Evaluation of spirometric testing as a routine preoperative assessment in patients undergoing bariatric surgery

The value of spirometry as a routine preoperative test for bariatric surgery is debatable. The aim of this study was to assess the relationship between spirometry results and the frequency of postoperative pulmonary complications in 602 obese patients.

Clinical files of patients undergoing bariatric surgery between 2004 and 2013 were reviewed. Demography, risk factors, respiratory symptoms, and spirometry results (forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC) were recorded, and their relationship with postoperative pulmonary complications was evaluated.

There were 256 males and 346 females with a mean age of 40.2 ± 11.6 years and a mean BMI of 42.1 ± 6.4 kg/m2. History of smoking was found in 408 patients (68 %). Preoperative respiratory symptoms were present in 328 (54.5 %). Most frequent symptoms were snoring (288), dyspnea (119), bronchospasm [6], and chronic productive cough [6]. In 153 patients, history of respiratory disease was documented. The obstructive sleep apnea syndrome (OSAS) was present in 124, 20 requiring continuous positive airway pressure (CPAP). Asthma was present in 27 and chronic obstructive pulmonary disease (COPD) in 2. Variables associated to a higher risk of pulmonary complications were OSAS (OR 2.3), an abnormal spirometry (OR 2.6), male gender (OR 1.9), and preoperative respiratory symptoms (OR 1.9). Using multivariate logistic regression, an abnormal spirometry was a significant predictor of postoperative pulmonary complications in patients with respiratory symptoms and/or OSAS. However, it lost prognostic significance when both conditions were subtracted.

In obese patients undergoing bariatric surgery, abnormal preoperative spirometry predicts postoperative respiratory complications only in patients with OSAS.