RISK FACTORS PREDICTING POSTOPERATIVE RESPIRATORY FAILURE IN SURGICAL PATIENTS

Abstract

PURPOSE: To identify factors associated with postoperative respiratory failure (PRF: requiring mechanical ventilation > 48 hours after surgery or unplanned intubation within 30 days of surgery). METHODS: Multivariate logistic regression of the American College of Surgeons' 2007 National Surgical Quality Improvement Program (NSQIP) data. 203,836 patients of this multicenter, prospective dataset were studied. RESULTS: PRF was seen in 5,992 patients (2.94%). 30-day mortality was higher in patients who developed PRF than those who did not (25.62% vs. 0.98%, p < 0.0001). Preoperative risk factors which predict PRF include ASA class (OR 2.1), ascites (OR 1.4), bleeding disorder (OR 1.2), dyspnea (OR 1.3), emergency case (OR 1.8), esophageal varices (OR 1.8), alcoholism (OR 1.5), functional status (OR 1.6), heart failure (OR 1.2), COPD (OR 1.4), hypertension (OR 1.3), inpatient status (OR 5.8), sepsis (OR 1.6), prior operation within 30 days (OR 1.3), acute renal failure (OR 1.3), male sex (OR 1.2), smoking (OR 1.3), steroid use (OR 1.2), > 10% weight loss (OR 1.2), ventilator dependence within 48 hours prior to surgery (OR 1.8), and days from admission to operation (OR 1.0). Age < 40 was a lower risk factor for PRF than 40-60 (OR 0.8) which was lower than 60-80 (OR 0.7) which was lower than > 80 (OR 0.8). In comparison to a group of surgeries with low incidence of PRF (anorectal, bariatric, breast, ENT/neck, obstetric/gynecologic, hernia, spine and vein surgeries), higher rates of PRF occurred after aortic (OR 4.1), cardiac (OR 2.1), esophageal, stomach, pancreas, duodenum, liver and bile duct (OR 4.5), intestinal (OR 3.0), brain (OR 4.4), other abdominal (OR 2.0), skin (OR 1.4), thoracic (OR 3.4), urologic (OR 1.7), gallbladder, appendiceal, adrenal and spleen (OR 1.2) and other vascular surgeries (OR 1.2). All confidence intervals were significant. CONCLUSION: PRF, while uncommon, is associated with increased 30-day mortality. CLINICAL IMPLICATIONS: Variables associated with increased risk of PRF include factors related to age, gender, comorbidity, functional status and the type of surgery.