Association of preoperative anaemia with cardiopulmonary exercise capacity and postoperative outcomes in noncardiac surgery: a substudy of the Measurement of Exercise Tolerance before Surgery (METS) Study

Abstract

Background: Preoperative anaemia is associated with elevated risks of postoperative complications. This association may be explained by confounding related to poor cardiopulmonary fitness. We conducted a pre-specified substudy of the Measurement of Exercise Tolerance before Surgery (METS) study to examine the associations of preoperative haemoglobin concentration with preoperative cardiopulmonary exercise testing performance (peak oxygen consumption, anaerobic threshold) and postoperative complications. Methods: The substudy included a nested cross-sectional analysis and nested cohort analysis. In the cross-sectional study (1279 participants), multivariate linear regression modelling was used to determine the adjusted association of haemoglobin concentration with peak oxygen consumption and anaerobic threshold. In the nested cohort study (1256 participants), multivariable logistic regression modelling was used to determine the adjusted association of haemoglobin concentration, peak oxygen consumption, and anaerobic threshold with the primary endpoint (composite outcome of death, cardiovascular complications, acute kidney injury, or surgical site infection) and secondary endpoint (moderate or severe complications). Results: Haemoglobin concentration explained 3.8% of the variation in peak oxygen consumption and anaerobic threshold (P<0.001). Although not associated with the primary endpoint, haemoglobin concentration was associated with moderate or severe complications after adjustment for peak oxygen consumption (odds ratio¼0.86 per 10 g L À1 increase; 95% confidence interval, 0.77e0.96) or anaerobic threshold (odds ratio¼0.86; 95% confidence interval, 0.77e0.97). Lower peak oxygen consumption was associated with moderate or severe complications without effect modification by haemoglobin concentration (P¼0.12). Conclusion: Haemoglobin concentration explains a small proportion of variation in exercise capacity. Both anaemia and poor functional capacity are associated with postoperative complications and may therefore be modifiable targets for preoperative optimisation.

The effect of coincidental SARS‐CoV‐2 infection on pre‐operative cardiopulmonary exercise testing

“…Our patient's comorbidities included iron deficiency anaemia. Anaemia is associated with poor cardiorespiratory fitness, but recent international studies have concluded that the contribution of anaemia to reduced exercise capacity is small [8]. Iron deficiency itself is also associated with reduced exercise capacity owing to its role in oxygen delivery and cellular respiration, however, studies in athletes have demonstrated that intravenous iron transfusion does not lead to increased aerobic capacity [9].…”

Effects of Electrical Impedance Tomography-Guided Positive End-Expiratory Pressure on Postoperative Cardiopulmonary Exercise Capacity in Elderly Patients: Study Protocol for a Randomized Controlled Trial

“…During this process, patients will pedal at a speed of 60 rotations per min. Typically, untrained individuals increase their productivity by 10 watts per min, while participants who regularly participate in sports activities increase their productivity by 20 to 30 watts per min [ 23 , 24 ]. The main recorded indicators are, peak oxygen consumption (VO 2peak ), and anaerobic threshold.…”

“…According to previous studies [ 27 , 28 ], it is estimated that the incidence of postoperative cardiopulmonary exercise capacity declines in elderly patients, with intermediate or high risk of 30% to 45%. Based on these reports and the results of a preliminary trial, we assume that titration of iPEEP will reduce the decline of postoperative cardiopulmonary exercise capacity by 50% of fixed PEEP.…”

Biomarker-Based Preoperative Risk Stratification for Patients Undergoing Non-Cardiac Surgery

“…The association between low functional capacity and increased morbidity and mortality is robust [6,7], however, evidence for a clear cut-off value is lacking. Therefore, all current guidelines use 4 MET as the cut-off for the definition of low functional capacity.…”