Portable Blood Pressure Recorder Research Articles

Ring-Shaped Pulse Oximeter and Its Application: Measurement of SpO2 and Blood Pressure During Sleep and During Flight

Respiratory and cardiovascular functions show circadian and day-to-day changes. We have developed a wireless ring-shaped pulse oximeter in collaboration with MC Medical Inc. and Advanced Medical Inc. We investigated the accuracy of this pulse oximeter and its application in daily life. Percutaneous arterial oxygen saturation (SpO2) of 47 volunteers was measured simultaneously with the ring-shaped pulse oximeter and a standard pulse oximeter. A total of 103 volunteers underwent measurement of SpO2 for 24 hr, and 11 healthy volunteers underwent measurement of SpO2 and blood pressure (BP) during flight. SpO2 and heart rate (HR) were measured and recorded every 20 sec, cabin barometric pressure and cabin oxygen concentration equivalent to sea level were measured minute-to-minute, and BP was measured every 3 min with a portable BP recorder during each flight. The SpO2 values measured with the ring-shaped pulse oximeter were similar to those measured with the standard method. The mean SpO2 during sleep was significantly lower in the group with high-normal BP or mild hypertension than in the group with normal BP. During flight, the mean change in SpO2 was -2.4 +/- 1.7% during nose-up flight, and 2.1 +/- 2.6% during nose-down flight. There was a significant correlation between change in SpO2 and change in systolic BP during nose-up flight. The wireless ring-shaped pulse oximeter was useful for investigating changes in SpO2 and its effect on BP in daily life during sleep and during air travel.

Ring-Shaped Pulse Oximeter and Its Application: Measurement of SpO2 and Blood Pressure During Sleep and During Flight

Respiratory and cardiovascular functions show circadian and day-to-day changes. We have developed a wireless ring-shaped pulse oximeter in collaboration with MC Medical Inc. and Advanced Medical Inc. We investigated the accuracy of this pulse oximeter and its application in daily life. Percutaneous arterial oxygen saturation (SpO2) of 47 volunteers was measured simultaneously with the ring-shaped pulse oximeter and a standard pulse oximeter. A total of 103 volunteers underwent measurement of SpO2 for 24 hr, and 11 healthy volunteers underwent measurement of SpO2 and blood pressure (BP) during flight. SpO2 and heart rate (HR) were measured and recorded every 20 sec, cabin barometric pressure and cabin oxygen concentration equivalent to sea level were measured minute-to-minute, and BP was measured every 3 min with a portable BP recorder during each flight. The SpO2 values measured with the ring-shaped pulse oximeter were similar to those measured with the standard method. The mean SpO2 during sleep was significantly lower in the group with high-normal BP or mild hypertension than in the group with normal BP. During flight, the mean change in SpO2 was − 2.4 ± 1.7% during nose-up flight, and 2.1 ± 2.6% during nose-down flight. There was a significant correlation between change in SpO2 and change in systolic BP during nose-up flight. The wireless ring-shaped pulse oximeter was useful for investigating changes in SpO2 and its effect on BP in daily life during sleep and during air travel.

Toward a portable blood pressure recorder device equipped with an accelerometer

The 24-h ambulatory systolic blood pressure (ASBP) recording has become a helpful tool in the diagnosis of hypertension and evaluation of the efficiency of anti-hypertensive drugs. Yet, the very high variability of ASBP makes the analysis of the recording rather difficult. A potential solution to reduce ASBP variability has been studied and is presented in this article. It consists of equipping the portable ASBP recorder device with other sensors, a three axes accelerometer and a heart rate recorder, so as to enable an analysis to be undertaken of the arterial pressure profile in the light of these concomitant data. A database has been collected, and a model linking ASBP variations with body acceleration and heart rate measurements is developed. Its performance is tested in prediction and the results compared with those obtained from one of the solutions currently used by physicians to deal with ASBP variability. The results obtained with 16 young subjects from the database, for whom two 24-h recordings are available, are significantly improved and very encouraging.

Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used for measurement of blood flow rates. An automatic portable blood pressure recorder and processor unit was used for measurement of systolic blood pressure, diastolic blood pressure, and heart rate every 15 min. The change from upright to supine position at the beginning of the night period was associated with a 30-40% increase in blood flow rate and a highly significant decrease in mean arterial blood pressure and heart rate (P less than 0.001 for all). Approximately 100 min after the subjects went to sleep an additional blood flow rate increment (mean 56%) and a simultaneous significant decrease in mean arterial blood pressure (P less than 0.001) were observed. The duration of this hyperemic phase was 116 min. A highly significant reduction of the subcutaneous vascular resistance (50%) was demonstrated during the hyperemic blood flow rate phase compared with the surrounding phases (P less than 0.0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.

Twenty-four-hour variation of blood pressure in vascular dementia of the Binswanger type.

Using a noninvasive portable blood pressure recorder, we compared 24-hour variations of blood pressure among 1) 35 patients with Binswanger-type dementia, 2) 43 with lacunar-type dementia, 3) 26 with a single lacunar stroke, and 4) 30 controls. Each group was divided into antihypertensive-treated and -untreated subgroups. Among the untreated subgroups, patients with Binswanger-type dementia had significantly greater 24-hour mean systolic blood pressures, 24-hour systolic blood pressure standard deviations, and maximal systolic blood pressure variations than the controls (p less than 0.05). Among the treated patients, blood pressure variability increased similarly in all subgroups with cerebrovascular lesions compared with the controls (p less than 0.05). The nocturnal blood pressure decreases seen in the controls were absent among both untreated and treated patients with Binswanger- or lacunar-type dementia (p less than 0.05). Our results suggest the importance of hypertension, short-term variations in blood pressure, and a sustained nighttime elevation of blood pressure for the pathogenesis of both Binswanger-type and lacunar-type dementia in patients receiving antihypertensive medication.

Long-term haemodynamic effects of amlodipine at rest and during exercise in essential hypertension

The long-term haemodynamic responses to amlodipine, a new long-acting calcium antagonist, were studied both at rest and during exercise in 18 patients (mean age 43 years) with essential hypertension. Blood pressure was measured intra-arterially, cardiac output by dye dilution and heart rate by electrocardiogram. After 11 months of treatment with 5-10 mg amlodipine once daily (mean dose 9 mg/day), mean arterial pressure was reduced by 14% sitting at rest. The reduction in blood pressure was associated with a marked reduction in the total peripheral resistance index (TPRI) of 19% (P less than 0.001). Similar responses were seen supine at rest and during 50W, 100W and 150W bicycle exercise. No significant changes were seen in heart rate. There was a slight increase in stroke index, and cardiac index was preserved at rest and during exercise with a slight trend towards an increase. In 10 of the patients, blood pressure was monitored by a portable blood pressure recorder (Accutracker II, Suntech Medical instruments, Raleigh, North Carolina, USA). Blood pressure was well controlled throughout the full 24 h period after one daily dose. In conclusion, amlodipine exerts a clear antihypertensive effect, both at rest and during exercise, through reduction in the TPRI and without a fall in cardiac pump function. No changes in heart rate were seen and there was no tendency for a reduction in the stroke index during 8 min of exercise at 150 W; on the contrary there was a trend towards an increase. The incidence of side-effects was low (ankle oedema in two patients).

Transdermal Clonidine Therapy in Hypertensive Patients

The antihypertensive effect of clonidine hydrochloride delivered at a constant rate for seven days by transdermal disks was evaluated in seven patients with essential hypertension. Blood pressure values measured at the physician's office were not significantly decreased by one month of treatment with one (n = 2) or two (n = 5) once-weekly applied clonidine transdermal disks. In contrast, blood pressure values recorded during patients' customary daily activities by means of a portable blood pressure recorder were considerably reduced, from 159/97 +/- 2/2 to 136/76 +/- 7/5 mm Hg. Plasma drug concentration at the end of the fourth week averaged 1.22 +/- 0.24 ng/mL. Plasma renin, vasopressin, and epinephrine levels were not modified by clonidine, whereas plasma norepinephrine level was significantly reduced. Local skin erythema developed in three patients and dry mouth in six. These findings suggest that clonidine transdermal disks lower blood pressure in hypertensive patients, but produce local skin lesions and general side effects.

Discrepancy between antihypertensive effect and angiotensin converting enzyme inhibition by captopril.

Captopril, an inhibitor of angiotensin converting enzyme, was administered twice daily to 13 hypertensive patients for a mean period of 9 weeks. Continuous blood pressure control in the ambulatory patients was established with a portable blood pressure recorder. Notwithstanding, in eight patients with normal renal function, plasma converting enzyme was found to resume normal activity before administration of the morning dose of captopril. Only in 5 patients with impaired renal function did some blockade of plasma converting enzyme persist for more than 12 hours. Measured plasma converting enzyme activity seemed to reflect total conversion of angiotensin I, including conversion in the pulmonary vascular bed, since changes in its activity were closely paralled by changes in plasma aldosterone levels. Bradykinin accumulation seems unlikely when converting enzyme and thus, presumably, kininase II has resumed normal activity. Captopril administration does not seem to alter plasma epinephrine or norepinephrine levels. Blood pressure reduction in the face of normal angiotensin converting enzyme activity is probably due to hyporesponsiveness of the arterioles to pressor hormones, which may be due to specific renin-related and/or nonspecific effects of captopril.

An improved fully automatic portable blood pressure recorder.

ArticleAn improved fully automatic portable blood pressure recorder.R A Schneider, G O Kimmel, and A P Van Meter JrR A Schneider, G O Kimmel, and A P Van Meter JrPublished Online:01 Nov 1974https://doi.org/10.1152/jappl.1974.37.5.776MoreSectionsPDF (955 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByNoninvasive measurement of arterial blood pressure and elastic properties using photoelectric plethysmography techniqueLong-term ambulatory monitoring of indirect arterial blood pressure using a volume-oscillometric methodMedical & Biological Engineering & Computing, Vol. 23, No. 5Ambulatory blood pressure recordings. Reproducibility and unpredictability.Hypertension, Vol. 6, No. 1Ambulatory monitoring30 November 2000 | Journal of Physics E: Scientific Instruments, Vol. 15, No. 6Portable blood pressure measurements: performance of Korotkov sound analysis techniques.Hypertension, Vol. 3, No. 5Ambulatory blood pressure monitoring: Recent advances and clinical applicationsAmerican Heart Journal, Vol. 101, No. 6Instrumentation for Physiological MeasurementsTwenty-four hour automatic monitoring of blood pressure and heart rate at work and at homeAmerican Heart Journal, Vol. 90, No. 6 More from this issue > Volume 37Issue 5November 1974Pages 776-9 https://doi.org/10.1152/jappl.1974.37.5.776PubMed4436207History Published online 1 November 1974 Published in print 1 November 1974 Metrics

A fully automatic portable blood pressure recorder.

ArticleA fully automatic portable blood pressure recorder.R A SchneiderR A SchneiderPublished Online:01 Jan 1968https://doi.org/10.1152/jappl.1968.24.1.115MoreSectionsPDF (1009 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByAmbulatory blood pressure monitoring and circadian variation of cardiovascular disease; clinical and research applicationsInternational Journal of Cardiology, Vol. 36, No. 2Methodological developments and problems of recorders for automatic, indirect, ambulatory 24-hour monitoring of blood pressureMethodische Entwicklung und Probleme automatischer, indirekt messender Monitoren zur ambulanten LangzeitblutdruckregistrierungIndirekte ambulante, automatische 24-h-Blutdruckmessung: Möglichkeiten und GrenzenLong-term ambulatory monitoring of indirect arterial blood pressure using a volume-oscillometric methodMedical & Biological Engineering & Computing, Vol. 23, No. 5Technik der BlutdruckmessungPortable blood pressure measurements: performance of Korotkov sound analysis techniques.Hypertension, Vol. 3, No. 5Ambulatory blood pressure monitoring: Recent advances and clinical applicationsAmerican Heart Journal, Vol. 101, No. 6A Monologue on Biofeedback and PsychophysiologyPsychophysiology, Vol. 14, No. 3Effects of Beta-Adrenergic Blockade on Diurnal Variability of Blood Pressure and Plasma Noradrenaline Levels24 April 2009 | Acta Medica Scandinavica, Vol. 202, No. 1-6Basiswerte und Alltagsblutdruck bei HochdruckkrankenA Portable Semiautomatic Blood Pressure Recorder8 July 2009 | Scandinavian Journal of Clinical and Laboratory Investigation, Vol. 29, No. 1Arterial pressures recorded in hospital and during ordinary daily activities: Contrasting data in subjects with and without ischemic heart diseaseJournal of Chronic Diseases, Vol. 23, No. 9 More from this issue > Volume 24Issue 1January 1968Pages 115-8 https://doi.org/10.1152/jappl.1968.24.1.115PubMed5635761History Published online 1 January 1968 Published in print 1 January 1968 Metrics

Portable blood pressure recorder Accuracy and preliminary use in evaluating intradaily variations in pressure

The portable blood pressure recorder described in this report offers a practical technique for determining intradaily variations in the level of pressure. The instrument is worn by the subject, enabling him to record his blood pressure at frequent intervals during the day while in his usual environment and performing his usual tasks. The readings are taken semiautomatically, and the aid of a physician or technician is not required. The subject does not know the levels recorded by the instrument. Preliminary observations on normotensive subjects showed that the portable recorder is sufficiently accurate for clinical purposes. In additional experiments, 3 subjects recorded their levels of pressure at intervals while carrying out their daily routines. The results indicated that the portable recorder provides valid data on variations in blood pressure throughout the day. Expanded studies on hypertensive patients should yield useful information for evaluating the highly variable natural history of hypertension.