Diastolic Blood Pressure Readings Research Articles

The effect of smoking on the risk of gestational hypertension

Data from the 1988 National Maternal and Infant Health Survey were used to examine the effect of smoking on the risk of gestational hypertension (GH). GH was defined as the occurrence of two consecutive diastolic blood pressure readings of at least 90 mmHg after the 20th week of gestation in the absence of proteinuria in subjects normotensive prior to pregnancy. One-hundred ten subjects with gestational hypertension were compared with 4371 subjects free of all hypertensive disorders. Smoking during pregnancy was associated with a reduction in risk of GH overall (Odds Ratio (95% CI) = 0.18 (0.07–0.43)) and within each race and parity subgroup. When the protective effect of smoking was examined by race, black subjects appeared to benefit less from smoking compared with whites but the weaker effect in blacks was attributable to less smoking by blacks. Parous subjects experienced a larger reduction in the risk of GH associated with smoking than nulliparous subjects and this persisted at each dose level of smoking. Neither the protective effect of smoking nor the difference by parity appeared to be due to confounding by race, age, weight gain, alcohol use or marijuana use (adjusted OR (95% CI): nulliparous 0.28 (0.09–0.94) vs. parous 0.10 (0.03–0.30)).

Evaluation of the Colin STBP-680 at rest and during exercise: an automated blood pressure monitor using R-wave gating.

The application of automated blood pressure measurement during exercise has been limited by inaccuracies introduced by the effects of accompanying motion and noise. We evaluated a newly developed automated blood pressure monitor for measuring exercise blood pressure (Colin STBP-680; Colin, San Antonio, Texas, USA). The STBP-680 uses acoustic transduction with the assistance of the electrocardiogram R-wave to trigger the sampling period for blood pressure measurement. The automated monitor readings were compared with simultaneous technician mercury sphygmomanometric readings in the same arm. Blood pressure was measured in 18 men at rest and during exercise at 40% VO2 peak, (low intensity), 70% VO2 peak (moderate intensity) and VO2 peak (high intensity) on the cycle ergometer. Mean(s.d.) systolic blood pressure difference between the automated monitor and mercury manometer readings at rest and during exercise at low, moderate and high work intensities were 3(0) mmHg, 3(2) mmHg, 1(1) mmHg, and 0(11) mmHg respectively (analysis of variance; P > 0.05). Resting diastolic blood pressure obtained with the STBP-680 was similar to the mercury manometer readings (78(10) versus 81(7) mmHg (P > 0.05). Exercise diastolic pressure at the low level of work intensity was almost identical between the automated monitor and mercury manometer readings (64(8) versus 65(10) mmHg (not significant)). Diastolic blood pressure readings between the STBP-680 and mercury manometer showed a greater difference at the moderate and high workloads (11 mmHg and 9 mmHg, respectively), but this difference was not significant (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinic blood pressure measurements and blood pressure load in the diagnosis of hypertension.

We have retrospectively compared the blood pressure load derived from 24 hour ambulatory blood pressure monitoring in patients with all clinic blood pressure readings elevated with those with only some elevated pressures to establish whether clinic readings alone are good predictors of blood pressure status. Fifty-seven patients attending a district general hospital hypertension clinic who were not on anti-hypertensive treatment were selected. Between two and six clinic readings were taken over a period of 1-6 months. Forty out of 57 patients had at least one clinic diastolic blood pressure reading of < 90 mmHg and, of these, 14 (35%) had a high blood pressure load and 26 (65%) had a normal blood pressure load. Patients with all diastolic blood pressure readings > 90 mmHg totalled 17 and of these 11 (65%) had high load and six (35%) had normal load. Patients with clinic diastolic blood pressure > 90 mmHg were significantly more likely to be truly hypertensive on the basis of blood pressure load than if one or more clinic readings was below 90 mmHg (P < 0.05). Diastolic pressures have some predictive power as to the blood pressure status defined by blood pressure load, but even consistently raised diastolic pressures do not necessarily indicate hypertension. Likewise one or more clinic diastolic blood pressure < 90 mmHg does not assuredly indicate normotension. Twenty-four hour ambulatory blood pressure monitoring may have an increasingly important role in the assessment of hypertension.

Limitations of an oscillometricambulatory blood pressure monitor in physically active children

To determine the limitations of an oscillometric device for measuring ambulatory blood pressure in physically active children. Observational descriptive. Sixty-one children 4.3 to 18.7 years of age. Twenty-two high school students wore an ambulatory blood pressure monitor (SpaceLabs model 90202) for 24 hours. A subject-kept activity diary facilitated data interpretation. In 39 additional subjects, measurements were recorded during strenuous exercise, at rest, and after ambulation. Before and after the students wore the unit, oscillometric and auscultatory blood pressure measurements were simultaneously taken to calibrate the ambulatory blood pressure monitor, evaluate its accuracy, and assess deterioration in the calibration of the unit with use. During 24-hour ambulatory monitoring, 29% of the readings were edited because of error codes, primarily because of vibratory interference. At the end of the 24-hour monitoring period, simultaneous pressures by oscillometric and auscultatory techniques agreed within 6 mm Hg in 17 of 18 cases for both systolic and diastolic blood pressures. During exercise, 88.4% of the systolic and diastolic blood pressure readings agreed within 8 mm Hg. In 20 other ambulatory subjects with 80 simultaneous oscillometric and auscultatory measurements, all systolic and 88.5% of the diastolic values agreed within 10%. These results indicate that the SpaceLabs model 90202 unit provides a reasonably accurate assessment of ambulatory blood pressures in mildly active and inactive children and that blood pressure can be monitored with time.

Assessment of oscillometric non-invasive blood pressure monitors using the Dynatech Nevada CuffLink analyser.

The assessment of the functional performance of non-invasive blood pressure (NIBP) monitors using a commercially available NIBP analyser (Dynatech CuffLink) was evaluated. The CuffLink includes facilities for performing a static pressure calibration, and safety cut-out pressure, leak rate and rapid deflate time measurements. Cuff pressure oscillations simulating a range of blood pressures at a range of heart rates enable dynamic tests of NIBP monitors to be performed. By reducing the magnitude of the cuff pressure oscillations the sensitivity of a monitor to weak pulsations can be determined. The CuffLink does not provide facilities for assessing the ability of the monitor to reject movement artifact. The CuffLink tests were performed on 10 different models of NIBP monitor. The results demonstrate the variable nature of systolic, diastolic and mean blood pressure readings from NIBP monitors (even under stable laboratory conditions), reinforcing the importance of not relying on individual readings, but rather to consider the average of a few successive readings. Normative data for two models of NIBP monitor are provided. Applications of the CuffLink are discussed with reference to a protocol for NIBP monitor performance checks.

Repeated Systolic, But not Diastolic Blood Pressure Readings Fall at a Single Visit in the Elderly

Repeated Systolic, But not Diastolic Blood Pressure Readings Fall at a Single Visit in the Elderly

Effects of alterations in fatty acid intake on the blood pressure of adolescents: the Exeter-Andover Project

To judge the effect on blood pressure, the ratio of polyunsaturated to saturated fatty acids (P:S) of foods served to students at two boarding high schools was modified alternately at each school for one school year. The average P:S of the diet of males increased from 0.53 to 0.93 during the intervention whereas among females it increased from 0.64 to 0.98. Comparison of repeated systolic and diastolic blood pressure measurements near the end of the school year did not demonstrate a beneficial effect of the dietary fat changes on the blood pressure of these normotensive adolescents. Compared with the blood pressure patterns during control years, the dietary intervention resulted in slightly higher systolic (+0.88 mm Hg; 95% CI -0.66, +2.42) and diastolic (+1.23 mm Hg; 95% CI = +0.04, +2.42) blood pressure readings among males. Among females the intervention resulted in slightly lower systolic (-0.54 mm Hg; 95% CI = -1.95, +0.88) and diastolic (-0.80 mm Hg (95% CI -2.18, +0.58) blood pressure readings.

Pedigree analysis of blood pressure in subjects from rural Greece and relatives who migrated to Melbourne, Australia.

Diastolic blood pressure readings taken in 1983-1984 on 1,474 Greek individuals (628 living on the island of Levkada, 846 relatives having migrated to Melbourne, Australia) from 204 two generational pedigrees were analysed. Blood pressure was regressed as a quadratic in age by sex and migrant status, and on temperature. Variance increased with age and was greater in migrant males. The covariance between relatives in different countries was significant. Variation was modeled by a multivariate normal model for pedigree analysis in terms of genetic effects, a common environment effect, and effects particular to an individual. The genetic component was 25.9 mm Hg2, independent of sex and migrant status. Importantly, the common environment component was not significant. The third component was greatest in migrant males. Spouse correlation was -0.09 (SE = 0.03). Exclusion of 86 individuals who reported currently receiving medication for elevated blood pressure stabilised the variance and decreased the genetic component. The data suggest that familial aggregation of diastolic blood pressure is due to genetic factors which produce the same variation in males and females, living on Levkada or in Melbourne. Nongenetic factors explain the greater variation in blood pressure of migrant males living in Melbourne.

Blood pressure changes associated with tilting in normotensive subjects: Differences in response pattern as measured by oscillometry and auscultation

Three non-invasive instruments were used to measure blood pressure in the supine position and on tilting--a conventional and a random-zero sphygmomanometer, and an oscillometric device (Accutorr 1A). Twenty normotensives volunteered for the study. There was no statistically significant difference in systolic blood pressure and diastolic blood pressure measured by the conventional and random-zero sphygmomanometers in the supine position. There was a difference between these recordings and those of the Accutorr, with the Accutorr giving higher readings of systolic blood pressure (p less than 0.001), analysis of variance, 95% confidence interval of the difference between the Accutorr and the random-zero was 5.1-15.7 mmHg) and lower readings of diastolic blood pressure (p less than 0.0001, analysis of variance, 95% confidence interval of the difference between the Accutorr and the random-zero was -12.2- -2.2 mmHg). On tilting, the Accutorr showed an increase in systolic blood pressure while the other two machines did not (p less than 0.01, analysis of variance). By contrast, the Accutorr detected a smaller rise in diastolic blood pressure than with the other two instruments (p less than 0.05, analysis of variance). The difference between blood pressure measurements made in the supine position by the two different techniques, auscultation and oscillometry, might be expected. However, the two different techniques do not detect the same blood pressure responses to a change in posture.

Normal fluctuation of physiologic cardiovascular variables during anesthesia and the phenomenon of “smoothing”

With the advent of automated anesthesia record keeping devices, concern has arisen that "abnormal" values will appear in the record and possibly lead to medicolegal compromise. A retrospective review of automated records from a series of anesthesia cases was undertaken to determine if abnormal values do occur, how frequent they are, and whether they cause problems. A total of 14,826 (4,942 each) noninvasive heart rate, systolic, and diastolic blood pressure readings from 118 case printouts generated by a Diatek Arkive Patient Information Management System (63 cases) or a Datascope Datatrac record keeper (55 cases) were recorded. The study sample covered a broad range of surgical operations, anesthetic procedures, and patient ages and medical histories. During these 118 anesthetics, the majority of readings of all three variables fell within normal ranges (defined for this study as 80 to 180 and 50 to 110 mm Hg for systolic and diastolic blood pressures, respectively, and 60 to 140 beats/min for heart rate). During the anesthetics, 3.6% of the systolic pressure readings, 13.25% of the diastolic readings, and 4.25% of the heart rate readings were recorded outside these ranges. No serious intraoperative or postoperative anesthesia complications were associated with these out-of-range readings, nor would they be expected in a sample of this size, since serious anesthetic complications are rare. This preliminary observation of one person's experience may help address the concern associated with allowing high and low blood pressure and heart rate readings to be automatically recorded "unsmoothed." In medicolegal situations, it should also begin to demonstrate that such fluctuations are neither uncommon nor abnormal, and that a true record of these readings should be neither a cause for concern nor an opportunity for medicolegal exploitation.

Ambulatory Blood Pressure Patterns in Children and Adolescents: Influence of Renin-Sodium Profiles

A renin-sodium nomogram for normotensive children and adolescents was developed at our institution. The ambulatory blood pressure patterns of subjects classified by the nomogram were then compared. A biracial sample of 159 children and adolescents were classified as having a low, intermediate, or high renin-sodium profile based on the relationship between their plasma renin activity and 24-hour urinary sodium excretion. Casual (106/58 vs 107/61 vs 106/62 mm Hg) and awake (116/69 vs 117/69 vs 116/70 mm Hg) blood pressure values were comparable among subjects with low, intermediate, and high renin-sodium profiles. Subjects with high renin-sodium profiles, however, had a smaller decline in systolic blood pressure with sleep than did subjects with low renin-sodium profiles (7 vs 11 mm Hg; P less than .04), and higher diastolic blood pressure readings during sleep than subjects with intermediate renin-sodium profiles (65 vs 62 mm Hg; P less than .05). Subjects with high renin-sodium profiles also had greater variance of diastolic blood pressure readings during sleep than either subjects with low renin-sodium profiles (P less than .01) or those with intermediate renin-sodium profiles (P less than .02). The blunted nocturnal decline and increased nocturnal variance of blood pressure among subjects with high renin-sodium profiles may be a marker or mechanism for the future development of essential hypertension.

Antihypertensive Effects of a New Sustained‐Release Formulation of Nifedipine

The blood pressure response to a new sustained-release formulation of nifedipine was evaluated in an 8-week, double-blind, placebo-controlled study. Twenty-nine patients with mild essential hypertension were randomized to receive placebo (N = 9), 30 mg nifedipine (N = 10), or 60 mg nifedipine (N = 10). During treatment, 30-mg and 60-mg doses of nifedipine administered once daily decreased office blood pressures from 137/98 +/- 8/2 mm Hg and 141/98 +/- 15/2 mm Hg at baseline, respectively, to 126/89 +/- 9/7 mm Hg and 126/86 +/- 6/7 mm Hg (P less than .005). Noninvasive automatic ambulatory blood pressure monitoring demonstrated a marginally significant (P less than .10) reduction in the mean 24-hour blood pressure of 2/6 +/- 8/8 mm Hg and 5/6 +/- 9/9 mm Hg for patients taking 30 mg and 60 mg nifedipine once daily, respectively. Diastolic blood pressure load (the percentage of ambulatory diastolic blood pressure readings greater than 90 mm Hg) during 24 hours was decreased by 41% and 35%, with 30 mg and 60 mg nifedipine administered once daily, respectively. No significant dose response to nifedipine at these dose levels was observed. Although the once-daily formulation of nifedipine achieved effective control of office blood pressure, similar control was not observed in awake and 24-hour periods in all patients.

Blood Pressure in Children As Determined Under Office Conditions

From painstaking measurements of the supine blood pressure in 735 healthy boys and 738 healthy girls, this study done in St. Louis, Mo., establishes needed refer ence standards for both 80 and 90 per cent ranges of both systolic and diastolic blood pressure readings.

Reliability of the Dinamap Non-invasive Monitor in the Measurement of Blood Pressure of III Asian Newborns

Four hundred thirty-one paired sets of readings of systolic and diastolic blood pressure and 438 paired sets of readings of mean arterial BP from 49 ill newborns, including 21 very low birth weight infants, were analyzed for the extent and pattern of agreement and the linear relationship between the Dinamap oscillometric monitor and the direct intraarterial blood pressure readings. Agreement between the two methods was measured by the intraclass correlation, whereas the linear relationship was assessed by the product-moment correlation. The intraclass correlations for systolic, diastolic and mean blood pressures were 0.696, 0.766, and 0.781, respectively. The product-moment correlations for systolic, diastolic and mean blood pressures were 0.706, 0.768, and 0.786, respectively. BP measurements by the Dinamap monitor showed reasonably close agreement to those obtained by the intraarterial mean arterial pressure ranges above 40 mmHg. For mean arterial pressure of 40 mmHg and lower, BP readings by the Dinamap monitor tended to be higher than those obtained by the intraarterial method. These findings appeared to be consistent regardless of the birth weight of the newborn.

Correlation Between Objective Automatic and Auscultatory Mercury Manometer Blood Pressure Measurements

The automatic blood pressure (BP) measurement device (A) developed for the World Health Organization (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study was compared in Spain with the standard auscultatory-mercury manometer (M) in 440 randomly selected subjects, 50-54 years old (50% men and 50% women). BPs were recorded simultaneously in the same arm. Systolic BP (SBP), analyzed in 1,440 readings, was 127.5 +/- 18.9 mm Hg by A system and 127.6 +/- 18.6 mm Hg by M system (NS). Diastolic BP (DBP) was 71.3 +/- 11.7 mm Hg by A and 79.3 +/- 11 mm Hg by M (p less than 0.001). We confirmed good correlations in SBP and DBP measured by both methods (r = 0.95 and r = 0.88, respectively; both p less than 0.001). Nearly complete consistency was noted between SBP readings by both methods but not between DBP readings; the readings by M were significantly higher than those by A. Since A's consistency with SBP and DBP readings obtained by the intra-arterial method (the most commonly used method) previously had been proven to be satisfactory, DBP obtained by clinical practice is possibly overestimated in adults.

Correlation Between Objective Automatic and Auscultatory Mercury Manometer Blood Pressure Measurements

The automatic blood pressure (BP) measurement device (A) developed for the World Health Organization (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study was compared in Spain with the standard auscultatory-mercury manometer (M) in 440 randomly selected subjects, 50–54 years old (50% men and 50% women). BPs were recorded simultaneously in the same arm. Systolic BP (SBP), analyzed in 1,440 readings, was 127.5 ± 18.9 mm Hg by A system and 127.6 ± 18.6 mm Hg by M system (NS). Diastolic BP (DBP) was 71.3 ± 11.7 mm Hg by A and 79.3 ± 11 mm Hg by M (p < 0.001). We confirmed good correlations in SBP and DBP measured by both methods (r = 0.95 and r = 0.88, respectively; both p < 0.001). Nearly complete consistency was noted between SBP readings by both methods but not between DBP readings; the readings by M were significantly higher than those by A. Since A's consistency with SBP and DBP readings obtained by the intra-arterial method (the most commonly used method) previously had been proven to be satisfactory, DBP obtained by clinical practice is possibly overestimated in adults.

Blood Pressure and Blood Pressure Variability Following Withdrawal of Propranolol and Clonidine

The effects of placebo, propranolol, and clonidine on blood pressure and blood pressure variability were examined in 14 subjects who had moderate essential hypertension. Hydrochlorothiazide was given throughout successive 4- to 5-week periods of placebo, propranolol, and clonidine administration. During each treatment period, subjects were admitted twice to the clinical research unit for 24-hour blood pressure monitoring performed during administration of placebo, propranolol and clonidine and repeated 1 to 2 weeks later during the first 24 hours after the abrupt cessation of placebo or drug administration. Blood pressure was recorded at 15-minute intervals using an automated noninvasive recorder (Arteriosonde, Roche, New Jersey). Systolic and diastolic blood pressure readings were averaged and the standard deviation taken as the measure of long-term variability (LTV). Systolic and diastolic blood pressure in sequential overlapping blocks of seven readings were averaged and the standard deviation calculated. Short-term variability (STV) was estimated as the average of the standard deviations of the running means. During placebo administration and withdrawal, systolic and diastolic blood pressures as well as LTV and STV were unchanged. Systolic and diastolic pressures did not differ during propranolol administration from those during propranolol withdrawal or placebo withdrawal. Systolic and diastolic LTV and STV did not differ during propranolol administration and withdrawal from those observed during placebo administration or withdrawal. After clonidine withdrawal, both systolic and diastolic pressures increased to values significantly greater than during clonidine administration. These values were significantly greater than those observed after placebo withdrawal, thereby indicating rebound hypertension. After clonidine withdrawal, seven of fourteen subjects developed systolic pressure rebound; diastolic pressure rebound was observed in three patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A historical perspective of elevated systolic vs diastolic blood pressure from an epidemiological and clinical trial viewpoint

The decision to use diastolic blood pressure as the basis for therapeutic intervention for hypertension was based primarily on clinical trials experience. The majority of observational studies shows as great or greater risk for elevated systolic blood pressure readings. Even many of the clinical trials in which a posteriori analyses have been performed confirm a greater effect of systolic rather than diastolic blood pressure as a predictor of coronary heart disease mortality. The current practice of using diastolic blood pressure readings as the sole treatment criterion should be reexamined in light of the observational studies and clinical trials reviewed here.

Situational anxiety and blood pressure lability in the physician's office.

In order to evaluate the association between situational anxiety levels and blood pressure variability during physician's office visits, 19 patients were assessed at the beginning of the visit and before and after being examined by the physician. Assessment included blood pressure measurement as well as self-report of current anxiety level. Previous findings that systolic readings do significantly diminish over the course of the visit were replicated for both hypertensive and normotensive patients, accompanied by correlative decreases in state anxiety. Diastolic blood pressure readings were more stable and less associated with fluctuations in state anxiety, except in patients with initially higher diastolic readings. Results were interpreted as indicating the importance of using more than one blood pressure measurement in diagnosing hypertension and monitoring its management. In particular, patients' anxiety responses upon entering the examining room may produce artificial elevations.

How many blood pressure measurements are enough? An application of generalizability theory to the study of blood pressure reliability.

ABSTRACTGeneralizability theory was applied to blood pressure measurements collected under various designs in order to determine the number of readings needed to attain reliable estimates. The designs assessed variation within the same day in the laboratory, home, and work; variation across days in the laboratory; and variation across measuring devices. Two samples of normotensive (n=40 and n=79) subjects participated in the study. Blood pressure was measured using either a mercury sphygmomanometer, a Dinamap Adult/Pediatric monitor, or a Spacelabs Ambulatory monitor.The results showed that only one reading is necessary whenever generalizations are restricted to the same day in the laboratory. At least six readings of systolic blood pressure are needed at home and at work, and 6 to 10 diastolic blood pressure readings may be required from work and home, respectively. To generalize across days, one or two readings from each of two days for systolic blood pressure and from more than three days for diastolic blood pressure may be required. At least one replication with each of two instruments is necessary in order to generalize across instruments in the laboratory.