Aplicability of respiratory muscle strength as part of the surgical risk scale based on Tonrrington and Henderson scoring system

Abstract

Objective: Evaluate the applicability of mean percentage from the predicted value of respiratory muscle strength (maximal inspiratory pressure-MIP; maximal expiratory pressure-MEP), as (% MIP + % MEP)/2, as well as the peak expiratory flow (% PEF) preoperatively, as part of a surgical risk scale for predicting the risk of postoperative pulmonary complications (PPC). Methods: Data on patients undergoing elective surgery of chest, abdomen and limbs were assessed preoperatively using the items and the scoring system proposed by the Torrington and Henderson, and replacing spirometry by the mean values of both (% MIP + % MEP)/2 and % PEF. Results: The proposed scale applied to 108 patients with a mean age of 55.2 ± 14.0 presented PPC rate of 37.0% (p = 0.0001), of which 20.0% were classified as high risk (HR), and 62.5% moderate risk (MR). The mean value of respiratory muscle strength showed a statistically significant correlation with PPC (p = 0.000). Conclusion: The proposed scale allowed the appropriate stratification of patients at risk for development of PPC. The use of the mean values of (% MIP + % MEP)/2 and % PEF based on the predicted values can be easily applied, making spirometry unnecessary.