Routine delirium monitoring is independently associated with a reduction of hospital mortality in critically ill surgical patients: A prospective, observational cohort study

Abstract Purpose Although delirium monitoring is recommended in international guidelines, there is lacking evidence for improved outcome due to it. We hypothesized that adherence to routine delirium monitoring would improve clinical outcome in adult critically ill patients. Material and Methods We present the results of a prospective, non-interventional, observational cohort study that was conducted on two ICUs of a tertiary care medical centre between July and October 2007 (ISRCTN-identifier: 76,100,795). We assessed delirium monitoring and outcome parameters on a daily basis. Besides multivariate logistic and robust linear regression to analyze the relationship between delirium monitoring and outcome, we used the doubly-robust augmented inverse-probability-weight method for observational data to estimate effect sizes. Results Of 355 screened patients, we included 185 surgical ICU-patients into our final analysis of which 87 were mechanically ventilated. We found an independent association between delirium monitoring adherence and in-hospital mortality for ventilated patients (OR 0.973, p = 0.041). Estimating the effect-size, delirium monitoring indicated a reduction of 22% of in-hospital mortality if conducted ≥ 50% of ICU-days per patient. The average ICU length of stay of 46 days was estimated to be reduced by 19 days (p = 0.031) if patients were sufficiently monitored. Conclusion Our data suggest an improved outcome for mechanically ventilated patients being screened for delirium in clinical routine.