Evaluation and Prediction of Orthostatic Tolerance Related to Gravity Re-adaptation

Liu Zhaoxia; Wu Dawei; Huang Weifen; Wu Bin; Li Zhili; Chen Zhanghuang; Zhong Chongfa; Li Yinghui

doi:10.16289/j.cnki.1002-0837.2018.02.015

Abstract：Objective To develop a safe method for early evaluation of orthostatic tolerance soon after re-exposure to gravity and to construct a prediction model for orthostatic tolerance during gravity re-adaption. Methods Fifteen male volunteers performed 20 min passive orthostatic tolerance test. The results were rescored based on the 3 min, 5 min and 10 min data with original standard. Threshold was redefined by ROC method, and orthostatic tolerance grade was reclassified. Leave one out cross validation was used to confirm the consistency of the reclassification results with the original one. Prediction model was constructed on head down bed rest test data of 15 male volunteers based on Bayes principle. After leave one out cross validation, the prediction model was further verified by spaceflight data. Results The area under the ROC curve for the 3 min test was 0.944, the area of 5 min and 10 min were both 1.00. Five prediction characteristic variables and its likelihood ratio were established based on the bed rest test data. The result of leave one out cross validation showed that the area under the ROC curve was 0.75. The result of 4 spaceflight data showed that the area under the ROC curve was 1, and the orthostatic tolerance during re-adaptation gravity was effectively predicted. Conclusions The grading results of 3 min, 5 min, and 10 min passive orthostatic tolerance test with new evaluation method was consistent with the 20 min original one. The orthostatic tolerance prediction model showed a good prediction ability.