Acute respiratory failure in Pakistani patients: risk factors associated with mortality.

To assess the outcome and risk factors associated with mortality in patients with acute respiratory failure (ARF).Observational study.The Aga Khan University Hospital, Karachi, between January 1997 and June 2001.All adult patients admitted with a medical cause of acute respiratory failure were reviewed. The primary outcome measure was mortality and secondary outcome measures were factors associated with mortality in ARF. Multiple logistic regression analysis was used to identify the independent risk factors for mortality.A total of 270 patients were admitted with ARF. Hypercapnic respiratory failure was seen in 186 (69%) and hypoxemic in 84 (31%) cases. Pneumonia and COPD exacerbation were the most common underlying causes of ARF. Ventilator support was required in 93 (34.4%) patients. Hospital mortality was 28%. Chronic renal failure, malignancy, hypokalemia, severe acidosis (pH <7.25) septicemia and ARDS independently correlated with mortality. Mortality rate increased sharply (84%) with the presence of three or more risk factors.Acute respiratory failure has a high mortality rate (28%). Development of ARDS or septicemia was associated with high mortality. Presence of more than one risk factor significantly increased the mortality rate.