Analysis Of The Factors Affecting Cerebroyascular Reactivity Of Pilots

Objective:To investigate influencing factors of the cerebrovascular reactivity of pilots.Methods: The pilots breath-holding index(BHI) of the middle cerebral arteries wereexamined with transcranial doppler(TCD). The hypercapnia of pilots were produced withbreath-holding, cerebrovascular reactivity(CVR) represented by BHI. The following dataof pilots were obtained:pilot’s age, blood glucose, serum triglycerides and totalcholesterol, serum low-density lipoprotein，red blood cell count, hemoglobin detectionvalue, systolic blood pressure, diastolic blood pressure, time of flight, type of aircraft,smoking history. Taking these data as independent variables, taking breath-holding indexas the dependent variable. The data were subjected to multiple stepwise linear regressionanalysis using SPSS13.0software.According to the Statistics (multiple stepwise linear regression) results, The pilots（basisfor smoking status）were divided into the smoking group and non-smoking group.According to the aircraft types were divided into the fighter airplane group and thehelicopter and transporter group. Their BHI, increased percentage of systolic velocity（Vs）and diastolic velocity(Vd), decreased percentage of pulsitility index(PI) andresistance index(RI) were calculated and compared between two groups using t-testmethod of SPSS13.0statistical software, respectively.The BHI was were calculated and compared between non-smoking group and control group using t-test method of SPSS13.0statistical software.Results: multiple stepwise linear regression analysis of variance showed that there wasstatistically significant between smoking and type of aircraft impact of the BHI（F=5.25、4.75，P=0.02、0.01）. A negative correlation was significant between smoking and BHI,Partial regression coefficient is﹣0.17（t=﹣2.14，P=0.04），and a significantly positivecorrelation was also found between type of aircraft and BHI, Partial regression coefficientis0.16（t=2.01，P=0.05）. There was no significant effect on the other factors of BHI（P＞0.10）.BHI of Smoking pilots and non-smoking pilots were1.00±0.40and1.20±0.34(t value2.19, P value0.03) respectively. The BHI was significantly worse in Smoking pilots thanin Non-smoking pilots(P <0.05). There was no significant difference in increasedpercentage of systolic velocity（Vs）and diastolic velocity(Vd), decreased percentage ofpulsitility index(PI) and resistance index(RI) between smoking and non-smoking pilots(tvalue0.60，0.57,﹣0.48,﹣0.19, respectively. P value0.03,0.55,0.57,0.64,0.85,respectively).BHI of fighter airplane group and the helicopter/transporter group were1.21±0.38，0.98±0.35, t value2.19respectively. The BHI was significantly better in fighter airplanepilots than in helicopter/transporter pilots(P <0.05). There was significant difference inincreased percentage of systolic velocity（Vs）and diastolic velocity(Vd), decreasedpercentage of pulsitility index(PI) and resistance index(RI) between fighter airplane pilotsand helicopter/transporter group(t value﹣4.10,﹣4.04，2.11，2.64, respectively. Pvalue0.00,0.00，0.04,0.01，respectively).BHI of non-smoking pilots and control group were1.20±0.34and1.19±0.38，T-testmethod of SPSS13.0statistical software showed that there was no statistically significant between non-smoking pilots and control group of the BHI.Conclusion: The breath-holding method with transcranial doppler offers as a convenient,well-tolerated screening method of assessing cerebrovascular reactivity.It can be used forthe selection and identification of the health of pilots. Smoking and type of aircraftinfluencing of the cerebrovascular reactivity of pilots. Smoking can decrease the CVR ofpilots. Fighter airplane pilots CVR is better than helicopter and transporter pilots.Cerebrovascular reactivity is no significant difference between active pilots and healthyground personnel.