Showing papers on "Ambulatory blood pressure published in 1981"

Blood pressure after stroke.

Abstract: In 334 consecutive admissions for acute stroke, the blood pressure was elevated in 84% on the day of admission. The blood pressure decreased spontaneously an average of 20 mm Hg systolic and 10 mm Hg diastolic in the ten days following the acute event without specific antihypertensive therapy and was elevated in only one third of the cases on the tenth hospital day. The early elevation in blood pressure is likely a physiological response to brain ischemia, and blood pressure falls as recovery of brain function occurs. (JAMA1981;246:2177-2180)

Do Borderline Hypertensive Patients Have Labile Blood Pressure

Abstract: The 24-hour patterns of ambulatory blood pressure were investigated in borderline (labile) hypertensive patients (office blood pressures fluctuating about 140/90 mm Hg). Sixty-three patients (21 normotensive, 21 borderline hypertensive, and 21 fixed hypertensive) had blood pressures recorded every 7.5 to 15 minutes using noninvasive automatic recorders. The mean 24-hour blood pressures (normotensive, 115 +/- 14/74 +/- 12 mm Hg; borderline hypertensive, 127 +/- 16/81 +/- 13 mm Hg; fixed hypertensive, 143 +/- 17/91 +/- 12 mm Hg) were significantly different from each other (p less than 0.005), but the standard deviations were not significantly different. The percentages of elevated blood pressures on the 24-hour recordings of the borderline hypertensive patients were intermediate between those of the normotensive and fixed hypertensive patients, but within the borderline group there was a broad range in percentage of elevated blood pressures (7.9% to 81.2%). Thus, borderline hypertensive patients have blood pressures no more labile than those in normotensive or fixed hypertensive patients, but because of their broad range of percentage of elevated blood pressures, their pressures are best evaluated with multiple measurements.

The Antihypertensive Effects of a Pure and Selective Serotonin-Receptor Blocking Agent (R 41 468) in Elderly Patients:

Abstract: In a first experiment, an acute intravenous administration of 10 mg R 41 468, a pure serotonin-receptor blocking agent with high selectivity for blood vessels and thrombocytes and devoid of central effects, dramatically reduced systolic and diastolic blood pressure in 23 elderly hypertensive patients. Heart rate and cardiac output remained virtually unchanged.In a second double-blind placebo-controlled cross-over study a highly significant decrease of systolic and diastolic blood pressure was obtained in 14 elderly hypertensive patients during an 8-day oral treatment with 40 mg t.i.d. of R 41 468. No serious side-effects were observed. An oral maintenance therapy with R 41 468 for 3 weeks showed a further reduction of blood pressure, resulting in a normalization of blood pressure, taking into account the advanced age of the patients.R 41 468 most probably acts by decreasing the venous capacitance bed constriction. Essential hypertension might be causally related to an impair ment of venous function, in wh...

Blood Pressure and Heart Rate Responses to Anticipated High-stress Dental Treatment

Abstract: Twenty-four healthy adults participated in a study to determine the effects of anticipated high-stress dental treatment on blood pressure and heart rate. Blood pressure, heart rate, and state anxiety were assessed prior to four consecutive dental appointments. Appointments 1, 2, and 4 were of relatively low stress and appointment 3 was of relatively high stress. Blood pressure was unaffected while heart rate was highest prior to appointment 3 and lowest prior to appointment 1.

A study of the antihypertensive action of xipamide using ambulatory intra-arterial monitoring.

Abstract: 1 The antihypertensive activity of the diuretic xipamide has been studied in 18 patients with mild/moderate essential hypertension using the technique of continuous ambulatory intra-arterial blood pressure recording. Full data from 48 h blood pressure recordings before and after treatment were available from 13 patients. 2 After a mean period of 3 months' treatment with xipamide 20 mg once daily, both systolic and diastolic blood pressure were markedly reduced throughout the whole 24 h day, the reductions of systolic being statistically significant throughout the whole period, and of diastolic for 19 out of the 24 hourly periods measured. There was no postural hypotension seen during treatment and there was a conspicuous lack of side effects. 3 Xipamide would appear to be as effective as many beta-adrenoceptor blockers but without their side effects and produces a better control of blood pressure throughout the whole day and night.

Blood pressure measurement apparatus

Abstract: Long-term blood pressure measuring apparatus, particularly adapted for ambulatory blood pressure monitoring where the subject can be engaged in normal activities while blood pressure is being measured and to be worn by the subject whose blood pressure is to be measured uses an inflatable cuff, a pump for inflating the cuff, valves for controlling the pressure in the cuff, sensors for the cuff pressure and for auscultatory (Korotkoff) sounds from the subject, a recorder for recording the sounds and blood pressure measurement cycle control circuits. The control circuits provide for blood pressure measurement cycles to recur repetitively at predetermined time intervals, for example every 30 or 60 minutes over a period of many hours, as well as when the subject manually activates the cycle control circuit to produce a blood pressure measurement cycle, but only when an automatic cycle occurs between successive manual cycles so as to limit the frequency of the blood pressure measurement so as to prevent harm to the subject and to conserve power needed for long-term operation of the apparatus. Circuits which control a valve use a linear ramp generator and triangular wave generator to provide a linear change in cuff pressure while the auscultatory sounds are recorded to enable accuracy of indication of the blood pressure from the recorded sounds.

Indoramin: 24 hour profile of intra-arterial ambulatory blood pressure, a double-blind placebocontrolled crossover study

Abstract: 1 Indoramin is a new α-adrenoceptor blocking agent. We have evaluated the profile of blood pressure reduction over 24 h with intra-arterial ambulatory blood pressure monitoring by means of a double-blind placebo-controlled crossover trial. The effect on the heart rate was also recorded. 2 The blood pressure response to standardized procedures including supine rest, tilt, isometric and dynamic bicycle exercise were also recorded. 3 Indoramin caused a significant reduction of the ambulatory blood pressure during 16 h of the day for systolic pressures and 12 h for diastolic pressures. 4 There was no evidence of postural hypotension or sustained reflex tachycardia. The absolute blood pressures were lowered during isometric and dynamic exercise. 5 Indoramin was associated with a high incidence of side-effects; however if used in combination with other antihypertensive agents a lower dose might well be better tolerated.

Evaluation of a slow-release clonidine preparation by direct continuous blood pressure recording in essential hypertensive patients.

Abstract: The antihypertensive effect of a slow-release (SR) clonidine preparation was evaluated in hypertensive patients not confined to bed using a 24-h intraarterial blood pressure monitoring (Oxford) method. The monitoring was carried out during placebo administration and after 7-10 days of daily administration of SR clonidine in a single oral dose (250 or 500 microgram). An analysis of all the blood pressure values obtained was performed by computer. The results were as follows: (a) SR clonidine significantly reduced the 24-h systolic and diastolic arterial pressure by 16 and 10 mm Hg, respectively (mean +/- SE). (b) The reduction was well evident throughout the 24-h period, the average decrease in mean arterial pressure observed during the first, second, and third 8-h period after the administration of the drug being 11, 14, and 14 mm Hg, respectively. (c) The blood pressure reduction was similar during the daytime and the nighttime, despite the lower base-line value that occurred in the latter condition. (d) There was no consistent change in blood pressure variability, as measured in each patient by the standard deviation of the blood pressure values, with SR clonidine. SR clonidine caused a reduction in heart rate that, as that in blood pressure, was well evident throughout the 24 h. It is concluded that SR clonidine is an effective antihypertensive agent and that a single administration of this drug can produce a clear-cut reduction in the blood pressure values of hypertensive patients for a 24-h period.

Clinical evaluation of the Dinamap noninvasive blood pressure monitor in pre-term neonates

Abstract: The performance of the Dinamap 847 non-invasive blood pressure monitor was evaluated in a group of 10 severely ill pre-term newborn babies. The mean gestational age was 30 weeks and mean birthweight of 1610 gm. The values of systolic, diastolic and mean arterial pressure obtained by the Dinamap were compared with the corresponding values of actual pressure through a right radial artery catheter. All these values showed a high degree of correlation. No complications were noted. It was concluded that the Dinamap 847 should be considered as an alternative for monitoring the arterial blood pressure in pre-term neonates where arterial catheterisation is either not justified or impossible.

Studies on neural regulation of blood pressure in hypertension

Abstract: Resetting of baroreceptor afferent firing in hypertensive animals, and the reduction in baroreflex regulation of the heart rate seen in man, are thought to be secondary to changes in vascular distensibility in hypertension. Diminished baroreflex sensitivity should be reflected in a withdrawal of inhibition of sympathetic nervous function. This hypothesis was investigated in 62 hypertensive subjects using three indirect indices of sympathetic nervous activity: (1) the haemodynamic responses to mental and physical exercise, (2) plasma noradrenaline concentrations at rest, and on exercise, and (3) the beat-to-beat variability of waking ambulatory blood pressure. Subjects with diminished baroreflex sensitivity (1) achieved higher maximum mean arterial blood pressures during four different exercises, and greater absolute increases in blood pressure when bicycling, (2) tended (P The time course and extent of changes in baroreflex sensitivity, in relation to changes in the heart and (by inference from previous work) the peripheral vasculature, during the development and reversal of 2-kidney 1-clip Goldblatt hypertension was investigated in rats. A reduction in baroreflex sensitivity occurred within three days of renovascular hypertension, before the occurrence of cardiovascular changes and resetting of the threshold for carotid sinus activation. Baroreflex sensitivity returned to normal one day after the reversal of renovascular hypertension, at a time when these structural changes were still present. It was concluded that 'non-structural', rather than 'structural' factors were responsible for the reduction in baroreflex sensitivity during the initial stages of renovascular hypertension.

Clinical relevance of ambulatory blood pressure measurements.

Abstract: The development of vascular complications in patients with hypertension is related to the level of blood pressure. A more representative measure of blood pressure is obtained by repeatedly measuring pressure after a period of rest or activity, and on several occasions. Really satisfactory values are, however, only obtained by multiple measurements throughout the day during a patient's normal activities. This is achieved with the Remler equipment (Model M-100-1 and M 2000). The working of the apparatus is described and its accuracy investigated. The findings of 675 untreated patients with essential hypertension are reviewed, and a few individual cases described which have been followed up to 10 years.

Effects of long-term, once-daily administration of atenolol on ambulatory blood pressure of hypertensive patients.

Abstract: We measured intraarterial, ambulatory blood pressure over a 24-h period in 12 subjects 24--63 years (mean 47.6) of age with newly diagnosed untreated hypertension. Measurements were performed both before and after 2--9 months of once-daily treatment with atenolol, a cardioselective beta-adrenoceptor antagonist. Significant reductions in arterial pressure (p less than 0.005) during treatment with atenolol (dose range 50--200 mg) were observed over the full 24-h period.

Cardiovascular changes during controlled blood loss and replacement.

Abstract: Changes in central venous pressure, systolic arterial pressure and pulse rate were recorded in 31 patients undergoing surgery involving withdrawal of 1 litre of blood and subsequent transfusion. Central venous pressure gave immediate and consistent indications of blood loss and replacement but blood volume changes could not be correlated numerically with central venous pressure. No difference was found between patients anaesthetised using spontaneous ventilation with halothane and intermittent positive pressure ventilation.

Continuous tape-recording of ambulatory blood pressure. Technical considerations.

Abstract: A technique of recording continuous intra-arterial blood pressure in fully ambulatory subjects, on to magnetic tape is described. This method makes use of a specially developed transducer-perfusion unit, which incorporates a strain-gauge pressure transducer and a perfusion system using an electrical "delta" pump. The signal is recorded on cassette tape using a miniature physiological recorder. This recording method has been fully evaluated in the laboratory and has been used clinically on 550 occasions with satisfactory results. Technical limitations and clinical experience of this recording technique are discussed.

Piretanide in the treatment of hypertension. Effects on arterial blood pressure and several blood variables.

Abstract: Piretanide presented in 6 mg sustained-release capsules was administered twice daily for 12 weeks as antihypertensive monotherapy to 16 patients with mild-to-moderate hypertension. No steady or monotonic statistically significant decrease in blood pressure occurred during piretanide treatment, and the drug was therefore not found to be an effective antihypertensive agent. Statistically significant falls in serum potassium values were found at the ends of weeks 4 (P less than 0.01) and 8 (P less than 0.01), but these had no clinical importance. Serum magnesium values had decreased significantly (P less than 0.02) by the end of week 12. Mean blood glucose values did not change significantly, but 4 patient developed diabetic hyperglycaemia.

Home blood pressure and circadian variation of blood pressure in the evaluation of hypertensive patients.

Abstract: Clinic blood pressures measured at clinic by physician were higher than home blood pressures measured at home by patients in the majority of untreated patients with essential hypertension, but equivalent or lower in some patients. Clinic minus home blood pressure (ΔP) were correlated with the levels of clinic blood pressure (r = 0.51, p<0.005 for systolic; r = 0.35, p<0.02 for diastolic blood pressure, respectively). The systolic ΔP might be greater in the middle-aged women, especially in the fifties of females than the age-matched males (p<0.05). The ΔP could not be altered by any antihypertensive drugs with the exception of systolic ΔP with diuretic alone. The blood pressure tended to remain more stable throughout the 24-hour period in proportion as the severity of hypertension increased. The observation of circadian variation in blood pressure disclosed that the blood pressure was lower in the morning, but increased gradually, resulting in the relatively high blood pressure between the afternoon and evening in the low renin and volume expanded type of hypertension. On the contrary, the blood pressure was already high in the early morning in hypertensive patients characterized by the accelerated renin-angiotensin system and contracted volume factor.

Effects of oxprenolol on the intra-arterial blood pressure response to dynamic exercise in hypertensive men.

Abstract: The intra-arterial blood pressure of 20 male patients with essential hypertension was continuously recorded during dynamic exercise. Graded exercise testing on a bicycle ergometer and a stair-climbing test were performed prior to and during treatment with oxprenolol. Acute oxprenolol therapy was associated with a reduction in heart rate but little reduction in blood pressure. Chronic treatment for 14.3 weeks with oxprenolol (mean daily dose, 344 mg) was associated with a substantial reduction of blood pressure at rest and at each level of bicycle exercise. A similar antihypertensive effect was demonstrated during stair climbing. The normal blood pressure response to exercise as assessed by the relative (percentage) increase in pressure above the pre-exercise level and the rate of increase in blood pressure (per unit of work), as well as exercise tolerance, were unchanged by chronic beta-blockade with oxprenolol.

Blood pressure variations to be considered in the treatment of hypertension.

Abstract: Diurnal variations of the basal blood pressure in patients with essential hypertension were investigated by the indirect recording methods. To estimate the reduction in blood pressure at midnight, disturbance of sleep in the patients should be considered. Relationship between neurohumoral factors and the diurnal blood pressure variations were also evaluated. 1) Variations of the casual blood pressure at the clinic visits may be stabilized beyond 15 minutes of the sitting rest. 2) During the out-patient treatment of essential hypertension with placebo for 6 weeks, 16% of the patients showed reduction in mean arterial pressure of 13 mmHg or more. 3) Significant influence of seasons on blood pressure was not apparent for 6 weeks of the placebo treatment of hypertension. But in patients under the long-term antihypertensive treatment, blood pressure in summer was maintained significantly lower than in winter. 4) Self-monitoring of blood pressure by patients at home is valuable for estimating diurnal changes of blood pressure with the antihypertensive treatment.