Evaluation of surgical risk in patients with COPD

Abstract

In this overview general risk factors for postoperative complications are discussed with special reference to pulmonary complications, which frequently occur in patients with chronic obstructive pulmonary disease (COPD). In a second part the functional evaluation of lung resection candidates is presented. Pulmonary complications are the most frequent cause of postoperative morbidity and mortality. Risk factors include: underlying respiratory disease, especially COPD, current smoking, duration of anaesthesia, type of surgical procedure (upper abdominal or thoracic surgery), age and obesity. The preoperative evaluation of patients at risk is discussed. For non-thoracic surgery preoperative pulmonary function testing and a preoperative chest radiograph are indicated for high-risk patients only, whereas they are mandatory for all lung resection candidates. There are no cut-off values in pulmonary function testing which would preclude non-thoracic surgical procedures. In patients with COPD, laparascopic procedures are recommended; and regional or epidural anaesthesia have less adverse effects on pulmonary function than general anaesthesia. Prevention of postoperative pulmonary complications includes smoking cessation at least eight weeks before surgery, and, if indicated preoperative treatment with antibiotics, beta2-agonists, steroids (steroid-trial) and intensive perioperative chest physiotherapy (incentive spirometry). The functional reserves of lung resection candidates is assessed with an algorithm based on the forced expiratory volume in one second (FEV1), the transfer factor of the lung for carbon monoxide (DLCO), and the maximal oxygen uptake on exercise (VO2max). In critical patients additional split function studies are necessary to estimate the remaining pulmonary function depending on the extent of resection.