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.

Automated blood pressure measuring devices: how are they clinically validated for accuracy?

Accurate blood pressure (BP) assessment is essential for the optimal diagnosis and management of hypertension. Contemporary clinical practice guidelines strongly endorse use of automated cuff blood pressure measuring devices (BPMD) as the preferred means of measuring and monitoring BP in the office, at home and with ambulatory blood pressure monitoring. To ensure that they are accurate, automated BPMDs should undergo clinical validation testing, performed using an established clinical validation standard. Unfortunately, most BPMDs sold on the global market have not been clinically validated. Furthermore, in the last thirty years, several different clinical validation protocols have been published, with major differences apparent between these standards, causing controversy with respect to which standard is considered acceptable for clinical validation. Complexly worded standards, multiple revisions, and firewalled access also contribute to a lack of understanding and use of clinical validation standards and the number of expert centers performing clinical validations is small. Recently, joint society collaborations have led to creation of the AAMI/ESH/ISO universal standard for the clinical validation of automated cuff BPMDs. Not only is this unified standard a necessary step, but oversight from regulators and influential stakeholders to ensure that only clinically validated BPMDs can be marketed is additionally needed.

Characterizing Hypertension Specialist Care in Canada: A National Survey.

Background: The hypertension specialist often receives referrals of patients with young-onset, severe, difficult-to-control hypertension, patients with hypertensive emergencies, and patients with secondary causes of hypertension. Specialist hypertension care compliments primary care for these complex patients and contributes to an overall hypertension control strategy. The objective of this study was to characterize hypertension centres and the practice patterns of Canadian hypertension specialists. Methods: Adult hypertension specialists across Canada were surveyed to describe hypertension centres and specialist practice in Canada, including the following: the patient population managed by hypertension specialists; details on how care is provided; practice pattern variations; and differences in access to specialized hypertension resources across the country. Results: The survey response rate was 73.5% from 25 hypertension centres. Most respondents were nephrologists and general internal medicine specialists. Hypertension centres saw between 50 and 2500 patients yearly. A mean of 17% (± 15%) of patients were referred from the emergency department and a mean of 52% (± 24%) were referred from primary care. Most centres had access to specialized testing (adrenal vein sampling, level 1 sleep studies, autonomic testing) and advanced therapies for resistant hypertension (renal denervation). Considerable heterogeneity was present in the target blood pressure in young people with low cardiovascular risk and in the diagnostic algorithms for investigating secondary causes of hypertension. Conclusions: These results summarize the current state of hypertension specialist care and highlight opportunities for further collaboration among hypertension specialists, including standardization of the approach to specialist care for patients with hypertension.

Contexte: Le spécialiste de l'hypertension reçoit souvent des patients orientés pour une hypertension sévère, d'apparition précoce et difficile à maîtriser, pour une urgence hypertensive ou pour des causes secondaires de l'hypertension. Les soins spécialisés de l'hypertension complètent les soins primaires pour ces cas complexes et font partie d'une stratégie globale de maîtrise de l'hypertension. Cette étude avait pour objectif de caractériser les centres de traitement de l'hypertension et les habitudes de pratique des spécialistes canadiens qui traitent l'hypertension. Méthodologie: Un sondage a été mené auprès de spécialistes de l'hypertension adulte de l'ensemble du Canada afin de décrire les centres de traitement de l'hypertension et la pratique des spécialistes au Canada, notamment les éléments suivants : la population de patients prise en charge par des spécialistes de l'hypertension, les renseignements sur la façon dont les soins sont prodigués, les variations dans les habitudes de pratique ainsi que les différences relatives à l'accès aux ressources spécialisées en hypertension à l'échelle du pays. Résultats: Le taux de réponse au sondage a été de 73,5 % dans 25 centres de l'hypertension. La plupart des répondants étaient des néphrologues et des spécialistes en médecine interne générale. Les centres de l'hypertension recevaient entre 50 et 2500 patients par année. En moyenne, 17 % (± 15 %) des patients provenaient du service des urgences et 52 % (± 24 %) provenaient d'une unité de soins primaires. La plupart des centres avaient accès à des tests spécialisés (prélèvements veineux surrénaliens, études du sommeil de niveau 1, tests autonomes) et à des traitements avancés pour l'hypertension résistante (dénervation rénale). Une hétérogénéité considérable a été constatée en ce qui concerne la pression artérielle cible chez les jeunes présentant un faible risque cardiovasculaire et les algorithmes diagnostiques pour étudier les causes secondaires de l'hypertension. Conclusions: Ces résultats résument la situation actuelle des soins spécialisés de l'hypertension et font ressortir des occasions d'accroître la collaboration entre les spécialistes de l'hypertension, notamment en ce qui concerne une normalisation de l'approche des soins spécialisés pour les patients hypertendus.

Telemonitoring and protocolized case management for hypertensive community dwelling older adults (TECHNOMED): a randomized controlled trial.

BACKGROUND: Home blood pressure (BP) telemonitoring combined with case management leads to BP reductions in individuals with hypertension. However, its benefits are less clear in older (age ≥ 65 years) adults. METHODS: Twelve-month, open-label, randomized trial of community-dwelling older adults comparing the combination of home BP telemonitoring (HBPM) and pharmacist-led case management, vs. enhanced usual care with HBPM alone. The primary outcome was the proportion achieving systolic BP targets on 24-h ambulatory BP monitoring (ABPM). Changes in HBPM were also examined. Logistic and linear regressions were used for analyses, adjusted for baseline BP. RESULTS: Enrollment was stopped early due to coronavirus disease 2019. Participants randomized to intervention (n = 61) and control (n = 59) groups were mostly female (77%), with mean age 79.5 years. The adjusted odds ratio for ABPM BP target achievement was 1.48 (95% confidence interval 0.87-2.52, P = 0.15). At 12 months, the mean difference in BP changes between intervention and control groups was -1.6/-1.1 for ABPM (P-value 0.26 for systolic BP and 0.10 for diastolic BP), and -4.9/-3.1 for HBPM (P-value 0.04 for systolic BP and 0.01 for diastolic BP), favoring the intervention. Intervention group participants had hypotension (systolic BP < 110) more frequently (21% vs. 5%, P = 0.009), but no differences in orthostatic symptoms, syncope, non-mechanical falls, or emergency department visits. CONCLUSIONS: Home BP telemonitoring and pharmacist case management did not improve achievement of target range ambulatory BP, but did reduce home BP. It did not result in major adverse consequences.

Impact of Home Telemonitoring and Management Support on Blood Pressure Control in Nondialysis CKD: A Systematic Review and Meta-Analysis.

Background: Hypertension is a major cause of cardiovascular disease, chronic kidney disease (CKD), and death. Several studies have demonstrated the efficacy of home blood pressure telemonitoring (HBPT) for blood pressure (BP) control and outcomes, but the effects of this intervention remain unclear in patients with CKD. Objective: To determine the impact of HBPT on cardiovascular-related and kidney disease-related outcomes in patients with CKD. Design: Systematic review and meta-analysis. Setting: All studies that met our criteria regardless of country of origin. Participants: Patients with chronic kidney disease included in studies using HBPT for BP assessment and control. Measurements: Descriptive and quantitative analysis of our primary and secondary outcomes. Methods: We searched MEDLINE, Embase, CINAHL Plus, PsycINFO, Cochrane CENTRAL, Web of Science, and gray literature from inception for observational and randomized controlled studies in nondialysis (ND) CKD using HBPT for BP control. We selected studies that used HBPT as intervention (with or without a control arm) for BP control in ND-CKD populations. The primary outcome was change in mean systolic BP (SBP) and mean diastolic BP (DBP). Results: We selected 7 studies from 1669 articles that were initially identified. Overall, pooled estimates in the mean difference (MD) for SBP and DBP were -8.8 mm Hg; 95% confidence interval (CI): -16.2 to -1.4; P = .02 and -2.4 mm Hg; 95% CI: -3.8 to -1.0; P < .001, respectively. For studies comparing intervention with usual care (UC), pooled estimate in MD for SBP was -8.0 mm Hg (P = .02) with no significant reduction for DBP (-2.6 mm Hg; P = .18). In studies without a UC arm, both SBP and DBP were not significantly reduced (P > .05). The pooled estimate in MD for estimated glomerular filtration rate showed a significant improvement (5.4 mL/min/1.73 m2; P < .001). Limitations: Heterogeneity and few available studies for inclusion limited our ability to identify a robust link between HBPT use and BP and kidney function improvement. Conclusion: Home blood pressure telemonitoring is associated with mild lowering of BP and moderately improved kidney function in patients with CKD. However, larger studies with improved designs and prolonged interventions are still needed to assess the effects of HBPT on patients' outcomes. PROSPERO registration ID: CRD42020190705.

Contexte: L'hypertension est une cause majeure de maladie cardiovasculaire, d'insuffisance rénale chronique (IRC) et de mortalité. Plusieurs études ont montré l'efficacité de la télésurveillance de la pression artérielle à domicile (TSPA) pour le contrôle de la pression artérielle (PA) et les évènements cliniques, mais les effets de cette intervention demeurent mal connus chez les patients atteints d'IRC. Objectif: Évaluer l'effet de la TSPA sur les évènements cardiovasculaires et rénaux chez les patients atteints d'IRC. Conception: Revue systématique et méta-analyse. Sources: Toutes les études satisfaisant nos critères, peu importe le pays d'origine. Sujets: Les patients atteints d'IRC inclus dans les études portant sur l'utilisation de la TSPA pour réguler la pression artérielle. Mesures: Analyse descriptive et quantitative de nos résultats primaires et secondaires. Méthodologie: Nous avons consulté les bases de données MEDLINE, embase, CINAHL plus, PsycINFO, Cochrane CENTRAL et Web of Science, de même que la littérature grise depuis leur début, à la recherche des études observationnelles contrôlées et randomisées portant sur l'utilisation de la TSPA pour contrôler la PA chez des patients atteints d'IRC non dialysés. Nous avons sélectionné les études (avec ou sans bras témoin) utilisant l'intervention (TSPA pour contrôler la PA) dans des populations de patients atteints d'IRC non dialysés. Le principal critère d'évaluation était un changement de la pression systolique moyenne (PSM) et de la pression diastolique moyenne (PDM). Résultats: Nous avons retenu sept études parmi les 1 669 articles initialement répertoriés. Dans l'ensemble, les estimations regroupées de la différence moyenne (DM) pour la PSM et la PDM étaient de −8,8 mmHg (IC 95%: −16,2 à −1,4; P = 0,02) et de −2,4 mmHg (IC 95%: −3,8 à −1,0; P < 0,001) respectivement. Dans les études qui comparaient l'intervention aux soins habituels (SH), les estimations regroupées de la DM s'établissaient à −8,0 mmHg (P = 0,02) pour la PSM, sans réduction significative pour la PDM (−2,6 mmHg; P = 0,18). Dans les études sans bras SH, aucune réduction significative n'a été observée pour la PSM et la PDM (P > 0,05). L'estimation groupée de la DM pour le débit de filtration glomérulaire estimé (DFGe) a montré une amélioration significative (5,4 ml/min/1,73 m2; P < 0,001). Limites: Le peu d'études disponibles pour inclusion et leur hétérogénéité limitent notre capacité à établir un lien robuste entre l'utilisation de la TSPA et une amélioration de la PA et de la fonction rénale. Conclusion: La TSPA est associée à une légère baisse de la PA et à une amélioration modérée de la fonction rénale chez les patients atteints d'IRC. Des études de plus grande envergure, avec des conceptions améliorées et des interventions prolongées, sont nécessaires pour mieux évaluer les effets de la TSPA sur les résultats des patients.

Telemonitoring and Case Management for Hypertensive and Remote-Dwelling Patients With Chronic Kidney Disease-The Telemonitoring for Improved Kidney Outcomes Study (TIKO): A Clinical Research Protocol.

BACKGROUND: Hypertension, together with poorly controlled blood pressure (BP) are known risk factors for kidney disease and progression to kidney failure as well as increased cardiovascular (CV) morbidity and mortality. Several studies in patients without kidney disease have demonstrated the efficacy of home BP telemonitoring (HBPT) for BP control. OBJECTIVE: The primary aim of this study is to assess the mean difference in systolic BP (SBP) at 12 months, from baseline in remote dwelling patients with hypertension and chronic kidney disease (CKD) in Northern Alberta, Canada, comparing HBPT + usual care versus HBPT + a case manager. Other secondary objectives, including cost-effectiveness and acceptability of HBPT as well as occurrence of adverse events will also be assessed. DESIGN: This study is designed as a pragmatic randomized controlled trial (RCT) of HBPT plus clinical case management compared to HBPT with usual care. SETTING: Peace River region in Northern Alberta Region, Canada. PATIENTS: Primary care patients with CKD and hypertension. MEASUREMENTS: Eligible patients will be randomized 1:1 to HBPT + BP case management versus HBPT + usual care. In the intervention arm, BP will be measured 4 times daily for 1 week, with medications titrated up or down by the study case manager until guideline targets (systolic BP [SBP]: <130 mmHg) are achieved. Once BP is controlled, (ie, to guideline-concordant targets), this 1-week protocol will be repeated every 3 months for 1 year. Patients in the control arm will also follow the same BP measurement protocol; however, there will be no interactions with the case manager; they will share their BP readings with their primary care physicians or nurse practitioners at scheduled visits. LIMITATIONS: Potential limitations of this study include the relatively short duration of follow-up, possible technological pitfalls, and need for patients to own a smartphone and have access to the internet to participate. CONCLUSIONS: As this study will focus on a high-risk population that has been characterized by a large care gap, it will generate important evidence that would allow targeted and effective population-level strategies to be implemented to improve health outcomes for high-risk hypertensive CKD patients in Canada's remote communities. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT number: NCT04098354).

CONTEXTE: L'hypertension et la pression artérielle (PA) mal contrôlée sont des facteurs de risque reconnus pour la néphropathie et la progression vers l'insuffisance rénale, en plus de poser un risque accru de morbidité et de mortalité cardiovasculaires. Plusieurs études chez des patients sans néphropathie ont démontré l'efficacité de la télésurveillance de la PA à domicile (TSPA) pour le contrôle de la PA. OBJECTIFS: Le principal objectif est d'évaluer la différence moyenne de pression artérielle systolique (PAS) après 12 mois par rapport à sa valeur initiale chez des patients atteints d'hypertension et d'insuffisance rénale chronique (IRC) habitant les communautés éloignées du nord de l'Alberta (Canada). Cet objectif sera atteint en comparant la TSPA + soins habituels à la TSPA + gestionnaire de cas. D'autres objectifs secondaires, notamment le rapport coût/efficacité de la TSPA, son acceptation et la survenue d'événements indésirables seront également évalués. TYPE D'ÉTUDE: Cette étude est conçue comme un essai randomisé contrôlé (ERC) pragmatique comparant la TSPA + prise en charge clinique des cas à la TSPA + soins habituels. CADRE: Région de Peace River dans le nord de l'Alberta (Canada). SUJETS: Patients atteints d'IRC et d'hypertension recevant des soins de santé primaires. MESURES: Les patients admissibles seront répartis 1:1 dans le groupe TSPA + prise en charge du cas d'hypertension ou dans le groupe témoin (TSPA + soins habituels). Dans le groupe d'intervention, la PA sera mesurée quatre fois par jour pendant une semaine, avec augmentation ou réduction de la médication par le gestionnaire de cas de l'étude jusqu'à ce que la cible de référence (PAS : <130 mmHg) soit atteinte. Une fois la PA contrôlée (c.-à-d. conforme aux cibles recommandées), ce protocole sur une semaine sera répété tous les trois mois pendant un an. Les patients du groupe témoin suivront le même protocole de mesure de la PA, mais sans interactions avec le gestionnaire de cas, ils transmettront plutôt leurs mesures de PA à leur médecin de soins primaires ou aux infirmières praticiennes lors de visites prévues. LIMITES: Cette étude est notamment limitée par la durée relativement courte du suivi, de possibles difficultés technologiques et la nécessité pour les participants de posséder un téléphone intelligent et d'avoir accès à l'Internet. CONCLUSION: Puisque cette étude se penchera sur une population à risque élevé et marquée par d'importantes lacunes en matière de soins, elle générera des données importantes qui aideront à mettre en œuvre des stratégies ciblées et efficaces au niveau de la population afin d'améliorer les évènements cliniques des patients hypertendus et atteints d'IRC à haut risque habitant les communautés éloignées au Canada.

Optimum waveform envelopes and amplitude ratios in oscillometric blood pressure estimation.

OBJECTIVE: To determine if, when using the oscillometric method, there is a specific range of amplitude ratios in the fixed-ratio algorithm that will result in blood pressure estimates that consistently fall within a mean error ≤5 mmHg and a SD of the error <8 mmHg. Additionally, to apply different representations of the oscillometric waveform envelope to verify if this will affect the accuracy of the results. METHODS: SBP and DBP were obtained using the fixed-ratios method applied to a dataset of 219 oscillometric measurements obtained from 73 healthy volunteers and compared to their corresponding auscultation values. Ratio and envelope analysis were done on Matlab (The MathWorks, Inc., Natick, Massachusetts, USA). RESULTS: Depending on the envelope representation, ratios between 0.44-0.74 for systolic pressure and 0.51-0.85 for diastolic pressure yield results within the limits mentioned above. When a set of optimum envelope representations and ratios are selected based on population mean, the highest percentage of subjects presenting blood pressure estimates within the limits were 72.6% for systolic and 69.9% for diastolic. CONCLUSION: The range of ratios presenting optimum results appears to be independent of the degree of arterial stiffness given the wide range of ages of the subjects in the study. Different representations of the oscillometric waveform envelope may improve the accuracy of the method. However, there remains a considerable percentage of the population with unreliable results. It is therefore important to only use devices that have been properly validated according to standard protocol.

Effect of Elevated Ambient Temperature on Simulator-Derived Oscillometric Blood Pressure Measurement.

BACKGROUND: Oscillometric blood pressure (BP) devices are typically labeled for use up to 40 °C. Many geographic regions have ambient temperatures exceeding 40 °C. We assessed the effect of increased ambient temperature (40-55 °C) on simulator-derived oscillometric BP measurement. METHODS: Three Omron BP769CAN devices, 3 A&D Medical UA-651BLE devices, and accompanying cuffs were used. A custom heat chamber heated each device to the specified temperature. A noninvasive BP simulator was used to take 3 measurements with each device at differing temperatures (22, 40, 45, 50, and 55 °C) and BP thresholds: 80/50, 100/60, 120/80, 140/90, 160/110, and 180/130 mm Hg. Using each device as its own control (22 °C), we determined the relative differences in mean BP for each device at each temperature and BP setting, assessed graphical trends with increasing temperature, and examined variability. RESULTS: Graphical trends of mean simulator-subtracted BP differences from room temperature showed no discernable pattern, with differences clustered around zero. Overall mean difference in BP (combined elevated temperatures minus room temperature) was -0.8 ± 2.1 (systolic ± SD)/1.2 ± 3.5 (diastolic ± SD) mm Hg for the A&D device and 0.2 ± 0.4 (systolic ± SD)/-0.1 ± 0.1 (diastolic ± SD) mm Hg for the Omron. All individual elevated temperature differences (elevated temperature minus room temperature) except A&D diastolic BP at 50 °C were within 5 mm Hg. CONCLUSIONS: In this simulator-based study assessing within-device differences, higher ambient temperatures resulted in oscillometric BP measurements that were comparable to those performed at room temperature.

Impact of choosing the closest rather than the mean auscultatory blood pressure value on the European Society of Hypertension International Protocol device validation results.

OBJECTIVE: When calculating the difference between alternating auscultatory reference standard (ARS) and the automated device-under-test (DUT) blood pressure (BP) measurements, the European Society of Hypertension International Protocol (ESH-IP) allows investigators to choose the closest ARS value to the DUT value, rather than using the mean of the ARS readings [which is mandated by the International Organization for Standardization (ISO)]. The impact of this rule on ESH-IP validation study results is unknown and was assessed. DESIGN AND METHODS: Nine alternating BP measurements performed according to the ISO protocol were obtained in 94 subjects. The impact of using the closest rather than the mean ARS reading on mean error, SD of the difference, and proportion of readings with DUT-ARS differences within 5, 10, and 15 mmHg was determined. RESULTS: Mean age was 58.6 ± 18.3 years, screening BP was 126.4/77.7 mmHg, and arm circumference was 32.0 ± 4.7 cm. DUT-ARS difference was 0.0 ± 5.3/-0.5 ± 5.0 mmHg using the closest ARS and -0.2 ± 6.5/-0.7 ± 5.9 mmHg using the mean ARS. When using the closest rather than the mean ARS value, the proportion of systolic readings with absolute DUT-ARS differences ≤5 mmHg was 73% (vs. 60% for the mean ARS method), ≤10 mmHg was 93% (vs. 88%), and ≤15 mmHg was 99% (vs. 98%). Corresponding values for diastolic BP were 73% (vs. 62%) for differences ≤5 mmHg, 94% (vs. 91%) for ≤10 mmHg, and 99% (vs. 99%) for ≤15 mmHg. CONCLUSION: Using the closest rather than the mean ARS value results in more favourable validation study results and increases likelihood of passing.

Barriers to learning and using point-of-care ultrasound: a survey of practicing internists in six North American institutions.

BACKGROUND: Point-of-care ultrasound (POCUS) is increasingly used in internal medicine, but a lack of trained faculty continues to limit the spread of POCUS education. Using a framework based on organizational change theories, this study sought to identify barriers and enablers for hospital-based practicing internists to learn and use POCUS in clinical practice. METHODS: We invited practicing internists at six North American institutions to participate in an electronic survey on their opinions regarding 39 barriers and enablers. RESULTS: Of the 342 participants invited, 170 participated (response rate 49.3%). The top barriers were lack of training (79%), lack of handheld ultrasound devices (78%), lack of direct supervision (65%), lack of time to perform POCUS during rounds (65%), and lack of quality assurance processes (53%). The majority of participants (55%) disagreed or strongly disagreed with the statement "My institution provides funding for POCUS training." In general, participants' attitudes towards POCUS were favourable, and future career opportunities and the potential for billing were not considered significant factors by our participants in the decision to learn or use POCUS. CONCLUSIONS: This survey confirms the perceived importance of POCUS to practicing internists. To assist in closing faculty development gap, interventions should address training, supervision, quality assurance processes, availability of handheld devices, as well as dedicated time to perform POCUS during clinical care.

Validation of the BIOS BD240 home blood pressure monitor in a multi-racial, multi-morbid Canadian population according to the International Standards Organization 2018 Protocol.

OBJECTIVE: Assess the accuracy of the BIOS BD240 home blood pressure (BP) monitor and wide-range cuff according to the International Organization for Standardization (ISO) 2018 standard. METHODS: Eighty-five subjects (aged ≥18 y) with arm circumferences between 24 and 43 cm were studied. Blinded, two-observer, mercury-based auscultation performed using a two-piece cuff chosen for upper arm size was used for reference measurements. Accuracy criteria 1 and 2 of the ISO standard were determined and Bland-Altman plots generated. RESULTS: Sixty percent of the study sample was female and 42% had hypertension. Mean device-to-reference standard differences in SBP/DBP were 0.0 ± 6.2/-0.2 ± 6.3 for criterion 1 and 0.0 ± 4.8/-0.2 ± 5.8 for criterion 2. CONCLUSION: The BIOS BD240 passed the requirements of the American National Standards Institute/Association for the Advancement of Medical Instrumentation/ISO standard for both SBP and DBP and can be recommended for use.

Correction to: Internal Medicine Point of Care Ultrasound: Indicators It's Here to Stay.

This editorial, "Internal Medicine Point of Care Ultrasound: Indicators It's Here to Stay" (DOI: 10.1007/s11606-019-05268-0), was intended to accompany "Education Indicators for Internal Medicine Point-of-Care Ultrasound: a Consensus Report from the Canadian Internal Medicine Ultrasound (CIMUS) Group".

Patient perceptions of ambulatory blood pressure monitoring testing, tolerability, accessibility, and expense.

Use of 24-hour ambulatory blood pressure monitoring is strongly endorsed by contemporary hypertension guidelines. The objective of this study was to assess patient perceptions of ambulatory blood pressure testing, tolerability, accessibility, and expense. A convenience sample of 50, consenting patients undergoing ambulatory blood pressure monitoring at the University of Alberta Hypertension Clinic in Edmonton, Canada was studied. A 16-item structured questionnaire was administered in person or electronically. Questions regarding the tolerability of ambulatory monitoring were evaluated using a 5-point Likert scale and wait times, expenditures, and willingness to pay were evaluated by direct questioning. Mean age was 53.1 ± 15.4 years, 32 (64%) were female, and 23 (46%) were employed. Mean 24-hour ambulatory BP was 134 ± 12/79 ± 8 mmHg. Ambulatory monitoring caused discomfort in 40 (80%) patients and disturbed sleep in 39 (78%). Forty-one (82%) patients perceived that the home (vs pharmacy, primary care clinic, and speciality care clinic) would be the easiest venue to access future testing. On average, patients waited 27.3 ± 23.7 days for testing; they felt that a wait time of 21.3 ± 12.3 days was appropriate. Mean time taken off work was 8.6 ± 10.8 hours. Twelve (24%) patients indicated that they would be willing to pay out-of-pocket to undergo testing sooner, at a mean expenditure of $120 ± 69. Nineteen (62%) patients were willing to buy a monitor and felt that a mean purchase cost of $125 ± 89 was appropriate. These findings extend current knowledge of patient perceptions of ambulatory monitoring and may help to refine and optimize future delivery of this essential test.

Comparability of oscillometric to simultaneous auscultatory blood pressure measurement in children.

OBJECTIVE: Uncertainty exists regarding the accuracy of automated blood pressure (BP) measurement in children. We recorded oscillometric waveforms in children, derived oscillometric BPs using two standard algorithms, and compared the results to simultaneous auscultation. PATIENTS AND METHODS: Twenty children aged 2-12 years were recruited from a tertiary-care Pediatric Nephrology Clinic. Sex, height, weight, arm circumference, history of hypertension, and clinic BP were recorded. Two, simultaneously measured, oscillometric and auscultatory BP readings were obtained 30-60 s apart. The first reading was discarded and, the second, used for analyses. Fixed-ratio and slope-based algorithms were used for BP derivation. RESULTS: Mean age was 7.95±2.82 years, 40% were female, mean arm circumference was 21.86±4.06 cm, and 50% had hypertension or a history of hypertension. Mean auscultatory BP for all participants (systolic±SD/diastolic±SD) was 93.40±11.80/50.50±9.04 mmHg, oscillometric fixed-ratio BP was 99.20±11.90/57.35±7.15 mmHg and oscillometric slope-based algorithm was 91.60±13.94/60.65±7.71 mmHg. Compared to auscultation, the fixed-ratio method differed by 5.80±12.72/6.85±7.51 mmHg (P=0.06 and <0.01) and the slope-based method differed by -1.80±13.59/10.15±8.07 mmHg (P=0.56 and <0.01). Differences from auscultation were statistically significant for diastolic BP with both fixed-ratio and slope-based methods for all age categories but of greatest magnitude in the youngest children. CONCLUSION: Oscillometric BP derived using two commonly used algorithms differed by more than 5 mmHg in either systolic BP or diastolic BP from simultaneous auscultatory BP in children aged 2-11. These findings emphasize the need for greater understanding of the functionality and accuracy of oscillometry in children.

Accuracy of oscillometric blood pressure algorithms in healthy adults and in adults with cardiovascular risk factors.

BACKGROUND: Fixed-ratio and slope-based algorithms are used to derive oscillometric blood pressure (BP). However, a paucity of published data exists assessing the accuracy of these methods. Our objective was to determine the accuracy of fixed-ratio and slope-based algorithms in healthy adults and in adults with cardiovascular risk factors. PATIENTS AND METHODS: Overall, 85 healthy adults (age≥18 years) and 85 adults with cardiovascular risk factors were studied. Three oscillometric and four two-observer mercury-based auscultation measurements were performed in each, according to International Standards Organization 2013 methodology. Two fixed-ratio algorithms and one slope-based algorithm were applied to process oscillometric waveform envelopes and derive oscillometric BP. Paired and unpaired t-tests were used to compare mean oscillometric BP within and between each group, respectively. RESULTS: For healthy adults, mean age was 50.3±17.8 years, mean arm circumference was 30.4±3.8 cm, and 62% were female. In the cardiovascular risk group, mean age was 63.8±12.4 years, mean arm circumference was 31.9±4.2 cm, and 62% were female. For systolic BP, the fixed-ratio algorithms produced the lowest mean error and narrowest SD. For diastolic BP, mean errors were similar for all three algorithms, but the fixed-ratio algorithms had higher precision. The comparison of healthy adults and those with cardiovascular risk factor showed high variability for systolic and diastolic BP (SD: 8.113.9 mmHg). CONCLUSION: In both healthy adults and in those with cardiovascular risk factors, the fixed-ratio technique performed better than the slope-based algorithm. High between-group variability indicates that subject-specific algorithms may be needed.

Comparability of Automated Office Blood Pressure to Daytime 24-Hour Ambulatory Blood Pressure.

BACKGROUND: Clinical practice guidelines endorse automated office blood pressure (AOBP) measurement as the preferred in-office measurement modality. However, recent data indicate that this method may underestimate daytime ambulatory BP. The objective of this study was to further assess the comparability of mean AOBP and daytime ambulatory BP in clinical practice. METHODS: A retrospective cross-sectional chart review was conducted of 96 consecutive patients referred from primary or specialty care practices to a tertiary care ambulatory BP monitoring service. Six AOBP readings were taken using an appropriately cuffed BpTRU (BpTRU Medical Devices, Coquitlam, Canada) device on the nondominant arm and no rest period (first reading discarded). Twenty-four-hour ambulatory BP monitoring was then performed. Between-group means were compared with paired t tests. The proportion of patients with differences of ≥ 5, 10, and 15 mm Hg was tabulated. RESULTS: Mean age was 52.6 ± 16.7 years, 60% were women, and 79% had previously diagnosed hypertension. Mean AOBPs were 130.8 ± 15.5/82.3 ± 10.7 mm Hg, and mean daytime ambulatory BPs were 142.8 ± 14.9/83.9 ± 11.2 mm Hg (difference of -11.9 ± 13.5/-1.6 ± 7.6; P < 0.001 for systolic BP and P < 0.04 for diastolic BP). Between-group differences were greater in patients with previous hypertension and in those with daytime ambulatory BP levels ≥ 135 mm Hg. The proportions of patients with systolic or diastolic BP differences of ≥ 5, 10 and 15 mm Hg were 89%, 52%, and 33%, respectively. CONCLUSIONS: Mean AOBP underestimates daytime ambulatory BP. Variability between the 2 methods is high. These findings do not support the premise that AOBP closely approximates daytime ambulatory BP.