Related Experiment Video
Updated: Sep 1, 2025

Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery
Published on: March 27, 2018
Inspiratory muscle training and functional capacity following coronary artery bypass grafting in high-risk patients:
André Luiz Lisboa Cordeiro1,2, Bianca Silva Cavalcante De Carvalho1, Eduarda Gomes Da Silva1
1Department of Physiotherapy, Faculdade Nobre, Feira de Santana, Brazil.
Background:
Coronary artery bypass graft (CABG) surgery is associated with worsened functional capacity, pulmonary complications, and increased length of hospital stay. These negative effects are exacerbated in patients who are at high risk of post-operative (PO) pulmonary complications before CABG. Inspiratory muscle training (IMT) has been shown to benefit CABG patients in their recovery process. However, in high-risk patients, there is little evidence to support the post-operative implementation of IMT for purposes of faster recovery.
Aim:
The aim of the study was to test the hypothesis that IMT improves the functional capacity, pulmonary complications, and length of hospital stay in patients prone to pulmonary complications who had undergone CABG.
Methods:
This is a pilot clinical trial carried out with patients at high risk for pulmonary complications in the PO phase. In the pre-operative period, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and 6-min walk test (6MWT) were determined and administered. On the first PO day, patients were divided into two groups: A control group (CG) that received routine intervention and an IMT group that, in addition to routine care, was subjected to an IMT protocol until hospital discharge. On the day of discharge, the patients were reassessed with respect to ventilatory muscle strength, functional capacity, PO complications, and length of stay.
Results:
Twenty-nine patients were evaluated, 15 in the CG and 14 in the IMT group. No significant differences were observed in relation to MIP (difference between the mean of -7 cmH2O; 95% CI = -16.52-2.52), MEP (difference between the mean of -7cm H2O; 95% CI = -15.39-1.39), and in the 6MWT (difference between the mean of -9 m; 95% CI = -43.71-25.71). There was a decrease in the length of stay in the IMT group compared to the CG (9 ± 3 vs. 12 ± 4 days; P = 0.04). The IMT group had a lower rate of atelectasis and pneumonia.
Conclusion:
IMT does not minimize the loss of functional capacity, but it reduces pulmonary complications and the length of stay of patients undergoing CABG who are preoperatively at a high risk of pulmonary complications.
Relevance For Patients:
The increase in ventilatory muscle strength, associated with IMT, can reduce PO pulmonary complications, resulting in shorter hospital stays, and improved quality of life.
Related Concept Videos
Cardiomyopathy VII: Pre and Post Operative Nursing Management
Coronary Artery Disease V: Interprofessional Care
Cardiomyopathy V: Interprofessional Care
Cardiopulmonary Resuscitation II: ACLS Airway Management
Respiratory Capacities
One key metric is the Inspiratory Capacity (IC), which represents the maximum amount of air that can be inhaled with full effort. IC is calculated by summing the tidal volume and inspiratory reserve volume, typically ranging from 2.4 to 3.6 liters.
The Functional Residual Capacity (FRC) represents the air in the...
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...

