Validation of the Nexfin® non-invasive continuous blood pressure monitoring validated against Riva-Rocci/Korotkoff in a bariatric patient population.

STUDY OBJECTIVE: The present study aimed to validate the Nexfin® monitor and to assess the accuracy compared to classical sphygmomanometry (Riva-Rocci/Korotkoff (RRK)) blood pressure (BP) measurements in patients with obesity scheduled for bariatric surgery. DESIGN: Validation study. SETTING: Outpatient clinic for bariatric surgery. PATIENTS: 33 patients scheduled for bariatric surgery. MEASUREMENTS: The validation process was done according to the protocols developed by the European Society of Hypertension from 2010. The Nexfin® monitor (Edwards Lifesciences/BMEYE B.V., Amsterdam, The Netherlands) calculates beat-to-beat blood pressure from finger pulse wave analysis. Measurements of systolic and diastolic BP were obtained using classical sphygmomanometry and the Nexfin® alternatingly. MAIN RESULTS: In total 99 pairs of BP measurements were used. The device failed pass phase 1 as 65 systolic readings fell within 5mmHg (73 required). And 61, 76 and 90 diastolic readings fell within 5, 10 and 15mmHg respectively. Finally, it failed to pass phase 2 as 23 patients for systolic and 25 for diastolic had at least 2/3 of their comparisons falling within 5mmHg (24 required) but 10 subjects for systolic and 8 for diastolic had all three comparisons more than 5mmHg different from the RRK readings (zero allowed). Mean differences were 7.8±6.9mmHg for SBP and 8.0±7.2mmHg for DBP. CONCLUSION: Using the revised protocol, the Nexfin® device was not able to pass validation. However using the original protocol, the Nexfin® device passed phase 1 and 2.1 of the validation process and failed to pass phase 2.2.

Use of Postoperative Peak Arterial Lactate Level to Predict Outcome After Cardiac Surgery.

OBJECTIVES: In the present study, the authors investigated the predictive value of postoperative peak arterial lactate levels for early and late mortality after cardiac surgery. DESIGN: Retrospective analysis of prospectively collected data. SETTING: Single-center study in an academic hospital. PARTICIPANTS: Adult patients who underwent cardiac surgery between 2004 and 2014 (n = 16,376). INTERVENTIONS: Different cardiac surgical procedures. MEASUREMENTS AND RESULTS: Patients were classified according to the peak arterial lactate level (PALL) within 3 days postoperatively. Logistic regression analysis and Cox regression analysis were performed to identify postoperative peak arterial lactate level as a predictor for early and late mortality respectively. In 8460 patients (51.7%), lactate was not measured postoperatively because these patients were managed according to the fast-track protocol. These patients constituted group 1 in our population but were excluded from the regression analysis. The remaining patients (n = 7,916; 48.3%) were divided according to the postoperative peak arterial lactate level (PALL): PALL<5 mmol/L (group 2), PALL 5 to 10 mmol/L (group 3), and PALL of>10 mmol/L (group 4). Early mortality was 3.7%, 20.4%, and 62.9% in groups 2, 3, and 4 respectively (p<0.0001). This mortality rate was significantly higher than that of group 1 (1.6%); p<0.0001. Multivariate regression analyses revealed postoperative peak arterial lactate as a significant predictor of 30-day mortality (odds ratio = 1.44 [1.39-1.48], p<0.001) as well as for late mortality (hazard ratio = 1.05 [1.01-1.10], p<0.025). CONCLUSIONS: Postoperative peak arterial lactate level in patients undergoing cardiac surgery is an independent predictor for both early and late mortality.