Inhalational sedation during transport to the intensive care unit

Introduction

Inhalational ICU sedation is increasingly applied since the introduction of AnaConDa^® (Sedana Medical, Sweden). This anaesthetic-conserving device (ACD) retains exhaled sevofluorane (SEV) and resupplies it during inspiration [1]. A syringe pump delivers liquid SEV into the device. Since January 2004 we have used the ACD as a standard practice. Our patients anaesthetised with SEV in the OR and scheduled for ICU sedation with SEV only need propofol on transport. Could this be avoided when using the ACD during transport?

Methods

Forty-one patients after major abdominal surgery were included in this quality assurance project. In 20 patients the ACD was inserted into the anaesthesia circuit to take up warmth, humidity and SEV for 15 minutes and used for transport. SEV infusion was started in the ICU after gas monitoring. Twenty-one patients scheduled for propofol sedation served as controls. During transport all patients were ventilated with Oxylog2000 (Dräger, Germany), vital parameters were monitored, and the Ramsay Score (RS) was assessed at five time points. If necessary, propofol injections of 0.5 mg/kg were given. Statistics were t test for parametric data (mean ± standard deviation), U test for nonparametric data (median (interquartile range)), SPSS 11.04.

Results

The age, weight, duration of anaesthesia (ACD/controls 7.3 ± 2.0/6.3 ± 2.2 hours), total sufentanil (124 ± 75/118 ± 57 μg) and transport time (16.3 ± 2.7/17.0 ± 2.7 min) were not different between groups, and neither were heart rates, mean arterial pressures and RS at five time points during transport. ACD patients needed less propofol injections (0 (0–1)/3 (2–4), P < 0.001) and reached the ICU with a similar RS (5 (4.5–5)/5 (4.75–5)). End-tidal SEV concentrations were similar in the OR (1.3 ± 0.2/1.2 ± 0.2 vol%), but different when arriving in the ICU (0.6 ± 0.2/0.2 ± 0.1 vol%, P < 0.001).

Conclusion

AnaConDa^® effectively retains SEV in patients and permits inhalational sedation during >15 minutes transport. Hemodynamic stability and depth of sedation are as good as the standard regime with Propofol. Less SEV exhaled by the patients during transport also means less contamination of the workplace.