Abstract:

Ｏｂｊｅｃｔｉｖｅ： To explore the value of bioimpedance analysis （BIA） in assessment of predicting prognosis.
Ｍｅｔｈｏｄｏｌｏｇｙ：Two hundred and one patients in the intensive care units of our hospital were voluntarily enrolled.They were assessed using a device QuadScan 4000 for measurement of BIA,as well as by Acute Physiology and Chronic Health Evaluation Ⅱ(APACHE Ⅱ),Simplified Acute Physiology Score Ⅱ(SAPS Ⅱ) and Sequential Organ Failure Assessment(SOFA).The association between clinical conditions,outcomes and BIA parameters were analyzed.
Ｒｅｓｕｌｔｓ：Among 201 enrolled patients,the 90day mortality was 358%.The relationship of individual bioimpedance values and the current frequencies was in good fitting of nature lograrithmic function,with a regression coefficient S value.Other parameters obtained from BIA included phase angle(PA),ratio of bioimpedance in high frequency and in low frequency(IR),and extracellular water (ECW), intracellular water (ICW) and  total body water (TBW).Compared to the survivors in 7day,the IR,S value,ratio of ECW/weight,and ratio of ECW/TBW were higher while the PA were lower in the dead (P<005).Compared to the survivors in 90day,the IR,S value and ratio of ECW/weight were higher while the PA were lower in the dead (P<005).Multinomial logistic regression analysis showed that,only SAPS Ⅱ and S value were the independent risk factors for 7day and 90day death(P＜001).Analyzed by ROC,the AUC of S value for predicting 90day death was nonsignificantly lower than SAPS Ⅱ(S vsSAPS Ⅱ,0701 vs 0779，P＞005).Importantly,both the 7day and the 90day mortality in patients with S value ≤-255 were 0,and for the others，the mortality was in linear correlation with S value; while for patients with SAPS Ⅱ≤33,the mortality remained little varied,for patients with SAPS Ⅱ 33～55,the mortality increased with the score of SAPS Ⅱ,and for patients with SAPS Ⅱ>55,the mortality was 100%.
Ｃｏｎｃｌｕｓｉｏｎ：
The S value and SAPS Ⅱ are independent risk factors for 7day and 90day death in critically ill patients,the former is better to predict survivor while the latter is better to predict nonsurvivor.