Oscillometric Measurement Research Articles

Automated Ankle-Brachial Pressure Index Measurement by Clinical Staff for Peripheral Arterial Disease Diagnosis in Nondiabetic and Diabetic Patients

Clairotte et al. (1) recently reported in Diabetes Care that the oscillometric measurement of the ankle-brachial index (Osc-ABI) has lower diagnostic performance in diagnosing peripheral arterial disease (PAD) in diabetic patients when compared with the Doppler-measured ankle-brachial pressure index (Dop-ABI). Our group has validated the use of an automatic oscillometer (Omron M-7) for Osc-ABI calculation. We chose this model because the sleeve adapts better to the truncated cone morphology of the leg. We used the Doppler Hadeco Bidop (Koven Technology, St. Louis, MO) to measure the sonorous and graphical signal. For the Osc-ABI calculation, three measurements were made and the greatest of …

Automated Ankle-Brachial Pressure Index Measurement by Clinical Staff for Peripheral Arterial Disease Diagnosis in Nondiabetic and Diabetic Patients

Gomez-Huelgas et al. (1) reported on the use of oscillometric measurement of the ankle-brachial index (Osc-ABI) in diabetic and nondiabetic patients for diagnosis of occlusive peripheral arterial disease (PAD). That study was similar to our previous research (2), although important methodological differences may be noted, especially with the use of magnetic resonance angiography imaging and not ultrasound as a gold standard technique. Consistent with our study, Gomez-Huelgas et al. …

A comparison of blood pressure and pulse pressure values obtained by oscillometric and central measurements in hypertensive patients

Objective. Wide pulse pressure (PP) affects the accuracy of oscillometric blood pressure measurements (OBPM): however, the degree of this impact on different patient groups with wide PPs is unclear. This study will investigate the accuracy of OBPM in achieving target BP and PP in isolated systolic hypertension (ISH) group compared with mixed hypertension (MHT) group. Method. A total of 115 patients (70 with ISH and 45 with MHT) were enrolled in the study. Upper arm and wrist OBPM, obtained by OmronM3 and OmronR6 devices respectively, were compared with the simultaneously measured values from the ascending aorta. The ISH was defined as a systolic blood pressure (SBP) ≥140 mmHg and a diastolic blood pressure (DBP) <90 mmHg. MHT was defined as a SBP≥140 mmHg and a DBP≥90 mmHg. Results. The mean central arterial blood pressure (BP) and central PP were higher in the ISH group than those in the MHT group. The upper arm OBPM underestimated the central SBP in two groups (−5 mmHg, −3 mmHg, p=0.5, respectively), but overestimated DBP in the ISH group compared with MHT patients (6.8 mmHg, 1 mmHg, p=0.04, respectively). Wrist OBPM similarly underestimated to the central SBP in each group (−16 mmHg, −19 mmHg, p=0.15), whereas the sum of overestimation of DBP was significantly higher in the ISH than in the MHT group (+6 mmHg, − 1 mmHg, p=0.001, respectively). Also, each of the devices underestimated the central PP in the ISH group (about 10 mmHg) as being higher than that of the MHT group. Conclusion. Oscillometric devices may be used for self-BP measurement in patients with ISH without clinically important disadvantages compared with the patients with MHT. For PP measurement in patients with ISH, there were substantial differences between intra-arterial and indirect arm BP measurements.

Non-esterified fatty acids increase arterial pressure via central sympathetic activation in humans

Previous studies have shown that acute increases in plasma NEFAs (non-esterified fatty acids) raise SVR (systemic vascular resistance) and BP (blood pressure). However, these studies have failed to distinguish between CNS (central nervous system) mechanisms that raise sympathetic activity and paracrine mechanisms that increase SVR directly, independent of CNS involvement. The aim of the present study was to directly determine whether the sympathetic nervous system contributes to the pressor response to NEFAs. On 2 days separated by at least 2 weeks, 17 lean healthy volunteers (ten male/seven female; age, 22+/-1 years; body mass index, 23+/-1 kg/m2; values are means+/-S.E.M.) received a 4-h intravenous infusion of 20% Intralipid or placebo (in a single-blind randomized balanced order). MSNA (muscle sympathetic nerve activity), HR (heart rate), BP (oscillometric brachial measurement) and Q (cardiac output; acetylene rebreathing) were measured before and throughout infusion. The change in HR (+8.2+/-1.0 and +2.4+/-1.2 beats/min), systolic BP (+14.0+/-1.6 and +3.2+/-2.5 mmHg) and diastolic BP (+8.2+/-1.0 and -0.1+/-1.7 mmHg) were significantly greater after the 4-h infusion of Intralipid compared with placebo (P<0.001). The change in BP with Intralipid resulted from an increase in SVR (Q/mean arterial pressure; P<0.001) compared with baseline, without a change in Q. MSNA burst frequency increased during Intralipid infusion compared with baseline (+4.9+/-1.3 bursts/min; P<0.05), and total MSNA (frequencyxamplitude) was augmented 65% (P<0.001), with no change during placebo infusion. Lipid infusion increased insulin, aldosterone and F2-isoprostane, but not leptin, concentrations. On the basis of the concomitant increase in BP, MSNA and SVR, we conclude that central sympathetic activation contributes to the pressor response to NEFAs.

Validation of automated oscillometric versus manual measurement of the ankle–brachial index

We validated automated oscillometric measurement of the ankle-to-arm ratio of systolic blood pressure (ankle-brachial blood pressure index, ABI) against the manual approach, which requires trained observers and has an intra-observer variability of approximately 10%. A single observer measured ABI in 105 subjects (age range, 20-80 years; women, 51.9%). The manual approach involved the auscultatory measurement of systolic pressure at the brachial artery and Doppler measurements of systolic pressure at the anterior and posterior tibial arteries. The automated oscillometric VP-2000 (Omron Healthcare, Kyoto, Japan) was used to measure systolic pressure at the arm and ankle simultaneously. We applied Bland and Altman's methods to study reproducibility. Ankle-brachial blood pressure index averaged (+/-s.d.) 1.13+/-0.07 units and 1.12+/-0.10 units on automated and manual measurements, respectively. The absolute and percentage differences (P=0.64) between the two ABI measurements were 0.005 units (95% confidence interval, -0.015 to 0.024) and 0.60 (-0.69 to 1.04), respectively. The intra-observer variability of repeat ABI measurements was smaller on automated than on manual measurement (0.17 versus -0.84%; P=0.04). Automated ABI measurement by an oscillometric technique requires little observer training, and significantly increases the reproducibility of ABI estimates compared with the manual approach.

Evaluation of indirect blood pressure monitoring in awake and anesthetized red-tailed hawks (Buteo jamaicensis): effects of cuff size, cuff placement, and monitoring equipment

ObjectiveTo compare Doppler and oscillometric methods of indirect arterial blood pressure (IBP) with direct arterial measurements in anesthetized and awake red-tailed hawks. Study designProspective, randomized, blinded study. AnimalsSix, sex unknown, adult red-tailed hawks. MethodsBirds were anesthetized and IBP measurements were obtained by oscillometry (IBP-O) and Doppler (IBP-D) on the pectoral and pelvic limbs using three cuffs of different width based on limb circumference: cuff 1 (20–30% of circumference), cuff 2 (30–40%), and cuff 3 (40–50%). Direct arterial pressure measurements were obtained from the contralateral superficial ulnar artery. Indirect blood pressure measurements were compared to direct systolic arterial pressure (SAP) and mean arterial pressure (MAP) during normotension and induced states of hypotension and hypertension. Measurements were also obtained in awake, restrained birds. Three-way anova, linear regression and Bland–Altman analyses were used to evaluate the IBP-D data. Results are reported as mean bias (95% confidence intervals). ResultsThe IBP-O monitor reported errors during 54% of the measurements. Indirect blood pressure Doppler measurements were most accurate with cuff 3 and were comparable to MAP with a bias of 2 (−9, 13 mmHg). However, this cuff consistently underestimated SAP with a bias of 33 (19, 48 mmHg). Variability in the readings within and among birds was high. There was no significant difference between sites of cuff placement. Awake birds had SAP, MAP and diastolic arterial pressure that were 56, 43, and 38 mmHg higher than anesthetized birds. Conclusions and clinical relevanceIndirect blood pressure (oscillometric) measurements were unreliable in red-tailed hawks. Indirect blood pressure (Doppler) measurements were closer to MAP measurements than SAP measurements. There was slightly better agreement with the use of cuff 3 on either the pectoral or pelvic limbs. Awake, restrained birds have significantly higher arterial pressures than those under sevoflurane anesthesia.

Do maternal‐ or pregnancy‐associated disease states affect blood pressure in the early neonatal period?

Placental vascular changes associated with maternal disease states may affect fetal vascular development. There is evidence suggesting that being born prematurely is associated with a higher blood pressure (BP) in later life. To determine whether maternal disease state affects BP in the early neonatal period. Cohort study of neonates admitted to neonatal intensive care unit with exposure to maternal hypertension and diabetes. Inclusion criteria were neonates greater than 27 weeks gestation not ventilated or requiring inotropes for more than 24 h, materna l hypertension (pregnancy induced or essential) or diabetes of any kind requiring treatment, and spontaneous delivery. Exclusion criteria included chromosomal or congenital anomaly and illicit maternal drug use. Oscillometric BP measurements taken until discharge on days 1, 2, 3, 4, 7, 14, 21 and 28. Placental histopathology was performed. One hundred and ninety infants enrolled, 104 in the control and 86 in the study group. Sixty-five infants were born between 28-31 weeks and 125 infants between 32-41 weeks gestation. Those born between 28-31 weeks with a history of diabetes had a statistically higher systolic, mean and diastolic BP throughout the first 28 days of life (P = 0.001; P = 0.007; P = 0.02). Those born between 32-41 weeks gestation with placental pathology associated with altered uteroplacental perfusion had a higher systolic BP (P = 0.005). Maternal- or pregnancy-associated disease states appear to influence BP in the early neonatal period. Diabetes and altered placental perfusion were associated with higher BP readings. Clinical significance of these statistically elevated BPs in the early neonatal period is unknown.

A poor correlation exists between oscillometric and radial arterial blood pressure as measured by the Philips MP90 monitor

In anesthesia and critical care, invasive arterial blood pressure monitoring is the gold standard against which other methods of monitoring are compared. In this assessment of the Philips MP90 monitor, the objective was to determine whether or not oscillometric measurements were within the accuracy standards set by the Association for the Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society (BHS). Three hundred and one invasive and noninvasive paired measurements were obtained from eleven adult patients on the neurosurgical service at Stanford University Medical Center. Bland-Altman plots were created to assess agreement between the two measurement systems. Paired correlation analysis, bias and precision calculations were performed. Oscillometric blood pressure measurements correlated with arterial measurements yielding Pearson r values of 0.68, 0.67 and 0.62 for systolic, diastolic and mean pressures, respectively (P < 0.01.) Mean differences with 95% confidence intervals were -3.8 mmHg +/- 13.6, -2.4 mmHg +/- 10.0, and 4.0 mmHg +/- 13.1 for systolic, diastolic and mean pressures, respectively. The mean difference for these measurements was <or=5 mmHg as stipulated by the AAMI guidelines, but the standard deviation was greater than the 8 mmHg allowed by the AAMI guidelines. When the BHS guidelines were applied, the device merited a grade "D" for systolic and mean arterial pressure, and a grade "C" for diastolic pressure, with the highest possible grade level being "A." There was a poor correlation between noninvasive and invasive measurements of arterial blood pressure as measured with a cuff and radial arterial cannula using the Philips MP90 monitor. These inaccuracies could lead to unnecessary interventions, or lack of appropriate interventions in anesthetic management. Further study is needed to specify the absolute inaccuracy of the monitor, and to determine if accuracy between the two methods varies with patient co-morbidities, surgical procedures, or anesthetic management.

Automated Ankle-Brachial Pressure Index Measurement by Clinical Staff for Peripheral Arterial Disease Diagnosis in Nondiabetic and Diabetic Patients

OBJECTIVEPeripheral arterial disease (PAD) is a prognostic marker in cardiovascular disease. The use of Doppler-measured ankle-brachial pressure index (Dop-ABI) for PAD diagnosis is limited because of time, required training, and costs. We assessed automated oscillometric measurement of the ankle-brachial pressure index (Osc-ABI) by nurses and clinical staff.RESEARCH DESIGN AND METHODSClinical staff obtained Osc-ABI with an automated oscillometric device in 146 patients (83 with diabetes) at the time of Dop-ABI measurement and ultrasound evaluation.RESULTSMeasurements were obtained in most legs (Dop-ABI 98%; Osc-ABI 95.5%). Dop- and Osc-ABI were significantly related in diabetic and nondiabetic patients with good agreement over a wide range of values. When Dop-ABI ≤0.90 was used as the gold standard for PAD, receiver operating characteristic curve analysis showed that PAD was accurately diagnosed with Osc-ABI in diabetic patients. When ultrasound was used to define PAD, Dop-ABI had better diagnostic performance than Osc-ABI in the whole population and in diabetic patients (P = 0.026). Both methods gave similar results in nondiabetic patients. The cutoff values for the highest sensitivity and specificity for PAD screening were between 1.0 and 1.1. Estimation of cost with the French medical care system fees showed a potential reduction by three of the screening procedures.CONCLUSIONSPAD screening could be improved by using Osc-ABI measured by clinical staff with the benefit of greater cost-effectiveness but at the risk of lower diagnostic performance in diabetic patients.

Prevalence of children with blood pressure measurements exceeding adult cutoffs for optimal blood pressure in Germany

Despite a growing interest in the epidemiology of paediatric hypertension, data on how often blood pressure in children and adolescents already exceeds adult thresholds for optimal blood pressure are scarce. The aim of this study was to estimate the prevalence of higher-than-optimal and hypertensive blood pressure values according to adult cutoffs in an unselected representative sample of children and adolescents living in Germany. Standardized oscillometric blood pressure measurements were performed in 14 730 children aged 3-17 years (7203 girls and 7527 boys) participating in a nationally representative examination survey of children and adolescents living in Germany (The German Health Interview and Examination Survey for Children and Adolescents, KiGGS, response rate 67%). The mean of two measurements was used for this analysis. The prevalences of higher-than-optimal blood pressure values by adult criteria (>or=120/80 mmHg) increased with age and was 52.2% in boys aged 14-17 years and 26.2% in girls aged 14-17 years (including 6.0% of boys and 1.4% of girls with hypertensive values >or=140/90 mmHg). More than half of these adolescents with nonoptimal blood pressure values had additional cardiovascular risk factors (overweight defined as body mass index >or=90th percentile for sex and age, dyslipidaemia defined as total cholesterol >5.0 mmol/l or high-density lipoprotein cholesterol less than 1.0 mmol/l or smoking). These results suggest the need for routine blood pressure measurements in children and adolescents as required by clinical guidelines, for more attention to coexisting other cardiovascular risk factors and for a sustained focus on healthy lifestyles that can be learned best at a young age.

Digital recording system of sphygmomanometry

Validation of blood pressure measurement devices is always difficult because the gold standard method depends on the observer's manual assessment. To improve the assessment algorithm in automatic blood pressure measurement devices, knowing the reference blood pressure values and analyzing various data are always necessary. A digital system to record Korotkoff sound and cuff pressure is suggested. The recording system consists of cuff, microphone, amplifier, and all the components of an oscillometric measurement device, which enable the collection of various data from patients. After collecting the data, the browsing software can playback the recorded sound and pressure variation on a computer. The system records the Korotkoff sound faithfully. The sound can be played with sound card on a personal computer. Cuff pressure can also be displayed with Korotkoff sound at the same time. With this playback software, the observer can assess systolic blood pressure and diastolic blood pressure . The observer can listen again and discuss with others when the decision is not clear. The digital recording system of sphygmomanometry can be used for validation of blood pressure measurement devices, collecting of oscillometric data for research, and educating the students who learn blood pressure measurement.

Unreliable oscillometric blood pressure measurement: prevalence, repeatability and characteristics of the phenomenon

Oscillometric devices are being widely used for ambulatory, home and office blood pressure (BP) measurement. However, even successfully validated oscillometric devices fail to provide accurate measurements in some patients. This study investigated the prevalence, the reproducibility and the characteristics of the phenomenon of unreliable oscillometric BP (UOBP) measurement. A total of 5070 BP measurements were obtained simultaneously (Y connector) using a professional oscillometric device (BpTRU) and a mercury sphygmomanometer in 755 patients (1706 visits). UOBP readings were defined as those with >10 mm Hg difference (systolic or diastolic) between the two methods. UOBP was found in 15% of systolic and 6.4% of diastolic BP measurements. In all, 18% of the participants had UOBP in their first but not their second visit, or the reverse. However, 49% of these participants had at least one more UOBP visit after their second visit within the study database. Patients with persistent UOBP were more likely to be female and had lower arm circumference. The systolic BP discrepancy between the two methods was associated with pulse pressure (r=0.41) and inversely with diastolic BP (r=0.40) and arm circumference (r=0.30), whereas the diastolic discrepancy with diastolic BP (r=0.61) and inversely with pulse pressure (r=0.32). There was a consistent significant trend for larger systolic BP discrepancy and smaller diastolic from the lower to the higher pulse pressure quintile (P<0.0001). A decreasing arm circumference was a significant predictor of persistent UOBP. These data suggest that the UOBP measurement is particularly common, not very reproducible and mainly affected by pulse pressure and arm circumference.

Cluster-Randomized Controlled Trial of Oscillometric vs. Manual Sphygmomanometer for Blood Pressure Management in Primary Care (CRAB)

Although mercury sphygmomanometers are seen as the gold standard instrument for blood pressure (BP) measurement, they are being withdrawn due to safety concerns. CRAB was a cluster-randomized controlled trial in 24 family practices in Tasmania, Australia, which aimed to determine the effect of an oscillometric device on BP management. Cluster-randomized controlled trial. Intervention practices were supplied with automated monitors and control (usual care) practices used mercury or aneroid sphygmomanometers. They were subsequently audited by a research nurse. Usual care practice audit periods were matched to intervention practices. All analyses were intention-to-treat and adjusted for potential clustering. Differences in BP were analyzed using generalized estimating equations. All other outcomes were analyzed using multilevel mixed-effects Poisson regression. Post hoc analyses were performed to determine the mediators of changes in prescribing behavior. A total of 3,355 records were reviewed (828 visits had BP recordings). The percentage of BP recordings ending in "0" was significantly lower in intervention vs. usual care practices (systolic BP (SBP) 18% (107/587) vs. 71% (233/329), diastolic BP (DBP) 20% (119/584) vs. 70% (229/328), P < 0.001). The mean of SBP recordings in the intervention group was 7.5 mm Hg (95% confidence interval (CI) 5.2, 9.9 mm Hg, P < 0.001) higher than in the usual care group. Patients taking BP lowering drugs were more likely (incidence rate ratio (IRR) 1.3, 95% CI 1.1, 1.7, P = 0.01) to have a BP lowering drug prescribed if they were in the intervention compared to the usual care. Although digit preference was largely eliminated by oscillometric measurement, prescribing behavior was mediated by SBP.

Non-invasive determination of instantaneous brachial blood flow using the oscillometric method

The oscillometric method has been widely used to measure arterial systolic and diastolic blood pressures, but its potential for arterial blood flow measurements still remains to be explored. The aim of this study was to non-invasively determine arterial blood flow using an oscillometric blood flow measurement system. The system consists of a pneumatic elastic cuff, an air-pumping motor, a releaser valve, a pressure transducer, and an airflow meter. To build a non-linear cuff model, we measured airflow pumped into the pneumatic cuff and cuff pressure using an airflow meter and pressure transducer during the inflation period, respectively. During the deflation period, only the pressure transducer was used to record cuff pressure. Based on the cuff model, the oscillometric blood flow waveform was obtained by integrating the oscillometric pressure waveform. We compared arterial blood flow derived from the maximum amplitude of the oscillometric blood flow waveform with Doppler-measured blood flow calculated with the diameters and blood velocities of the brachial arteries in 32 subjects who underwent diagnostic evaluations for peripheral arterial embolism. A linear correlation coefficient of r = 0.716 was found between the oscillometry- and Doppler-based blood flow measurements in the 32 subjects. These results suggest that blood flow passing through the brachial artery can be quantified non-invasively using the oscillometric approach after appropriate calibration.

Distal Airway Function Assessed by Oscillometry at Varying Respiratory Rate: Comparison with Dynamic Compliance

Distal airways disease causes significant morbidity yet remains insufficiently identified. We hypothesize that: () when spirometry is normal impulse oscillometry may provide information about mechanical properties of the distal airways in a manner comparable to dynamic compliance and () variation of breathing frequency will influence oscillometric measurements similar to effects of breathing frequency on dynamic compliance. Fifty-three symptomatic subjects with normal large airway function (spirometry) were studied; distal airway dysfunction was identified by presence of frequency dependence of compliance (FDC). Oscillometric parameters evaluated were resistance at 20 Hz (R20) and 5–20 Hz (R5 − 20), reactance at 5Hz (X5), and reactance area (AX). R20 correlated with airway resistance by esophageal manometry (r = 0.74, p< 0.001); X5 correlated with dynamic compliance at a respiratory rate of 60bpm (r = 0.61, p< 0.001); R5-20 and AX correlated with FDC (r = 0.48, p< 0.001; r = 0.53, p< 0.01). IOS indices were further evaluated at increased respiratory rate (RR40). Oscillometric parameters changed minimally at RR40 in normal subjects ΔR20 = 0.20 = 0.08 cmH2O/L/s, ΔR5-20 = 0.10 ± 0.03 cmH2O/L/s, Δ AX = 0.33 ± 0.19 cmH2O/L). However, in symptomatic subjects, while R20 increased minimallyat RR40 (Δ R20 = 0.37 ± 0.10 cmH2O/L/s), R5 − 20 and AX increased markedly (Δ R5 − 20 = 0.54 ± 0.06 cmH2O/L/s, Δ AX = 4.28 ± 0.67 cmH2O/L) and reversed post bronchodilator. IOS evaluates physiology of the distal airways in a manner comparable to dynamic compliance. Elevated respiratory rate influences oscillometric parameters and must be considered when interpreting oscillometric data. IOS provides a non-invasive tool for assessment of distal airway function when spirometry is normal, which can be applied to various clinical settings including early diagnosis of COPD (GOLD stage 0), asthma in clinical remission and occupational/ environmental irritant exposure.

The impact of pulse pressure on the accuracy of wrist blood pressure measurement

There is an increasing number of wrist blood pressure measurement devices that successfully passed the validation procedures of the British Hypertension Society (BHS) and the European Society of Hypertension (ESH). It remains unknown, however, whether pulse pressure as a marker of arterial stiffness and vascular ageing affects the accuracy of these devices. An ESH protocol validated wrist device was compared with the upper arm mercury sphygmomanometry in a study population (33 patients, 99 measurements) including a relevant number of subjects with pulse pressure >50 mm Hg (84.8%) and isolated systolic hypertension (27.3%). Mean systolic bias was 10.2 mm Hg with 95% limits of agreement of -13.1 and 33.6 mm Hg, mean diastolic bias was 4.8 mm Hg with limits of agreement of -11.0 and 20.7 mm Hg. The impact of body mass index, age, systolic blood pressure and pulse pressure on the absolute value of blood pressure bias was tested by stepwise multiple regression analysis. The systolic bias significantly depended on pulse pressure, whereas there was no significant effect of the independent variables on the diastolic bias. Separate correlation analysis showed a significant correlation between pulse pressure and both absolute systolic bias (Pearson r=0.48, P<0.001) and relative systolic bias (systolic bias divided by systolic blood pressure, Pearson r=0.29, P=0.003). Even well-validated wrist blood pressure devices can show a clinically relevant bias in patients with elevated pulse pressure. Increased arterial stiffness may impair the accuracy of oscillometric blood pressure measurement at the wrist.

Oscillometric blood pressure measurement: a simple method in screening for peripheral arterial disease

Blood pressure at the ankle level is a reliable indicator of peripheral arterial disease (PAD) and the ankle brachial index (ABI) is a useful non-invasive screening tool for the early detection of atherosclerosis. In the first part of the study, systolic blood pressures obtained by oscillometry and plethysmography were compared in 80 subjects referred for possible vascular disease. In the second part of the study, 31 general practitioners enrolled 1258 consecutive patients aged more than 60 years. ABI was estimated by oscillometry. Patients with an ABI lower than 0.9 were referred to the local hospital for standardized measurements. In the first part, oscillometry showed a sensitivity of 97% and a specificity of 62% with a positive and negative predictive value of 71% and 96%, respectively. In the second part, significant PAD was found in 111 cases corresponding to a prevalence of 12.2%. In this population, the oscillometry showed a positive predictive value of 47%. The presence of PAD was significantly correlated to exercise related leg pain, a diagnosis of hypertension and smoking, whereas no correlation could be found with a diagnosis of heart disease, stroke, or with the presence of diabetes. The prevalence of PAD was sufficiently high in subjects over the age of 60 years to warrant screening. The ankle brachial index based on measurements with an oscillometric device was shown reliable in the exclusion of PAD, thereby fulfilling an important criterion for the use in screening.

Validation of the Microlife Watch BP Office professional device for office blood pressure measurement according to the International protocol

To assess the accuracy of oscillometric and auscultatory blood pressure (BP) measurement taken using the professional electronic device Microlife Watch BP Office according to the European Society of Hypertension International Protocol. Thirty-three participants were included for the assessment of each measurement mode (oscillometric and auscultatory). Simultaneous BP measurements were taken by two observers (mercury sphygmomanometers) four times, sequentially with three measurements taken using the tested device. Absolute observer device BP differences were calculated. For each participant the number of measurements with a difference within 5 mmHg was calculated. In phase 1 the device produced 32, 40 and 40 oscillometric systolic BP (SBP) measurements within 5, 10 and 15 mmHg, respectively and diastolic BP (DBP) 30, 40 and 43 (for auscultatory SBP 29, 42, 45 and DBP 33, 43, 45). In phase 2.1 the device produced 71, 90 and 96 SBP measurements within 5, 10 and 15 mmHg, respectively and DBP 71, 88 and 97 (for auscultatory SBP 72, 96, 99 and DBP 83, 96, 99). Twenty-four participants had at least two of their SBP differences within 5 mmHg and one participant had no difference within 5 mmHg, and DBP 23 and three participants, respectively (for auscultatory SBP 29 and 0 and DBP 29 and 1). Mean SBP difference was -1.4+/-6.3 mmHg and DBP -0.8+/-6.0 mmHg (auscultatory SBP -1.8+/-4.5 and DBP -0.4+/-4.0). The Microlife Watch BP Office device used in the oscillometric or the auscultatory mode fulfills the validation criteria of the International protocol and therefore can be recommended for clinical use.

Population-based hypertension screening in preschool children

Hypertension is the leading risk factor for cardiovascular diseases in adults. Due to the common lack of clinical symptoms, hypertension frequently remains undiagnosed and untreated until late in the course of disorder [1, 2]. In contrast to adults, hypertension in childhood is preferentially due to secondary causes, most commonly renoparenchymal disease [3, 4]. Routine blood pressure measurements are still rarely performed by general paediatricians, and the prevalence of essential hypertension in children may be underestimated due to diagnostic neglect. Blood pressure during adolescence clearly tracks at least into early and middle adult age (“tracking” of blood pressure) [5]. Children in the top quintile of systolic blood pressure are 3–4 times more likely to develop clinical hypertension by age 30 than their peers, and 50% of hypertensive adults had elevated childhood systolic blood pressure [6]. The minimal age at which significant blood pressure tracking into adult life becomes manifest has not been determined. There are a number of possible explanations for the phenomenon of blood pressure tracking. The “fetal origins” hypothesis assumes that malnutrition during critical intrauterine growth periods leads to life-long programming of the cardiovascular system [7]. Obesity is another major determinant of childhood blood pressure. A significant association between systolic blood pressure and the body mass index has been demonstrated already in preschool children [8]. Moreover, socio-economic condition may play an independent role; associations of living conditions in childhood with adult blood pressure have been described [9]. Finally, genetic factors predisposing to hypertension would be expected to be operative already in childhood. The diagnosis of hypertension in childhood is rendered difficult by several factors. Due to the lack of outcome studies, hypertension is defined by the deviation of blood pressure from the distribution in the general population. Since blood pressure changes dynamically throughout childhood [10–12], it is critical to have a firm basis for the normal range of blood pressure at different ages and heights. Another important methodological issue is the unknown equivalence of auscultatory measurements with oscillometric readings. While semi-automatic oscillometric devices are rapidly gaining ground in the pediatric field, very few validation studies have been performed with individual devices. These suggest systematic differences between the methods in the pediatric age group, indicating a need for specific centile curves based on oscillometric measurements.

Automated device that complies with current guidelines for office blood pressure measurement: design and pilot application study of the Microlife WatchBP Office device

Current guidelines for office blood pressure (BP) measurement recommend mercury devices, both arms measurement in the initial assessment and at least duplicate measurements at follow-up visits. This study presents the design and a pilot application study of an automated device that fulfils American, European, and International guidelines for office BP measurement. The Microlife WatchBP Office is a professional electronic mercury-free device with three function modes designed for: (a) initial assessment: triplicate automated simultaneous oscillometric both arms measurement at 60-s intervals and when there is a consistent interarm difference more than 20 mmHg systolic and/or more than 10 mmHg diastolic, the arm with the higher BP is indicated. (b) Follow-up assessment: triplicate automated oscillometric single arm measurements at 60-s intervals and their average is displayed. (c) Auscultatory measurement: by an observer using a stethoscope and a digital countdown BP display for patients with arrhythmias and other individuals in whom the oscillometric measurement is not accurate. The 'initial assessment' mode was applied by three physicians in 63 patients (189 readings). Average interarm systolic BP difference was 0.04+/-5.1 mmHg and diastolic 0.4+/-3.2 mmHg. A value more than 10 mmHg interarm difference in nine systolic BP readings (5%) and three (2%) diastolic. No patient had a consistent interarm difference more than 10 mmHg in all three or two of the three readings. The Microlife WatchBP Office professional device fulfils current international requirements for office BP measurement and seems to overcome several limitations of this method when applied in clinical practice.