Association Between Timing of Out-of-Bed Mobilization and Functional Outcomes at Intensive Care Unit Discharge in Patients With COVID-19: An Analysis of Potential Clinical Reference Points

Importance In patients who are critically ill, functional dependence and muscle weakness may be influenced by side effects related to the timing of out-of-bed mobilization, but there is a knowledge gap regarding the impact of exercise prescriptions in specific intensive care unit (ICU) populations. Objective The objective of this study was to determine clinical reference values for the time to start out-of-bed mobilization of patients in the ICU with to avoid functional dependence and muscle weakness at ICU discharge. Design This study was a secondary analysis of a prospective multicenter cohort. Setting The settings were the ICUs of 5 Brazilian hospitals. Participants The participants were adult patients with COVID-19, an ICU stay of ≥4 days, and prior functional independence. Exposure Time for out-of-bed mobilization was the first day the patient was mobilized to higher postures, provided there were no contraindications. Main outcomes and measures Functional status (Barthel Index [BI]) and muscle strength (Medical Research Council Scale [MRC]) were assessed within 2 days of ICU discharge. Receiver operating characteristic analysis identified clinical thresholds for days to initiate out-of-bed mobilization in association with 2 levels of functional dependence and muscle weakness. Optimal cutoffs were based on sensitivity, specificity, and area under the curve (AUC). Results A total of 339 patients (58 years old [SD = 46–66 years old]; Simplified Acute Physiology Score III = 51.3 [SD = 16.5]; 36% women; 53% on mechanical ventilation) were analyzed. Days to start out-of-bed mobilization for each outcome were as follows: 3 days for a BI of <85 points (sensitivity = 67%, specificity = 65%, AUC = 0.68 [95% CI = 0.63–0.74]); 4 days for a BI of <60 points (sensitivity = 60%, specificity = 65%, AUC = 0.66 [95% CI = 0.59–0.73]); 5 days for an MRC score of <48 points (sensitivity = 54%, specificity = 73%, AUC = 0.66 [95% CI = 0.59–0.73]); and 5 days for an MRC score of <36 points (sensitivity = 69%, specificity = 67%, AUC = 0.67 [95% CI = 0.49–0.85]). Conclusions Early out-of-bed mobilization, initiated within 3 to 5 days of physiological readiness, may differentiate patients who develop functional dependence or ICU-acquired weakness at ICU discharge from those who do not. However, since discrimination ranged from 66% to 68%, with a narrow margin for worse outcomes, this recommendation should be interpreted within context. Relevance Knowing clinical reference points for days to initiate out-of-bed exercises may help minimize poor physical outcomes at ICU discharge.