Predictors of requirement of mechanical ventilation in patients with chronic obstructive pulmonary disease with acute respiratory failure

BACKGROUND AND OBJECTIVE: Acute exacerbation of chronic obstructive pulmonary disease (COPD) leads to increased morbidity, mortality and requirement of invasive mechanical ventilation (MV). The aim of this study was to identify predictors of need of MV in these patients. MATERIALS AND METHODS: Clinical symptomatology, demographic profile, biochemical parameters including renal functions, liver functions and acid base parameters, and acute physiology and chronic health evaluation II (APACHE II) score at the time of admission were recorded in 100 patients of COPD exacerbation. Various parameters were compared between patients in whom MV was required with those managed with medical therapy. RESULTS: MV was required in 73% of the patients. Parameters found to be independent predictors of need of MV were: Admission APACHE-II score ≥ 11.5 {adjusted odds ratio (OR) [95% confidence interval (CI)]: 1.42 [1.08-1.86]; P = 0.012}, first day pH ≤ 7.28 (adjusted OR [95% CI]: 1.09 [1.02-1.15]; P = 0.008), first day PaCO(2) ≥ 68.6 mmHg (adjusted OR [95% CI]: 1.09 [1.02-1.15]; P = 0.004) and worse premorbid functional status (adjusted OR [95% CI]: 17.01 [1.95-148.68]; P = 0.01). CONCLUSIONS: Underlying disease severity as assessed by premorbid functional status and APACHE-II score, and the acuity of respiratory system decompensation as assessed by the admitting arterial pH and PaCO(2), are independent predictors of need of MV in patients with exacerbation of COPD.