The Influence Of Hypoxygen Environment On The Sleepness Of The Crew Of Qinghai-Xizang Railway

Objective:This study aimed to investigate the condition of sleepness and the chang of hematology at high altitude of the crew of Qinghai-Xizang railway who go through plain to plateau at the first time.We also discuss the relationship between sleepness disorder and acute mountain sickness further.Thirty healthy volunteers were faculties of Beijing Railway Bureau,18 to 35 years old,BMI(body mass index)≤25kg/m~2,all born in Beijing,no experience of living at plateau and no drug or drinking.The woking period includes 120 hours through Peking to Lasa(72 hours at plateau continuously,including 12 hours staying at Lasa) and they rest at Peking for 120 hours.Methods:Thirty subjects underwent polysomnographic studies including sleep electroencephalogram and eye movement gram,ECG,breathing from mouth and nose,abdominal and thoracic respiration,ETCO2 and oxygen saturation(SaO2).They were also checked with index of haematology and asked to fill with the Lake Lusious score of acute mountain sickness. After 2 month(6 working period) they fill with the Pittsburgh Sleep Quality Index,PSQI and evaluate the effect of working at plateau intermittently on sleep quality.Result:The thirty subjects all have sleep disorder at plateau mainly in sleep structure(stageⅠandⅡof NREM are increasing,stageⅢandⅣof NREM are decreasing,REM sleep is decreasing,5 have no REM sleep). They all have periodic breathing(PB) in different degree,increasing arousal index(AI),significantly decreasing oxygen saturation(SO2) and increasing desaturation index(DI).Apnoea/hypopnoea index(AHI) of 23 sujects is higher than 10,AHI of 14 subjects is higher than 20,18 subjects is central sleep apnoea,5 is central sleep apnoea and hypopnoea.The results at plateau are significantly different from at plain.2.ETC02 at plateau is significantly lower than at plain.3.HB,RBC,HCT and EPO at plateau are significantly higher than at plain.4.PB,AI,AHI,DI have obviously positive relation with AMS,negative relation with SaO2,ETCO2 and no relation with sleep struction.Multiple stepwise regression showed that only AI,SO2 significantly correlated with AMS.The stepwise regression equation is Y=66.494-0.741SO2+0.112AI We divided 30 subjects into 2 groups.One is AHI≥20 group(14 subjects), the other is AHI＜20 group(16 subjects).The sleep structure of the two groups have no difference,but SO2 is lower and AI is higher in AHI≥20 group.The SO2 and AI in AHI≥20 group are significantly different from the results in AHI＜20 group,the Lake Lusious score in AHI≥20 group are significantly higher than AHI＜20 group.HB,RBC,HCT and EPO in AHI≥20 group are also significantly higher than AHI＜20 group.Conclusion:1.the faculties of Qinghai-Xizang railway who go through to plain to plateau have sleep disorder and lower SO2 at night at plateau,sleep quality is decreasing.SO2 and AI are related to acute mountain sickness.2.The serious is the sleep disorder,the obvious is the change of hematology,HB.RBC.HCT.EPO are all increasing.capacity.This is the aim we should work further at it.