Longitudinal Monitoring of Physiological Variables during Mechanical Ventilation and Weaning in Intensive Care

Abstract

Mechanical Ventilation (MV) is used with 40% of intensive care unit (ICU) patients to assist breathing (1,2). A deleterious effect of MV includes rapid (i.e., within 18-69 hours) atrophy of the diaphragm muscle, which compromises the ability of patients to breathe independently (3). These patients have lower indices of weaning success and higher mortality (4–6). A previous study monitored physiological data during liberation procedures called spontaneous breathing trials (SBTs) and identified variables predictive of weaning success (7). However, that study was limited by its brief monitoring period and small sample size. Overall, a relative dearth exists of studies that compare ventilated patients who pass and fail SBT. The purpose of this study is to describe the trends in physiological variables during MV and SBTs. We are conducting a retrospective, secondary analysis of data collected from 37 ICU patients, all of whom were ventilated for greater than 48 hours. Of those, 27 passed an SBT, 5 failed, and 5 did not undergo an SBT. Descriptive statistics and data visualizations will be computed in R. Of the 17 variables that were measured, we expect to see consistent trends in blood pressure, heart rate, minute ventilation, end tidal carbon dioxide, and derived variables because of their responsiveness to physical stress. We will compare the trends in patients who passed an SBT to those who did not. This research will provide a foundation for future studies that seek to evaluate physiological predictors of weaning outcomes.