Neurosurgical procedures in sitting position need advanced cardiovascular monitoring. Transesophageal echocardiography (TEE) to measure cardiac output (CO)/cardiac index (CI) and stroke volume (SV), and invasive arterial blood pressure measurements for systolic (ABPsys), diastolic (ABPdiast) and mean arterial pressure (MAP) are established monitoring technologies for these kind of procedures. A noninvasive device for continuous monitoring of blood pressure and CO based on a modified Penaz technique (volume-clamp method) was introduced recently. In the present study the noninvasive blood pressure measurements were compared with invasive arterial blood pressure monitoring, and the noninvasive CO monitoring to TEE measurements.
Measurements of blood pressure and CO were performed in 35 patients before/after giving a fluid bolus and a change from supine to sitting position, start of surgery, and repositioning from sitting to supine at the end of surgery. Data pairs from the noninvasive device (Nexfin HD) versus arterial line measurements (ABPsys, ABPdiast, MAP) and versus TEE (CO, CI, SV) were compared using Bland-Altman analysis and percentage error.
All parameters compared (CO, CI, SV, ABPsys, ABPdiast, MAP) showed a large bias and wide limits of agreement. Percentage error was above 30% for all parameters except ABPsys.
The noninvasive device based on a modified Penaz technique cannot replace arterial blood pressure monitoring or TEE in anesthetized patients undergoing neurosurgery in sitting position.
*Department of Anesthesiology
‡Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center, Johannes Gutenberg University Mainz, Mainz
†Department of Anesthesiology, Christophorus Hospital, Coesfeld, Germany
Data presented in this manuscript are part of a doctoral thesis presented by T.G. (Medical Student, Department of Anesthesiology, University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany) to the Medical Faculty.
BMeye (Amsterdam, The Netherlands) gave an unrestricted educational grant to this study by a loan agreement for the Nexfin HD monitor and disposables. G.P. received honoraria for lectures from BMeye, Amsterdam, The Netherlands, and Nihon-Kohden Europe, Rosbach, Germany. The remaining authors have no conflicts of interest to disclose.
Address correspondence to: Patrick Schramm, MD, PhD, Department of Anesthesiology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany (e-mail: firstname.lastname@example.org).
Received July 24, 2015
Accepted February 28, 2016