Inhalative sedation with small tidal volumes under venovenous ECMO

Area of Science:

• Critical Care Medicine
• Anesthesiology
• Pulmonology

Background:

• Inhalative sedation is an emerging technique for long-term sedation in intensive care.
• Its use in patients with compromised lung function, particularly those on venovenous extracorporeal membrane oxygenation (vv-ECMO), is not well understood.
• This study investigates inhalative sedation in patients with lung failure requiring vv-ECMO.

Purpose of the Study:

• To evaluate the feasibility and effectiveness of inhalative isoflurane sedation in patients with lung failure supported by vv-ECMO.
• To determine the relationship between isoflurane concentration and sedation depth in this patient population.

Main Methods:

• Retrospective analysis of 7 patients receiving vv-ECMO and inhalative isoflurane sedation in a surgical ICU.
• Isoflurane administered via the AnaConDa®-system.
• Sedation assessed using the Richmond Agitation and Sedation Scale (RASS).

Main Results:

• A median of 7 patients (age 50 years, all male) were identified.
• Median ECMO runtime was 129 hours with a survival rate of 57.9%.
• Higher isoflurane concentrations (inspiratory and expiratory) were significantly associated with increased sedation depth (p<0.05).

Conclusions:

• This is the first study demonstrating an association between inhalative isoflurane concentrations and sedation depth in lung failure patients on vv-ECMO.
• Targeted sedation using volatile anesthetics is feasible despite significant lung impairment.
• A dose-response relationship between isoflurane and sedation depth appears to exist.