Rest PETCO2 as a Predictor of Post-operative Complications

Cardiopulmonary exercise testing (CPET) is considered to be a golden standard in preoperative risk assessment and stratification of high risk patients scheduled for major surgery. However, not all of the patients requiring surgery are willing or able to complete this type of testing. Moreover, inability to perform CPET has been linked with inferior outcomes following surgery.

Vascular surgery patients are predominantly elderly people, with significant comorbidity and high degree of frailty. Therefore, CPET as a mean of risk stratification would be of an especial interest in this group of patients. However, vascular surgery patients often present with peripheral arterial disease, which may contribute to early leg ischemia during exercise and therefore invalid cardiorespiratory reserve function measurement.

In recent years, new parameters with similar prognostic value as standard CPET parameters were studied. Specifically, the partial pressure of end-tidal carbon dioxide (PETCO2) at rest has been shown to have the same prognostic value as ventilatory efficiency in the prediction of post-operative complications in lung resection surgery patients. Whether the same parameter can be used to predict postoperative complications in a different sub-set of surgical patients (i.e. vascular surgery patients) is yet to be determined.

We hypothesized low PETCO2 at rest will be associated with the development of pulmonary and cardiovascular post-operative complications in patients after major vascular surgery. Accordingly, our aim is to compare PETCO2 measured at rest before surgery in patients who develop post-operative complications and in those who do not.

Inclusion criteria

• indication for major vascular surgery (aortobifemoral bypass surgery)

Exclusion criteria

• tracheostomy