Sevoflurane in combination with esketamine is an effective sedation regimen in COVID-19 patients enabling assisted spontaneous breathing even during prone positioning

Background
Effective analgosedation for control of dyspnoea and for toleration of prone positioning (PP) in severe coronavirus disease 2019 (COVID-19) associated acute respiratory distress syndrome (ARDS) is difficult to adjust. This study was designed to evaluate the feasibility and safety of sedation with inhaled sevoflurane in combination with intravenous esketamine during PP in patients with COVID-19-ARDS (CARDS).

Methods
All mechanically ventilated COVID-19 patients admitted to the departmental intensive care unit from March to June 2020 were included in this epidemiological cohort study. Patients were sedated with inhaled sevoflurane in combination with eske­tamine during PP and not or only lightly sedated during the supine position. Assisted spontaneous breathing was applied in both prone and supine position.

Results
Adverse events were documented prospectively, and routine ventilation parameters, hemodynamic parameters, Richmond Agitation and Sedation Scale (RASS) and sevoflurane consumption were monitored. Altogether, 146 episodes of PP in 15 patients were observed. No severe sedation-related event was observed during 2610 hours of PP. In 2498 hours (96%) patients were successfully converted to a pressure-supported spontaneous breathing mode.

Conclusions
Inhaled sedation with the AnaConDa-S-System (Sedana Medical AB, Danderyd, Sweden) alone is insufficient as soon as minute volume exceeds 7–8 L min–1, most likely due to technical reasons. Inhaled sedation with sevoflurane in combination with esketamine, however, safely enables prolonged prone positioning in patients with CARDS. Moreover, sedation depth was light enough to enable assisted spontaneous breathing during prone positioning.