Comparisons of an automated oscillometric device with a hybrid manual auscultatory device for the Korea National Health and Nutrition Examination Survey.

This study evaluated an oscillometric device (OD), Microlife WatchBP Office AFIB, and a hybrid manual auscultatory device (AD), Greenlight 300TM, to determine a suitable blood pressure (BP) measurement device for the Korea National Health and Nutrition Examination Survey in a mercury-free context. Adhering to the 2018 Universal Standard's suggested consensus, the study involved 800 subjects (mean age 51.2 ± 17.5 years; 44.3% male), who underwent triplicate BP measurements following 5 min of rest in a randomized order (OD-first: 398 participants; AD-first: 402 participants). BP difference was calculated as OD value minus AD value, with results stratified by measurement sequence. The overall BP difference and tolerable error probability were -1.1 ± 6.5/-2.6 ± 4.9 mmHg and 89.2%/92.5% for systolic/diastolic BP (SBP/DBP), respectively. Lin's concordance correlation coefficient was 0.907/0.844 for SBP/DBP (OD-first/AD-first: 0.925/0.892 for SBP, 0.842/0.845 for DBP). The overall agreement for hypertension (BP ≥ 140 and/or 90 mmHg) was 0.71 (p < 0.0001), and the OD underestimated the overall hypertension prevalence by 5.1%. Analysis of the AD-first data revealed a lower level of agreement compared to the OD-first data; however, the observed blood pressure difference adhered to Criterion 1 of the 2018 Universal Standard. Microlife met the Criterion 1 of 2018 Universal Standard but underestimated the prevalence of hypertension. The BP discrepancy increased with higher BP levels, male sex, and smaller AC. With increasing age, the discrepancy decreased for SBP and increased for DBP.

Feasibility of non-invasive measurement of central blood pressure and arterial stiffness in shock.

BACKGROUND: Patients in haemodynamic shock are in need for an intensive care treatment. Invasive haemodynamic monitoring is state of the art for these patients. However, evolved, non-invasive blood pressure monitoring devices offer advanced functions like the assessment of central blood pressure and arterial stiffness. We analysed the feasibility of two oscillometric blood pressure devices in patients with shock. METHODS: We performed a monocentre prospective study, enrolling 57 patients admitted to the intensive care unit (ICU), due to septic and/or cardiogenic shock. We assessed invasive and non-invasive peripheral and central blood pressure <24 hours and 48 hours after admission on the ICU. Additional haemodynamic parameters such as pulse wave velocity (PWV), augmentation pressure and augmentation index were obtained through Mobil-o-Graph PWA (IEM) and SphygmoCor XCEL (AtCor Medical). RESULTS: A complete haemodynamic assessment was successful in all patients (48) with the Mobil-o-Graph 24 hours PWA and in 29 patients with the SphygmoCor XCEL (P = .001), when cases of death or device malfunction were excluded. Reasons for failure were severe peripheral artery disease, haemodynamic instability, oedema and agitation. Invasive blood pressure showed a sufficient correlation with both devices; however, large differences between invasive and non-invasive techniques were recorded in Bland-Altmann analysis (P < .05 for all parameters). PWV differed between the two devices. CONCLUSION: Non-invasive peripheral blood pressure measurement remains a rescue technique. However, non-invasive assessment of arterial stiffness and central blood pressure is possible in patients with septic or cardiogenic shock. Further studies are required to assess their clinical significance for patients in shock.

Evaluation of an oscillometric blood pressure monitor in anesthetized dogs: Agreement with direct measurements and ability to detect hypotension.

We evaluated the agreement between oscillometric and direct blood pressure monitors in anesthetized dogs and evaluated the ability of the oscillometric method to detect MAP <60 mmHg. Forty client-owned dogs, three months to 14 years old, 4.6-50.2 kg, under general anesthesia were studied. Systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were measured directly via an arterial catheter and with an oscillometric cuff (Cardell Touch monitor). Paired values were compared with mixed effect models. Bias and limits of agreement (LOA) were calculated. The sensitivity and false negative rate to detect hypotension (invasive MAP <60 mmHg) using an oscillometric MAP <60 and < 70 mmHg were calculated. A receiver operating characteristics (ROC) curve was constructed and the area under the curve calculated. SAP and DAP differed between methods (both P < 0.001), but MAP did not (P = 0.5). Bland-Altman plots showed small biases but wide LOA for all variables. The sensitivity to detect hypotension was 40% with a false negative rate of 60% when using an oscillometric MAP <60 mmHg, and 68% and 32%, respectively, with a MAP <70 mmHg. The area under the ROC curve for MAP was 0.82. While the oscillometric MAP did not differ from invasive values, the device failed to recognize hypotensive events when 60 mmHg was used as the threshold to detect hypotension. Higher MAP values increased the ability to correctly recognize hypotension, but at the expense of a higher incidence of false positives.

Clinical Evaluation of a High-fidelity Upper Arm Cuff to Measure Arterial Blood Pressure during Noncardiac Surgery.

BACKGROUND: In most patients having noncardiac surgery, blood pressure is measured with the oscillometric upper arm cuff method. Although the method is noninvasive and practical, it is known to overestimate intraarterial pressure in hypotension and to underestimate it in hypertension. A high-fidelity upper arm cuff incorporating a hydraulic sensor pad was recently developed. The aim of the present study was to investigate whether noninvasive blood pressure measurements with the new high-fidelity cuff correspond to invasive measurements with a femoral artery catheter, especially at low blood pressure. METHODS: Simultaneous measurements of blood pressure recorded from a femoral arterial catheter and from the high-fidelity upper arm cuff were compared in 110 patients having major abdominal surgery or neurosurgery. RESULTS: 550 pairs of blood pressure measurements (5 pairs per patient) were considered for analysis. For mean arterial pressure measurements, the average bias was 0 mmHg, and the precision was 3 mmHg. The Pearson correlation coefficient was 0.96 (P < 0.0001; 95% CI, 0.96 to 0.97), and the percentage error was 9%. Error grid analysis showed that the proportions of mean arterial pressure measurements done with the high-fidelity cuff method were 98.4% in zone A (no risk), 1.6% in zone B (low risk) and 0% in zones C, D, and E (moderate, significant, and dangerous risk, respectively). The high-fidelity cuff method detected mean arterial pressure values less than 65 mmHg with a sensitivity of 84% (95% CI, 74 to 92%) and a specificity of 97% (95% CI, 95% to 98%). To detect changes in mean arterial pressure of more than 5 mmHg, the concordance rate between the two methods was 99.7%. Comparable accuracy and precision were observed for systolic and diastolic blood pressure measurements. CONCLUSIONS: The new high-fidelity upper arm cuff method met the current international standards in terms of accuracy and precision. It was also very accurate to track changes in blood pressure and reliably detect severe hypotension during noncardiac surgery.

Wearable Wireless-Enabled Oscillometric Sphygmomanometer: A Flexible Ambulatory Tool for Blood Pressure Estimation.

This article presents the design of an unobtrusive and wireless-enabled blood pressure (BP) monitoring system that is suitable for ambulatory use. By adopting low-profile electromechanical actuators and a compact printed circuit board design, this lightweight device can be worn directly on the occlusive cuff, therefore eliminating the need of a long and obtrusive tubing interconnect between the device and the cuff, as seen in traditional ambulatory BP monitors (ABPM). Instead of executing the BP estimation algorithm directly on the device, the proposed design rather sends the raw oscillometric signal through a Bluetooth Low Energy link, thus granting any Bluetooth-enabled device to gather and process the signal using a dedicated application. This in turn allows to assess several BP estimation algorithms found in the literature without being limited by the device resources. Three of them were tested with the designed prototype and validated with a reference equipment on 11 subjects. Overall, two of the algorithms revealed a mean absolute difference with the reference equipment of less than 5 mmHg and almost zero bias along with a standard deviation of less than 6 mmHg. Reproducibility results shown a mean difference between successive measurements of less than 3.1 mmHg and a standard deviation of less than 2.4 mmHg. The assembled prototype dimensions are 63.8 × 134.8 × 24.8 mm and features an autonomy of 63.1 hours. Comparison with commercial ABPM devices shown that the proposed design is 18% to 33% smaller volume-wise, 5% to 27% weight-wise and height is reduced by 17% to 25%.

Response to exercise-induced blood pressure elevation is blunted in wrist-cuff automated oscillometric measurement in healthy young college students.

BACKGROUND: A wrist-cuff automated oscillometric device is portable and useful for self-monitoring of blood pressure (BP) at home and outdoors when an upper arm device is not available. Although the height of the forearm in wrist BP measurement is acknowledged to be the major cause of measurement error, it remains unclear whether exercise affects subsequent wrist BP measurement. METHODS AND RESULTS: Ninety-seven healthy college students (median age of 20 years with an age range of 19 to 36 years, 70.1% males) participated in this study. Care was taken to keep the position of the wrist at a level near the upper arm level in BP measurement. At rest, BP measured by a wrist-cuff oscillometric device (Omron HEM-6183) was generally acceptable when it was compared with BP measured by an upper arm oscillometric device (Omron HEM-7130-HP) and with BP measured by the auscultatory method using a mercury sphygmomanometer. However, the ratio of systolic BP measured by oscillometric devices just after a two-step exercise test to that before exercise on the wrist (1.22 ± 0.14) was significantly lower than the ratio on the upper arm (1.27 ± 0.14), and the difference was significantly correlated with exercise-induced increase in pulse rate (Spearman's ρ = 0.23), suggesting a possible role of autonomic nerve activity in the blunted response to exercise-induced BP elevation in wrist BP measurement. CONCLUSIONS: The results indicate that the blunted response to exercise-induced BP elevation should be considered in wrist BP measurement when using a wrist-cuff oscillometric device.

Accuracy and Reliability of the Ankle Brachial Index Measurement Using a Multicuff Oscillometric Device Versus the Doppler Method.

OBJECTIVE: Ankle brachial index (ABI) is widely used for the diagnosis of lower extremity artery disease (LEAD). The purpose of this prospective study was to validate the diagnostic ability and reproducibility of a four cuff automated oscillometric device vs. the Doppler method. METHODS: Patients with suspected LEAD or asymptomatic individuals at risk because of the presence two or more cardiovascular risk factors were enrolled. For each patient, Doppler and oscillometric ABI measurements were repeated by two observers to address intra- and interobserver reproducibility. RESULTS: In total, 118 patients were evaluated. The prevalence of Doppler ABI (Dop-ABI) ≤ 0.90 was 45.8%. Taking the Dop-ABI as the reference, the sensitivity, specificity, accuracy, positive and negative predictive values of oscillometric ABI (Osc-ABI) during the first measurement by the first observer were 89.1%, 94.4%, 94.1%, 91.8%, and 92.4%, respectively. The concordance for diagnosing ABI ≤0.90 between methods was excellent (kappa coefficients ranging from 0.80 to 0.88 with different observers). Intra-observer reproducibility assessed by intraclass correlation coefficient (ICC) between methods were 0.94 for observer 1 and 0.96 for observer 2. The intra-observer reproducibility using the same method was also excellent (ICC 0.94, 95% confidence interval [CI] 0.91-0.95) for Dop-ABI and 0.95 (95% CI 0.93-0.97) for Osc-ABI). The ICC for interobserver reproducibility using the same method was 0.95 (95% CI 0.92-0.96) for Dop-ABI and 0.96 (95% CI 0.94-0.97) for Osc-ABI. CONCLUSION: This study validates the excellent diagnostic performances of a four cuff oscillometric device specifically designed for screening for LEAD. The simple measurement method could therefore be advocated in primary care where fast, easy, and reliable methods are suitable.

Addressing Reduced Laboratory-Based Pulmonary Function Testing During a Pandemic.

To reduce the spread of the severe acute respiratory syndrome coronavirus 2, many pulmonary function testing (PFT) laboratories have been closed or have significantly reduced their testing capacity. Because these mitigation strategies may be necessary for the next 6 to 18 months to prevent recurrent peaks in disease prevalence, fewer objective measurements of lung function will alter the diagnosis and care of patients with chronic respiratory diseases. PFT, which includes spirometry, lung volume, and diffusion capacity measurement, is essential to the diagnosis and management of patients with asthma, COPD, and other chronic lung conditions. Both traditional and innovative alternatives to conventional testing must now be explored. These may include peak expiratory flow devices, electronic portable spirometers, portable exhaled nitric oxide measurement, airwave oscillometry devices, and novel digital health tools such as smartphone microphone spirometers and mobile health technologies along with integration of machine learning approaches. The adoption of some novel approaches may not merely replace but could improve existing management strategies and alter common diagnostic paradigms. With these options comes important technical, privacy, ethical, financial, and medicolegal barriers that must be addressed. However, the coronavirus disease 19 pandemic also presents a unique opportunity to augment conventional testing by including innovative and emerging approaches to measuring lung function remotely in patients with respiratory disease. The benefits of such an approach have the potential to enhance respiratory care and empower patient self-management well beyond the current global pandemic.

Validation Study to Determine the Accuracy of Central Blood Pressure Measurement Using the Sphygmocor Xcel Cuff Device.

Numerous devices purport to measure central (aortic) blood pressure (BP) as distinct from conventional brachial BP. This validation study aimed to determine the accuracy of the Sphygmocor Xcel cuff device (AtCor Medical, CardieX, Sydney, Australia) for measuring central BP. 296 patients (mean age 61±12 years) undergoing coronary angiography had simultaneous measurement of invasive central BP and noninvasive cuff-derived central BP using the Xcel cuff device (total n=558 individual comparisons). A subsample (n=151) also had invasive brachial BP measured. Methods were undertaken according to the Artery Society recommendations, and several calibration techniques to derive central systolic BP (SBP) were examined. Minimum acceptable error was ≤5±≤8 mm Hg. Central SBP was significantly underestimated, and with wide variability, when using the default calibration of brachial-cuff SBP and diastolic BP (DBP; mean difference±SD, -7.7±11.0 mm Hg). Similar variability was observed using other calibration methods (cuff 33% form-factor mean arterial pressure and DBP, -4.4±11.5 mm Hg; cuff 40% form-factor mean arterial pressure and DBP, 4.7±11.9 mm Hg; cuff oscillometric mean arterial pressure and DBP, -18.2±12.1 mm Hg). Only calibration with invasive central integrated mean arterial pressure and DBP was within minimal acceptable error (3.3±7.5 mm Hg). The difference between brachial-cuff SBP and invasive central SBP was 3.3±10.7 mm Hg. A subsample analysis to determine the accuracy of central-to-brachial SBP amplification showed this to be overestimated by the Xcel cuff device (mean difference 4.3±9.1 mm Hg, P=0.02). Irrespective of cuff calibration technique, the Sphygmocor Xcel cuff device does not meet the Artery Society accuracy criteria for noninvasive measurement of central BP.

The accuracy of central blood pressure obtained by oscillometric noninvasive method using Mobil-O-Graph in children and adolescents.

OBJECTIVES: Central blood pressure (CBP) can now be reliably measured noninvasively with a number of devices in adult; however, noninvasive assessment of CBP has not been validated in children and adolescents. The purpose of this study was to clarify the accuracy of noninvasive oscillometric CBP measurements in children and adolescents. METHODS: This study included 60 patients with an average age of 7.9 ±â€Š4.4 years (range 1-18 years) who underwent a cardiac catheterization. We compared CBP, estimated with a noninvasive oscillometric method using a Mobil-O-Graph, with simultaneous invasive recordings using a catheter in children and adolescents. RESULTS: Comparison of the SBP values measured by the two methods, showing a linear correlation (r = 0.85; P < 0.0001) with the mean difference aortic SBP minus estimated central SBP of 2.0 ±â€Š5.6 mmHg (95% limits of agreement = -9.0-13.1). In DBP values, there was a correlation (r = 0.72; P < 0.0001) with the mean difference aortic DBP minus estimated central DBP of -0.1 ±â€Š6.4 mmHg (95% limits of agreement = -12.6-12.4). Sex and cardiac function did not affect central SBP estimation; however, the correlation between aortic and estimated central SBP in adolescents was better than that in children (r = 0.93, P < 0.0001 vs. r = 0.77, P < 0.0001), though the difference was not statistically significant (P = 0.483). CONCLUSION: Estimated CBP using Mobil-O-Graph in children and adolescents shows a certain degree of accuracy, which will be helpful in future for evaluating CBP in children and adolescents.

Validity of transit time-based blood pressure measurements in patients with and without heart failure or pulmonary arterial hypertension across different breathing maneuvers.

PURPOSE: Pulse transit time (PTT) derived by ECG and plethysmographic signal can be a promising alternative to invasive or oscillometry-based blood pressure (BP) monitoring in sleep laboratories because it does not cause arousals from sleep. Therefore, this study assessed the validity of PTT for BP monitoring under sleep laboratory-like conditions. METHODS: Ten volunteers (55.8 ± 19.6 years), 12 patients with heart failure with reduced ejection fraction (HFrEF; 67.3 ± 8.6 years), and 14 patients with Nizza class I pulmonary arterial hypertension (PAH; 59.5 ± 13.4 years) performed different breathing patterns to simulate nocturnal sleep-disordered breathing (SDB). BP was measured at least every 15 min over 1 h using oscillometry (Task Force Monitor™) and PTT (SOMNOscreen™) devices in free breathing conditions and during SDB simulation (alternating phases of hyperventilation and apneas). RESULTS: One hundred forty-two points of measurements were collected. No difference was found in both mean systolic BP (SBP) and diastolic BP (DBP) between oscillometric PTT-based BP measurements in the whole population and throughout the whole recording (SBP 111.3 ± 15.1 mmHg versus 110.0 ± 14.7 mmHg, p = 0.051; DBP 69.9 ± 12.2 versus 69.9 ± 14.2 mmHg, p = 0.701). Likewise, no significant difference in SBP and DBP was found between the two methods in the subgroups of healthy subjects, HFrEF patients and PAH patients, both in free breathing conditions (p > 0.05) and during SDB simulation (p > 0.05). CONCLUSIONS: When monitoring BP in healthy subjects, and in patients with HFrEF or PAH, PTT provides a BP estimation comparable with oscillometric measurement, though slightly inaccurate, both in the condition of regular and unstable breathing.

Validation of the InBody BP170 oscillometric home blood pressure monitor in general population according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization Universal Standard.

OBJECTIVE: To evaluate the accuracy of the InBody BP170 oscillometric upper-arm home blood pressure (BP) monitor in general population according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard (ISO 81060-2:2018). METHODS: Subjects were recruited to fulfill the age, gender, BP and cuff distribution criteria of the AAMI/ESH/ISO Universal Standard in general population using the same arm sequential BP measurement method. Two cuffs of the test device were used for arm circumference 22-32 (medium) and 32-42 cm (large). RESULTS: One-hundred five subjects were recruited and 88 were analyzed. For validation Criterion 1, the mean ± SD of the differences between the test device and reference BP readings was 0.9 ± 6.9/0.5 ± 5.5 mmHg (systolic/diastolic). For Criterion 2, the SD of the averaged BP differences between the test device and reference BP per subject was 5.77/4.80 mmHg (systolic/diastolic). CONCLUSION: The InBody BP170 oscillometric home BP monitor fulfilled all the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018) in general population and can be recommended for clinical use.

Comparison of two blood pressure oscillometric devices: Datascope Accutorr Plus and Mobil-O-Graph PWA and conversion of blood pressure values from one device to the other.

OBJECTIVE: This study aims to compare two oscillometric devices used in national health surveys in Germany, Datascope Accutorr Plus and Mobil-O-Graph PWA and to develop formulas for the conversion of blood pressure (BP) values. METHODS: One hundred and four adults aged 21-86 years had nine alternate same-arm BP measurements according to the International Protocol revision 2010 for the validation of BP measuring devices in adults of the European Society of Hypertension. Measurements 2-8 yielded six pairs of measurements at 30- to 60-second interval with the two devices, totaling 743 pairs used for analysis. RESULTS: Mean Mobil-O-Graph SBP and DBP were higher than those from Datascope. Mean differences (Mobil-O-Graph minus Datascope) increased within BP ranges (optimal, normal, high normal, hypertensive stage 1, stage 2 and stage 3): SBP 0.5 ± 8.5, 3.1 ± 8.2, 3.7 ± 8.0, 5.3 ± 8.8, 13.8 ± 10.2 and 15.0 ± 25.9, respectively, and DBP 2.6 ± 5.6, 6.0 ± 4.9, 6.6 ± 5.2, 8.4 ± 4.8, 12.3 ± 4.6 and 20.4 ± 4.2, respectively. For Mobil-O-Graph pulse pressure less than 43 mm Hg, the DBP difference was 6.3 ± 5.5, and for Mobil-O-Graph pulse pressure more than 50 mm Hg, the SBP difference was 7.4 ± 9.3. The prevalence of BP at least 140/90 mm Hg was 28.8% with Mobil-O-Graph and 20.5% with Datascope. Bidirectional conversion models of SBP and DBP adjusting for BP, pulse pressure, sex, age and cuff width to arm circumference ratio were developed. CONCLUSION: The disagreement in oscillometric devices can reach a magnitude that can be relevant for clinical and epidemiological contexts. The here generated conversion formulas may help to improve comparability.

Accuracy of fully automated oscillometric central aortic blood pressure measurement techniques.

BACKGROUND: Central aortic blood pressure (cBP) is a valuable predictor of cardiovascular risk. The lack of fully automated measurement devices impeded an implementation in daily clinical practice so far. The present study compares two novel automated oscillometric devices with invasively measured cBP. METHODS: From March 2017 to March 2018, we enrolled consecutive patients undergoing elective coronary angiography to this cross-sectional study. Noninvasive assessment of cBP was performed by the SphygmoCor XCEL device and the Mobil-O-Graph NG device simultaneously to invasive measurement. RESULTS: Our study included 502 patients (228 women, 274 men) with a mean age of 67.9 ±â€Š11.6 years. The noninvasive measurement of cBP was successful in 498 patients (99%) with SphygmoCor XCEL device and in 441 patients (88%) with Mobil-O-Graph NG device (P = 0.451). Measurements of both devices revealed a high correlation to invasively measured systolic (SphygmoCor R 0.864, P < 0.001; Mobil-O-Graph R 0.763, P < 0.001) and diastolic (SphygmoCor R 0.772, P < 0.001; Mobil-O-Graph R 0.618, P < 0.001) cBP. Both devices slightly underestimated systolic and overestimated diastolic central blood pressure: biases were -5.0 ±â€Š7.7/0.5 ±â€Š6.2 mmHg with SphygmoCor XCEL and -6.0 ±â€Š10.4/3.6 ±â€Š8.3 mmHg with Mobil-O-Graph NG device. Correlations (R) were higher and biases were lower with the SphygmoCor device (P < 0.001 each). CONCLUSION: The present study is the largest validation study of noninvasive cBP measurement techniques so far and shows that two current automated oscillometric monitors are able to assess cBP with acceptable accuracy. Automated oscillometric devices may facilitate the implementation of cBP in daily clinical practice.

Measurement reliability of automated oscillometric blood pressure monitor in the elderly with atrial fibrillation: a systematic review and meta-analysis.

OBJECTIVES: This study aimed to identify whether automated oscillometric blood pressure monitor (AOBPM) is a reliable blood pressure (BP) measurement tool in geriatric patients with atrial fibrillation (AF) with high variability in BP and to evaluate whether it can be applied in practice. METHODS: Electronic searches were performed in databases including MEDLINE, EMBASE, the Cochrane Library, and CINAHL by using the following keywords: 'atrial fibrillation,' 'atrial flutter, 'blood pressure monitor', 'sphygmomanometer.' The QUADAS-2 was applied to assess the internal validity of selected studies. Meta-analysis was performed using RevMan 5.3 program. DESIGN: Systematic review. RESULTS: We identified 10 studies, including 938 geriatric patients with AF. We compared with the previously used BP measurement method (mainly office) and AOBPM, and the patients with AF were divided into the AF-AF (atrial fibrillation rhythm continued) and AF-SR groups (sinus rhythm recovered). The difference in the systolic BP was -3.0 mmHg [95% confidence interval (CI): -6.58 to 0.59] and -1.62 (95% CI: -6.08 to 2.84) mmHg in the AF-AF and AF-SR groups, respectively. The difference in the diastolic BP was 0.17 (95% CI: -2.90 to 3.25) mmHg and -0.23 (95% CI: -5.11 to 4.65) mmHg, respectively. CONCLUSION: This review showed that the BP difference from AOBPM compared with the auscultatory BP method was less than 5 mmHg in the elderly with AF. This difference is acceptable in clinical practice. However, AOBPM compared with invasive arterial BP in the diastolic BP was a difference of 5 mmHg or more, and so its accuracy cannot be assured.

Blood pressure measurement by oscillometric and auscultatory methods in normotensive pregnant women.

OBJECTIVE: to compare blood pressure values obtained by auscultatory and oscillometric methods in different gestational periods, considering cuff width. METHOD: it is a cross-sectional and quasi-experimental study approved by the Research Ethics Committee. The sample consisted of 108 low-risk pregnant women. Blood pressure measurements were performed in gestational periods of 10-14, 19-22 and 27-30 weeks. RESULTS: The oscillometric device presented values similar to the auscultatory method in systolic blood pressure, but overestimated diastolic blood pressure. Underestimation of blood pressure occurred when using the standard width cuff rather than the correct width cuff in both measuring methods. CONCLUSION: Verification of brachial circumference and use of adequate cuffs in both methods are indispensable to obtain reliable blood pressure values in pregnant women. We recommend performance of additional studies to evaluate diastolic blood pressure overestimation by the Microlife 3BTO-A.

Assessment of a commercially available veterinary blood pressure device used on awake and anesthetized dogs.

OBJECTIVE: To compare results of a commercially available device for oscillometrically measured blood pressure (OBP) with invasively measured blood pressure (IBP) in awake and anesthetized dogs. ANIMALS: 19 adult dogs (mean ± SD body weight, 17.8 ± 7.5 kg). PROCEDURES: Blood pressures were measured in dogs while they were awake and anesthetized with isoflurane. The OBP was recorded on a thoracic limb, and IBP was simultaneously recorded from the median caudal artery. Agreement between OBP and IBP was evaluated with the Bland-Altman method. Guidelines of the American College of Veterinary Internal Medicine (ACVIM) were used for validation of the oscillometric device. RESULTS: In awake dogs, mean bias of the oscillometric device was -11.12 mm Hg (95% limits of agreement [LOA], -61.14 to 38.90 mm Hg) for systolic arterial blood pressure (SAP), 9.39 mm Hg (LOA, -28.26 to 47.04 mm Hg) for diastolic arterial blood pressure (DAP), and -0.85 mm Hg (LOA, -40.54 to 38.84 mm Hg) for mean arterial blood pressure (MAP). In anesthetized dogs, mean bias was -12.27 mm Hg (LOA, -47.36 to 22.82 mm Hg) for SAP, -3.92 mm Hg (LOA, -25.28 to 17.44 mm Hg) for DAP, and -7.89 mm Hg (LOA, -32.31 to 16.53 mm Hg) for MAP. The oscillometric device did not fulfill ACVIM guidelines for the validation of such devices. CONCLUSIONS AND CLINICAL RELEVANCE: Agreement between OBP and IBP results for awake and anesthetized dogs was poor. The oscillometric blood pressure device did not fulfill ACVIM guidelines for validation. Therefore, clinical use of this device cannot be recommended.

Frequency Modulated Parametric Oscillation for Antenna Powered Wireless Transmission of Voltage Sensing Signals.

Wireless transmission of voltage signals are particularly useful for sensors embedded inside a closed environment where long-term operation without internal batteries is desirable. For this purpose, voltage tuning resonators can be used, because their voltage-dependent frequency responses can be contactlessly characterized by loop antennas connected to the output and input ports of a network analyzer. However, such passive sensors have limited remote detectability and temporal resolution, especially for smaller frequency shifts that would require repetitive averaging for acceptable measurement accuracy. To overcome these limitations, a double frequency parametric resonator is inductively coupled with a voltage tuning resonator to convert resonance frequency shifts of the passive sensor into frequency encoded oscillation signals that can be instantaneously detected over larger distance separations. This antenna powered FM transmitter has a compact design to achieve good voltage sensitivity and linearity, making it potentially useful for multiple applications from PH sensing to electrophysiological recording.