**5. Challenges to anaesthesia delivery and airway management in space**

Anaesthesia is important for airway management. Blunting airway reflexes and hemodynamic response to airway instrumentation is a chief consideration. This can be achieved by anaesthesia.

Delivery of anaesthesia in space is highly demanding and complicated, and the reasons can be grouped into three main categories: physiological, technical and human as shown in **Table 2** [16, 17, 35].

#### **5.1 Physiological considerations**

#### *5.1.1 Challenges related to cardiovascular changes in space*

In weightlessness, a new physiological equilibrium is established, adapted to the reduced loading conditions. However, this equilibrium is delicate as is the tolerance to any additional event or even an interventional procedure. Reaction of the human body to blood loss, anaphylaxis or any event that reduces cardiac function, may be further compromised. General anaesthesia and mechanical ventilation may also adversely affect this physiological equilibrium [16].

On landing in gravity environments different from Earth, cardiovascular changes and hypovolemia causes orthostatic intolerance. The aerobic capacity is also impaired as a result of hypovolemia, anaemia and orthostatic intolerance [16, 36]. These factors combined with space motion sickness, limits the crew's ability to perform tasks effectively.

**201**

*5.1.2 Fluid shift*

mended, in microgravity [38].

*5.1.4 Pharmacology in the space environment*

corresponding drug dosages need to be altered as well [39].

*5.1.3 Gastrointestinal system*

weightlessness [39].

*Challenges to Airway Management in Space DOI: http://dx.doi.org/10.5772/intechopen.98932*

• Cardiovascular changes

• Gastrointestinal System

• Pharmacology in Space environment • Choice of anaesthetic technique

• Telemedicine and information technology

• Fluid generation and handling

• Psychological effects on crew

*Factors complicating delivery of medical care in space.*

1. Physiological

• Fluid shift

2. Technical

3. Human • Crew Skills

**Table 2.**

• Vascular access • Closed cabin pressures • Medical equipment • Use of restraints

hypovolemia should be treated concomitantly with IV fluids and vasopressors. Alpha agonists such as phenylephrine, metaraminol, midodrine, norepinephrine should be at hand; higher doses than usual may be required. Beta-agonists and betaantagonists should be used with care [16]. For induction of anaesthesia, drugs that

Although not documented, headward fluid shift and facial oedema can complicate the intubating conditions [16]. Drug distribution during spinal anaesthesia may also be altered due to the cephalad fluid shift and is therefore not recom-

Space motion sickness accompanies gastroesophageal reflux in astronauts, sometimes lasting the entire mission. It may even persist after their return to Earth. The gastroesophageal reflux along with decreased gastrointestinal motility puts the crew at a risk for pulmonary aspiration, both during and after flight [16, 17].

Both the pharmacokinetics and pharmacodynamics of drugs are altered in

Cardiovascular changes, weight changes, changes in hormonal, electrolyte and immunoglobulin levels, decrease in the amount of microsomal P-450 as well as its dependent enzymes are some of the factors that cause changes to the pharmacokinetic and pharmacodynamic properties of drugs in space [16, 40]. As a result, the

Also, long term storage of drugs may render them ineffective or even toxic [16].

preserve cardiovascular stability, such as ketamine, are preferred [37].

Preloading with intravenous (IV) fluids before the induction of general anaesthesia is important to prevent cardiovascular collapse [37]. Any significant

#### 1. Physiological

*Special Considerations in Human Airway Management*

Confinement and isolation in constrained spaces, for extended periods of time,

affects one's psychological health. Even with screening, training, and support; behavioural issues, cognitive conditions, and psychiatric disorders among crew members, is to be expected. Decline in mood, cognition and morale can occur. Sleep disorders due to changes in their circadian rhythms is also quite common [2, 3]. Extended exposure to stress, isolation and changes in circadian rhythm can have a psychological impact on astronauts. Cognitive impairment, sleep disorders,

Personnel skills like team coordination, communication, logistics, etc. and technical skills like troubleshooting equipment, use of safety equipment, orientation, etc. contribute to the health and safety of astronauts. Selection of suitable crew, training and maintenance of skills during the mission, is important. Therefore, medical and psychological benchmarks for crew-member selection

Space travel presents the additional risk of exposure to harmful radiation. On Earth, we are shielded from cosmic radiation by the Earth's magnetic field and its atmosphere. However, on a space station astronauts are exposed to up to ten times the radiation they are exposed to while on Earth. Radiation in space can cause radiation sickness and degenerative tissue disease, among many other serious

**5. Challenges to anaesthesia delivery and airway management in space**

Anaesthesia is important for airway management. Blunting airway reflexes and hemodynamic response to airway instrumentation is a chief consideration. This can

Delivery of anaesthesia in space is highly demanding and complicated, and the reasons can be grouped into three main categories: physiological, technical and

In weightlessness, a new physiological equilibrium is established, adapted to the reduced loading conditions. However, this equilibrium is delicate as is the tolerance to any additional event or even an interventional procedure. Reaction of the human body to blood loss, anaphylaxis or any event that reduces cardiac function, may be further compromised. General anaesthesia and mechanical ventilation may also

On landing in gravity environments different from Earth, cardiovascular changes and hypovolemia causes orthostatic intolerance. The aerobic capacity is also impaired as a result of hypovolemia, anaemia and orthostatic intolerance [16, 36]. These factors combined with space motion sickness, limits the crew's ability to perform tasks

Preloading with intravenous (IV) fluids before the induction of general anaesthesia is important to prevent cardiovascular collapse [37]. Any significant

psychosomatic symptoms, anxiety and even depression can occur [7].

**4.10 Psychological effects**

ought to be very high [7].

**4.11 Exposure to radiation**

be achieved by anaesthesia.

human as shown in **Table 2** [16, 17, 35].

*5.1.1 Challenges related to cardiovascular changes in space*

adversely affect this physiological equilibrium [16].

**5.1 Physiological considerations**

issues [3].

**200**

effectively.

	- Fluid generation and handling
	- Vascular access
	- Closed cabin pressures
	- Medical equipment
	- Use of restraints
	- Telemedicine and information technology
	- Crew Skills
	- Psychological effects on crew

#### **Table 2.**

*Factors complicating delivery of medical care in space.*

hypovolemia should be treated concomitantly with IV fluids and vasopressors. Alpha agonists such as phenylephrine, metaraminol, midodrine, norepinephrine should be at hand; higher doses than usual may be required. Beta-agonists and betaantagonists should be used with care [16]. For induction of anaesthesia, drugs that preserve cardiovascular stability, such as ketamine, are preferred [37].
