[Prevention of respiratory complications after abdominal surgery]

Abstract

Abdominal surgery, especially upper abdominal surgical procedures are known to adversely affect pulmonary function. Pulmonary complications are the most frequent cause of postoperative morbidity and mortality. This review article aimed to analyse the incidence and risk factors for postoperative pulmonary morbidity and their prevention. The most important means for preoperative assessment is the clinical examination; pulmonary function tests (spirometry) are not reliably predictive for postoperative pulmonary complications. Age, type of surgical procedure, smoking and nutritional state have all been identified as potential predictors for postoperative complications. However, usually there is not enough preoperative time available to obtain beneficial effects of stopping smoking and improvement of nutritional state. In patients with COPD, a preoperative multidisciplinary evaluation including the primary care physician, pulmonologist/intensivist, anesthesiologist and surgeon is required. Consensus as to preoperative physiologic state, therapeutic preparation, and postoperative management is essential. Simple spirometry and arterial blood gas analysis are indicated in patients exhibiting symptoms of obstructive airway disease. There are no values that contra-indicate an essential surgical procedure. Smoking should stop at least 8 weeks preoperatively. Preoperative therapy for elective surgery with antibiotics, beta2-agonist, or anticholinergic bronchodilator aerosols, as well as training in cough and lung expansion techniques should begin at least 24 to 48 hours preoperatively. Postoperative therapy should be continued for 3 to 5 days. Usually, anaesthesia is responsible for early complications, whereas surgical procedures are often associated with delayed morbidity. Laparoscopic procedures are recommended, as postoperative morbidity and hospital stay seem reduced in patients without COPD. Regional anaesthesia is given as having less adverse effects on pulmonary function than general anaesthesia. However, for unknown reasons these benefits are not associated with a decrease in postoperative respiratory complications. Moreover, the quality or the type of postoperative analgesia does not influence postoperative respiratory morbidity. Postoperatively, oxygen administration increases SaO2, but cannot abolish desaturation due to obstructive apnea. The various techniques of physiotherapy (chest physiotherapy, incentive spirometry, continuous positive airway pressure breathing) seem to be equivalent in efficacy; but intermittent positive pressure breathing has no advantages, compared with the other treatments and could even be deleterious. Chest physiotherapy and incentive spirometry are the most practical methods available for decreasing secretion contents of airways, whereas continuous positive airway pressure breathing is efficient on atelectasis. In stage II or III COPD patients, admission in a intensive therapy unit and prolonged mechanical ventilation may be required.