What is the accuracy of clinic blood pressure measurement?
ABSTRACT In clinical practice, blood pressure (BP) is frequently measured at the end of the visit in patients sitting on one side of the bed and not on a chair according to guidelines.
In 540 consecutive subjects with essential hypertension (EH) attending a hospital outpatient clinic, BP was measured in the following sequence: 1) patient seated on chair for at least 5 min, 2) patient supine, 3) patient seated on bed, and 4) patient standing for a few minutes.
We found that mean (+/-SEM) BP was 143.5/87.2 +/- 0.9/0.5, 153.4/89.7 +/- 1.0/0.5, 148.9/90.9 +/- 1.0/0.5, and 144.8/91.7 +/- 1.0/0.6 mm Hg, respectively (P < .05 v position 1 for all). In 14% of patients, either systolic BP (SBP) or diastolic BP (DBP) was above the conventional upper limits of normality in the seated-on-bed but not in the recommended seated-on-chair position ("false" high clinic BP), whereas SBP and DBP were "false" normal (below limit for bed-seated and above limit for chair-seated position) in only 6% and 2% of patients, respectively. Overall, SBP and DBP increments from the chair- to the bed-seated position were inversely related to the baseline chair-seated values; systolic increments were directly related to age, in particular in the subgroup of untreated EH (n = 70), and to body mass index. A gender-related difference was apparent, as female subjects had more pronounced increments in SBP (+7.4 +/- 0.8 v +3.5 +/- 0.7 mm Hg) and DBP (+4.4 +/- 0.5 v 2.9 +/- 0.4 mm Hg) than did male subjects (P < .05 for both).
Clinic SBP and DBP are overestimated in the bed-seated position at the end of the visit compared with the recommended chair-seated position in treated and untreated patients with EH, in particular in elderly obese women with mild hypertension.
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ABSTRACT: We present a prototype of an integrated blood pressure (BP) and electrocardiogram (ECG) device for multi-parameter physiologic monitoring. A standard BP pressure cuff and an ordinary wristband have been modified to incorporate in them dry ECG electrodes made of thin conductive fabric. The modified BP cuff and wristband are coupled with commercially available hardware and software to harvest simultaneous arterial pulse wave and ECG data from the arm and wrist of the other hand. Software has been written for assessing multiple physiologic parameters from the harvested pulse wave and ECG signals. We provide an initial validation of the performance of our prototype by conducting a study on six healthy subjects.Instrumentation and Measurement Technology Conference (I2MTC), 2010 IEEE; 06/2010
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ABSTRACT: The epidemiology of blood pressure in very old age has not been thoroughly studied. The objective of this study was to study blood pressure changes throughout old age and changes in blood pressure and antihypertensive drug use from 1981 to 2005. The study includes 1133 blood pressure measurements from two studies carried out in Umeå, Sweden. The U70 study (1981-1990) included individuals aged 70-88 and the Umeå 85+/GERDA study (2000-2005) covered people aged 85, 90 or 95 years. The impact of age, sex and year of investigation on blood pressure was investigated using linear regression. Mean diastolic blood pressure (DBP) decreased by 0.35 mm Hg (P<0.001) for each year of age. An inverted U-shaped relation was found between age and systolic blood pressure (SBP), with SBP reaching its maximum at 74.5 years. Mean SBP and DBP also decreased over time (SBP by 0.44 mm Hg per year, P<0.001 and DBP by 0.34 mm Hg per year, P<0.001). The proportion of participants on antihypertensive drugs increased from 39.0% in 1981 to 69.4% in 2005. In this study of people aged 70 years, mean SBP and DBP decreased with higher age and later investigation year. Antihypertensive drug use increased with time, which might partly explain the observed cohort effect.Journal of Human Hypertension advance online publication, 19 April 2012; doi:10.1038/jhh.2012.14.Journal of human hypertension 04/2012; · 2.80 Impact Factor
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ABSTRACT: Oscillometry is a popular technique for automatic estimation of blood pressure (BP). However, most of the oscillometric algorithms rely on empirical coefficients for systolic and diastolic pressure evaluation that may differ in various patient populations, rendering the technique unreliable. A promising complementary technique for automatic estimation of BP, based on the dependence of pulse transit time (PTT) on cuff pressure (CP) (PTTCP mapping), has been proposed in the literature. However, a theoretical grounding for this technique and a nonparametric BP estimation approach are still missing. In this paper, we propose a novel coefficient-free BP estimation method based on PTTCP dependence. PTT is mathematically modeled as a function of arterial lumen area under the cuff. It is then analytically shown that PTTCP mappings computed from various points on the arterial pulses can be used to directly estimate systolic, diastolic, and mean arterial pressure without empirical coefficients. Analytical results are cross-validated with a pilot investigation on 10 healthy subjects where 150 simultaneous ECG and oscillometric BP recordings are analyzed. The results are encouraging whereby the mean absolute errors of the proposed method in estimating systolic and diastolic pressures are 5.31 mmHg and 4.51 mmHg, respectively, relative to the Food and Drug Administration (FDA)-approved Omron monitor. Our work thus shows promise towards providing robust and objective BP estimation in a variety of patients and monitoring situations.IEEE transactions on bio-medical engineering 01/2013; · 2.15 Impact Factor