Aerospace Physiology & Human Factors Flashcards

What is the primary pathophysiological mechanism of hypoxic hypoxia in aviation, and which altitude range is associated with the 'indifferent zone' where symptoms are minimal?

Answer: Reduced partial pressure of inspired oxygen causing decreased alveolar and arterial oxygen; sea level to 10,000 feet

Hypoxic hypoxia results from reduced PO2 in inspired air at altitude. The indifferent zone (sea level to approximately 10,000 feet) produces minimal physiological effects in healthy individuals.

What is 'G-LOC' (G-force induced loss of consciousness) and which type of acceleration is primarily responsible for it in high-performance aviation?

Answer: Positive Gz acceleration (head-to-foot) causing blood pooling in the lower body and reduced cerebral perfusion

G-LOC results from sustained positive Gz (head-to-foot) acceleration, which pools blood in the lower body, reduces venous return to the heart, and decreases cerebral perfusion pressure below the threshold for consciousness.

During a high-altitude decompression event, a pilot begins demonstrating apparent euphoria and increasing confusion but does not seem to recognize their own incapacitation. What physiological phenomenon explains this pattern?

Answer: Hypoxic impairment of the frontal cortex - the self-awareness and executive function regions are preferentially affected early in hypoxia

Early cerebral hypoxia preferentially impairs frontal lobe executive function and self-awareness, producing euphoria and poor self-assessment - the pilot cannot recognize their own impairment.

What is the pathophysiology of barotitis media (aerotitis), and which applicants are at highest risk of developing it during flight?

Answer: Inability to equalize middle ear pressure with ambient pressure during descent due to Eustachian tube dysfunction, highest risk in applicants with URI, allergies, or anatomical obstruction

Barotitis media results from failure to equalize middle ear pressure during altitude change - most critically during descent - due to Eustachian tube dysfunction from inflammation, congestion, or anatomical factors.

How does circadian rhythm disruption from shift work or transmeridian flight contribute to a pilot's risk of cognitive impairment, and what is the AME's role in evaluating this?

Answer: Circadian disruption causes performance decrements equivalent to clinical sleep deprivation, including impaired attention, decision-making, and situational awareness; AMEs should counsel and evaluate for chronic sleep disorders

Circadian disruption from irregular schedules or time zone crossing produces performance decrements equivalent to sleep deprivation, affecting the cognitive capacities critical for safe flight. AMEs play a counseling and screening role.

An AME is evaluating a commercial pilot who reports chronic fatigue and daytime sleepiness despite 8 hours of nightly sleep. Which clinical evaluation tool is most appropriate as an initial screening instrument for obstructive sleep apnea?

Answer: STOP-BANG questionnaire

The STOP-BANG questionnaire is specifically validated as a screening tool for obstructive sleep apnea and is recommended for pre-surgical and clinical screening in populations at risk including pilots with excessive daytime sleepiness.