Feasibility of a capnometry device for respiratory biofeedback in patients undergoing coronary artery bypass graft surgery

Background: Psychophysiological patient´s state during hospital stay influences coronary arterial bypass graft (CABG) surgery outcomes. Biofeedback is used in the treatment of posttraumatic stress disorder and anxiety disorders. The aim of the current study was to evaluate feasibility of respiratory biofeedback (RB) in patients undergoing CABG surgery during hospital stay. Methods: Before CABG surgery all patients (n=93, aged 40 to 77 years) were divided into three groups after performing capnography and trial course of RB. The first group (usual care or USU group, n=48) consisted of patients who refused additional psychological support and RB, the second group consisted of patients who agreed to get psychological support (PSY group, n=25), and the third group were patients who accepted RB with psychological support (RB group, n=20). The task of the RB training for the participants was to maintain end-tidal partial pressure of carbon dioxide 10-20 % above the initial level. Results: RB was chosen by 21.5 % of the patients, psychological support was chosen by 26.9 % of the patients. Half of the patients (51.6 %) refused the offered additional programs. There were breathing frequency reduction and expiratory time increment in the RB group in contrast to other two groups at discharge. The RB group demonstrated a significantly shorter length of postoperative hospital stay (mean 9.5 [SE 1.0] days) than the USU group (13.9 [0.7]) and the PSY group (12.4 [0.8]). Conclusion: RB appears to be a feasible method of rehabilitation of the patients undergoing CABG surgery during hospital stay. Future randomized research is needed to examine effectiveness of the method.