title: Finger arterial versus intrabrachial pressure and continuous cardiac output during head-up tilt testing in healthy subjects.
abstract: 1. The aims of this study were to determine the clinical feasibility of continuous, non-invasive Finapres recordings as a replacement for intrabrachial pressure during a 30 min head-up tilt, and the reliability of continuous cardiac output computation by pulse contour analysis from the finger arterial versus the brachial waveform. 2. In eight healthy subjects a 30 min 70 degrees passive head-up tilt was performed. Finger arterial (FINAP) and intrabrachial (IAP) pressures were measured simultaneously. Beat-to-beat changes in stroke volume were computed using a pulse contour algorithm. 3. Accuracy (the group-averaged FINAP-IAP difference) and precision (the SD of the difference) of Finapres measurements were 4 and 9 mmHg for systolic blood pressure, -5 and 9 mmHg for mean blood pressure and -5 and 9mmHg for diastolic blood pressure. 4. The time course of the FINAP-IAP differences during head-up tilt showed a linear trend (P < 0.001 for all pressure levels). Averaged for the group, the difference increased 7 mmHg for mean blood pressure. The difference in stroke volume computed from FINAP and IAP was 0.3 +/- 5% (mean +/- SD), and independent of the duration of the tilt (P > 0.05). This difference did not change at low blood pressure levels (0.5 +/- 6%). 5. The qualitative performance of the Finapres allows it to be used in the clinical setting as a monitor of sudden changes in blood pressure induced by a 30 min head-up tilt. Relative changes in stroke volume, as obtained by pulse contour analysis of the finger arterial waveform, closely follow intrabrachial values during long-duration head-up tilt and associated arterial hypotension.
authors.affiliation: Department of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: W T
authors.initials: WT
authors.lastname: Jellema
authors.forename: B P
authors.initials: BP
authors.lastname: Imholz
authors.forename: J
authors.initials: J
authors.lastname: van Goudoever
authors.forename: K H
authors.initials: KH
authors.lastname: Wesseling
authors.forename: J J
authors.initials: JJ
authors.lastname: van Lieshout
mesh_terms: D000328:Adult; D000465:Algorithms; D001794:Blood Pressure / Q000502:physiology; D001795:Blood Pressure Determination / Q000379:methods*; D002302:Cardiac Output / Q000502:physiology*; D005240:Feasibility Studies; D005385:Fingers; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013318:Stroke Volume / Q000502:physiology; D018667:Tilt-Table Test