Prediction of NIV late failure among acute hypercapnic respiratory failure patients

<bold>Background:</bold> Non-invasive ventilation (NIV) is the main ventilatory support used in hypercapnic acute respiratory failure (HARF). We aimed to determine the predictive factors of late failure of NIV in HARF. <bold>Methods:</bold> All patients who underwent NIV therapy for HARF [2021-2023] were recruited in this retrospective study. Late NIV failure was defined by the recurrence of a HARF requiring rehospitalization. Two groups were compared: G1 (failure) and G0 (no failure). <bold>Results:</bold> Fifty-two cases included (G0: 40, G1: 12 patients). Mean age: [G1: 65 years vs G0: 67 years; p=NS]. Smoking was higher in G1 (p=0.03). Chronic respiratory disease was found in the majority of patients. Heart failure was more frequent in G1 (p=0.04). The mean Charlson score was comparable between the 2 groups (p=NS). The main cause of HARF was acute COPD exacerbation (33%). The ventilation pressures used were comparable between the 2 groups (p=0.03). Since initiating NIV, the mean time to neutral pH was : [G1: 12 vs G0: 4 hours; p=NS]. The mean length of hospital stay and in-hospital use of NIV were respectively: [G1: 24 vs G0: 14 days; p=0.02] and [G1: 15 vs G0: 11 days; p=0.02]. The mean time to HARF recurrence was 72 days. <bold>Conclusion:</bold> Predictors of late NIV failure would be heavy smoking, underlying heart failure, and late weaning from in-hospital NIV.