Ventilatory efficiency slope is associated with cardiopulmonary complications after thoracoscopic anatomical lung resection

OBJECTIVES: The aim of this study was to identify whether steeper (V)over dotE/(V)over dot CO2 slope was associated with cardiopulmonary complications (CPC) after anatomical resection by video-assisted thoracic surgery. Long-term survival was analysed as secondary outcome. METHODS: We reviewed the files of all consecutive patients who underwent pulmonary anatomical resections by video-assisted thoracic surgery between January 2010 and October 2020 at the Centre for Thoracic Surgery of Western Switzerland. Logistic regression was used to investigate the risk of CPC associated with the (V)over dotE/(V)over dotCO(2) slope and other possible confounders. Survival was analysed with Kaplan-Meier curves. Risk factors associated with survival were analysed with a Cox proportional hazards model. RESULTS: The (V)over dotE/(V)over dotCO(2) slope data were available for 145 patients [F/M: 66/79; mean age (standard deviation): 65.8 (8.9)], which were included in the analysis. Patients underwent anatomical resection [lobectomy (71%) or segmentectomy (29%)] mainly for lung cancer (96%). CPC and all-cause 90-day mortality were 29% and 1%, respectively. The mean (standard deviation) percentage of the predicted V.O-2peak was 70% (17). Maximum effort during cardiopulmonary exercise test was reached in only 31% of patients. The (V)over dotE/(V)over dotCO(2) slope (standard deviation) was not different if the maximum effort was reached or not [39 (6) vs 37 (7), P = 0.21]. (V)over dotE/(V)over dotCO(2) slope >35 was associated with an increased risk of CPC (odds ratio 2.9, 95% confidence interval 1.2, 7.2, P = 0.020). (V)E/(V)over dotCO(2) slope >35 was not associated with shorter survival censored for lung cancer-related death. CONCLUSIONS: V.E/V.CO2 slope >35 is significantly associated with postoperative CPC after anatomical resections by video-assisted thoracic surgery.

Automated summary

This study found that a V.E/V.CO2 slope >35 is significantly associated with an increased risk of cardiopulmonary complications after video-assisted thoracic surgery.