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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- "Accurate measurement of BP employing noninvasive methods such as Korotkoff sounds  and oscillometry  is a challenge. Factors like arrhythmias, obesity, and postural changes tend to obscure arterial amplitude pulsations that are sensed by a cuff (or by a stethoscope), thus introducing errors in these measurements –. Therefore, robust and reliable noninvasive estimation of BP remains a topic of active research and inquiry. "
ABSTRACT: Accurate automatic noninvasive assessment of blood pressure (BP) presents a challenge due to conditions like arrhythmias, obesity, and postural changes that tend to obfuscate arterial amplitude pulsations sensed by the cuff. Researchers tried to overcome this challenge by analyzing oscillometric pulses with the aid of a higher fidelity signal-the electrocardiogram (ECG). Moreover, pulse transit time (PTT) was employed to provide an additional method for BP estimation. However, these methods were not fully developed, suitably integrated, or tested. To address these issues, we present a novel method whereby ECG-assisted oscillometric and PTT (measured between ECG R-peaks and maximum slope of arterial pulse peaks) analyses are seamlessly integrated into the oscillometric BP measurement paradigm. The method bolsters oscillometric analysis (amplitude modulation) with more reliable ECG R-peaks provides a complementary measure with PTT analysis (temporal modulation) and fuses this information for robust BP estimation. We have integrated this technology into a prototype that comprises a BP cuff with an embedded conductive fabric ECG electrode, associated hardware, and algorithms. A pilot study has been undertaken on ten healthy subjects (150 recordings) to validate the performance of our prototype against United States Food and Drug Administration approved Omron oscillometric monitor (HEM-790IT). Our prototype achieves mean absolute difference of less than 5 mmHg and grade A as per the British Hypertension Society protocol for estimating BP, with the reference Omron monitor.IEEE transactions on bio-medical engineering 03/2012; 59(3):608-18. DOI:10.1109/TBME.2011.2180019 · 2.23 Impact Factor
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ABSTRACT: The measurement of blood pressure in clinical practice by the century-old technique of Riva Rocci/Korotkov is dependent on the accurate transmission and interpretation of a signal (Korotkov sound or pulse wave) from a subject via a device (the sphygmomanometer) to an observer. The observer must be competent in performing the technique of blood pressure measurement, because it has long been recognized that the observer is one of the major sources of error. There are two problems:American Journal of Hypertension 08/2006; 19(7):659. DOI:10.1016/j.amjhyper.2005.11.001 · 3.40 Impact Factor
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ABSTRACT: The optimal time at rest before clinic blood pressure (BP) measurement is still undefined. In this study in patients with essential hypertension, the time course of the hemodynamic changes during a 16-min rest in the chair-seated position was evaluated and compared with that observed in a stabilized postural condition, such as after a prolonged supine rest. In 55 untreated essential hypertensive patients, BP, heart rate, stroke volume (impedance cardiography), and systemic vascular resistances were measured every other minute during a 16-min rest in the chair-seated position and, in random sequence, in the last 16 min of a 60-min supine rest. Overall, systolic BP (SBP) and diastolic BP (DBP) decreased by 11.6 and 4.3 mm Hg, respectively, during the chair-seated rest; only a 1.8-mm Hg decrease in SBP was observed in the control supine study. The chair-seated fall in BP was associated with a decrease in systemic vascular resistances, in the absence of significant changes in cardiac index. From the logarithmic curve of SBP and DBP decrements, a half-time of 5.8 and 5.5 min respectively, was calculated. Decrements in SBP, but not DBP, were inversely related to the corresponding baseline values. In untreated essential hypertensive patients a significant decrease in SBP and DBP associated with a systemic vasodilation was observed during a 16-min rest in the chair-seated position. Because approximately 75% of the spontaneous fall in BP occurred within 10 min, it appears that this time at rest before clinic BP evaluation could improve the precision and accuracy of the measurement.American Journal of Hypertension 08/2006; 19(7):713-7. DOI:10.1016/j.amjhyper.2005.08.021 · 3.40 Impact Factor