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.