Patients at high risk for pulmonary complications after coronary artery bypass graft surgery can reduce risk with preoperative breathing exercises and respiratory muscle training, according to a study in the October 18 issue of the Journal of the American Medical Association.

Despite improvements in surgical technique and perioperative care, the rate of postoperative pulmonary complications has remained stable, possibly because surgery is now performed in more high-risk patients than previously. Postoperative pulmonary complications continue to affect risk of death, length of hospital stay, and overall use of resources, according to background information in the article.

Dutch researchers led by Erik H. J. Hulzebos, PT, MSc, of the University Medical Center, Utrecht, hypothesized that the prehospitalization period could be used to improve a patient's pulmonary condition through inspiratory muscle training.

In the study, inspiratory muscle training consisted of individualized, tailored exercises, seven times a week, for at least two weeks before the date of surgery; treatment included education in breathing techniques, forced expiration techniques, and use of a spirometer.

The investigators examined the effectiveness of preoperative physical therapy, including training, on the incidence of postoperative pulmonary complications, especially pneumonia, in patients at high risk who underwent surgery.

Of 655 patients referred for elective surgery, 299 (45.6 percent) met criteria for high risk of pulmonary complications; 279 enrolled and were followed until discharge. Patients were randomly assigned to receive either preoperative inspiratory muscle training (140) or usual care (139). Both groups received the same postoperative physical therapy.

In high-risk patients, inspiratory muscle training resulted in significant improvement in average inspiratory muscle strength and respiratory muscle endurance. After surgery, complications developed in 25 (18.0 percent) of 139 patients in the intervention group and 48 (35.0 percent) of 137 patients in the usual care group, a reduction of 48 percent. The incidence of pneumonia was 6.5 percent in the intervention group and 16.1 percent in the usual care group. The median duration of postoperative hospitalization was 7 days (range, 5-41 days) in the intervention group versus 8 days (range, 6-70 days) in the usual care group.