IJCS | Volume 32, Nº2, March/April 2019

106 Table 1 - Clinical characteristics of the patients who had coronary artery bypass grafting Variable n = 30 (%) Gender Male 18 (60%) Female 12 (40%) Age (years) 62 ± 9 BMI (kg/m 2 ) Eutrophic 8 (27%) Overweight 16 (53%) Obesity 6 (20%) Comorbidities SAH 22 (81%) DM 15 (50%) DLP 18 (60%) BMI: body mass index; SAH: systemic hypertension; DM: diabetes mellitus; DLP: dyslipidemia. Table 2 - Surgical characteristics of patients that had coronary artery bypass grafting Variable Mean and standard deviation CPB time (minutes) 88 ± 15 MV time (hours) 7 ± 3 Number of grafts 2 ± 0.8 Number of surgical drains 2 ± 0.4 CPB: cardiopulmonary bypass; MV: mechanical ventilation. Cordeiro et al. Pulmonary function after hospital discharge Int J Cardiovasc Sci. 2019;32(2)104-109 Original Article Results Between August 2017 and April 2018, 30 patients who were admitted for coronary artery bypass grafting at Instituto Nobre de Cardiologia were evaluated. Of these, 18 (60%) weremen and the average sample agewas 62 ± 9. Other data related to the patient’s clinical characteristics are presented in table 1. The patients had CPB time of 88 ± 15 minutes and average MV time of 7 ± 3 hours. Other data related to the patients’ surgical characteristics are shown in table 2. Table 3 shows the three evaluation phases in the variables. There was a significant reduction in pulmonary function behavior at hospital discharge compared to the preoperative period and surgical revision. At hospital discharge, MIP (cmH 2 O) dropped to 88 ± 9 and the preoperative value was 116 ± 5 (p < 0.001), as well as in the surgical revision with 109 ± 5 (p < 0.001). In MEP (cmH 2 O), the variables also dropped compared to the preoperative period. At hospital discharge, the value was 67 ± 10 (p < 0.001) and, at surgical revision, it was 90 ± 8 (p < 0.001). As for the variables of vital capacity (ml/kg), the preoperative period obtained 45 ± 12, and there was as a decrease in the hospital discharge figures (31 ± 9, p < 0.001) and surgical revision figures (39 ± 7, p = 0.33). At the peak expiratory flow (L/min), the preoperative period was 430 ± 40. At hospital discharge, the value dropped to 310 ± 59 (p < 0.001) and, at surgical revision, it was 390 ± 32 (p < 0.001). Discussion Based on the results reported, it can be seen that coronary artery bypass grafting surgery may lead to reduced pulmonary function and it is not reestablished even after one month of the surgical procedure. According to Barros et al., 7 inspiratory and peripheral muscle strength is often described as reduced after cardiac surgery. As analyzed in this study. Patients undergoing cardiac surgery repeatedly develop postoperative pulmonary dysfunction, always presenting severe reduction in pulmonary volumes, impaired respiratory mechanics and increased respiratory work. 8 According to Cavenaghi et al., 9 pulmonary dysfunction after cardiac surgery is normal, in which the patient has severely reduced pulmonary volumes and capacities, decreased lung compliance, poorer respiratory mechanics and increased respiratory work. For Soares et al., 10 some intraoperative factors that may interfere with and justify the impairment of pulmonary function, such as the use of CPB, the degree of sedation, the intensity of surgical manipulation and the number of pleural drains, are indicated as some responsible for altering respiratory mechanics. The results obtained in this article confirm these data and corroborate the current literature, since a significant drop was observed in all spirometric variables analyzed, comparing the values obtained in the postoperative period with those from the preoperative period, hospital