Observational study of the effect of ketamine infusions on sedation depth, inflammation, and clinical outcomes in mechanically ventilated patients with SARS-CoV-2

Abstract

Severely ill patients with COVID-19 are challenging to sedate and often require high-dose sedation and analgesic regimens. Ketamine can be an effective adjunct to facilitate sedation of critically ill patients but its effects on sedation level and inflammation in COVID-19 patients have not been studied. This retrospective, observational cohort study evaluated the effect of ketamine infusions on inflammatory biomarkers and clinical outcomes in mechanically ventilated patients with SARS-CoV-2 infection. A total of 186 patients were identified (47 received ketamine, 139 did not). Patients who received ketamine were significantly younger than those who did not (mean (standard deviation) 59.2 (14.2) years versus 66.3 (14.4) years; P = 0.004), but there was no statistically significant difference in body mass index ( P = 0.25) or sex distribution ( P = 0.91) between groups. Mechanically ventilated patients who received ketamine infusions had a statistically significant reduction in Richmond Agitation-Sedation Scale score (–3.0 versus –2.0, P < 0.001). Regarding inflammatory biomarkers, ketamine was associated with a reduction in ferritin ( P = 0.02) and lactate ( P = 0.01), but no such association was observed for C-reactive protein ( P = 0.27), lactate dehydrogenase ( P = 0.64) or interleukin-6 ( P = 0.87). No significant association was observed between ketamine administration and mortality (odds ratio 0.971; 95% confidence interval 0.501 to 1.882; P = 0.93). Ketamine infusion was associated with improved sedation depth in mechanically ventilated COVID-19 patients and provided a modest anti-inflammatory benefit but did not confer benefit with respect to mortality or intensive care unit length of stay.