Subject(s)
Accidents, Aviation/history , Accidents, Aviation/prevention & control , Accidents, Traffic/history , Accidents, Traffic/prevention & control , Automobiles/history , Aviation/history , Safety/history , Automobiles/standards , Aviation/standards , History, 20th Century , Humans , Male , Seat BeltsABSTRACT
INTRODUCTION: The impact of pharmacological agents on aviators concerns all flight surgeons. This study tested the related hypotheses that acute fatigue reduces +Gz tolerance and endurance, and that stimulants can partially reverse this impact. Additionally, the researchers attempted to develop a test battery sensitive enough to detect subtle differences in aviator cognition and performance among conditions. METHODS: To determine the effect of fatigue on +Gz tolerance and the impact of stimulant use, 10 male centrifuge subjects, mean age 32, from Brooks City-Base, TX, were tested in a repeated measures study under five nighttime conditions following an average of 22 h of sustained wakefulness during their circadian nadir. Using a within-subject design, subjects received placebo, dextroamphetamine 10 mg, modafinil 200 mg, methylphenidate 10 mg, and pemoline 37.5 mg at night, and were tested during a daytime control session. Cognitive/performance tests were administered before each centrifuge run. RESULTS: No difference in +Gz tolerance or endurance was detected among conditions. The cognitive/performance tests also did not detect any differences. Subject perception that anti-G straining maneuver (AGSM) difficulty was greater during the night placebo condition than during the daytime control, methylphenidate and modafinil night conditions reached statistical significance (P = 0.005, 0.012, 0.022, respectively). DISCUSSION: Physiological changes during the circadian nadir following acute sleep deprivation do not appear to negatively impact +Gz tolerance. A standardized protocol sufficiently sensitive to detect subtle behavioral and performance effects would be useful to test and compare the effect of other pharmacological agents on aviators.
Subject(s)
Acceleration , Adaptation, Physiological/physiology , Aerospace Medicine , Central Nervous System Stimulants/pharmacology , Circadian Rhythm/physiology , Fatigue/physiopathology , Physical Endurance/physiology , Adaptation, Physiological/drug effects , Adult , Amphetamine/pharmacology , Analysis of Variance , Benzhydryl Compounds/pharmacology , Circadian Rhythm/drug effects , Cognition , Fatigue/drug therapy , Humans , Male , Methylphenidate/pharmacology , Modafinil , Pemoline/pharmacology , Physical Endurance/drug effects , Sleep Deprivation/drug therapy , Sleep Deprivation/physiopathologyABSTRACT
Neurologic and respiratory decompression sickness (DCS) symptoms occurring in the same individual represent complications rarely observed in altitude research. A case is presented of multi-symptom serious DCS resulting from exposure to 12,192 m (40,000 ft). Following 90 min of preoxygenation, the patient was decompressed in a hypobaric chamber from ground level to 12,192 m in 30 s. After 69 min at altitude he developed substernal chest pressure and the flight was immediately terminated. During the chamber descent the patient appeared disoriented. By 5486 m (18,000 ft) his chest pressure had resolved. The post-flight medical exam revealed multiple neurological abnormalities. He underwent a Table VI hyperbaric oxygen treatment with complete resolution of all abnormal neurological findings.
