Background: Measurement of maximal respiratory pressures and vital capacity are essential in evaluating respiratory function. However, methodological variations may interfere with the interpretation of results. Objective: To compare values obtained using mouthpiece and face-mask evaluation methods in the measurement of maximal respiratory pressures and vital capacity. Method: We studied 30 patients (16 male), with a mean age of 55.9 ± 15.7, in the preoperative phase of abdominal surgery. Maximal inspiratory pressure and maximal expiratory pressure, as well as vital capacity, were evaluated using either a rigid flanged mouthpiece or a face mask, in randomized order. Results: Evaluation with a face mask did not significantly alter vital capacity and maximal inspiratory pressure values, although maximal expiratory pressure values were significantly lower than when measured using a rigid mouthpiece. During measurement of maximal expiratory pressure, air leakage from around the mask was observed in 60% of cases. When maximal expiratory pressure measurements in which there was no such leakage were considered in isolation, face-mask values were higher than those obtained with the moutpiece. Conclusion: With a face mask, maximal inspiratory pressure and vital capacity can be accurately evaluated. Maximal expiratory pressure can also be adequately evaluated using a face mask, provided that air leakage from the mask edges can be avoided. However, such leakage and the consequent reduction in the values obtained are common and limit the use of this method of evaluation.

Keywords: Respiratory function tests. Maximal voluntary ventilation. Respiratory muscles.

Abstract Objective: To evaluate the influence of pleural drainage on the distance covered on the six-minute walk test, pain intensity and vital capacity in patients submitted to pulmonary resection. Methods: Thirteen consecutive patients from the Thoracic Surgery Infirmary of Hospital São Paulo, Brazil, submitted to closed pleural drainage (0.5-in multiperforated chest tube) in the postoperative period following pulmonary resection (lobectomy, segmentectomy and pulmonary nodule resection) were evaluated. The decision for chest tube removal followed clinical criteria defined by the surgical team, who did not participate in the study. Vital capacity, pain intensity (using a visual analog pain scale) and the distance covered on the six-minute walk test were determined 30 min prior to and 30 min after the removal of the chest tube. The statistical analysis was performed using paired t-tests, and the level of significance was set at 0.05. Results: After the removal of the chest tube, the visual analog scale pain scores were significantly lower (3.46 cm vs. 1.77 cm; p = 0.001) and the distance covered on the six-minute walk test was significantly higher (374.34 m vs. 444.62 m; p= 0.03). Vital capacity prior to and after chest tube removal was not significantly affected (2.15 L and 2.25 L, respectively; p = 0.540). Conclusions: The results of the present study suggest that the presence of a chest tube is a factor significantly associated with postoperative pain and functional limitation in patients submitted to pulmonary resection.

Keywords: Thoracic surgery; Exercise test; Respiratory function tests; Pain, postoperative.