Independent determinants of early death in critically ill surgical patients

Abnormalities in cardiocirculatory, respiratory, or coagulatory parameters are frequent after major surgery, but so far, no study has investigated their predictive value for early intensive care unit (ICU) mortality. We aimed to describe and quantify the relation between these parameters that are routinely determined on ICU admission and early death after complex surgery. Individual patient data were available from a local ICU database. We performed a retrospective observational cohort study using prospectively collected data from March 1, 1993, through February 28, 2005. A cohort of 4,214 cases who were admitted to the ICU immediately after operation was analyzed. We studied age, sex, number of red blood cell units transfused on admission day, and admission values for heart rate, systolic blood pressure, hemoglobin concentration, partial thromboplastin time, prothrombin time, respiratory function (Pao2/Fio2 ratio), and body temperature for their association with 4-day mortality. Effects were adjusted for the underlying disease and for disease severity during the first 24 h after admission. We used generalized additive models to fit continuous variables individually before combining them into the final generalized model. We found an independent linear association between the number of transfused red blood cell units, partial thromboplastin time, and body temperature with acute outcome. A smoothed model described the independent interaction between admission blood pressure and early death. Only values of less than 80 mmHg were associated with an increased risk of 4-day mortality. According to these results, bleeding complications after ICU admission should be treated aggressively to prevent early death of the patient. However, normotensive conditions do not seem to be required to prevent early mortality. Whether rapid rewarming may improve outcome needs further rigorous study.