The effects of mechanical insufflation-exsufflation on lung function and complications in cardiac surgery patients: a pilot study

Background: Postoperative positive pressure lung expansion is associated with decreased pulmonary complications and improved clinical outcomes. The aim of the present study was to compare the differences in post-operative pulmonary complications and clinical outcomes between two groups of study subjects who underwent cardiac surgery; one included subjects who received mechanical insufflation-exsufflation (MI-E) and the other included subjects who received intermittent positive pressure breathing (IPPB) therapy. Methods: This retrospective study included 51 subjects, who underwent cardiac surgery in an intensive care unit of a tertiary hospital during the time period from June 2017 to February 2018. After liberation from mechanical ventilation, the subjects received lung expansion therapy by means of two types of positive pressure devices, MI-E (n = 21) or IPPB (n = 30). The pulmonary complications, lung function, and clinical outcomes were compared between the two groups. Results: Subjects in both groups displayed similar baseline characteristics and underwent similar types of surgical procedures. Compared to subjects who received non-oscillatory therapy, those who received MI-E therapy had higher post-operative force vital capacity (58.4 ± 4.74% vs. 46.0 ± 3.70%, p = 0.042), forced expiratory volume in one second (62.4 ± 5.23% vs. 46.8 ± 3.83%, p = 0.017), and peak flow rate (67.1 ± 5.53 L vs. 55.7 ± 4.44 L p = 0.111). However, the incidence of chest pain was higher in the MI-E group (n = 13, 61.9%) than in the IPPB group (n = 4, 16.7%; odds ratio, 0.123, 95% confidence interval, 0.03–0.45; p = 0.002). The length of hospital and ICU stay, development of atelectasis, pneumonia, and pleural effusion were similar in both the groups. Conclusion: Both IPPB and MI-E therapies have similar effects on preventing post-operative complications in cardiac surgery patients. However, compared to IPPB therapy, MI-E therapy was associated with better-preserved pulmonary function and higher incidence of chest pain.