Breathing reserve as a predictor of postoperative pulmonary complications in patients with lung cancer

Abstract

The objective was to assess the possibility of using breathing reserve (BR) to evaluate the individual risk of postoperative pulmonary complications (PPC) in patients who underwent open surgery for lung cancer.Materials and methods. The study involved 185 patients who underwent open surgery for lung cancer in the clinic of the Pavlov University in 2018–2020. All patients underwent cardiopulmonary exercise testing (CPET) in the preoperative period to determine the BR. All patients were retrospectively divided into 2 groups depending on the presence of PPC during 7 days after the surgery. To assess the information content of BR for predicting PPC and their outcome, the data were statistically processed: the Mann–Whitney U-test, Fisher’s exact test, Youden index and linear regression method were used.Results. PPC developed in 7 patients (3.8%), in 3 of them (42.9% of the group with PC and 1.6% of the total group) they were accompanied by acute respiratory failure (ARF), requiring reintubation and mechanical ventilation; these patients died. At the anaerobic threshold (AT), there were significant differences in BR (p = 0.003). A direct correlation was found between BR at the AT not only at the peak load but also during the unloaded cycling (UC) (closeness of connection on the Chaddock scale BR (AT) – BR (peak) ρ = 0.724, BR (AT) – BR (UC) ρ = 0.734, p < 0.001). The chances to develop PC changed as follows: in the group of patients with BR (UC) < 72.025% were 21.4 times higher (95% CI: 2.499 – 182.958); with BR (AT) < 44.136% were 27.2 times higher (95% CI: 4.850 – 152.167); with BR (peak) < 36.677% were 7.6 times higher (95% CI: 1.426 – 40.640).Conclusions. Dynamic measurement of the BR is informative at all stages of CPET. The risk of PPC and their unfavorable outcome increases when the BR is below 72.025% at the unloaded cycling, below 44.136% at the anaerobic threshold and below 36.377% at the peak load. BR can be used as a marker of the development of PPC in patients undergoing lung cancer surgery.