Lauren Kelly, MPH
Biostatistician I
Beth Israel Deaconess Medical Center
Disclosure information not submitted.
Lena Novack, PhD
Biostatistician
Beth Israel Deaconess Medical Center, United States
Disclosure information not submitted.
Valerie Banner-Goodspeed, MPH
Clinical Research Administrator
Beth Israel Deaconess Medical Center, United States
Disclosure information not submitted.
Somnath Bose, MD FASA
Assistant Professor of Anesthesia
n/a, United States
Disclosure information not submitted.
Title: Polypharmacy Mediates the Effect of Mechanical Ventilation on Incidence of Delirium
Introduction: Delirium in ICU is associated with poor outcomes. Delirium among critically ill COVID-19 patients is due at least in part to iatrogenic causes such as staffing constraints, restricted mobility, and polypharmacy stemming from drug shortages. The aim of this study was to describe the sedation practices and prevalence of delirium at a tertiary level academic medical center. We tested the hypothesis that polypharmacy (PP, use of > 4 classes of sedatives), is a mediator in the causal pathway of mechanical ventilation and delirium.
Methods: 212 patients admitted to ICUs at a tertiary level academic medical center in Boston, MA between Jan 2020 and April 2021 with a primary diagnosis of SARS-CoV2 were included.
Mediation analysis was conducted with bootstrap estimation to assess whether association between mechanical ventilation and incidence of delirium was mediated by PP. Analyses were adjusted for potential confounders found to be related to the treatment, mediator, and outcome, including age, gender, vasopressor use, median RASS scores, and maximum CRP levels.
Results: Of the 212 patients in the cohort, 72.6% had delirium during their ICU stay, 76.9% were mechanically ventilated, and 54.7% received > 4 classes of sedatives. The percentage of patients given Opioids, Benzodiazepines, Ketamine, Propofol, and Dexmedetomidine, were 81.1%, 60.4%, 40.6%, 75.9%, and 54.3%, respectively. Adjusting for potential confounders, patients given > 4 classes of sedatives had 7.4 (95% CI: 2.5 – 22.4) times the odds of developing delirium compared to those given < 4. Mechanically ventilated patients had 4.9 (95% CI: 1.6 – 15.2) times the odds of developing delirium compared to patients not mechanically ventilated. Approximately 42.1% (95% CI: 39.8 – 50.6) of the mechanical ventilation effect is attributed to the mediation of PP.
Conclusion: Mechanical ventilation is associated with higher risk of delirium and PP mediates > 40% of this effect which is clinically and statistically significant. Prospective studies should explore whether limiting PP among mechanically ventilated patients could reduce delirium.