Predicting Time to Death after Terminal Withdrawal of Mechanical Ventilation

Abstract

Discussions about withdrawal of life-sustaining therapies often include family members of critically ill patients. These conversations should address essential components of the dying process, including expected time to death after withdrawal. Identification of predictors of time to death after terminal withdrawal of mechanical ventilation may aid physician communication about the dying process. We conducted an observational analysis from a single-center, before-after evaluation of an intervention to improve end-of-life care. We studied 330 patients who died after terminal withdrawal of mechanical ventilation. Predictors included patient demographics, laboratory variables, respiratory variables, physiologic variables, and medication use. The median (IQR) time to death for the entire cohort was 0.58 hours (0.22-2.25 hours) after withdrawal of mechanical ventilation. Using Cox regression, independent predictors of shorter time to death included positive end-expiratory pressure (per-1 cm H2O increase hazard ratio [HR], 1.07; 95% CI, 1.04-1.11), static pressure (per-1 cm H2O HR, 1.02; 95% CI 1.01-1.04), male sex (HR, 1.28; 95% CI 1.00-1.65), and presence of diabetes (HR, 1.57; 95% CI 1.14-2.18). Non-invasive mean arterial pressure predicted longer time to death (per-1 mmHg HR, 0.98; 95% CI 0.97-0.99). Patient sex, comorbid illness, and physiologic parameters may inform physician predictions of time to death after withdrawal and facilitate communication with family members of dying patients.