Sevoflurane sedation in COVID-19 acute respiratory distress syndrome: an observational study with a propensity score matching model (preprint)

ABSTRACT

Background: Patients that are affected by severe induced respiratory failure (C-ARDS) formCOVID-19, frequently need deep sedation in order to perform adequate ventilator support. Volatile anesthetics (VAs) constitute a convenient alternative to intravenous molecules, allowing to fine-tune the desired level of sedation. Moreover, VAs might have anti-inflammatory and bronchodilatatory effects, which are particularly appropriate for COVID-19 patients. Methods: In this study, we show the results of a retrospective single-center non-profit observational cohort study. To achieve this, we enrolled patients hospitalized for C-ARDS in the COVID Intensive Care Unit of Hospital Santo Stefano (Prato, Italy) during the period March 2020 - June 2021. A total of 112 patients were enrolled in the study that were all submitted to invasive mechanical ventilation. Participants were divided in two groups i) Group 1 received the VA sevoflurane and, ii) Group 2 were sedated with propofol and remifentanil. A propensity score matching model (PSM) was applied in order match each treated unit with a non-treated unit of similar characteristics between the two groups. The calculation of PSM was performed considering anthropometric data such as age, sex, body mass index (BMI) and comorbidities such as arterial hypertension, chronic obstructive pulmonary disease (COPD), ischemic heart disease, and chronic kidney damage as covariates. Level of sedation (BIS monitoring), respiratory and ventilator parameters, i.e., PaO2/FiO2, pulmonary static compliance and positive end expiratory pressure (PEEP) and biochemical parameters were evaluated at three time-points at the time of the invasive ventilation (T1), after 72 hours (T2) and after 7 days (T3). Results: 56 patients who received inhaled sedation with sevoflurane were matched with 56 participants receiving an intravenous sedation by means of PSM. An adequate level of sedation was obtained in both groups. In the sevoflurane group, an increase of PaO2/FiO2 and of the static compliance was observed while mortality was slightly decreased. Conclusions: In this work, we demonstrate that deep sedation of invasively ventilated C-ARDS patients can be effectively obtained with sevoflurane. Interestingly, VA sedation with sevoflurane contributed to enhance respiratory mechanics, which has a clear clinical relevance in C-ARDS patients. In terms of pulmonary compliance, results obtained after three days of starting sedation therapy with sevoflurane demonstrated that static compliance was higher in those who received inhaled sedation. At the same timing, PaO2/FiO2 ratio at the same timing was greater in group 1 than in group 2. Further studies deem to confirm the potential of this treatment in a randomized clinical trial.