Breathing training reduces post-CABG (coronary artery bypass grafting) pulmonary complications
Hulzebos, et al, October 18, 2006, Journal of the American Medical Association October 17, 2006 Lisa Nainggolan

Utrecht, the Netherlands - The first randomized clinical trial of preoperative preventive inspiratory muscle training (IMT) in patients scheduled for bypass surgery shows that the procedure halves the incidence of postoperative pulmonary complications (PPCs)[1].
Physical therapist Dr Erik HJ Hulzebos (University Medical Center and Children’s Hospital, Utrecht, the Netherlands) and colleagues report their findings in the October 18, 2006 issue of the Journal of the American Medical Association. “We consider this to be an important presurgical intervention that appears to be effective at reducing morbidity,” they state.
But Hulzebos told heartwire that awareness of this technique would need to be raised. “Most cardiothoracic surgeons are unaware of the prophylactic effect of this preoperative training of the respiratory system in high-risk patients, and IMT is not wisely used at present.”
Tailored program of exercises for two weeks before surgery
Hulzebos et al explain that PPCs are graded in severity—mild symptoms include cough and dyspnea, whereas those more severely affected can suffer from pneumonia and pneumothorax and require ventilatory support. Thus, PPCs influence patient morbidity and mortality, length of hospital stay, and overall resource utilization.
The rate of PPCs has remained stable among CABG patients despite the fact that the surgery itself and perioperative care have improved considerably, they note. This is likely because CABG is now performed in higher-risk patients at greater risk of PPCs because of comorbidities, they say.
They selected patients deemed to be at high risk of developing PPCs on the basis of risk factors—a strategy developed by Hulzebos as part of his PhD thesis. Preoperative IMT was employed in half of the patients (n=139) while the other half received usual care (n=139).
IMT involved patients performing tailored exercises—incentive spirometry, education in active cycle of breathing techniques, and forced expiration techniques—daily at home for at least two weeks before the actual date of surgery. Each session was 20 minutes long and was performed six times a week without supervision and once a week with supervision by Hulzebos, who was the physical therapist for the trial. The weekly cost of the therapy was approximately €300, Hulzebos says.
Patients recorded their daily progression in a diary, along with any adverse events and complaints, and completed an anonymous questionnaire at the end of the intervention period. IMT resulted in significant improvement in average inspiratory muscle strength and respiratory muscle endurance.Hulzebos told heartwire, “The patients were very receptive to IMT; no participants dropped out, and all those in the IMT group returned the questionnaire (mean scores for satisfaction and motivation on a 10-point scale were 8.1 and 8.4, respectively).”
The usual-care group received care as normal the day before the surgery (instruction on deep breathing maneuvers, coughing, and early mobilization), and both groups received similar postoperative care.
The main outcome measures were incidence of PPCs, especially pneumonia, and duration of postoperative hospitalization.
Pneumonia cut by 60% in those receiving IMT
PPCs were present in 25 (18%) of patients receiving IMT training compared with 48 (35.0%) of patients in the usual-care group (odds ratio 0.52). Pneumonia occurred in 9 (6.5%) of the patients in the IMT group compared with 22 (16.1%) in the usual-care group (OR 0.40).
Median duration of postoperative hospitalization was seven days in the IMT group vs eight days in the usual-care group (p=0.02).
“Our data suggest that preoperative IMT makes the patients more resistant to the detrimental consequences of surgery, decreasing the median duration of mechanical ventilation, which was significantly longer in the usual-care group (five hours) than in the IMT group (four hours),” they note.
“IMT also promoted postoperative recovery, because the median duration of hospitalization was shorter in the nine patients in the IMT group who developed pneumonia than it was in the 22 patients in the usual-care group who developed pneumonia (11.5 vs 13 days, respectively).”
“Our program is safe and well tolerated and should be implemented in regular care as soon as possible,” Hulzebos concludes.