Influence of preoperative respiratory muscle strength on clinical evolution after myocardial revascularization surgery

Abstract

The aim of this study was to assess whether preoperative respiratory muscle strength: a) is related to other preoperative risk factors and b) represents a higher risk to postoperative pulmonary complications (PPC), higher time under mechanical ventilation (MV), intensive care unit (ICU) and hospitalization, after myocardial revascularization surgery. Twenty-four patients were studied and, after the analysis of preoperative measures taken, divided into two groups: G1, with maximum inspiratory pressure (MIP) over 70% predicted value (n=13, 54%); and G2, with MIP below 70% predicted value (n=11, 46%). At the statistical analysis, significance level was set at 5% (p<0.05); relative risk (RR) was also estimated. The groups were homogeneous as to most variables measured both in preoperative exams (to the exception of MIP and MEP) and as to surgical data (p>;0.05). Almost half of G2 patients, who had lower MIP, also presented maximum expiratory pressure (MEP) below predicted value. As for time under MV, postoperative ICU and in-hospital times, besides number of PPC, no statistical differences were found between the groups. When compared to G1, G2 patients showed higher relative risk to developing postoperative pulmonary complications.