Prevention of respiratory complications after abdominal surgery: a randomised clinical trial

Abstract

Objective: To evaluate the prevention of respiratory complications after abdominal surgery by a comparison of a global policy of incentive spirometry with a regimen consisting of deep breathing exercises for low risk patients and incentive spirometry plus physiotherapy for high risk patients. Design: Stratified randomised trial. Setting: General surgical service of an urban teaching hospital. Patients: 456 patients undergoing abdominal surgery. Patients less than 60 years of age with an American Society of Anesthesia classification of 1 were considered to be at low risk. Outcome measures: Respiratory complications were defined as clinical features consistent with collapse or consolidation, a temperature above 38°C, plus either confirmatory chest radiology or positive results on sputum microbiology. We also recorded the time that staff devoted to prophylactic respiratory therapy. Results: There was good baseline equivalence between the groups. The incidence of respiratory complications was 15% (35/231) for patients in the incentive spirometry group and 12% (28/225) for patients in the mixed therapy group (P=0.40; 95% confidence interval -3.6% to 9.0%). It required similar amounts of staff time to provide incentive spirometry and deep breathing exercises for low risk patients. The inclusion of physiotherapy for high risk patients, however, resulted in the utilisation of an extra 30 minutes of staff time per patient. Conclusions: When the use of resources is taken into account, the most efficient regimen of prophylaxis against respiratory complications after abdominal surgery is deep breathing exercises for low risk patients and incentive spirometry for high risk patients. Key messages Most postoperative respiratory complications were due to atelectasis: less than 1% of the patients developed pneumonia An American Society of Anesthesia classification >1 and an age >/=60 years is a simple way of defining patients at high risk of respiratory complications and other adverse events after abdominal surgery A regimen consisting of deep breathing exercises (low risk patients) and incentive spirometry (high risk patients) is an efficient way of providing prophylaxis against respiratory complications after abdominal surgery