Volatile Isoflurane in Critically Ill Coronavirus Disease 2019 Patients-A Case Series and Systematic Review

Abstract

Objectives: The ongoing coronavirus pandemic is challenging, especially in severely affected patients who require intubation and sedation. Although the potential benefits of sedation with volatile anesthetics in coronavirus disease 2019 patients are currently being discussed, the use of isoflurane in patients with coronavirus disease 2019-induced acute respiratory distress syndrome has not yet been reported.

Design: We performed a retrospective analysis of critically ill patients with hypoxemic respiratory failure requiring mechanical ventilation.

Setting: The study was conducted with patients admitted between April 4 and May 15, 2020 to our ICU.

Patients: We included five patients who were previously diagnosed with severe acute respiratory syndrome coronavirus 2 infection.

Intervention: Even with high doses of several IV sedatives, the targeted level of sedation could not be achieved. Therefore, the sedation regimen was switched to inhalational isoflurane. Clinical data were recorded using a patient data management system. We recorded demographical data, laboratory results, ventilation variables, sedative dosages, sedation level, prone positioning, duration of volatile sedation and outcomes.

Measurements & main results: Mean age (four men, one women) was 53.0 (± 12.7) years. The mean duration of isoflurane sedation was 103.2 (± 66.2) hours. Our data demonstrate a substantial improvement in the oxygenation ratio when using isoflurane sedation. Deep sedation as assessed by the Richmond Agitation and Sedation Scale was rapidly and closely controlled in all patients, and the subsequent discontinuation of IV sedation was possible within the first 30 minutes. No adverse events were detected.

Conclusions: Our findings demonstrate the feasibility of isoflurane sedation in five patients suffering from severe coronavirus disease 2019 infection. Volatile isoflurane was able to achieve the required deep sedation and reduced the need for IV sedation.

Keywords: acute respiratory distress syndrome; coronavirus disease 2019; critical care; deep sedation; severe acute respiratory syndrome coronavirus 2; volatile sedation.

Figure 1.

Oxygenation ratio, carbon dioxide, and hemodynamics during inhalation sedation with isoflurane over time. Oxygenation ratio, carbon dioxide and hemodynamics during inhalation sedation with isoflurane over time. The figure shows results of (A) oxygenation ratio, (B) Paco₂, (C) mean arterial blood pressure, and (D) heart rate over time. Data are presented as median. After termination of isoflurane = data after termination of isoflurane were collected in the first 30 min after the change of volatile to IV sedation, Baseline prior to isoflurane = data collected in the last 30 min before initiation of volatile sedation, day 1 = data were collected at 4 am on the first day after initiation of isoflurane treatment, kPa = pressure in kilopascals, min^–1 = per minute, mm Hg= millimeters mercury, Pao₂ Fio₂^–1 = oxygenation level as quotient of Pao₂ and Fio₂.