Early catecholamine dose as a predictor of outcome among patients in a multidisciplinary intensive care unit

Background. Vasoactive and/or inotropic agents are used in the management of patients with circulatory shock. It is a clinical perception that mortality in critically ill patients increases with increasing doses of inotropes and/or vasopressors; however, the clinical significance of catecholamine doses early in the management of critically ill patients has not been investigated well, especially in the South African (SA) context. Arbitrary "maximum" doses of catecholamine therapy are used that are not evidence based. This study will help clinicians by either showing that there is no clear cut-off beyond which survival is unlikely or by identifying a dose of inotropic support above which survival is unlikely. This article provides clinicians with an evidence base against which to direct their therapy. Objectives. To describe the inotropic prescribing practices in a heterogeneous population of shocked critically ill patients in a tertiary intensive care unit (ICU) in SA, establish an association between inotropic dose and outcome and ascertain the nature of this association. Methods. This was a retrospective observational study of 189 patients admitted to a multidisciplinary academic ICU. The admission, 24-hour and maximum inotrope doses were collected and analysed, and these and other biochemical and clinical parameters were evaluated as predictors of mortality. Results. A total of 189 patients met the study inclusion criteria. The overwhelming majority of patients (99%) received adrenaline, with only 7% of those requiring inotropes receiving noradrenaline. Median inotrope dose at admission, 24-hour dose and maximum dose in the first 24 hours were all significantly higher in non-survivors than survivors. ICU mortality increased with increasing inotrope dose, and an inotrope dose >= 60 mu g/min on admission was associated with an ICU mortality of 89%, with the same cut-off at 24 hours being associated with a mortality of 89%. Survivors at doses >80 mu g/min were only noted among trauma patients. Conclusions. High early inotrope doses are associated with increasing ICU mortality. The findings highlight the need for further research on the clinical use of inotrope dose in risk stratification in the critical care environment. The current results call into question the routine provision of high-dose inotropic support in non-trauma patients.