Kumar K V, Calkins D S, Waligora J M, Gilbert J H, Powell M R
KRUG Life Sciences, Houston, TX 77058.
Aviat Space Environ Med. 1992 Nov;63(11):961-4.
This study investigated the association between time at onset of circulating microbubbles (CMB) and symptoms of altitude decompression sickness (DCS), using Cox proportional hazard regression models. The study population consisted of 125 individuals who participated in direct ascent, simulated extravehicular activities profiles. Using individual CMB status as a time-dependent variable, we found that the hazard for symptoms increased significantly (at the end of 180 min at altitude) in the presence of CMB (Hazard Ratio = 29.59; 95% confidence interval [95% CI] = 7.66-114.27), compared to no CMB. Further examination was conducted on the subgroup of individuals who developed microbubbles during the test (n = 49), by using Cox regression. Individuals with late onset of CMB (> 60 min at altitude) showed a significantly reduced risk of symptoms (hazard ratio = 0.92; 95% CI = 0.89-0.95), compared to those with early onset (< or = 60 min), while controlling for other risk factors. We conclude that time to detection of circulating microbubbles is an independent determinant of symptoms of DCS.
本研究使用Cox比例风险回归模型，调查了循环微泡（CMB）出现时间与高空减压病（DCS）症状之间的关联。研究对象包括125名参与直接上升、模拟舱外活动方案的个体。将个体CMB状态作为时间依赖变量，我们发现与无CMB相比，存在CMB时（海拔180分钟结束时）症状发生风险显著增加（风险比=29.59；95%置信区间[95%CI]=7.66 - 114.27）。通过使用Cox回归对测试期间出现微泡的个体亚组（n = 49）进行了进一步检查。在控制其他风险因素的情况下，与CMB出现较早（≤60分钟）的个体相比，CMB出现较晚（海拔>60分钟）的个体症状风险显著降低（风险比=0.92；95%CI = 0.89 - 0.95）。我们得出结论，检测到循环微泡的时间是DCS症状的一个独立决定因素。
