Predicting Extubation Outcome by Cough Peak Flow Measured Using a Built-in Ventilator Flow Meter

BACKGROUND: Successful weaning from mechanical ventilation depends on the patient9s ability to cough efficiently. Cough peak flow (CPF) could predict extubation success using a dedicated flow meter but required patient disconnection. We aimed to predict extubation outcome using an overall model, including cough performance assessed by a ventilator flow meter. METHODS: This was a prospective observational study conducted from November 2014 to October 2015. Before and after a spontaneous breathing trial, subjects were encouraged to cough as strongly as possible before freezing the ventilator screen to assess CPF and tidal volume (V T ) in the preceding inspiration. Early extubation success rate was defined as the proportion of subjects not re-intubated 48 h after extubation. Diagnostic performance of CPF and V T was assessed by using the area under the curve of the receiver operating characteristic curve. Cut-off values for CPF and V T were defined according to median values and used to describe the performance of a predictive test combining them with risk factors of early extubation failure. RESULTS: Among 673 subjects admitted, 92 had a cough assessment before extubation. For the 81 subjects with early extubation success, the median CPF was −67.7 L/min, and median V T was 0.646 L. For the 11 subjects with early extubation failure, the median CPF was −57.3 L/min, and median V T was 0.448 L. Area under the curve was 0.61 (95% CI 0.37–0.83) for CPF and 0.64 (95% CI 0.42–0.84) for CPF/V T combined. After dichotomization (CPF T > 0.55 L), there was a synergistic effect to predict early extubation success ( P T combined. The overall model including pH before extubation CONCLUSIONS: CPF measured using the flow meter of an ICU ventilator was able to predict extubation success and to build a composite score to predict extubation failure. The results were close to that found in previous studies that used a dedicated flow meter. This could help to identify high-risk subjects to prevent extubation failure. (ClinicalTrials.gov registration NCT02847221.)