Environmental safety: Air pollution while using MIRUS™ for short-term sedation in the ICU

MIRUS™ is a device for target-controlled inhalational sedation in the ICU in combination with use of isoflurane, or sevoflurane, or desflurane. The feasibility of this device has recently been proven; however, ICU staff exposure may restrict its application. We investigated ICU ambient room pollution during daily work to estimate ICU personnel exposure while using MIRUS™.

This observational study assessed pollution levels around 15 adult surgical patients who received volatile anaesthetics-based sedation for a median of 11 hours. Measurements were performed by photoacoustic gas monitoring in real-time at different positions near the patient and in the personnel's breathing zone. Additionally, the impact of the Clean Air™ open reservoir scavenging system on volatile agent pollution was evaluated.

Baseline concentrations [ppm] during intervention and rest periods were isoflurane $$ = 0.58 ± 0.49, $$ = 5.72; sevoflurane $$ = 0.22 ± 0.20, $$ = 7.93; and desflurane $$ = 0.65 ± 0.57, $$ = 6.65. Refilling MIRUS™ with liquid anaesthetic yielded gas concentrations of $$ = 2.18 ± 1.48 ppm and $$ = 13.03 ± 9.37 ppm in the personnel's breathing zone. Air pollution in the patient's room was approximately five times higher without a scavenging system.

Ambient room pollution was minimal in most cases, and the measured values were within or below the recommended exposure limits. Caution should be taken during refilling of the MIRUS™ system, as this was accompanied by higher pollution levels. The combined use of air-conditioning and gas scavenging systems is strongly recommended.