Validation of the PreOperative Score to predict Post-Operative Mortality (POSPOM) in Dutch non-cardiac surgery patients.

BACKGROUND: Standardized risk assessment tools can be used to identify patients at higher risk for postoperative complications and death. In this study, we validate the PreOperative Score to predict Post-Operative Mortality (POSPOM) for in-hospital mortality in a large cohort of non-cardiac surgery patients. In addition, the performance of POSPOM to predict postoperative complications was studied. METHODS: Data from the control cohort of the TRACE (routine posTsuRgical Anesthesia visit to improve patient outComE) study was analysed. POSPOM scores for each patient were calculated post-hoc. Observed in-hospital mortality was compared with predicted mortality according to POSPOM. Discrimination was assessed by receiver operating characteristic curves with C-statistics for in-hospital mortality and postoperative complications. To describe the performance of POSPOM sensitivity, specificity, negative predictive values, and positive predictive values were calculated. For in-hospital mortality, calibration was assessed by a calibration plot. RESULTS: In 2490 patients, the observed in-hospital mortality was 0.5%, compared to 1.3% as predicted by POSPOM. 27.1% of patients had at least one postoperative complication of which 22.4% had a major complication. For in-hospital mortality, POSPOM showed strong discrimination with a C-statistic of 0.86 (95% CI, 0.78-0.93). For the prediction of complications, the discrimination was poor to fair depending on the severity of the complication. The calibration plot showed poor calibration of POSPOM with an overestimation of in-hospital mortality. CONCLUSION: Despite the strong discriminatory performance, POSPOM showed poor calibration with an overestimation of in-hospital mortality. Performance of POSPOM for the prediction of any postoperative complication was poor but improved according to severity.

TRACE (Routine posTsuRgical Anesthesia visit to improve patient outComE): a prospective, multicenter, stepped-wedge, cluster-randomized interventional study.

BACKGROUND: Perioperative complications occur in 30-40% of non-cardiac surgical patients and are the leading cause of early postoperative morbidity and mortality. Regular visits by trained health professionals may decrease the incidence of complications and mortality through earlier detection and adequate treatment of complications. Until now, no studies have been performed on the impact of routine postsurgical anesthesia visits on the incidence of postoperative complications and mortality. METHODS: TRACE is a prospective, multicenter, stepped-wedge cluster randomized interventional study in academic and peripheral hospitals in the Netherlands. All hospitals start simultaneously with a control phase in which standard care is provided. Sequentially, in a randomized order, hospitals cross over to the intervention phase in which patients at risk are routinely followed up by an anesthesia professional at postoperative days 1 and 3, aiming to detect and prevent or treat postoperative complications. We aim to include 5600 adult patients who are at high risk of developing complications. The primary outcome variable is 30-day postoperative mortality. Secondary outcomes include incidence of postoperative complications and postoperative quality of life up to one year following surgery. Statistical analyses will be performed to compare the control and intervention cohorts with multilevel linear and logistic regression models, adjusted for temporal trends and for clusters (hospitals). The time horizon of the economic (cost-effectiveness) evaluation will be 30 days and one year following surgery. DISCUSSION: TRACE is the first to study the effects of a routine postoperative visit by an anesthesia healthcare professional on mortality and cost-effectiveness of surgical patients. If the intervention proves to be beneficial for the patient and cost-effective, the stepped-wedge design ensures direct implementation in the participating hospitals. TRIAL REGISTRATION: Nederlands Trial Register/Netherlands Trial Registration, NTR5506 . Registered on 02 December 2015.

Minimally Invasive Determinations of Oxygen Delivery and Consumption in Cardiac Surgery: An Observational Study.

OBJECTIVE: Evaluate minimally invasive assessment of oxygen delivery (DO2) and oxygen consumption (VO2) and determine its level of agreement with the gold standard approach of those measurements in patients undergoing cardiac surgery. DESIGN: Observational study. SETTING: Single center, VU University Medical Center (Amsterdam, The Netherlands). PARTICIPANTS: The study comprised 29 adult patients. INTERVENTION: Parallel measurements of invasive and minimally invasive parameters required for the calculation of DO2 and VO2. MEASUREMENTS AND MAIN RESULTS: Measurements were performed after anesthesia induction (T1) and before sternal closure (T2) in adult cardiac surgery. The invasive approach included arterial and pulmonary artery catheter-derived blood sampling and cardiac output measurements. The minimally invasive approach included pulse oximetry, point-of-care hemoglobin, Nexfin-based cardiac output, and central venous catheter-derived blood sampling. Level of agreement was determined using Bland-Altman analysis and percentage error. DO2 and VO2 levels were determined in patients 71 ± 8 years old. DO2 measurements showed a level of agreement of -17 ± 57 L/min/m2 and -18 ± 72 L/min/m2 with percentage errors of 35% and 38% at T1 and T2, respectively. VO2 assessment showed a level of agreement of -5 ± 18 L/min/m2 and -12 ± 22 L/min/m2, with percentage errors of 47% at T1 and T2. The highest percentage errors were for cardiac output measurements, 33% and 28% at T1 and T2, respectively. CONCLUSION: Agreement between minimally invasive and invasive DO2 and VO2 determinations is, moderate and poor, respectively. These findings may be explained by the poor agreement between minimally invasive and invasive cardiac output measurements.