Continuous Finger Blood Pressure Measurement Research Articles

Feasibility of Noninvasive Continuous Finger Arterial Blood Pressure Measurements in Very Young Children, Aged 0–4 Years

Our goal was to study the feasibility of continuous noninvasive finger blood pressure (BP) monitoring in very young children, aged 0-4 y. To achieve this, we designed a set of small-sized finger cuffs based on the assessment of finger circumference. Finger arterial BP measured by a volume clamp device (Finapres technology) was compared with simultaneously measured intra-arterial BP in 15 very young children (median age, 5 mo; range, 0-48), admitted to the intensive care unit for vital monitoring. The finger cuff-derived BP waveforms showed good resemblance with the invasive arterial waveforms (mean root-mean-square error, 3 mm Hg). The correlation coefficient between both methods was 0.79 +/- 0.19 systolic and 0.74 +/- 0.24 diastolic. The correlation coefficient of beat-to-beat changes between both methods was 0.82 +/- 0.18 and 0.75 +/- 0.21, respectively. Three measurements were related to measurement errors (loose cuff application; wrong set-point). Excluding these erroneous measurements resulted in clinically acceptable measurement bias (-3.8 mm Hg) and 95% limits of agreement (-10.4 to + 2.8 mm Hg) of mean BP values. We conclude that continuous finger BP measurement is feasible in very young children. However, cuff application is critical, and the current set-point algorithm needs to be revised in very young children.

Accuracy and reliability of noninvasive continuous finger blood pressure measurement in critically ill patients.

To evaluate the accuracy and reliability of noninvasive continuous finger blood pressure measurement in critically ill patients. Prospective data collection. Emergency department in a 2,000-bed hospital. Thirty-nine patients admitted to the emergency department requiring invasive arterial blood pressure monitoring were enrolled to the study protocol. Continuous noninvasive blood pressure measurement was performed on the middle phalanx of the second and third finger, using a test instrument which provides continuous arterial waveform display with the use of a finger cuff. Invasive mean arterial blood pressure measurement was done by cannulation of the radial artery and direct transduction of the systemic arterial pressure waveform. Three thousand one hundred eighteen pairs of simultaneous finger cuff and intra-arterial blood pressure measurements were collected in 1-min intervals from 39 patients over a total of 51.8 hrs. The overall discrepancy between both measurements was 0.10 mm Hg. The standard deviation of the differences was +/- 5.02 mm Hg. The mean bias in patients treated with catecholamines was 0.01 mm Hg and was not different from the bias observed in patients without catecholamines (mean bias: 0.23 mm Hg; p > .22). Whereas 95% of all comparisons between finger cuff and intra-arterial measurement had a discrepancy < or = +/- 10 mm Hg, 4.7% had a discrepancy between +/- 10.1 to 15 mm Hg and 0.3% exhibited a discrepancy > +/- 15 mm Hg. In 29 (74%) patients, the duration of errors > 10 mm Hg was < or = 1 min. In seven (18%) patients, the duration of errors > 10 mm Hg was between 2 to 3 mins and in three (8%) patients, the errors lasted for > 3 mins. Our data provide a guide to the accuracy and reliability of noninvasive finger blood pressure measurements in critically ill patients. Although most test instrument measurements were reliable, in 8% of all patients large discrepancies (> 10 mm Hg) between both measurements with a duration of > 3 mins were noted. Concerning the considerable risk for arterial cannulation, our preliminary data demonstrate that the test instrument (PORTAPRES, TNO Biomedical Instrumentation Research Unit; The Netherlands) is an advance in noninvasive monitoring of critically ill patients and may be useful in most emergency clinical settings.

Assessment of blood pressure and cardiac output by noninvasive continuous finger blood pressure measurement.

Assessment of blood pressure and cardiac output by noninvasive continuous finger blood pressure measurement.

A comparison of non-invasive continuous finger blood pressure measurement (Finapres) with intra-arterial pressure during prolonged head-up tilt

Simultaneous intra-radial and non-invasive (Finapres, Ohmeda) blood pressures were compared during prolonged head-up tilt, in eight patients (mean age 49 years) with malignant vasovagal syncope. Twelve tilts were performed, of which eight resulted in vasovagal syncope. The mean bias (difference between Finapres and intra-arterial pressures) for systolic pressure was +0.7 mmHg (standard deviation 11.3 mmHg) and for diastolic pressure was +5.4 mmHg (standard deviation 7 mmHg). The within-tilt precision (standard deviation of the bias) of the non-invasive measurements varied between 2.9-12.4 mmHg (median 4.5 mmHg) for systolic comparisons, and 1.6-8.4 mmHg (median 4.4 mmHg) for diastolic comparisons. In all but one tilt highly significant positive increases in both systolic (median 7.1 mmHg) and diastolic bias (median 8.1 mmHg) occurred on tilt with respect to resting pre-tilt levels. Independent of the absolute level of agreement, the non-invasive measurements followed changes in intra-arterial pressure closely, with 89% of beat-to-beat changes in systolic pressure, and 95% of beat-to-beat changes in diastolic pressure followed to within +/- 2 mmHg. This study suggests that the Finapres is well suited for use during diagnostic tilt testing, demonstrating an acceptable within-tilt precision and closely following pressure changes during vasovagal syncope.

Twenty-Four-Hour Ambulatory Noninvasive Continuous Finger Blood Pressure Measurement with PORTAPRES

PORTAPRES model 1 is a portable 24 h continuous noninvasive blood pressure recorder based on the same principles as FINAPRES, the volume-clamp method of Peñaz and the physiocal criteria of Wesseling. In addition, PORTAPRES measures two adjacent fingers in alternation every 30 min and automatically corrects hydrostatic effects due to height changes of the measured fingers. The device measures 255 x 210 x 60 mm and weights about 3,000 g, including a lithium battery pack and a TEAC cassette FM instrumentation tape recorder to record the finger pressure wave form, the height signal, and beat-to-beat derived systolic, mean and diastolic pressure as well as heart rate. It appears to be an excellent new tool for cardiovascular research in humans. In a randomized, placebo-controlled, double-blind, crossover study the effect of oral administration of 2.5 mg cilazapril, a new potent long-acting, nonsulfhydryl-group angiotensin converting enzyme (ACE) inhibitor, given once daily for 7 days, was investigated in 16 healthy young men (mean age 25.3 +/- 1.6 years). Finger blood pressure and heart rate were measured with PORTAPRES for 24 h during everyday life and during standardized laboratory tasks, once about 1 to 2 h A.M. and once about 10 to 11 h P.M. once about 1 to 2 h A.M. and once about 10 to 11 h P.M. after drug administration. Physical activity was controlled by integrated thigh-EMG. Using stepwise multiple linear regression analysis it was shown that based on 64 s mean values, this measure of physical activity explains 34-77% of the heart rate variance within 24 h (median 53%), 10-52% (31%) of systolic, and 4-38% (25%) of diastolic blood pressure variance when up to 20 time lags of the EMG signal were introduced as possible predictors. This indicates that varying degrees of physical activity have a great impact on everyday blood pressure and heart rate. After one week cilazapril did not alter 24-h means of systolic and diastolic blood pressure or heart rate significantly, but reduced 30 min averages of both systolic and diastolic blood pressure by 6-10 and 4-6 mm Hg between 1 1/2 and 4 or 6 h after drug administration respectively during everyday life (p = 0.0067-0.066) without changing heart rate. On adjusting cardiovascular variables for the effects of physical activity, this blood pressure reduction was confirmed.(ABSTRACT TRUNCATED AT 400 WORDS)

Twenty-Four-Hour Ambulatory Noninvasive Continuous Finger Blood Pressure Measurement with PORTAPRES: A New Tool in Cardiovascular Research

Twenty-Four-Hour Ambulatory Noninvasive Continuous Finger Blood Pressure Measurement with PORTAPRES: A New Tool in Cardiovascular Research

Non-invasive continuous finger blood pressure measurement during orthostatic stress compared to intra-arterial pressure

The aim of the study was to evaluate whether invasive blood pressure responses to orthostatic stress can be replaced by non-invasive continuous finger blood pressure responses. DESIGN - Intrabrachial and Finapres blood pressures were simultaneously measured during passive head up tilt and during active standing from the supine or sitting position in healthy volunteers. Subjects (n = 11) were healthy males aged 22-40 years, mean age 30 years. Beat to beat values of systolic, diastolic, and mean arterial pressures were calculated for both methods of measurement and the differences compared during a 30 s control period before, and during the first 120 s after, the change of posture. In the control period the difference between finger pressure and intra-arterial pressure was +2 (SD11) mm Hg for systolic, -4(8) mm Hg for mean, and -3(7) mm Hg for diastolic pressure. Compared to these control differences, the average finger minus intra-arterial pressure differences for mean and diastolic pressures during the three orthostatic manoeuvres were always within the range -6 to +6 mm Hg. The average systolic deviations were larger, ranging from -10 to +11 mm Hg. Despite these differences the characteristic changes in intra-arterial pressure during the initial phase (first 30 s after change of posture), as well as during the early steady state phase (1-2 min after the change of posture) were well reflected by finger pressure measurements in all subjects. For the assessment of the continuous blood pressure responses to orthostatic stress similar information can be obtained with non-invasive Finapres blood pressure recordings as with invasive recordings.