Non-invasive blood pressure measurement in conscious rabbits: A comparison of Doppler ultrasonic and oscillometric devices.

BACKGROUND: This study aimed to compare Doppler (the most commonly used technique for non-invasive indirect blood pressure [NIBP] measurement in rabbits) and oscillometric devices for NIBP measurements in conscious rabbits. METHODS: Blood pressure (BP) measurements were obtained for 49 conscious rabbits using the Doppler and oscillometric devices. Each measurement was repeated in triplicate. Three rabbits were excluded from the study because it was not possible to obtain BP measurements using the oscillometric device. The American College of Veterinary Internal Medicine (ACVIM) guidelines were followed to compare the results obtained with the two devices. RESULTS: A total of 164 systolic BP measurements were obtained with the Doppler device and 182 were obtained with the oscillometric technique. The mean of the three values obtained for each animal with each device was used for statistical analysis. The analysis demonstrated a poor level of agreement between the measurements obtained with the two devices. LIMITATIONS: Oscillometric devices rely on built-in software algorithms to perform calculations and produce their measurements. However, the oscillometric devices currently available only have the software for dogs and cats installed. Therefore, these conclusions should be revised when a device with software specifically for rabbits is commercialised. CONCLUSIONS: This study indicates that oscillometric devices should not be used as a substitute for the Doppler technique when measuring BP in rabbits.

Differences between oscillometry measurements obtained by MostGraph-01 and MasterScreen-IOS in patients with asthma.

BACKGROUND: Oscillometry devices (also termed forced oscillation technique) devices such as MasterScreen-IOS® (Jaeger, Hochberg, Germany) and MostGraph-01® (Chest, Tokyo, Japan) are useful for obtaining physiological assessments in patients with obstructive lung diseases, including asthma. However, as oscillometry measurements have not been fully compared between MasterScreen-IOS® and MostGraph-01® in patients with asthma, it is unknown whether there are differences in the measurements between the devices. This study aimed to determine whether there is any difference in oscillometry measurements obtained using the two devices in patients with asthma. METHODS: Oscillometry measurements obtained using MasterScreen-IOS® and MostGraph-01® were retrospectively evaluated in 95 patients with asthma at Juntendo University Hospital between October 2009 and November 2009. RESULTS: There was a strong positive correlation in the measurements between the two devices. However, the values of R5, R20, ALX and Fres were lower when measured with MostGraph-01® than with MasterScreen-IOS®, and vice versa for the values of X5. The results were used in correction equations to convert oscillometry parameters measured using MasterScreen-IOS® to those measured using MostGraph-01®. CONCLUSIONS: To our knowledge, this is the first report to compare MostGraph-01® and MasterScreen-IOS® devices using practical clinical data obtained in patients with asthma. The values obtained by both devices can be interpreted in a similar way, although there is slight variation. The conversion equations produced in this study may assist to compare the oscillometry measurements obtained by each of the two devices.

[Respiratory oscillometry: Theoretical foundations and clinical applications]. / L'oscillométrie respiratoire : théorie et applications cliniques.

Oscillometry measures the mechanical properties of the respiratory system. As they are carried out during spontaneous breathing, oscillometry measurements do not require forced breathing maneuvers or the patient's active cooperation. The technique is complementary to conventional pulmonary function testing methods for the investigation of respiratory function, diagnosis and monitoring of respiratory diseases, and assessment of response to treatment. The present review aims to describe the theoretical foundations and practical methodology of oscillometry. It describes the gaps in scientific evidence regarding its clinical utility, and provides examples of current research and clinical applications.

[Research on portable airway impedance monitoring device based on expiratory oscillation].

Monitoring airway impedance has significant clinical value in accurately assessing and diagnosing pulmonary function diseases at an early stage. To address the issue of large oscillator size and high power consumption in current pulmonary function devices, this study adopts a new strategy of expiration-driven oscillation. A lightweight and low-power airway impedance monitoring system with integrated sensing, control circuitry, and dynamic feedback system, providing visual feedback on the system's status, was developed. The respiratory impedance measurement experiments and statistical comparisons indicated that the system could achieve stable measurement of airway impedance at 5 Hz. The frequency spectrum curves of respiratory impedance ( R and X) showed consistent trends with those obtained from the clinical pulmonary function instrument, specifically the impulse oscillometry system (IOS). The differences between them were all less than 1.1 cm H 2O·s/L. Additionally, there was a significant statistical difference in the respiratory impedance R5 between the exercise and rest groups, which suggests that the system can measure the variability of airway resistance parameters during exercise. Therefore, the impedance monitoring system developed in this study supports subjects in performing handheld, continuous measurements of dynamic changes in airway impedance over an extended period of time. This research provides a foundation for further developing low-power, portable, and even wearable devices for dynamic monitoring of pulmonary function.

Effect of limb and cuff positioning on measurement of arterial blood pressure with an oscillometry device (PetMAP) in anaesthetized cats.

Arterial blood pressure (ABP) is often measured with oscillometry during anaesthesia. Changing the height of the measuring cuff with respect to the level of the heart is known to affect oscillometry accuracy in some species; however, this effect has not been investigated in cats. The objective of this study was to determine the effects of raising and lowering the measuring cuff from standard position (level of the heart) on ABP, measured with PetMAP, in anaesthetised cats. ABP readings were obtained from 29 cats with the cuff at standard position (baseline), and 5 cm above and below the heart. The end-tidal isoflurane concentrations were maintained constant during data acquisition. There were no differences between baseline values and those measured below the heart, while ABP measured above the heart was consistently lower than baseline for both the thoracic and pelvic limbs (P < 0.001), with absolute differences of 8.2 (2.5 - 14) mmHg and 6.5 (3.0 - 15.0) mmHg, respectively. Systolic ABP readings at the pelvic limb were consistently higher than those at the thoracic limb at standard position (112 ± 26 versus 103 ± 21 mmHg, p = 0.010), above (106 ± 22 versus 95 ± 20 mmHg, p = 0.003), and below the heart (116 ± 26 versus 107 ± 22 mmHg, p = 0.011). This study shows that raising the cuff by 5 cm above the heart, which may become necessary during procedural positioning, results in clinically significant underestimation of ABP measured with PetMAP.

Validation of the RBP-9801 oscillometric blood pressure monitor in the general population according to the association for the Advancement of Medical Instrumentation/European Society of Hypertension/ International Organization for Standardization Universal Standard.

The aim of this study was to evaluate the accuracy of the single upper-arm cuff oscillometric blood pressure (BP) monitor RBP-9801 developed for office and home BP measurement in the 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). Subjects were recruited to fulfil 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. A total of 105 subjects were recruited and 85 were analyzed. For validation criterion 1, the mean ± SD of the differences between the test device and reference BP readings was 2.3 ± 6.4/3.1 ± 5.8 mmHg (systolic/diastolic). For criterion 2, the SD of the mean BP differences between the test device and reference BP per subject was 5.24/5.03 mmHg (systolic/diastolic). The conclusion is that the RBP-9801 oscillometric device for office and home BP measurement fulfilled all the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018) in the general population and can be recommended for clinic and self-use at home.

[Oscillometric devices vs. arterial Doppler in measuring the ankle-arm index for the diagnosis of peripheral arterial disease]. / Dispositivos oscilométricos frente a Doppler arterial en la medida del índice tobillo-brazo para el diagnóstico de la enfermedad arterial periférica.

INTRODUCTION: Peripheral arterial disease is a marker of vascular damage that is diagnosed by measuring the ankle-brachial index. The aim of this study was to determine the validity and agreement of the MESI ABPI-MD and Microlife WatchBP® office-ABI oscillometric devices with respect to the gold standard arterial Doppler. MATERIALS AND METHODS: Observational, cross-sectional, descriptive study of inpatients who underwent ABI measurement with the three devices. Values are considered normal between 1-1.4, indeterminate between 0.91-0.99 and pathological ≤0.9 and >1.4. RESULTS: A total of 187 patients (54.4% male) with a mean age of 66 years were included. The Doppler results were inferior to those of the oscillometric devices (median [IQR] 1.1 [0.2] vs. 1.2 [0.2], P<.05), with no significant differences between the automated devices (P=.29 for the right lower limb and P=.342 for the left lower limb). Both devices had high specificity (96.5-99.2%) and low sensitivity (29.5-45.4%). The correlation of the results was good-moderate for MESI and moderate for Microlife. The agreement between the two was acceptable-moderate. CONCLUSION: Automated oscillometric devices could be useful in asymptomatic patients as an alternative to arterial Doppler.

A comparison among oscillometric waveforms in healthy nonpregnant women, pregnancy and hypertensive disorders of pregnancy.

OBJECTIVE: Understanding of how oscillometric waveforms (OMW) vary between pregnant and nonpregnant individuals remains low. An exploratory analysis was completed to assess for quantitative and qualitative changes in OMW and oscillometric envelope features in pregnancy. DESIGN AND METHODS: Eighteen pregnant individuals (over 20 weeks gestational age) and healthy, nonpregnant (HNP) women were recruited. Six HNP were matched to six healthy pregnant (HP) women, and six pregnant women with a hypertensive disorder of pregnancy (HDP) by age, arm circumference, and cuff size. Blood pressure measurements were completed per the International Organization for Standardization (ISO) protocol using a custom-built oscillometric device as the test device and two-observer mercury auscultation as the reference measurement. Auscultatory blood pressure and blood pressure derived from slope-based and fixed ratio algorithms were determined. OMW and envelope features were compared among groups. RESULTS: In HNP, HP, and HDP groups respectively: mean auscultatory blood pressure (systolic mean ± SD/diastolic mean ± SD) was 103.4 ±â€…12.2/67.1 ±â€…7.9; 109.5 ±â€…3.1/58.1 ±â€…6.4; 135.6 ±â€…18.9/85.1 ±â€…14.2 mmHg. HDP had significantly higher auscultatory systolic and diastolic blood pressure than the HP group ( P  = 0.001). The pregnant groups had a lower average pulse width (mean ± SD: HNP = 0.8 ±â€…0 s, HP = 0.6 ±â€…0.1 s, HDP = 0.6 ±â€…0.1 s; HP vs. HNP mean difference [adjusted P value]: 0.2 [ P  = 0.004], HDP vs. HNP 0.1 [ P  = 0.018]) compared with the HNP group. The HDP group had a larger area under the OMW envelope than the HNP group (mean ± SD: HNP = 22.6 ±â€…3.4; HDP = 28.5 ±â€…4.2; HDP vs. HNP mean difference [adjusted P value]: 5.9 P  = 0.05). CONCLUSION: In this exploratory work, differences in the OMW morphology and parameters were found in pregnancy and in hypertensive disorders of pregnancy compared with healthy controls. Even small differences may have important implications in algorithm development; further work comparing OMW envelopes in pregnancy is needed to optimize the algorithms used to determine blood pressure in pregnancy.

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.