the challenging factors.

Loss of gravity alter the coordinated effort between the eye and the brain, which will impair eye - hand coordination [10].

Caregivers related factors are mainly related to the lack of expertise in this field, the crew will not likely be accompanied by a trained Anesthetist, and this is why most of the fine anesthesia techniques will be done by non-anesthesiologist during these missions. Facing these challenges, some scientists conducted clinical trials in a simulated environment, they compared the use of video-laryngoscopy in microgravity between the naïve and expertise in airway management. Results suggested that video- laryngoscopy help health care-givers to overcome these factors and it also decreases the difference in intubation efficacy between naive and expertise [21].

#### **4.1 Anesthesia and airway management in microgravity**

The approach to provide anesthesia on space flights missions would be necessary to the success of the mission. Physiological accommodation to microgravity may hinder any planning of anesthesia. A previously published assumption for anesthesia airway management reported monitoring, preoxygenation, induction then bag – mask ventilation then they used Rocuronium as a muscle relaxant, followed by endotracheal tube insertion using video laryngoscopy, the tube size was smaller than the proper size to avoid edema [21].

The adaptations of the muscle performance in microgravity particularly the functional changes in acetylcholine receptor variations can have an effect on the administration of depolarizing and non-depolarizing neuromuscular blockers in patients exposed to microgravity promoting their cautiously use [10].

Advance airway management requires adequate skills, knowledge and training to perform in the microgravity setting that add a new difficulty to the existing ones

**221**

*Airway Management in Aviation, Space, and Microgravity*

which necessities a proper training and knowledge [22]. Microgravity environments is a significant challenge for the person who is performing airway procedure since it is difficult to position the patient as the body is unsubstantiated, without the gravity

Caregiver loaded on the International Space Station (ISS). May be affected with situations that necessitate management of Airway to establish a patent airway for a

Airway management procedures had been investigated in a previous study which described using them in inadequate conditions pertaining to space flight. Actually, the optimal way for patient care aboard on space station require that caregiver and patient to be restrained. The Medical Operation Support Team (MOST), 2007 and others previously assessed how to secure airways in microgravity experiments using different techniques for establishing airways in substandard positions by caregiving non-physician – they had accomplished direct laryngoscopy and inserted a cuffed endotracheal tube [24]. As researches are advancing in this field, NASA doctors and companions would be able to provide proper airway manage-

There have been several important studies on airway management in microgravity, with the assumption that a laryngeal airway mask (LMA) had been used. Intubating Laryngeal Mask Airway effectively used which is a supraglottic airway device. Either approach is adequate to perform in substandard situations within a microgravity situation. [23, 25] The challenge to the advanced airway management during space journey is the presence of expertise to be one of the medical onboard team, occasionally the crew physician may had been diseased or incapacitated.

In studies investigating the efficacy of airway management during air transport. Air medical transport teams are periodically confronted with the responsibility of conducting airways in unexpected and difficult circumstances, meanwhile they should be essentially trained to do the task in a limited field with less resources

Unexpected abrupt patient deterioration prominently considered as the prevailing reason for Airway management during aviation. Intubation process achievement was not related to the category of aircraft. The total intubation successfulness rate for advanced airway handling procedures, was 96%. The successful Airway management procedures during flights was conducted with a high achievement percentage in a variety of venues and for a variety of patient status and conditions. Air medical transport teams achievement rates were proportionate to other emergency medical staff [26]. Anatomically the epiglottis lies at the base of tongue and provides an essential reference point for direct laryngoscopy. The epiglottis fulfills the function of gate that covers the glottis, the vallecula is the concavity between the base of the tongue and the epiglottis, shown as reference point where a curved laryngoscope blade is placed. The pressure exerted by the blade tip against the vallecula elevates the epiglottis and this elevation is affected by gravity. In 1978, LeJeune hypothesized that tracheal intubation using laryngoscopy would be difficult in microgravity, since the force exerted by the laryngoscope causes the head and neck move out of the field of vision by lever effect exerted on the head and generated through the laryngoscope blade by hand generating a lack of stability,

**4.2 The NASA flight surgeon and NASA space person companions**

**4.3 NASA studies on airway management in microgravity**

resulting in the difficulty to insert the tracheal tube [27].

*DOI: http://dx.doi.org/10.5772/intechopen.96603*

patient suffering respiratory distress.

ment during space trips.

during their duty in the aircraft.

of Earth's [23].

*Special Considerations in Human Airway Management*

airway in a patient with impaired alertness.

will impair eye - hand coordination [10].

than the proper size to avoid edema [21].

environment is achieved.

this topic to so that a better understanding of all the challenges in microgravity

The most common indications for advanced airway management in aviation are acute respiratory failure, hypoxemia or inadequate ventilation and protection of the

**4. Challenges in airway management during space exploration missions**

Challenges during space mission are very numerous, it can be classified into: patient related, environmental, and caregivers related. Medical emergency during

The patient factors are discussed in the physiological changes in microgravity. The environment during aviation is characterized by the loss of gravity which may make very important simple adjuncts as fluids unavailable, it also affects the actual force that the body control, this render the caregiver with a totally new circumstances while doing intubation. Any practicing Anesthesiologist will be able to appreciate the importance of the ability to create the same effect while holding the laryngoscope with the usual power that the operator tends to use in normal conditions. The weightlessness also creates a big difference in patient positioning, the patient will be in free floating position and precision will be difficult without adequate training as tracheal intubation will be a single-handed technique.

Multiple factors in space are expected to create a challenging environment for airway management and by so affecting patient safety. Stress and cognitive factors, environmental hazards, deficiency in equipment, lack of intubation skills and subop-

Caregivers related factors are mainly related to the lack of expertise in this field, the crew will not likely be accompanied by a trained Anesthetist, and this is why most of the fine anesthesia techniques will be done by non-anesthesiologist during these missions. Facing these challenges, some scientists conducted clinical trials in a simulated environment, they compared the use of video-laryngoscopy in microgravity between the naïve and expertise in airway management. Results suggested that video- laryngoscopy help health care-givers to overcome these factors and it also decreases the difference in intubation efficacy between naive and

Loss of gravity alter the coordinated effort between the eye and the brain, which

The approach to provide anesthesia on space flights missions would be necessary to the success of the mission. Physiological accommodation to microgravity may hinder any planning of anesthesia. A previously published assumption for anesthesia airway management reported monitoring, preoxygenation, induction then bag – mask ventilation then they used Rocuronium as a muscle relaxant, followed by endotracheal tube insertion using video laryngoscopy, the tube size was smaller

The adaptations of the muscle performance in microgravity particularly the functional changes in acetylcholine receptor variations can have an effect on the administration of depolarizing and non-depolarizing neuromuscular blockers in

Advance airway management requires adequate skills, knowledge and training to perform in the microgravity setting that add a new difficulty to the existing ones

patients exposed to microgravity promoting their cautiously use [10].

timal working conditions are not all but most of the challenging factors.

**4.1 Anesthesia and airway management in microgravity**

aviation will more likely to have high risk of morbidity or mortality.

**220**

expertise [21].

which necessities a proper training and knowledge [22]. Microgravity environments is a significant challenge for the person who is performing airway procedure since it is difficult to position the patient as the body is unsubstantiated, without the gravity of Earth's [23].

Caregiver loaded on the International Space Station (ISS). May be affected with situations that necessitate management of Airway to establish a patent airway for a patient suffering respiratory distress.
