Inspiratory Muscle Training Prior to Conventional and Minimal Invasive Heart Surgery (PRIMUS)

The PRIMUS Study: Effect of Pre-operative Inspiratory Muscle Training on Post-operative Pulmonary Recovery and Pulmonary Complications After Cardiac Surgery

The main objective of this study is to evaluate the effect of pre-operative Inspiratory muscle training (IMT) using an IMT Threshold device (Philips), on early postoperative lung function recovery and on the occurrence of post-operative pulmonary complications (PPC) after major cardiothoracic surgery with and without sternotomy. As frailty can affect postoperative outcome, the relation between frailty, maximal inspiratory pressure (MIP) and post-operative outcome is investigated additionally.

Patients eligible for cardiac surgery are pre-operatively randomized to standard physiotherapy or daily inspiratory muscle training for a period of 2-3 weeks. One therapy session a week is supervised by a physiotherapist in the IMT group. Post-operative physiotherapy is standardized. Pulmonary function and clinical status are evaluated pre-operatively, and during the early post-operative phase, approximately on the 3th and 6th post-operative day, or when necessary. The occurrence of postopercenterative pulmonary complications is determined using a validated scale, the Melbourne group scale, based on clinical status, chest x-ray and blood tests. Frailty is defined based on the Fried criteria. Two Belgian hospitals are involved in this study: the University Hospital Brussels and the Jessa Hospital (Hasselt), the latter mainly focussing on patients referred for minimal invasive heart surgery (minimally invasive-aortic valve replacement (mini-AVR) and Endoscopic - Atraumatic Coronary Artery Bypass (endo-ACAB).

Inspiratory capacity (l), Functional residual capacity (l),Residual volume (l), Total lung capacity (l). Baseline. Diagnosis of normal/obstructive/restrictive lungfunction

Inspiratory capacity (l), Functional residual capacity (l), Residual volume (l), Total lung capacity (l).Diagnosis of normal/obstructive/restrictive lungfunction and evolution after pre-operative physiotherapy.

Inspiratory capacity (l), Functional residual capacity (l) ,Residual volume (l),Total lung capacity (l). Diagnosis of normal/obstructive/restrictive lungfunction. Evolution after surgery.

Vital capacity (l), FVC: forced vital capacity (l), FEV1: forced expiratory volume in 1 second (l). Baseline. Diagnosis of normal/obstructive/restrictive lungfunction.

Vital capacity (l), FVC: forced vital capacity (l), FEV1: forced expiratory volume in 1 second (l). Diagnosis of normal/obstructive/restrictive lungfunction and evolution after pre-operative physiotherapy.

Vital capacity (l), FVC: forced vital capacity (l), FEV1: forced expiratory volume in 1 second (l).Diagnosis of normal/obstructive/restrictive lungfunction. Evolution after surgery.

Melbourne Group Scale (MGS), tool for recognition of postoperative pulmonary complications (PPC), based on 1) Temperature >38◦C 2)White blood cell count >11.2 or the use of respiratory antibiotics 3)Physician diagnosis of pneumonia or chest infection 4)Chest X-ray report of atelectasis/pneumonia 5)Production of purulent (yellow/green)sputum differing from preoperative 6)Positive signs on sputum microbiology 7)SpO2<90% on room air 8)Re-admission to or prolonged stay (over36 hours) on the intensive care unit/highdependency unit for respiratory problems. Postoperative pulmonary complications are defined as a score of four or more positive variables. the occurence of PPC is an endpoint in this study.

Inclusion Criteria: Candidates for coronary artery bypass grafting or minimally invasive valve repair/replacement Exclusion Criteria: Not able to perform pre-operative standard pulmonary function tests No understanding of Dutch, French or English and/or no ability to understand verbal instructions regarding the inspiratory muscle training Patients who participate in another clinical trial Patients suffering from neuromuscular disorders, unstable angina, a history of non-traumatic pneumothorax, chronic obstructive pulmonary disease (COPD) in exacerbation Patients in need for urgent surgery (within less than 2 weeks)