Noninvasive Blood Pressure Measurement by the Nexfin Monitor During Reduced Arterial Pulsatility: A Feasibility Study

Abstract

Noninvasive blood pressure measurements are difficult when arterial pulsations are reduced, as in patients supported by continuous flow left ventricular assist devices (cf-LVAD). We evaluated the feasibility of measuring noninvasive arterial blood pressure with the Nexfin monitor during conditions of reduced arterial pulsatility. During cardiopulmonary bypass(CPB) in which a roller pump based or a centrifugal pump based heart-lung machine generated arterial blood pressure with low pulsatility, noninvasive arterial pressures (NAP)measured by the Nexfin Monitor were recorded and compared with invasively measured radial artery pressures (IAP).We also evaluated NAP in 10 patients with a cf-LVAD during a pump speed change procedure (PSCP). During CPB in 18 patients, the NAP-IAP average difference was -1.3 +/- 6.5 mmHg. The amplitude of pressure oscillations were 4.3 +/- 3.8 mmHg measured by IAP. Furthermore, in the cf-LVAD patients, increase in pump speed settings led to an increase in diastolic and mean arterial pressures (MAP) while the NAP acquired a sinusoidal shape as the aortic valve become permanently closed. In conclusion, NAP was similar to IAP under conditions of reduced arterial pulsatility. The device also measured the blood pressure waveform noninvasively in patients supported by a cf-LVAD.

Impact of non invasive and beat-to-beat arterial pressure monitoring on intraoperative hemodynamic management

“…There is a study, using systemic vasoactive drugs, suggesting that regional vascular tone may not be a significant contributing factor to the results obtained by this technology [42]. Secondly, although many studies have validated the Finapres technology used by Nexfin compared to standard auscultatory sphygmomanometry and intra-arterial catheterization in different populations [14,[16][17][18][19][20][21], our study showed a significant mean percent error with Bland-Altman analysis between the SBP NXF compared to SBP CUFF as well as a concordance of only 81.3%. With the new method described by Critchley et al, primarily for cardiac output monitor trending, the authors recommend a mean polar angle or angular bias of less than ±5°and radial limits of agreement less than ±30°in order for a device to display good trending ability [26].…”

“…In addition, the Nexfin device provides cardiac output values calculated based on a pulse contour analysis method described by Bogert et al [15]. The Nexfin has been well-validatedto non-invasivelyand continuously monitor arterial pressures [16][17][18][19][20][21][22].…”

Left Ventricular Assist Device Management in the ICU

“…However, contraction of the native ventricle leads to regular fluctuations in arterial blood flow and pressure (31,36,37). During LV systole, the pressure differential decreases and blood flow across the pump increases resulting in oscillations in arterial blood flow even as the aortic valve remains closed.…”

Intensivbehandlung von Kranken mit Linksherzersatz

“…Sie messen mithilfe der sog. Volume-clamp-Methodik offenbar relativ prä-zise Blutdruck-und Herzleistungsdaten wie das Schlagvolumen, die Variation des Schlagvolumens, das HZV, den systemischen Gefäßwiderstand und den kontinuierlichen Blutdruck [18,19]. Eine nichtinvasive Blutdruckmessung mit Blutdruckmanschette und Dopplersonde scheint derzeit noch am verlässlichsten zu sein.…”