Effect of Step-altitude Acclimatization on Prevention of Acute Severe Altitude Sickness in Construction of Qinghai-Tibet Railway

[Objective]To understand the effect of step-altitude acclimatization on prevention of acute severe altitude sickness (high altitude pulmonary edema and high altitude cerebral edema).[Methods]From mid-March to mid-October 2003,the incidence of acute severe high altitude disease among 22,200 workers in the construction of Qinghai-Tibet Railway of Tibet section (Tanggula pass to Lhasa of Tibet) were investigated. The incidence of people with different forms into plateau was compared,The incidence of people with ladder mode into the plateau was analyzed.[Results]During 7 months in 2003,a total of 22 200 workers accessed to Tibet section of Qinghai-Tibet Railway;184 cases of high altitude pulmonary edema occurred (180male cases,4 female cases,aged 20～45 years),and 155 cases of high altitude cerebral edema (all male cases,aged 22~44 years). The incidence was 0.83% and 0.70%,respectively. Compared workers with step-altitude acclimatization with workers without acclimatization located in the same altitude,the incidence of the former was significantly lower than the latter.[Conclusion]The incidence of acute severe altitude sickness increases with the higher elevation. When large scale people entering plateau areas from plain,using the step-altitude acclimatization can effectively reduce the incidence of acute severe high altitude disease;and as for radical access to plateau by large crowds,the establishment of acclimatization station at an altitude of 2,500 meters,may be a better approach.