Predictors of failure of early shift from invasive to noninvasive ventilation in weaning chronic obstructive pulmonary disease patients who have failed the initial spontaneous breathing trial: a prospective cohort study

Abstract

Noninvasive ventilation (NIV) is a well-established modality for difficult and prolonged weaning of chronic obstructive pulmonary disease (COPD) patients. Although several studies have addressed the early shifting to NIV, predictors of its success remain to be determined. The aim of the study was to find predictors of success of early shift of COPD patients who have failed the spontaneous breathing trail (SBT) to NIV. This investigation was designed as a double-centered prospective cohort study involving the ICUs of Critical Care Medicine of Cairo University and Shebin El-Kom Teaching Hospital. Consecutive COPD patients who failed the initial SBT were extubated and shifted to NIV. We compared arterial blood gases, lung mechanics, and spontaneous breathing parameters in successful patients with these parameters in those who failed the early shift to NIV. Out of the 30 patients, 21 (70%) were successfully weaned by early shift to NIV. The failed group had a significantly higher autopositive end-expiratory pressure (P<0.001), rapid shallow breathing index (RSBI) (P<0.05), and significantly lower static compliance and negative inspiratory pressure (NIP) (P<0.001) on admission. Admission RSBI and NIP were the only predictors of failure of early shift to NIV. Just before SBT, the failed group had a significantly higher autopositive end-expiratory pressure (P<0.001), RSBI (P<0.001), and airway resistance (Raw) (P<0.001) and significantly lower static compliance, NIP, and PO2/FIO2 (P/F) ratio. Raw and NIP before SBT were the only predictors of success of early shift to NIV. RSBI, NIP, and Raw, rather than arterial blood gases, are the most important predictors for success of early shift to NIV in COPD patients who have failed the initial SBT.