| Objective: In the current high-tech war situation,the performance of the aircrafts gradually increased,so did the acceleration load.The incidence of loss of consciousness caused by +Gz in flight increased significantly,which is the main factor that threatens the safety of flight.In recent years,the Air Force has increased the intensity and frequency of live competitive training,and has put forward higher requirements for the quality of air combat training.Therefore,how to effectively enhance the acceleration tolerance is currently a hot research topic in the field of military aviation.Many studies show that HBOP can affect the function of the autonomic nervous system by changing the heart rate variability of the human body during acute stress,to improving the orthostatic tolerance of the human body.We hypothes that HBOP can be used as an effective measurement to improve the acceleration tolerance of pilots,so we designed this experiment to determine LBNP tolerance of pilots before and after HBOP,to exploring whether the HBOP can improve the pilot’s LBNP tolerance,effectively improving the anti-invasive endurance during acute stress,thereby improving the pilot’s acceleration endurance.Methods: subjects were 20 pilots under physical examination for modifications to equipment of fighter aircrafts.The aircraft type is J-7,the flight time is(577.80 + 272.98)h,the age is(26.30 + 2.89)years,the height is(174.65 + 3.82)cm,and the body weight is(72.43 + 4.40)Kg.They have no bad hobby,no history of cardiopulmonary diseases.Each subject finished twice of LBNP tolerance test,one testin is the basic state once for LBNP tolerance(i.e.enter the chamber before oxygen,the control group),another is the LBNP tolerance of subjects 3 days after of the oxygen chamber,(i.e.enter the chamber after oxygen,experimental group).The LBNP tolerance test process of is as follows: Adopt the Lightfood step up plan:-20 mm Hg/1min,-30 mm Hg/3min,-40 mm Hg/5min,-50 mm Hg/7min,-60 mm Hg/9min,-70 mm Hg/11 min,-80 mm Hg/13 min,-90 mm Hg/15 min.During the examination,we need to closely observe the physical signs and inquire subjective feelings.When the endurance endpoint signs appear,we should quickly remove the negative pressure in the LBNP instrument and terminate the experiment.Indications of endurance end point: A sudden drop of blood pressure to below 90/60 mm Hg;the heart rate suddenly dropped 15,or less than 60 beats per minute;Ear pulse flattened;complains of flustered,chest tightness,nausea,dizziness,binocular blackening,etc.Or lip and face turn pale,cold sweat and other signs;HBOP by multiple person and thrice hyperbaric oxygen inhalation method.After entering the chamber,the air increased gradually to 2.5ATA in 10 min and the pressure will sustain for up to 65min(wearing the mask to inhale pure oxygen for twice of 30 min,with a rest of 5min between then,).Then,it was reduced gradually to 1.3ATA in 10 min,then keep at this pressure for 5min,then continue to decompress in 5 min,and ending the test.One treatment last a total 95 min,once a day(fixed at 15:30~17:05 p.m.oxygen inhalation),in consecutive three days.Results: The heart ra、te blood pressure、blood satuation of subject before and after pretreatment with hyperbaric oxygen were not statistically significant(P > 0.05);After three times of HBOP,the LBNP tolerance of the subjects increased significantly.The cumulative stress index increased significantly before treatment is(-1353.50 + 449.95),while after it was(-1843.5 + 522.07),it increased significantly after inhaled oxygen(P<0.05).Conclusion: Hyperbaric oxygen preconditioning can improve the tolerance of the pilot’s LBNP and improve acceleration tolerance of pilot’s. |
