Cardiovascular responses to manual hyperinflation in post-operative coronary artery surgery patients

Abstract

The aims of this study were to investigate the acute cardiovascular response to manual hyperinflation and to determine whether the technique results in haemodynamic compromise in coronary artery surgery subjects in the early post-operative period. A repeated-measures clinical trial involving a single intervention period was conducted. Manual hyperinflation using a two-litre resuscitation circuit was delivered within 5 h of surgery by experienced physiotherapists for a period of 4 min to subjects (n = 30) who had undergone coronary artery surgery. Swan-Ganz catheters and bedside monitoring showed significant changes in heart rate, mean pulmonary artery pressure, central venous pressure and the pulmonary vascular resistance index measured during, or after, manual hyperinflation. These changes in mean pulmonary arterial pressure and central venous pressure may be due to alterations in intrathoracic pressures generated during manual hyperinflation; however, the changes in heart rate and the pulmonary vascular resistance index are not readily explained. We conclude that the use of manual hyperinflation as part of the immediate post-operative physiotherapy management of stable, mechanically ventilated coronary artery surgery patients does produce significant changes in some haemodynamic parameters, but none of the recorded changes were of a magnitude considered to be clinically significant.