The accuracy of blood pressure values obtained by continuous noninvasive finger blood pressure recording via the FINAPRES device was evaluated by comparison with simultaneous intraarterial monitoring both at rest and during performance of tests known to induce fast and often marked changes in blood pressure. The comparison was performed in 24 normotensive or essential hypertensive subjects. The average discrepancy between finger and intra-arterial blood pressure recorded over a 30-minute rest period was 6.5±2.6 mm Hg and 5.4±2.9 mm Hg for systolic and diastoiic blood pressure, respectively; a close between-method correspondence was also demonstrated by linear regression analysis. The beat-to-beat changes in finger systolic and diastoiic blood pressure were on average similar to those measured intra-arterially during tests that induced a pressor or depressor response (hand-grip, cold pressor test, diving test, Valsalva maneuver, intravenous injections of phenylephrine and trinitroglycerine) as well as during tests that caused vasomotor changes without major variations in blood pressure (application of lower body negative pressure, passive leg raising). The average between-method discrepancy in the evaluation of blood pressure changes was never greater than 4.3 and 2.0 mm Hg for systolic and diastoiic blood pressure, respectively; the corresponding standard deviations ranged between 4.6 and 1.6 mm Hg. Beat-to-beat computer analysis of blood pressure variability over the 30-minute rest period provided standard deviations almost identical when calculated by separate consideration of intra-arterial and finger blood pressure tracings (3.7 and 3.8 mm Hg, respectively). The two methods of blood pressure recording also allowed similar assessments of the sensitivity of baroreceptor control of heart rate (vasoactive drug injections) and blood pressure (neck chamber technique) to be obtained. Thus, beat-to-beat blood pressure recording via FINAPRES provides an accurate estimate of means and variability of radial blood pressure in groups of subjects and represents in most cases an acceptable alternative to invasive blood pressure monitoring during laboratory studies. (Hypertension 1989; 13:647-655) I n the early 1970s a Czech physiologist, Ian Penaz, described a new approach to continuous noninvasive recording of blood pressure at the finger level, 1 based on a volume-clamp method. This device was improved in its technical aspects (finger plethysmograph of reduced dimension, feedback system for finger volume control, and automatic calibration) by Wesseling and coworkers, Address for correspondence: Prof. Giuseppe Mancia, Centro di Fisiologia e Ipertensione, via F. Sforza 35, 20122 Milano, Italy. Received September 28, 1988; accepted January 19, 1989. studies performed in patients undergoing surgery, FINAPRES was shown to provide blood pressure values close to those simultaneously recorded intra-arterially. 3 -3 Our study was undertaken to evaluate the accuracy of FINAPRES in reproducing intra-arterial blood pressure v...

SUMMARYThe baroreceptor control of the sinus node was evaluated in 10 normotensive and 10 age-matched essential hypertensive subjects in whom ambulatory blood pressure was recorded intraarterially for 24 hours and scanned by a computer to identify the sequences of three or more consecutive beats hi which systolic blood pressure (SBP) and pulse interval (PI) progressively rose (+ PI/ + SBP) or fell ( -PI/ -SBP) in a linear fashion, according to a method validated in cats. In normotensive subjects, several hundred +PI/+SBP and -P I / -S B P sequences of 3 beats were found whereas the number of sequences of 4,5, and more than 5 beats showed a progressive drastic reduction. The mean slopes of + PI/ + SBP (7.6 ± 2.0 msec/mm Hg) and -P I / -SBP (6.4 ± 1.5 msec/mm Hg) sequences were similar, but in both instances there was a large scattering of the values around the mean (variation coefficients: 64.2 ± 4.7 and 62.6 ± 2.4%). The slopes decreased as a function of the sequence length and baseline heart rate and increased to a marked extent during the night as compared with daytime values. All sequences were more rare (-33.2% for +PI/ + SBP and -31.7% for -P I / -S B P ) and less steep in hypertensive subjects ( -4 0 . 3 and -3 6 . 2 % , respectively), who failed to show the marked nighttime increase in slope observed in normotensive subjects. To our knowledge, these observations provide the first description in humans of the baroreceptor-heart rate reflex in daily life. This reflex is characterized by marked within-subject variations hi sensitivity due in part to hemodynamic, temporal, and behavioral factors. All features of the baroreceptor-heart rate reflex are unpaired hi essential hypertension. (Hypertension 12: 214-222, 1988) KEY WORDS • baroreceptor reflexes • ambulatory blood pressure monitoring • hypertension sleep • humans • heart rate W E have previously reported 1 -2 that blood pressure in unanesthetized cats exhibits spontaneous rises or falls that are accompanied by linearly related increases or reductions in pulse interval (PI). We have also reported 12 that sinoaortic denervation abolishes these events, which therefore reflect baroreceptor modulation of the sinus node. We have concluded that evaluation of these events by computer analysis of intra-arterial blood pressure tracings represents a powerful tool for studying the baroreceptor-heart rate reflex in daily life.

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This study evaluated the accuracy of blood pressure values provided by the Spacelabs 90202 and 90207 devices in comparison with intra-arterial recording in 19 subjects at rest and in nine subjects in ambulatory conditions (Oxford method). At rest Spacelabs monitors reflected intra-arterial systolic blood pressure values very closely but overestimated to a considerable extent intra-arterial diastolic blood pressure (Spacelabs-intra-arterial differences, -0.8 +/- 9.2, NS, and 9.1 +/- 8.8 mm Hg, p less than 0.01, for systolic and diastolic blood pressures, respectively). In ambulatory conditions Spacelabs-intra-arterial average differences in 24-hour values were +0.4 +/- 5.1 mm Hg for systolic blood pressure (NS) and +14.0 +/- 2.9 mm Hg for diastolic blood pressure (p less than 0.01) when group data were considered. The performance of both Spacelabs devices was worse when assessed in individual subjects or for each hourly interval. In spite of these differences between noninvasive and intra-arterial absolute blood pressure values, however, Spacelabs 90202 and 90207 monitors were able to faithfully reflect directional hour-to-hour changes in intra-arterial blood pressure (chi 2 = 18.2 and chi 2 = 23.1 for systolic and diastolic blood pressures, respectively, p less than 0.01). No differences were found between the performance of the two Spacelabs devices. Thus, although the absolute accuracy of blood pressure values provided by these monitors in ambulatory subjects is still limited, they seem to be suitable for studies aimed at assessing 24-hour blood pressure profiles quantitatively as well as qualitatively.

According to the results of the validation study based on the European Society of Hypertension International Protocol the Omron M5-I, R5-I, and HEM-907 may be recommended for clinical use in elderly individuals, without atrial fibrillation or frequent ectopic beats.