Survival after long-term isoflurane sedation as opposed to intravenous sedation in critically ill surgical patients: Retrospective analysis.

BACKGROUND: Isoflurane has shown better control of intensive care sedation than propofol or midazolam and seems to be a useful alternative. However, its effect on survival remains unclear.

OBJECTIVE: The objective of this study is to compare mortality after sedation with either isoflurane or propofol/midazolam.

DESIGN: A retrospective analysis of data in a hospital database for a cohort of consecutive patients.

SETTING: Sixteen-bed interdisciplinary surgical ICU of a German university hospital.

PATIENTS: Consecutive cohort of 369 critically ill surgical patients defined within the database of the hospital information system. All patients were continuously ventilated and sedated for more than 96 h between 1 January 2005 and 31 December 2010. After excluding 169 patients (93 >79 years old, 10 <40 years old, 46 mixed sedation, 20 lost to follow-up), 200 patients were studied, 72 after isoflurane and 128 after propofol/midazolam.

INTERVENTIONS: Sedation with isoflurane using the AnaConDa system compared with intravenous sedation with propofol or midazolam.

MAIN OUTCOME MEASURES: Hospital mortality (primary) and 365-day mortality (secondary) were compared with the Kaplan-Meier analysis and a log-rank test. Adjusted odds ratios (ORs) [with 95% confidence interval (95% CI)] were calculated by logistic regression analyses to determine the risk of death after isoflurane sedation.

RESULTS: After sedation with isoflurane, the in-hospital mortality and 365-day mortality were significantly lower than after propofol/midazolam sedation: 40 versus 63% (P = 0.005) and 50 versus 70% (P = 0.013), respectively. After adjustment for potential confounders (coronary heart disease, chronic obstructive pulmonary disease, acute renal failure, creatinine, age and Simplified Acute Physiology Score II), patients after isoflurane were at a lower risk of death during their hospital stay (OR 0.35; 95% CI 0.18 to 0.68, P = 0.002) and within the first 365 days (OR 0.41; 95% CI 0.21 to 0.81, P = 0.010).

CONCLUSION: Compared with propofol/midazolam sedation, long-term sedation with isoflurane seems to be well tolerated in this group of critically ill patients after surgery.