A study on the outcome of preoperative pulmonary function tests on a patient undergoing rheumatic mitral valve surgery

Abstract

Evaluation of pulmonary function by spirometer in adult patients undergoing cardiac surgery is a simple test to assess pulmonary reserve that has important implications in operative morbidity. However, there is no established consensus regarding which patients should undergo preoperative pulmonary function tests (PFTs), including forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC). The primary aim was to evaluate the outcome of preoperative PFTs on patients undergoing rheumatic mitral valve surgery. One hundred patients undergoing rheumatic mitral valve surgery, meeting the inclusion criteria, were included in this prospective observational study. The pulmonary function of the patients was assessed using a spirometer before surgery. Preoperative pulmonary artery systolic pressure (PASP) and arterial blood gas (ABG) analyses were also performed. The correlation of PFTs with early postsurgical outcome, comprising mortality within 30 days of surgery and morbidity defined as the existence of at least one of the postoperative complications, such as low cardiac output state indicated by increased requirement of inotropes, prolonged ventilation (>24 hours), postoperative new-onset hemodynamically significant arrhythmias, renal dysfunction, and post-op infection, was assessed. With the increasing New York Heart Association (NYHA) class of the patient, there was a decline of FEV1% and FVC%, which was statistically significant (P < 0.0001). There was a significant positive correlation of FVC% with preoperative saturation of peripheral oxygen (SpO2) and preoperative saturation of peripheral carbon dioxide (PaO2) and FEV1% with preoperative SpO2 and preoperative PaO2. Patients who had postoperative prolonged ventilation had lower values of FVC% and FEV1%, which was statistically significant (P < 0.001). The patients who expired had significantly lower values of FVC% and FEV1%. Preoperative lung function has an implication on intraoperative morbidity during cardiac surgery although a common consensus on its application is lacking. Preoperative spirometry can be one of the parameters for predicting postoperative morbidity and mortality in patients undergoing rheumatic mitral valve surgery. Spirometry might have a role to play in predicting patient outcomes in rheumatic mitral valve surgeries; however, larger well-powered studies are needed.