Predictors of exercise oxygen desaturation following major lung resection

European Journal of Cardio-thoracic Surgery 24 (2003) 145–148 www.elsevier.com/locate/ejcts Predictors of exercise oxygen desaturation following major lung resection Unit of Thoracic Surgery, Department of Respiratory Diseases, ‘Umberto I’ Hospital, Ancona, Italy Received 12 December 2002; received in revised form 8 March 2003; accepted 17 March 2003 Abstract Objective: To identify predictors of postoperative exercise oxygen desaturation (EOD) in patients submitted to lobectomy or pneumonectomy for lung carcinoma. Patients and methods: A consecutive series of 227 patients with non-small cell lung cancer submitted to lobectomy or pneumonectomy from January 2000 through October 2002 were prospectively analyzed. Maximal stair-climbing tests were performed preoperatively (the day before the operation) and postoperatively (on average, 9.2 days after operation) in room air for all patients. A fall in oxygen saturation during the exercise below 90% was termed ‘desaturation’. Univariate and multivariate analyses were performed to identify predictors of postoperative EOD. Results: Thirty-five patients (15.4%) developed postoperative EOD. After multivariate analysis, the only independent predictor of postoperative EOD resulted a reduction in oxygen saturation during the preoperative exercise ðP ¼ 0:0004Þ. Conclusions: Patients with a reduction in oxygen saturation during the preoperative exercise test are at increased risk to develop a postoperative EOD below 90%. A postoperative exercise test should be performed in all these patients. Should EOD be confirmed, an intermittent home oxygen therapy is recommended in order to facilitate recovery from operation and improve the quality of life. q 2003 Elsevier Science B.V. All rights reserved. Keywords: Exercise test; Stair-climbing test; Oxygen desaturation; Lung resection; Lung cancer 1. Introduction 2. Patients and methods After pulmonary resection the patients slowly regain, more or less completely, their lost function by progressively resuming their daily activities or, more ideally, by participating in a rehabilitation program. However, following surgery, some patients experience arterial hypoxemia on effort, which limits their physical activity, hindering the postoperative recovery and worsening their quality of life. The objective of this study was to identify the predictors of postoperative exercise oxygen desaturation (EOD) following lobectomy or pneumonectomy for lung cancer, in order to select those patients to be submitted to postoperative maximal exercise test for assessment of their oxygen saturation status. Two hundred and twenty-seven patients with non-small cell lung cancer who underwent pulmonary lobectomy (189 patients) or pneumonectomy (38 patients) at our institution from January 2000 through October 2002 were prospectively enrolled in the study after giving informed consent. All the patients performed a preoperative (the day before the operation) and a postoperative (on average, 9.2 days after the operation) symptom-limited stair-climbing test. Our hospital has 16 flights of stairs, each flight having 11 steps. Each step is 0.155 m in height. The patients were asked to climb at a pace of their own choice the maximum number of steps and to stop only for exhaustion, limiting dyspnea, leg fatigue, or chest pain. A physician accompanied all patients during their exercise, and used a continuous verbal interaction with them for encouragement and assessment of the dyspnea and the occurrence of other symptoms. All tests were performed in room air. During the exercise, the pulse rate and capillary oxygen saturation were monitored by means of a portable pulse oximeter, and the same device was used for all patients. For the purpose of this study, a * Corresponding author. Via S. Margherita 23, 60129 Ancona, Italy. Tel.: þ 39-071-59-644-39; fax: þ 39-071-596-4433. E-mail address: (A. Brunelli). 1010-7940/03/$ - see front matter q 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S1010-7940(03)00175-1 Alessandro Brunelli*, Majed Al Refai, Marco Monteverde, Alessandro Borri, Michele Salati, Aroldo Fianchini 146 A. Brunelli et al. / European Journal of Cardio-thoracic Surgery 24 (2003) 145–148 3. Results Thirty-five patients (15.4%) developed postoperative EOD. Six of these patients experienced a preoperative EOD as well. Other six patients had a preoperative EOD but did not develop a postoperative EOD. None of the 12 patients with preoperative EOD had postoperative cardiopulmonary complications. The occurrence of postoperative EOD did not differ between complicated (seven of 33 patients) and non-complicated (28 of 194 patients) patients ðP ¼ 0:3Þ. Of the 35 patients with postoperative EOD, three had a desaturation of 3% (i.e. from 90 to 87%), eight had a desaturation between 4 and 6%, 13 had a desaturation between 7 and 9%, and 11 had a desaturation greater than 9%. All these patients stopped their postoperative maximal stair-climbing test for limiting dyspnea. In those patients who did not have postoperative EOD, 124 of 192 (64.6%) stopped their postoperative exercise test for limiting dyspnea, 30 for leg pain, 29 for exhaustion, and 9 for other reasons. The rate of dyspnea as a limiting symptom was significantly higher in patients with postoperative EOD compared with those without it (Chi-square test ¼ 17.7; P , 0:0001). The results of the comparison between patients with and without postoperative EOD are shown in Table 1. In particular, compared with the patients without postoperative EOD, the patients with postoperative EOD had a lower FEV1 ðP ¼ 0:001Þ, FVC ðP ¼ 0:009Þ, FEV1/FVC ratio ðP ¼ 0:04Þ, ppoFEV1 ðP ¼ 0:0007Þ, and ppoDLCO ðP ¼ 0:04Þ. They also showed a greater reduction in oxygen saturation during preoperative exercise ðP , 0:0001Þ. Moreover, patients who were submitted to pneumonectomy desaturated more frequently than those submitted to lobectomy ðP ¼ 0:04Þ. As shown in Table 1, preoperative values of PaO2 and PaCO2 did not differ between the two groups of patients. However, compared with the patients without postoperative EOD, those with postoperative EOD had a lower level of preoperative pH at rest (7.39 versus 7.41, respectively; P ¼ 0:02). Moreover, the levels of lactates immediately after the preoperative and postoperative efforts trended toward higher values in the patients with postoperative EOD (preoperative levels (mg/dl): 42.5 versus 39.5, P ¼ 0:2; postoperative levels (mg/dl): 31.7 versus 28.9, P ¼ 0:2). The logistic regression analysis showed that a reduction in oxygen saturation during the preoperative exercise was the only significant predictor of postoperative EOD (regression coefficient: 0.22; P ¼ 0:0004). Among the patients who experienced a preoperative reduction in oxygen saturation, the ratio of postoperative/ preoperative percent reduction in oxygen saturation between rest and peak exercise (delta satO2 ratio) was calculated. Three groups were derived: group A, pat (...truncated)