Risk of postoperative complications in chronic obstructive lung diseases patients considered fit for lung cancer surgery: beyond oxygen consumption

Abstract

VO is not the unique parameter to consider when CPET is performed to evaluate the postoperative risk of lung cancer surgery in COPD patients. The signs of ventilatory inefficiency such as VE/VCO slope predict complications better than VO does.

Minute ventilation-to-carbon dioxide slope is associated with postoperative survival after anatomical lung resection

“…In our specialty, previous reports have shown that patients with VE/V CO2 slope exceeding 35 had a significant higher incidence of respiratory complications and mortality after major pulmonary resection, while VO2 max was not associated with respiratory complications [9]. Moreover, some reports [10][11][12], which were almost consistent with our previous results [9], demonstrated the efficacy and importance of 4 4 VE/V CO2 slope for predicting surgical complications in patients with chronic obstructive pulmonary disease (COPD).…”

“…Torchio [11] et al adopted the cut-off of >34 as used in heart failure patients. Shafiek et al [10] also determined cut-off value of VE/V CO2 slope as >35 for predicting postoperative complications. However, they included patients submitted to pneumonectomy, who in our opinion represent a different group of patients and analysed separately from lesser resections for the higher physiologic burden imposed by that operation.…”

Physiological and clinical relevance of exercise ventilatory efficiency in COPD

“…Resting pulmonary function tests and, to a lesser extent, peak O 2 uptake (V′O 2 ) [99] have been used to assess perioperative risk in these patients. There is mounting evidence that a high V′E−V′CO 2 slope is also a powerful predictor of poor surgical outcome for lung resection surgery [46][47][48], likely superior to peak V′O 2 [48]. In this context, a high V′E−V′CO 2 slope might indicate greater VD due to more extensive emphysema and/or high pulmonary vascular pressures, poorer cardiac performance, higher sympathetic drive, worse exertional hypoxemia and greater ergorreceptor stimulation [100].…”

“…In this context, a high V′E−V′CO 2 slope might indicate greater VD due to more extensive emphysema and/or high pulmonary vascular pressures, poorer cardiac performance, higher sympathetic drive, worse exertional hypoxemia and greater ergorreceptor stimulation [100]. Of note, however, few patients with severe to very severe COPD (who usually present with lower V′E−V′CO 2 slopes) (figure 2) undergo extensive lung resection surgery and/or pre-operative CPET [46][47][48]. Thus, it remains to be investigated whether a low V′E−V′CO 2 slope predicts poor outcome in selected patients who despite severe to very severe airflow obstruction are potential candidates for resection, e.g.…”

“…Thus, single- [51] and double-lung [61] transplantation and lung volume reduction surgery [63,66] lessened VD and increased VT thereby reducing VD/VT with consequent benefits to ventilatory efficiency. This suggests that the marked effects of these interventions on VD/VT (which would lessen V′E) relatively outweighed the consequences of lower mechanical constraints, which would otherwise increase V′E [39,[46][47][48][49][98][99][100]. Lower neural drive (e.g.…”