NEURO-COGNITIVE AND PATHOPHYSIOLOGICAL CHANGES IN HYPOBARIC CHAMBER IN PILOTS OF PAKISTAN AIR FORCE

Neuro-Cognitive Changes in Hypobaric Chamber

Abstract

Objective: To determine the effects of hypoxia in hypobaric chamber and correlation of effects with time.
Design: Descriptive study.
Place and Duration of Study: Study was carried out at Aero medical Institute Masroor Base Karachi from July to December 2009.
Patients and Methods: All those aviators coming to aero medical Institute for various courses during the period of July 2009 to December 2009 were included in this study. In hypobaric chamber time of useful consciousness was measured after removing the oxygen mask at 25,000 ft and at 18,000 ft (with dimmed lights to observe hypoxia effects on vision during night flying). Simultaneously with the removal of mask we delivered to the aviators a form to fill. This form depicts the cognitive-motor degradation that occurs with the lack of oxygen.
Results: Total number of aviators that participated in this study was hundred and four. Time of useful consciousness in 68.3% was 5 minutes. 22% developed drowsiness, 11.5% developed nausea and headache each, 18.3% felt weakness, tingling was present in 12.5%, fatigue in 15.4%, 2.9% developed euphoria, feeling of insects crawling under skin, shortness of breath and decreased coordination of movements, 1% developed toothache and loss of color vision, burning sensation in body, decreased visual acuity, confusion and finger getting blue accounted for 4.8% each, hot and cold sensations were present in 8.7%, palpitations and spots before eyes were observed in 3.8%, blurred vision was present 10.6%, numbness in 5.8%, impaired judgment in 1.9% and no symptoms occurred during hypoxia in 8.7% of aviators.
Conclusion: It can be safely concluded on the basis of this study that at high altitudes with hypoxia useful consciousness in majority lasts only 5 minutes and majority will present with the symptoms of drowsiness, nausea, headache, weakness, fatigue and even euphoria. Results clearly indicate that time of hypoxia is directly proportional to the severity of hypoxic symptoms.