Post-cardiac Surgery Pleural Effusion and the Overlooked Importance of the Diaphragm: Setting Up an Inspiratory Training Program Correctly.

Pleural effusion (PE) is one of the most common complications after cardiac surgery. PE can cause both functional and structural changes in the diaphragm, leading to longer hospital stays and higher mortality rates. This narrative review article proposes a hypothesis regarding the inspiratory muscle training (IMT) parameters that patients could achieve in various clinical settings. We selected review articles and excluded case reports, editorials, and letters. We reviewed the most significant and recent articles on PubMed. This article defines PE, examines possible mechanisms of its onset after cardiac surgery, and identifies potential risk factors. It explores how the thorax and diaphragm adapt, emphasising the need to direct clinical attention to this muscle and to IMT, not only to promote the resolution of PE but also to improve the patient's symptoms. Diaphragm rehabilitation is a strategic measure to counteract PE. Based on the literature reviewed in the article, the Italian Association of Cardiovascular Rehabilitation (AIRC) proposes, as a hypothesis to be evaluated in future research, new IMT parameters: for red fibers 30% of PImax, 2-3 sets of 15 inhalations, with a 90 second rest between one set and the next and for the white fibres: 50% of PImax, 2-3 sets of 8-12 inhalations, with a three-minute rest between sets, 2-3 days a week. IMT, already present in the literature with parameters from different authors, is a fundamental strategy for improving the clinical picture of patients with PE.