The effect of different body positions on blood pressure

Comparison of forearm and intra-arterial blood pressure measurements according to body and arm positions in obese patients

RATIONALE

Noninvasive blood pressure (BP) monitoring is very important also difficult for accurate diagnosis and monitor of obese patients.

AIMS

The study aimed to assess the agreement between forearm arm BP and intra-arterial BP values in a different body and arm positions in obese patients.

METHODS

The descriptive study was carried out on 60 intensive care patients with a body mass index above 30 kg/m2 who were monitored with invasive radial BP in the general and surgical intensive care units. BP values obtained from the upper arm and forearm with different arm and body positions were compared with intra-arterial BP results. Bland-Altman analysis and correlation coefficient were used for the accuracy of upper and forearm noninvasive BP reading in different positions.

RESULTS

The best agreement was found between the forearm systolic BP in the supine and half-sitting position with the arm down and intra-arterial BP values. Also, the best agreement in diastolic BP was found between the half-sitting and half-sitting position with the arm down and intra-arterial BP.

CONCLUSIONS

Forearm systolic BP measurement, especially in the supine and half-sitting position with the arm below the heart level position, was best agreement with intra-arterial measurement, regarded as the gold standard. For this reason, it is more appropriate to use forearm BP measurement in obese patients monitored in intensive care to obtain accurate results.

Analysis of breathing patterns to stabilize cardiovascular changes in physical stress environments : inspiration responds to rapid changes in blood pressure

The thoracic nerves form a complex neural network that coordinates involuntary muscles such as breathing and the heart. Breathing has various patterns to maintain homeostasis in the human body. This study analyzes changes in the cardiovascular system and breathing patterns induced by stress caused by various mechanical movements performed in daily life and ultimately, the goal is to propose effective breathing patterns and breathing control methods to maintain cardiovascular homeostasis. The participants' age was 26.97 ± 3.93 years, height was 170.24 ± 8.61 cm, and weight was 65.69 ± 13.55 Kg, and there were 62 men and 38 women. Breathing and electrocardiogram were obtained using HiCard+, a biometric monitoring device. The measured electrocardiogram was analyzed for heartbeat interval, which indicates changes in the cardiovascular system, and standard deviation of normal to normal interval (SDNN) and root mean square of the successive differences (rMSSD), which indicate the activity of the autonomic and parasympathetic nervous systems. For respiration, time changes were analyzed as patterns by calculating inspiration and exhalation times. As a result of this study, rapid changes in blood pressure increased SDNN and rMSSD from 0.053 ± 0.06 and 0.056 ± 0.087 to 0.109 ± 0.114 and 0.125 ± 0.170 s, and induced an increase in spontaneous inspiratory time from 1.46 to 1.51 s (p < 0.05). Ultimately, we hope that the results of this study will be used as a breathing control training technique to prevent and manage rapid cardiovascular changes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-024-00379-y.

Defining systolic blood pressure normative values in hospitalized pediatric patients: a single center experience

BACKGROUND

Normative blood pressure (BP) values and definition of hypertension (HTN) in children in outpatient setting cannot be reliably used for inpatient therapy initiation. No normative exists to describe HTN in hospitalized pediatric populations. We aimed to study the prevalence of hypertension and produce normative BP values in hospitalized children.

METHODS

Cross sectional observational study of all children hospitalized on acute care floors, ≥2 and <18 years age, at Stanford Children's Hospital, from Jan-01-2014 to Dec-31-2018. Cohort included 7468 hospital encounters with a total of 118,423 automated, oscillometric, BPs measured in the upper extremity during a hospitalization of >24 hours.

RESULTS

Overall prevalence of HTN, defined by outpatient guidelines, was 12-48% in boys and 6-39% in girls, stage 1 systolic HTN in 12-38% of boys and 6-31% of girls, stage 2 systolic HTN in 3-10% of boys and 1-8% of girls. Centile curves were derived demonstrating overall higher BP reading for hospitalized patients compared to the outpatient setting.

CONCLUSION

Higher blood pressures are anticipated during hospitalization. Thresholds provided by the centile curves generated in this study may provide the clinician with some guidance on how to manage hospitalized pediatric patients based on clinical circumstances.

IMPACT

Hospitalized children have higher blood pressures compared to patients in the ambulatory setting, hence outpatient normative blood pressure values cannot be reliably used for inpatient therapy initiation. No normative exists to describe hypertension in hospitalized pediatric populations. The thresholds provided by the centile curves generated in this study may provide the clinician with some guidance on how to manage hospitalized pediatric patients based on clinical circumstances.

Blood pressure response to clonidine in children with short stature is correlated with postural characteristics: a retrospective cross-sectional study

BACKGROUND

Clonidine stimulation test has been widely used in the diagnosis of growth hormone deficiency in children with short stature with a high level of reliability. However, it may cause hypotension, which usually appears as headache, dizziness, bradycardia, and even syncope. It is well known that elevating the beds to make patients' feet above their cardiac level might relieve this discomfort. However, the real efficiency of this method remains to be proved while the best angle for the elevated bed is still unclear.

METHODS

A total of 1200 children with short stature were enrolled in this retrospective cross-sectional study. Age, gender, weight, and basic systolic and diastolic blood pressure were collected. Blood pressure at 1, 2, 3, and 4 h after stimulation tests were recorded. The participants were divided into 3 groups based on the angles of the elevated foot of their beds named 0°, 20°, and 40° groups.

RESULTS

At one hour after the commencement of the tests, participants lying on the elevated beds showed a higher mean increase on the change of pulse pressure. The difference in the angles of the elevated beds did not show statistical significance compared with those who did not elevate their beds (0.13 vs. 2.83, P = 0.001; 0.13 vs. 2.18, P = 0.005; 2.83 vs. 2.18, P = 0.369). When it came to 4 h after the tests began, participants whose beds were elevated at an angle around 20° had a significantly higher mean increase in the change of pulse pressure values compared with those whose beds were elevated at an angle around 40° (1.46 vs. -0.05, P = 0.042).

CONCLUSION

Elevating the foot of the beds of the patients who are undergoing clonidine stimulation tests at an angle of 20°might be a good choice to alleviate the hypotension caused by the tests.

Effect of Acute and Chronic Ingestion of Exogenous Ketone Supplements on Blood Pressure: A Systematic Review and Meta-Analysis

Exogenous ketone supplements have been suggested to have potential cardiovascular benefits, but their overall effect on blood pressure is unclear. Our objective was to perform a systematic review and meta-analysis on the effects of exogenous ketone supplements on blood pressure (BP) and concomitant changes in resting heart rate (HR). Five databases were searched on January 27th, 2023, for randomized and non-randomized studies. A random-effects model meta-analysis was performed including all studies jointly and separately for acute and chronic ingestion of ketone supplements. Out of 4012 studies identified in the search, 4 acute and 6 chronic studies with n = 187 participants were included. Pooled results (n = 10) showed no change in systolic (SMD [95% CI]= -0.14 [-0.40; 0.11]; I2= 30%; p = 0.17) or diastolic BP (-0.12 [-0.30; 0.05]; I2= 0%; p = 0.69), with a potential tendency observed toward increased resting heart rate (0.17 [-0.14; 0.47]; I2= 40%; p = 0.10). Similar results for systolic and diastolic BP were observed when assessing separately the effect of acute and chronic ingestion of ketone supplements (p ≥ 0.33). Supplement dosage was found to modulate the increase in resting heart rate (0.019 ± 0.006; p = 0.013; R2=100%), suggesting that higher supplement doses lead to a higher resting heart rate. Based on currently available data, acute or prolonged ingestion of ketone supplements does not seem to modulate BP. However, a tendency for HR to increase after acute ingestion was observed, particularly with higher doses. Higher quality studies with appropriate standardized measurements are needed to confirm these results.

A Case-Finding Protocol for High Cardiovascular Risk in a Primary Care Dental School-Model with Integrated Care

BACKGROUND

National Health Service (NHS) strategies in the United Kingdom (UK) have highlighted the need to maximise case-finding opportunities by improving coverage in non-traditional settings with the aim of reducing delayed diagnosis of non-communicable diseases. Primary care dental settings may also help to identify patients.

METHODS

Case-finding appointments took place in a primary care dental school. Measurements of blood pressure, body mass index (BMI), cholesterol, glucose and QRisk were taken along with a social/medical history. Participants with high cardiometabolic risk were referred to their primary care medical general practitioner (GP) and/or to local community health self-referral services, and followed up afterwards to record diagnosis outcome.

RESULTS

A total of 182 patients agreed to participate in the study over a 14-month period. Of these, 123 (67.5%) attended their appointment and two participants were excluded for age. High blood pressure (hypertension) was detected in 33 participants, 22 of whom had not been previous diagnosed, and 11 of whom had uncontrolled hypertension. Of the hypertensive individuals with no previous history, four were confirmed by their GP. Regarding cholesterol, 16 participants were referred to their GP for hypercholesterolaemia: 15 for untreated hypercholesterolaemia and one for uncontrolled hypercholesterolaemia.

CONCLUSIONS

Case-finding for hypertension and identifying cardiovascular risk factors has high acceptability in a primary dental care setting and supported by confirmational diagnoses by the GP.

Development of Real-Time Cuffless Blood Pressure Measurement Systems with ECG Electrodes and a Microphone Using Pulse Transit Time (PTT)

Research has shown that pulse transit time (PTT), which is the time delay between the electrocardiogram (ECG) signal and the signal from a photoplethysmogram (PPG) sensor, can be used to estimate systolic blood pressure (SBP) and diastolic blood pressure (DBP) without the need for a cuff. However, the LED of the PPG sensor requires the precise adjustment of both light intensity and light absorption rates according to the contact status of the light-receiving element. This results in the need for regular calibration. In this study, we propose a cuffless blood pressure monitor that measures real-time blood pressure using a microphone instead of a PPG sensor. The blood pulse wave is measured in the radial artery of the wrist using a microphone that can directly measure the sound generated by a body rather than sending energy inside the body and receiving a returning signal. Our blood pressure monitor uses the PTT between the R-peak of the ECG signal and two feature points of the blood pulse wave in the radial artery of the wrist. ECG electrodes and circuits were fabricated, and a commercial microelectromechanical system (MEMS) microphone was used as the microphone to measure blood pulses. The peak points of the blood pulse from the microphone were clear, so the estimated SBP and DBP could be obtained from each ECG pulse in real time, and the resulting estimations were similar to those made by a commercial cuff blood pressure monitor. Since neither the ECG electrodes nor the microphone requires calibration over time, the real-time cuffless blood pressure monitor does not require calibration. Using the developed device, blood pressure was measured three times daily for five days, and the mean absolute error (MAE) and standard deviation (SD) of the SBP and DBP were found to be 2.72 ± 3.42 mmHg and 2.29 ± 3.53 mmHg, respectively. As a preliminary study for proof-of-concept, these results were obtained from one subject. The next step will be a pilot study on a large number of subjects.

Applied machine learning for blood pressure estimation using a small, real-world electrocardiogram and photoplethysmogram dataset

Applying machine learning techniques to electrocardiography and photoplethysmography signals and their multivariate-derived waveforms is an ongoing effort to estimate non-occlusive blood pressure. Unfortunately, real ambulatory electrocardiography and photoplethysmography waveforms are inevitably affected by motion and noise artifacts, so established machine learning architectures perform poorly when trained on data of the Multiparameter Intelligent Monitoring in Intensive Care II type, a publicly available ICU database. Our study addresses this problem by applying four well-established machine learning methods, i.e., random forest regression, support vector regression, Adaboost regression and artificial neural networks, to a small, self-sampled electrocardiography-photoplethysmography dataset (n = 54) to improve the robustness of machine learning to real-world BP estimates. We evaluated the performance using a selection of optimal feature morphologies of waveforms by using pulse arrival time, morphological and frequency photoplethysmography parameters and heart rate variability as characterization data. On the basis of the root mean square error and mean absolute error, our study showed that support vector regression gave the best performance for blood pressure estimation from noisy data, achieving an mean absolute error of 6.97 mmHg, which meets the level C criteria set by the British Hypertension Society. We demonstrate that ambulatory electrocardiography- photoplethysmography signals acquired by mobile discrete devices can be used to estimate blood pressure.

Cerebral blood flow velocity progressively decreases with increasing levels of verticalization in healthy adults. A cross-sectional study with an observational design

Background

Autoregulation of the cerebral vasculature keeps brain perfusion stable over a range of systemic mean arterial pressures to ensure brain functioning, e.g., in different body positions. Verticalization, i.e., transfer from lying (0°) to upright (70°), which causes systemic blood pressure drop, would otherwise dramatically lower cerebral perfusion pressure inducing fainting. Understanding cerebral autoregulation is therefore a prerequisite to safe mobilization of patients in therapy.

Aim

We measured the impact of verticalization on cerebral blood flow velocity (CBFV) and systemic blood pressure (BP), heart rate (HR) and oxygen saturation in healthy individuals.

Methods

We measured CBFV in the middle cerebral artery (MCA) of the dominant hemisphere in 20 subjects using continuous transcranial doppler ultrasound (TCD). Subjects were verticalized at 0°, -5°, 15°, 30°, 45° and 70° for 3-5 min each, using a standardized Sara Combilizer chair. In addition, blood pressure, heart rate and oxygen saturation were continuously monitored.

Results

We show that CBFV progressively decreases in the MCA with increasing degrees of verticalization. Systolic and diastolic BP, as well as HR, show a compensatory increase during verticalization.

Conclusion

In healthy adults CBFV changes rapidly with changing levels of verticalization. The changes in the circulatory parameters are similar to results regarding classic orthostasis.

Registration

ClinicalTrials.gov, identifier: NCT04573114.

Exploring the acute cardiovascular effects of Floatation-REST

The central nervous system (CNS) exerts a strong regulatory influence over the cardiovascular system in response to environmental demands. Floatation-REST (Reduced Environmental Stimulation Therapy) is an intervention that minimizes stimulation from the environment, yet little is known about the autonomic consequences of reducing external sensory input to the CNS. We recently found that Floatation-REST induces a strong anxiolytic effect in anxious patients while paradoxically enhancing their interoceptive awareness for cardiorespiratory sensations. To further investigate the physiologic nature of this anxiolytic effect, the present study measured acute cardiovascular changes during Floatation-REST using wireless and waterproof equipment that allowed for concurrent measurement of heart rate, heart rate variability (HRV), breathing rate, and blood pressure. Using a within-subjects crossover design, 37 clinically anxious participants with high levels of anxiety sensitivity and 20 non-anxious comparison participants were randomly assigned to undergo a 90-min session of either Floatation-REST or an exteroceptive comparison condition that entailed watching a relaxing nature film. Measures of state anxiety and serenity were collected before and after each session, while indices of autonomic activity were measured throughout each session. HRV was calculated using both time-series and frequency domain analyses. Linear mixed-effects modeling revealed a significant main effect of condition such that relative to the film condition, Floatation-REST elicited significant decreases (p < 0.001) in diastolic blood pressure, systolic blood pressure, breathing rate, and certain metrics of HRV including the standard deviation of the interbeat interval (SDNN), low-frequency HRV, and very low-frequency HRV. Heart rate showed a non-significant trend (p = 0.073) toward being lower in the float condition, especially toward the beginning of the session. The only metric that showed a significant increase during Floatation-REST was normalized high-frequency HRV (p < 0.001). The observed physiological changes were consistent across both anxious and non-anxious participants, and there were no significant group by condition interactions. Blood pressure was the only cardiac metric significantly associated with float-related reductions in state anxiety and increases in serenity. These findings suggest that Floatation-REST lowers sympathetic arousal and alters the balance of the autonomic nervous system toward a more parasympathetic state.

Clinical trial registration

[https://clinicaltrials.gov/show/NCT03051074], identifier [NCT03051074].

Impaired postural control in diabetes-a predictor of falls?

New evidence points toward that impaired postural control judged by center of pressure measures during quiet stance is a predictor of falls in people with type 1 and type 2 diabetes-even in occurrence of well-known risk factors for falls.

INTRODUCTION/AIM

People with type 1 diabetes (T1D) and type 2 diabetes (T2D) are at risk of falling, but the association with impaired postural control is unclear. Therefore, the aim was to investigate postural control by measuring the center of pressure (CoP) during quiet standing and to estimate the prevalence ratio (PR) of falls and the fear of falling among people with diabetes compared to controls.

METHODS

In a cross-sectional study, participants with T1D (n = 111) and T2D (n = 106) and controls without diabetes (n = 328) were included. Study procedures consisted of handgrip strength (HGS), vibration perception threshold (VPT), orthostatism, visual acuity, and postural control during quiet stance measured by CoPArea (degree of body sway) and CoPVelocity (speed of the body sway) with "eyes open," "eyes closed" in combination with executive function tasks. A history of previous falls and fear of falling was collected by a questionnaire. CoPArea and CoPVelocity measurements were analyzed by using a multiple linear regression model. The PR of falls and the fear of falling were estimated by a Poisson regression model. Age, sex, BMI, previous falls, alcohol use, drug, HGS, VPT, orthostatism, episodes of hypoglycemia, and visual acuity were covariates in multiple adjusted analyses.

RESULTS

Significantly larger mean CoPArea measures were observed for participants with T1D (p = 0.022) and T2D (0.002), whereas mean CoPVelocity measures were only increased in participants with T2D (p = 0.027) vs. controls. Additionally, T1D and T2D participants had higher PRs for falls (p = 0.044, p = 0.014) and fear of falling (p = 0.006, p < 0.001) in the crude analyses, but the PRs reduced significantly when adjusted for mean CoPArea and mean CoPVelocity, respectively. Furthermore, multiple adjusted PRs were significantly higher than crude the analyses.    CONCLUSION: Impaired postural control during quiet stance was seen in T1D and T2D compared with controls even in the occurrence of well-known risk factors. and correlated well with a higher prevalence of falls.

A case of vertebral artery compression syndrome mimicking primary lateral sclerosis

PURPOSE

Vertebral artery compression syndrome (VACS) is an under-recognised condition that may be misdiagnosed as motor neuron disease. We report a case presenting features initially suggestive of primary lateral sclerosis (PLS) but later found to be VACS.

CASE PRESENTATION

A 65-year-old man with hypertension was referred to our neurology department in the suspect of PLS. He presented with a 10-year history of involuntary jerk of the left lower limb, which ascended to the left upper limb 9 years later. He also developed intermittent painful spasms with a tendency to drag his left leg. His symptoms fluctuated with blood pressure. Neurological examination revealed upper motor neuron signs without lower motor neuron or sensory involvement. Electrophysiology studies were unremarkable. Brain MRI disclosed the left side of medulla oblongata was compressed by the tortuous left vertebral artery. Diffusion tensor tractography confirmed the corresponding corticospinal tract disruption. He was diagnosed with VACS and treated with antispasmodic medications and antihypertensive drugs.

CONCLUSIONS

VACS should be considered into the differential diagnoses of PLS. A thorough clinical assessment and careful interpretation of brain MRI with advanced diffusion neuroimages can help confirm the diagnosis.

Mobilisation of critically ill patients receiving norepinephrine: a retrospective cohort study

BACKGROUND

Mobilisation and exercise intervention in general are safe and feasible in critically ill patients. For patients requiring catecholamines, however, doses of norepinephrine safe for mobilisation in the intensive care unit (ICU) are not defined. This study aimed to describe mobilisation practice in our hospital and identify doses of norepinephrine that allowed a safe mobilisation.

METHODS

We conducted a retrospective single-centre cohort study of 16 ICUs at a university hospital in Germany with patients admitted between March 2018 and November 2021. Data were collected from our patient data management system. We analysed the effect of norepinephrine on level (ICU Mobility Scale) and frequency (units per day) of mobilisation, early mobilisation (within 72 h of ICU admission), mortality, and rate of adverse events. Data were extracted from free-text mobilisation entries using supervised machine learning (support vector machine). Statistical analyses were done using (generalised) linear (mixed-effect) models, as well as chi-square tests and ANOVAs.

RESULTS

A total of 12,462 patients were analysed in this study. They received a total of 59,415 mobilisation units. Of these patients, 842 (6.8%) received mobilisation under continuous norepinephrine administration. Norepinephrine administration was negatively associated with the frequency of mobilisation (adjusted difference -0.07 mobilisations per day; 95% CI - 0.09, - 0.05; p ≤ 0.001) and early mobilisation (adjusted OR 0.83; 95% CI 0.76, 0.90; p ≤ 0.001), while a higher norepinephrine dose corresponded to a lower chance to be mobilised out-of-bed (adjusted OR 0.01; 95% CI 0.00, 0.04; p ≤ 0.001). Mobilisation with norepinephrine did not significantly affect mortality (p > 0.1). Higher compared to lower doses of norepinephrine did not lead to a significant increase in adverse events in our practice (p > 0.1). We identified that mobilisation was safe with up to 0.20 µg/kg/min norepinephrine for out-of-bed (IMS ≥ 2) and 0.33 µg/kg/min for in-bed (IMS 0-1) mobilisation.

CONCLUSIONS

Mobilisation with norepinephrine can be done safely when considering the status of the patient and safety guidelines. We demonstrated that safe mobilisation was possible with norepinephrine doses up to 0.20 µg/kg/min for out-of-bed (IMS ≥ 2) and 0.33 µg/kg/min for in-bed (IMS 0-1) mobilisation.

Variation in blood pressure and heart rate of radiological technologists in worktime tracked by a wearable device: A preliminary study

The aim of this preliminary study was to measure the systolic BP (SBP) and diastolic BP (DBP) and heart rate (HR) of radiological technologists by WD, and evaluate variation among individuals by worktime, day of the week, job, and workplace. Measurements were obtained using a wristwatch-type WD with optical measurement technology that can measure SBP and DBP every 10 minutes and HR every 30 minutes. SBP, DBP, and HR data obtained at baseline and during work time were combined with the hours of work, day of the week, job, and workplace recorded by the participants in 8 consecutive weeks. We calculated the mean, the ratio to baseline and coefficient of variation [CV(%)] for SBP, DBP, and HR. SBP, DBP, and HR values were significantly higher during work hours than at baseline (p<0.03). The ratio to baseline values ranged from 1.02 to 1.26 for SBP and from 1.07 to 1.30 for DBP. The ratio to baseline for SBP and DBP showed CV(%) of approximately 10% according to the day of the week and over the study period. For HR, ratio to baseline ranged from 0.95 to 1.29. The ratio of mean BP to baseline was >1.2 at the time of starting work, middle and after lunch, and at 14:00. The ratio to baseline of SBP were 1.2 or more for irradiation, equipment accuracy control, registration of patient data, dose verification and conference time, and were also working in CT examination room, treatment planning room, linac room, and the office. CV(%) of BP and HR were generally stable for all workplaces. WD measurements of SBP, DBP, and HR were higher during working hours than at baseline and varied by the individuals, work time, job, and workplace. This method may enable evaluation of unconscious workload in individuals.

Sources of automatic office blood pressure measurement error: a systematic review

OBJECTIVE

Accurate and reliable blood pressure (BP) measurement is important for the prevention and treatment of hypertension. The oscillometric-based automatic office blood pressure measurement (AOBPM) is widely used in hospitals and clinics, but measurement errors are common in BP measurements. There is a lack of systematic review of the sources of measurement errors.

APPROACH

A systematic review of all existing research on sources of AOBPM errors. A search strategy was designed in six online databases, and all the literature published before October 2021 was selected. Those studies that used the AOBPM device to measure BP from the upper arm of subjects were included.

MAIN RESULTS

A total of 1365 studies were screened, and 224 studies were included in this final review. They investigated 22 common error sources with clinical AOBPM. Regarding the causes of BP errors, this review divided them into the following categories: the activities before measurement, patient's factors, measurement environment, measurement procedure, and device settings. 13 sources caused increased systolic and diastolic BP (SBP and DBP), 2 sources caused the decrease in SBP and DBP, only 1 source had no significant effect on BPs, and the other errors had a non-uniform effect (either increase or decrease in BPs). The error ranges for SBP and DBP were -14 to 33 mmHg and -6 to 19 mmHg, respectively.

SIGNIFICANCE

The measurement accuracy of AOBPM is susceptible to the influence of measurement factors. Interpreting BP readings need to be treated with caution in clinical measurements. This review made comprehensive evidence for the need for standardized BP measurements and provided guidance for clinical practitioners when measuring BP with AOBPM devices.

Blood Pressure Response and Pulse Arrival Time During Exercise Testing in Well-Trained Individuals

Introduction: There is a lack of data describing the blood pressure response (BPR) in well-trained individuals. In addition, continuous bio-signal measurements are increasingly investigated to overcome the limitations of intermittent cuff-based BP measurements during exercise testing. Thus, the present study aimed to assess the BPR in well-trained individuals during a cycle ergometer test with a particular focus on the systolic BP (SBP) and to investigate pulse arrival time (PAT) as a continuous surrogate for SBP during exercise testing.

Materials and Methods: Eighteen well-trained male cyclists were included (32.4 ± 9.4 years; maximal oxygen uptake 63 ± 10 ml/min/kg) and performed a stepwise lactate threshold test with 5-minute stages, followed by a continuous test to voluntary exhaustion with 1-min increments when cycling on an ergometer. BP was measured with a standard automated exercise BP cuff. PAT was measured continuously with a non-invasive physiological measurements device (IsenseU) and metabolic consumption was measured continuously during both tests.

Results: At lactate threshold (281 ± 56 W) and maximal intensity test (403 ± 61 W), SBP increased from resting values of 136 ± 9 mmHg to maximal values of 219 ± 21 mmHg and 231 ± 18 mmHg, respectively. Linear within-participant regression lines between PAT and SBP showed a mean r² of 0.81 ± 17.

Conclusion: In the present study focusing on the BPR in well-trained individuals, we observed a more exaggerated systolic BPR than in comparable recent studies. Future research should follow up on these findings to clarify the clinical implications of the high BPR in well-trained individuals. In addition, PAT showed strong intra-individual associations, indicating potential use as a surrogate SBP measurement during exercise testing.

Retinal microvasculature and vasoreactivity changes in hypertension using optical coherence tomography-angiography

PURPOSE

To evaluate the retinal vasculature and vasoreactivity of patients with hypertension (HTN) using spectral domain optical coherence tomography angiography (SD-OCTA).

METHODS

Patients with and without a diagnosis of HTN were included in this cross-sectional observational study. All eyes were imaged with SD-OCTA using 3 mm × 3 mm and 6 mm × 6 mm centered on both the fovea and optic disk. A second 6 mm × 6 mm scan was taken after a 30 s breath-hold. Vessel density (VD), vessel skeletonized density (VSD), and fractal dimension (FD) were calculated using customized MATLAB scripts. Vessel diameter index (VDI) was obtained by taking the ratio of VD to VSD. Vasoreactivity was measured by subtracting the VD or VSD before and after breath-hold (∆VD, ∆VSD).

RESULTS

Twenty-three eyes with HTN (17 patients) and 17 control eyes (15 patients) were included. In the 6 mm × 6 mm angiogram centered on fovea, the superficial capillary plexus (SCP) VD (ß =  - 0.029, p = 0.012), VSD (ß =  - 0.004, p = 0.043) and the choriocapillaris VD (ß =  - 0.021, p = 0.030) were significantly decreased in HTN compared to control eyes. Similarly, FD was decreased in both the SCP (ß =  - 0.012, p = 0.013) and choriocapillaris (ß =  - 0.009, p = 0.030). In the 3 mm × 3 mm angiogram centered on optic disk, SCP VDI (ß =  - 0.364, p = 0.034) was decreased. ∆VD and ∆VSD were both reduced in the DCP (ß =  - 0.034, p = 0.032; ß =  - 0.013, p = 0.043) and ∆VSD was elevated in the choriocapillaris of HTN eyes (ß = 0.004, p = 0.032).

CONCLUSIONS

The study used SD-OCTA to show significant differences in the retinal vasculature of hypertensive patients. It was also the first to demonstrate the potential of OCT-A to investigate retinal vascular reactivity in patients with HTN.

Early pregnancy vitamin D status is associated with blood pressure in children: an Odense Child Cohort study

BACKGROUND

Blood pressure in childhood tracks into later life. Vitamin D status in adults is associated with blood pressure, but the impact of vitamin D status in pregnancy and childhood on blood pressure still needs investigation.

OBJECTIVE

We investigated whether fetal rather than current vitamin D status is associated with blood pressure in children.

METHODS

In a prospective observational study within the population-based Odense Child Cohort (OCC), we examined serum 25-hydroxyvitamin D2+3 [s-25(OH)D] in early and late pregnancy, cord blood, and at 5 y age, and the associations with systolic and diastolic blood pressure (SBP/DBP) in the 5-y-old children (n = 1,677). Multiple regression models were adjusted for maternal country of origin, parity, smoking during pregnancy, 5-y height, and weight. Two-stage mixed effect modeling was performed, integrating all s-25(OH)D data from pregnancy and cord blood.

RESULTS

The median (IQR) s-25(OH)D in early pregnancy, late pregnancy, the umbilical cord, and at 5 y was 65.5 (50.7-78.5), 78.5 (60.3- 95.8), 45.4 (31.1- 60.7), and 71.9 (54.6- 86.5) nmol/L, respectively. The mean ±SD 5-y SBP/DBP was 101.0/63.8 (7.1/5.9) mmHg. In adjusted analyses, a 10 nmol/L increase of s-25(OH)D in early pregnancy associated with a 0.3/0.2 mmHg lower SBP/DBP at 5 y (P < 0.05). Optimal s-25(OH)D (>75 nmol/L) in early pregnancy was associated with lower 5-y SBP and DBP, β (95% CI) -1.45 (-2.6, -0.3), and -0.97 (-1.9, -0.1), compared with reference s-25(OH)D (50-74.9 nmol/L). Two-stage analysis combining early pregnancy, late pregnancy, and cord s-25(OH)D data showed an inverse association with 5-y SBP and DBP for boys (P < 0.025) with significant sex-difference for DBP (Pinteraction = 0.004). No associations were found between s-25(OH)D and 5-y BP above the 90th percentile.

CONCLUSION

Early pregnancy s-25(OH)D concentrations, especially >75 nmol/L, were inversely associated with 5-y blood pressure in the offspring. A novel identified protective effect of optimal vitamin D levels in early pregnancy on offspring BP is suggested.

Validity of the ActivPAL monitor to distinguish postures: A systematic review

BACKGROUND

Posture has been recently integrated into activity guidelines, advising people to limit their sedentary time and break up sedentary postures with standing/stepping as much as possible. The thigh-worn activPAL is a frequently used objective measure of posture, but its validity has only been investigated by individual studies and has not been systematically reviewed.

RESEARCH QUESTION

Can the activPAL accurately characterize different postures?

METHODS

A rigorous systematic review protocol was conducted, including multiple study screeners and determiners of study quality. To be included, validation studies had to examine the accuracy of an activPAL posture outcome relative to a criterion measure (e.g., direct observation) in adults (>18 years). Citations were not restricted to language or date of publication. Sources were searched on May 16, 2021 and included Scopus, EMBASE, MEDLINE, CINAHL, and Academic Search Premier. The study was pre-registered in Prospero (ID# CRD42021248240). Study quality was determined using a modified Hagströmer Bowles checklist. The results are presented narratively.

RESULTS

Twenty-four studies (18 semi-structured laboratory arms, 8 uncontrolled protocol arms; 476 participants) met the inclusion criteria. Some studies (5/24) incorporated dual-monitor (trunk: 4/5; shin: 1/5) configurations. While heterogenous statistical procedures were implemented, most studies (n = 22/24) demonstrated a high validity (e.g., percent agreement >90%, no fixed bias, etc.) of the activPAL to measure sedentary and/or upright postures across semi-structured (17/18 arms) and uncontrolled study designs (7/8 arms). Specific experimental protocol factors (i.e., seat height, fidgeting, non-direct observation criterion comparator) likely explain the divergent reports that observed valid versus invalid findings. The study quality was 11.3 (standard deviation: 2.3) out of 19.

CONCLUSION

Despite heterogeneous methodological and statistical approaches, the included studies generally provide supporting evidence that the activPAL can accurately distinguish between sedentary and standing postures. Multiple activPAL monitor configurations (e.g., thigh and torso) are needed to better characterize sitting versus lying postures.

Changes in Retinal Optical Coherence Tomography Angiography Indexes Over 24 Hours

Purpose

To evaluate changes in the retinal microvasculature of young adults over 24 hours using optical coherence tomography angiography (OCT-A).

Methods

Participants (n = 44, mean age 23.2 ± 4.1 years, 24 myopes and 20 nonmyopes) with normal ophthalmological findings were recruited. Two macular OCT-A and OCT scans, systemic blood pressure, intraocular pressure (IOP), and biometry measurements were taken every four hours over 24 hours. Superficial and deep retinal layer en face images were analyzed to extract magnification-corrected vascular indexes using image analysis including foveal avascular zone metrics, vessel density, and perfusion density for the foveal, parafoveal, and perifoveal zones.

Results

Significant diurnal variations (P < 0.001) were observed in the vessel and perfusion density in the three superficial retinal layer regions, with acrophase between 4:30 PM and 8:30 PM. Only foveal and parafoveal regions of the deep retinal layer exhibited significant diurnal variations with acrophase between 9 AM and 3 PM. Myopes and nonmyopes had different acrophases but not amplitudes in the parafoveal perfusion density of superficial retinal layer (P = 0.039). Significant correlations were observed between diurnal amplitudes or acrophases of superficial retinal layer indexes and systemic pulse pressure, IOP, axial length and retinal thickness.

Conclusions

This study shows, for the first time, that significant diurnal variation exists in OCT-A indexes of macular superficial and deep retinal layer over 24 hours and were related to variations in various ocular and systemic measurements. Myopes and nonmyopes showed differences in the timing but not in amplitude of the superficial retinal layer parafoveal perfusion density variations but not in deep retinal layer.

Intrasession Reliability Analysis for Oscillometric Blood Pressure Method Using a Digital Blood Pressure Monitor in Peruvian Population

Blood Pressure (BP) is one of the most used measured clinical parameters in health promotion and intervention. BP measures can vary due to different parameters, so we aim to study the intrasession test–retest reliability for an oscillometric method using a digital tensiometer in the Peruvian population aged over 15 with and without a diagnosis of hypertension (HT). Data were taken from the Demographic and Family Health Survey conducted in Peru in 2019. Technicians had to follow a standardized protocol on the conditions to carry out a valid and reliable measurement. Relative reliability was excellent in most cases (intraclass correlation coefficient > 0.9); absolute reliability was excellent (standard error of measurement < 5%) and smallest real difference < 10% in most cases. The Bland–Altman plot showed a systematic error of 2.36 for systolic BP in men and 2.16 in women, and 0.823 for diastolic BP in men and 0.71 for diastolic BP in women. Results suggest that the oscillometric method with a digital blood pressure monitor was reliable in absolute and relative terms in this population, so it could be used as a reliable control test to measure changes after an intervention.

Childhood Blood Pressure, Carotid Intima Media Thickness, and Distensibility After In Utero Exposure to Gestational Hypertensive Disorders

Background

Offspring exposed to gestational hypertensive disorders have higher blood pressure and increased risk of stroke in later life. Gestational hypertensive disorders might influence vascular development in the offspring, predisposing them to a higher blood pressure and stroke in later life.

Methods and Results

In a population‐based cohort among 4777 mother–offspring pairs, we examined whether gestational hypertension, preeclampsia, and higher gestational blood pressure across the full blood pressure spectrum were associated with offspring blood pressure, carotid intima media thickness, and distensibility at the age of 10 years. Offspring exposed to gestational hypertension, but not preeclampsia, had higher systolic and diastolic blood pressure (0.17 [95% CI, 0.02–0.31] and 0.23 [95% CI, 0.08–0.38] increases in standard deviation scores, respectively), whereas no associations with intima media thickness and distensibility were present. Higher maternal systolic and diastolic blood pressure in early, mid, and late pregnancy were associated with higher offspring systolic and diastolic blood pressure and lower distensibility (P values <0.05), but not with intima media thickness. The associations were not explained by maternal, birth, or child factors. Paternal systolic and diastolic blood pressure were also associated with these offspring outcomes (P values <0.05), with a comparable strength as maternal–offspring associations.

Conclusions

Gestational hypertension and higher gestational blood pressure, even below the diagnostic threshold for gestational hypertensive disorders, are associated with higher offspring blood pressure and lower carotid distensibility. No associations were found for preeclampsia with offspring vascular outcomes. As maternal–offspring and paternal–offspring associations were comparable, these associations are more likely driven by genetic predisposition and shared lifestyle rather than by a direct intrauterine effect.

Systematic Review and Regression Modeling of the Effects of Age, Body Size, and Exercise on Cardiovascular Parameters in Healthy Adults

PURPOSE

Blood pressure, cardiac output, and ventricular volumes correlate to various subject features such as age, body size, and exercise intensity. The purpose of this study is to quantify this correlation through regression modeling.

METHODS

We conducted a systematic review to compile reference data of healthy subjects for several cardiovascular parameters and subject features. Regression algorithms used these aggregate data to formulate predictive models for the outputs-systolic and diastolic blood pressure, ventricular volumes, cardiac output, and heart rate-against the features-age, height, weight, and exercise intensity. A simulation-based procedure generated data of virtual subjects to test whether these regression models built using aggregate data can perform well for subject-level predictions and to provide an estimate for the expected error. The blood pressure and heart rate models were also validated using real-world subject-level data.

RESULTS

The direction of trends between model outputs and the input subject features in our study agree with those in current literature.

CONCLUSION

Although other studies observe exponential predictor-output relations, the linear regression algorithms performed the best for the data in this study. The use of subject-level data and more predictors may provide regression models with higher fidelity.

SIGNIFICANCE

Models developed in this study can be useful to clinicians for personalized patient assessment and to researchers for tuning computational models.

The Effect of Body Position and the Reliability of Upper Limb Arterial Occlusion Pressure Using a Handheld Doppler Ultrasound for Blood Flow Restriction Training

BACKGROUND

The precise calculation of arterial occlusive pressure is essential to accurately prescribe individualized pressures during blood flow restriction training. Arterial occlusion pressure in the lower limb varies significantly between different body positions while similar reports for the upper limb are lacking.

HYPOTHESIS

Body position has a significant effect in upper limb arterial occlusive pressure. Using cuffs with manual pump and a handheld Doppler ultrasound can be a reliable method to determine upper limb arterial blood flow restriction.

STUDY DESIGN

A randomized repeated measures design.

LEVEL OF EVIDENCE

Level 3.

METHODS

Forty-two healthy participants (age mean ± SD = 28.1 ± 7.7 years) completed measurements in supine, seated, and standing position by 3 blinded raters. A cuff with a manual pump and a handheld acoustic ultrasound were used. The Wilcoxon signed-rank test with Bonferroni correction was used to analyze differences between body positions. A within-subject coefficient of variation and an intraclass correlation coefficient (ICC) test were used to calculate reproducibility and reliability, respectively.

RESULTS

A significantly higher upper limb arterial occlusive pressure was found in seated compared with supine position (P < 0.031) and in supine compared with standing position (P < 0.031) in all raters. An ICC of 0.894 (95% CI = 0.824-0.939, P < 0.001) was found in supine, 0.973 (95% CI = 0.955-0.985, P < 0.001) in seated, and 0.984 (95% CI = 0.973-0.991, P < 0.001) in standing position. ICC for test-retest reliability was found 0.90 (95% CI = 0.814-0.946, P < 0.001), 0.873 (95% CI = 0.762-0.93, P < 0.001), and 0.858 (95% CI = 0.737-0.923, P < 0.001) in the supine, seated, and standing position, respectively.

CONCLUSION

Upper limb arterial occlusive pressure was significantly dependent on body position. The method showed excellent interrater reliability and repeatability between different days.

CLINICAL RELEVANCE

Prescription of individualized pressures during blood flow restriction training requires measurement of upper limb arterial occlusive pressure in the appropriate position. The use of occlusion cuffs with a manual pump and a handheld Doppler ultrasound showed excellent reliability; however, the increased measurement error compared with the differences in arterial occlusive pressure between certain positions should be carefully considered for the clinical application of the method.

STRENGTH OF RECOMMENDATIONS TAXONOMY (SORT)

B.

Orthostatic Hypotension and Orthostatic Intolerance Symptoms in Geriatric Rehabilitation Inpatients, RESORT

OBJECTIVES

Orthostatic hypotension (OH) and orthostatic intolerance symptoms are common in older community-dwelling adults and are associated with reduced quality of life and detrimental health outcomes. This study aimed to determine the prevalence, co-occurrence and determinants of OH and orthostatic intolerance symptoms in geriatric rehabilitation inpatients.

DESIGN

Observational, longitudinal cohort, "REStORing the health of acutely unwell adulTs" (RESORT).

SETTING AND PARTICIPANTS

Geriatric rehabilitation inpatients (n = 1505) of a tertiary teaching hospital in Melbourne, Australia.

METHODS

OH was defined as a drop in systolic blood pressure by ≥20 mm Hg and/or diastolic blood pressure by ≥10 mm Hg within three 3 of moving from supine to a standing or sitting position. Symptoms were recorded following the 3 minutes. Determinants included sociodemographics, reason for admission, cognitive health, nutritional status, physical performance, frailty, morbidity, medication use, length of stay (LOS), and number of geriatric conditions. Independent t-tests, Mann-Whitney U tests or χ² tests were used to analyze differences between inpatients with and without OH and symptoms. Logistic regression analyses were used to ascertain the determinants.

RESULTS

OH and orthostatic intolerance symptoms were prevalent in 19.8% (standing: 21.4%, sitting: 18.2%) and 22.6% (standing: 25.0%, sitting: 20.2%) of inpatients, respectively. Symptoms were reported by 32.8% of inpatients with OH and 20.1% without OH. Higher number of comorbidities and geriatric conditions, low functional independence, and longer LOS were determinants of OH. Female gender, higher number of morbidities and geriatric conditions, low functional independence, depression risk, poor physical performance, musculoskeletal and "other" reasons for admission, and long LOS during geriatric rehabilitation were determinants of symptoms.

CONCLUSIONS AND IMPLICATIONS

OH and orthostatic intolerance symptoms occur in one-fifth of geriatric rehabilitation inpatients, however, the co-occurrence is low and determinants differ. Poorer health in patients with orthostatic intolerance symptoms highlights the need to assess symptoms in clinical practice, independent of an OH diagnosis.

Does body position, age, and heart rate induce IOP's changes?

OBJECTIVES

The main goal of this research was to determine the differences between the values of intraocular pressure (IOP) in the supine and sitting positions, and to assess the effect of age and cardiovascular parameters.

METHODS

Seventy-two healthy adults were enrolled and classified into age groups: 20-30 years (group A), 31-40 years (group B), and 41-71 years (group C). Corneal biometry and cardiovascular parameters, such as heart rate (HR), were measured. IOP measurements were taken in the sitting position (IOP_S) and in the supine position (IOP_L) using the iCare^® Pro tonometer.

RESULTS

A significant difference between the IOP_S and IOP_L in the entire cohort was found (p < 0.001). Regarding the age subgroups, a significant difference (p < 0.001) between the IOP_S and IOP_L was obtained in group A (2.6 ± 1.6 mmHg) and group C (1.5 ± 1.3 mmHg). There were no significant differences in the IOP_S between groups. The highest IOP values were obtained for group A. The correlations between HR and IOP_S are statistically significant for group A and group B, and for HR and IOP_L-S for group B only. Multivariate analysis showed that HR has a significant influence on the difference in IOP in the two body positions.

CONCLUSION

A statistically significant difference between the effect of age and the values of IOP_S and IOP_L was shown. Cardiovascular parameters showed some relevant statistical dependencies, but with a rather marginal significance in young people. The influence of body position for the measurement of IOP for healthy subjects does not seem to matter, despite the fact that there are some dependencies that are statistically significant.

Contralateral training effects of low-intensity blood-flow restricted and high-intensity unilateral resistance training

PURPOSE

Determine whether unilateral low-intensity blood-flow restricted (LIBFR) exercise is as effective as high-intensity (HI) resistance training for improving contralateral muscle strength.

METHODS

Thirty healthy adults (20-30 years) were randomly allocated to the following dynamic plantar-flexion training interventions: HI [75% of one-repetition maximum (1RM), 4 sets, 10 reps] and LIBFR [20% of 1RM, 4 sets, 30 + 15 + 15 + 15 reps]. Evoked V-wave and H-reflex recruitment curves, as well as maximal voluntary contraction (MVC) and panoramic ultrasound assessments of the trained and untrained soleus muscles were obtained pre-training, post-4 weeks of training and post-4 weeks of detraining.

RESULTS

Both interventions failed to increase contralateral MVC and muscle cross-sectional area (CSA). Yet, contralateral rate of torque development (RTD) was enhanced by both regimens (12-26%) and this was accompanied by heightened soleus EMG within the first milliseconds of the rising torque-time curve (14-22%; p < 0.05). These improvements were dissipated after detraining. Contralateral adaptations were not accompanied by changes in V-wave or H-reflex excitability. Conversely, LIBFR and HI elicited a similar magnitude of ipsilateral increase in MVC, RTD and CSA post-training (10-18%). Improvements in V-wave amplitude and soleus EMG were limited to the trained leg assigned to LIBFR training (p < 0.05). While gains in strength and CSA remained preserved post-4 weeks of detraining, this did not occur with RTD.

CONCLUSION

Since gains in RTD were similar between interventions, our findings indicate that both training regimens can be used interchangeably for improving contralateral rapid torque production. Ultimately, this may be beneficial in circumstances of limb immobilization after injury or surgery.

Effect of Static Posture on Online Performance of P300-Based BCIs for TV Control

To implement a practical brain–computer interface (BCI) for daily use, continuing changes in postures while performing daily tasks must be considered in the design of BCIs. To examine whether the performance of a BCI could depend on postures, we compared the online performance of P300-based BCIs built to select TV channels when subjects took sitting, recline, supine, and right lateral recumbent postures during BCI use. Subjects self-reported the degrees of interference, comfort, and familiarity after BCI control in each posture. We found no significant difference in the BCI performance as well as the amplitude and latency of P300 and N200 among the four postures. However, when we compared BCI accuracy outcomes normalized within individuals between two cases where subjects reported relatively more positively or more negatively about using the BCI in a particular posture, we found higher BCI accuracy in those postures for which individual subjects reported more positively. As a result, although the change of postures did not affect the overall performance of P300-based BCIs, the BCI performance varied depending on the degree of postural comfort felt by individual subjects. Our results suggest considering the postural comfort felt by individual BCI users when using a P300-based BCI at home.

Medical disposals and problem solving: About high blood pressure in Morocco

In this article, I analyze how in basic health-care facilities in Morocco, general practitioners transform patients' problems into solvable problems, taking into account constraints related to medical standards, financial issues, the organization of the health system, and care. My focus is on hypertension, or high blood pressure. I argue that standards allow the solving of patients' problems through the production of an entity called high blood pressure. However, the 'high blood pressure' enacted is different from the entity defined by standards. Fragments of the latter, borrowed from other contexts, are put to work in Morocco, while the material arrangements needed to enforce and have them work without discontinuities do not exist. This contributes to the production of an entity configured at a moment in time between standards and patients' lives.

Supine blood pressure—A clinically relevant determinant of vascular target organ damage in hypertensive patients

Night‐time blood pressure (BP) is an important predictor of cardiovascular outcomes. Its assessment, however, remains challenging due to limited accessibility to ambulatory BP devices in many settings, costs, and other factors. We hypothesized that BP measured in a supine position during daytime may perform similarly to night‐time BP when modeling their association with vascular hypertension‐mediated organ damage (HMOD). Data from 165 hypertensive patients were used who as part of their routine clinic workup had a series of standardized BP measurements including seated attended office, seated and supine unattended office, and ambulatory BP monitoring. HMOD was determined by assessment of kidney function and pulse wave velocity. Correlation analysis was carried out, and univariate and multivariate models were fitted to assess the extent of shared variance between the BP modalities and their individual and shared contribution to HMOD variables. Of all standard non‐24‐hour systolic BP assessments, supine systolic BP shared the highest degree of variance with systolic night‐time BP. In univariate analysis, both systolic supine and night‐time BP were strong determinants of HMOD variables. In multivariate models, supine BP outperformed night‐time BP as the most significant determinant of HMOD. These findings indicate that supine BP may not only be a clinically useful surrogate for night‐time BP when ambulatory BP monitoring is not available, but also highlights the possibility that unattended supine BP may be more closely related to HMOD than other BP measurement modalities, a proposition that requires further investigations in prospective studies.

The Effects of Gradual Change in Head Positioning on the Relationship between Systemic and Cerebral Haemodynamic Parameters in Healthy Controls and Acute Ischaemic Stroke Patients

(1) Background: Larger blood pressure variability (BPv) in the first 3 h post-stroke onset increases pathophysiological effects such as infarct size, and leads to greater risk of disability, comorbidities and mortality at 90 days. However, there is limited information on the relationship between systemic and cerebral haemodynamic and variability parameters. (2) Objectives: This study determined the effect of a gradual change in head position (GHP) on cerebral blood flow velocity variability (CBFVv) and mean arterial blood pressure variability (MABPv), in healthy controls and acute ischaemic stroke (AIS) patients. Methods: CBFVv and MABPv were expressed as standard deviation (SD) and coefficient of variation. A total of 16 healthy controls (mean age 57 ± 16 years) were assessed over two visits, 12 ± 8 days apart, and 15 AIS patients (mean age 69 ± 8.5 years) were assessed over three visits (V1: 13.3 ± 6.9 h, V2: 4.9 ± 3.2 days and V3: 93.9 ± 11.5 days post-stroke). (3) Results: In response to GHP, MABPv does not initially increase, but over time MABPv showed a significant increase in response to GHP in AIS (visits 2 and 3) and controls (visit 2). Additionally, in response to GHP in AIS, CBFVv increased in the affected hemisphere. Lastly, in AIS, a significant correlation between CBFVv and MABPv, assessed by SD, was seen in the unaffected hemisphere, whereas this relationship was not demonstrated in the affected hemisphere. (4) Conclusions: To our knowledge, this is the first study to analyse the relationship between CBFVv and MABPv. Shedding light on the effect of head position on the relationship between cerebral blood flow and blood pressure is important to improve our understanding of the underlying effects of cerebral autoregulation impairment. This early mechanistic study provides evidence supporting supine head positioning in healthy controls and stroke patients, through demonstration of a reduction of MABPv and increase in CBFVv.

Simultaneous influence of sex and age on blood pressure difference between supine and sitting body positions

OBJECTIVES

Doctors' offices and outpatient departments typically measure blood pressure (BP) with the patient in a sitting position, whereas inpatient departments also use the supine position. As sex and age influence the autonomic function associated with BP regulation our study compared BP measurements in supine and sitting positions for men and women of different ages.

METHODS

We included 91 men and 118 women (≥18 years) without severe diseases. Hypertension was not an exclusion criterion because it is common in older persons. Mean left brachial BP and heart rate were determined by a digital sphygmomanometer in supine position as well as in sitting position before and after hand force measurement.

RESULTS

In a supine position women had slightly lower diastolic BP values than men. After sitting up, the diastolic BP increased in nearly all subjects. This increase was greater in women older than 50 years than for aged-matched men. In contrast to diastolic BP the systolic BP increased after sitting up in only two thirds of the subjects. Especially in women younger than 50 years the systolic BP often did not increase but decreased in response to postural change. The pulse pressure was mostly reduced after sitting up. This reduction was more pronounced in women than men independent of age and physical effort (i.e. hand force measurement). The sitting position also caused an increased heart rate, which was independent of sex and age.

CONCLUSION

Postural changes in the systolic and diastolic BP simultaneously depend on sex and age that needs to be considered for BP measurements in supine and sitting body positions.

Blood pressure and orthostatic hypotension as measures of autonomic dysfunction in patients from the transthyretin amyloidosis outcomes survey (THAOS)

INTRODUCTION

Autonomic dysfunction, an early symptom of transthyretin amyloidosis (ATTR amyloidosis), requires investigations not readily available in many clinics. Although monitoring of orthostatic hypotension (OH) will not be a substitute for more specialized tests, it can add important information about initiation of dysautonomia. The aim of this study was to investigate whether simple blood pressure (BP) monitoring may be a useful tool for evaluation of disease progression and an early sign of autonomic dysfunction.

METHODS

BP and OH data were from subjects enrolled in the Transthyretin Amyloidosis Outcomes Survey (THAOS). Characteristics associated with changes in BP and orthostatic difference were identified by regression analyses.

RESULTS

OH tended to be present relatively early in the course of disease and was more common at enrollment (11.7%) than either diarrhea (2.4%) or unintentional weight loss (3.1%). In subjects with OH at enrollment, progressive increase in systolic and diastolic orthostatic difference was observed. OH was also associated with significantly worse quality of life.

DISCUSSION

BP variability is a useful tool for assessing disease onset and severity in ATTR amyloidosis, particularly in patients with OH. Trial registration ClinicalTrials.gov: NCT00628745.

Evaluation and management of elevated blood pressures in hospitalized children

Elevated blood pressures (BP) are common among hospitalized children and, if not recognized and treated promptly, can lead to potentially significant consequences. Even though we have normative BP data and well-developed guidelines for the diagnosis and management of hypertension (HTN) in the ambulatory setting, our understanding of elevated BPs and their relationship to HTN in hospitalized children is limited. Several issues have hampered our ability to diagnose and manage HTN in the inpatient setting including the common presence of physiologic conditions, which are associated with transient BP elevations (i.e., pain or anxiety), non-standard approaches to BP measurement, a lack of clarity regarding appropriate diagnostic and therapeutic thresholds, and marginal outcome data. The purpose of this review is to highlight the issues and challenges surrounding BP monitoring, assessment of elevated BPs, and the diagnosis of HTN in hospitalized children. Extrapolating from currently available clinical practice guidelines and utilizing the best data available, we aim to provide guidelines regarding evaluation and treatment of elevated BP in hospitalized children.

Excess early postnatal weight gain and blood pressure in healthy young children

Blood pressure (BP) tracks from childhood to adulthood, and early BP trajectories predict cardiovascular disease risk later in life. Excess postnatal weight gain is associated with vascular changes early in life. However, to what extent it is associated with children's BP is largely unknown. In 853 healthy 5-year-old children of the Wheezing-Illnesses-Study-Leidsche-Rijn (WHISTLER) birth cohort, systolic (SBP) and diastolic BP (DBP) were measured, and z scores of individual weight gain rates adjusted for length gain rates were calculated using at least two weight and length measurements from birth until 3 months of age. Linear regression analyses were conducted to investigate the association between weight gain rates adjusted for length gain rates and BP adjusted for sex and ethnicity. Each standard deviation increase in weight gain rates adjusted for length gain rates was associated with 0.9 mmHg (95% CI 0.3, 1.5) higher sitting SBP after adjustment for confounders. Particularly in children in the lowest birth size decile, high excess weight gain was associated with higher sitting SBP values compared to children with low weight gain rates adjusted for length gain rates. BMI and visceral adipose tissue partly explained the association between excess weight gain and sitting SBP (β 0.5 mmHg, 95% CI -0.3, 1.3). Weight gain rates adjusted for length gain rates were not associated with supine SBP or DBP. Children with excess weight gain, properly adjusted for length gain, in the first three months of life, particularly those with a small birth size, showed higher sitting systolic BP at the age of 5 years.

Non-contact Quantification of Jugular Venous Pulse Waveforms from Skin Displacements

The jugular venous (JV) pressure waveform is a non-invasive, proven indicator of cardiovascular disease. Conventional clinical methods for assessing these waveforms are often overlooked because they require specialised expertise, and are invasive and expensive to implement. Recently, image-based methods have been used to quantify JV pulsation waveforms on the skin as an indirect way of estimating the pressure waveforms. However, these existing image-based methods cannot explicitly measure skin deformations and rely on the use of photoplethysmography (PPG) devices for identification of the pulsatile waveforms. As a result, they often have limited accuracy and robustness and are unsuitable in the clinical environment. Here, we propose a technique to directly measure skin deformations caused by the JV pulse using a very accurate subpixel registration algorithm. The method simply requires images obtained from the subject’s neck using a commodity camera. The results show that our measured waveforms contained all of the essential features of diagnostic JV waveforms in all of 19 healthy subjects tested in this study, indicating a significantly important capability for a potential future diagnostic device. The shape of our measured JV displacement waveforms was validated using waveforms measured with a laser displacement sensor, where the average correlation score between the two waveforms was 0.93 ± 0.05. In addition, synchronously recorded ECG signals were used to verify the timings of diagnostic features of the measured waveforms. To our knowledge, this is the first use of image registration for direct measurement of JV displacement waveforms. Significant advantages of our novel method include the high precision of our measurements, and the ability to use ordinary cameras, such as those in modern mobile phones. These advantages will enable the development of affordable and accessible devices to measure JV waveforms for cardiac diagnostics in the clinical environment. Future devices based on this technology may provide viable options for telemedicine applications, point of care diagnostics, and mobile-based cardiac health monitoring systems.

Oscillometric central blood pressure and central systolic loading in stroke patients: Short-term reproducibility and effects of posture and fasting state

BACKGROUND

This study examined the short-term reproducibility of non-invasive estimates of central and peripheral blood pressure and markers of central systolic loading (augmentation index [AIx; a measure of central systolic loading] and AIx75 [AIx standardised to 75 b·min-1 heart rate]) and the effect of posture and fasting state on these variables in patients with acute stroke.

METHODS

Twenty-two acute stroke patients (72 ± 10y) had blood pressure measured using the SphygmoCor XCEL in supine and seated postures and whilst fasted and non-fasted.

RESULTS

Acceptable short-term reproducibility (ICC >0.75) was reported for all peripheral and central variables in all conditions (ICC = 0.77-0.90) and for AIx and AIx75 in both fasted postures (ICC = 0.78-0.81). Food consumption significantly lowered all blood pressures (p <0.05; η2p = 0.20-0.55). The seated posture resulted in a significantly greater AIx than supine (p <0.05; η2p = 0.22). Fasting state had significant main effects on AIx and AIx75 (p <0.05; η2p = 0.14-0.22).

CONSLUSIONS

Oscillometric estimates of central blood pressure have high short-term reproducibility in different postures and fasting states but markers of systolic load should be assessed whilst fasted. Fasting state has a large effect on central and peripheral blood pressures and on measures of systolic loading. It is important for clinicians to be aware of optimal assessment conditions without this impacting on patient wellbeing.

TRIAL REGISTRATION

Clinical trial registry name: NCT02537652.

For a More Reliable Measure of Wrist Blood Pressure Using Smartwatch

Background: If blood pressure (BP) measurement is important to monitor blood hypertension and other cardiac diseases, and can be taken using a wrist device, learned societies recommend to take it in specific conditions. In a telemedicine context, patients are likely to perform it without any help from a medical practitioner. Therefore, the device must guide individuals using it. Materials and Methods: A smartwatch application integrating an Attitude and Heading Reference System algorithm was developed. It was combined with a wrist BP monitor to help users position the BP monitor properly. Results: The system was tested on 30 individuals and a survey conducted to evaluate its usability. The experiment showed that individuals needed to be guided to measure correctly their BP and our application helped them in positioning the wrist BP monitor in a user-friendly way. Conclusions: In a telemedicine context, it is possible to guide easily individuals to position correctly any commercialized wrist BP monitor using a smartwatch. Manufacturers could also integrate affordable sensors into their BP monitors to provide this assistance without the need of external devices.

Sexual Dimorphism in the Estimation of Upper-Limb Blood Flow Restriction in the Seated Position

Borges, A, Teodósio, C, Matos, P, Mil-Homens, P, Pezarat-Correia, P, Fahs, C, and Mendonca, GV. Sexual dimorphism in the estimation of upper-limb blood flow restriction in the seated position. J Strength Cond Res 32(7): 2096-2102, 2018-Arterial occlusion pressure (AOP) is typically used to normalize blood flow restriction (BFR) during low-intensity BFR exercise. Despite strong evidence for sexual dimorphism in muscle blood flow, sex-related differences in AOP estimation remain a controversial topic. We aimed at determining whether the relationship of upper-limb AOP with arm circumference and systolic blood pressure (BP) differs between men and women resting in the seated position. Sixty-two healthy young participants (31 men: 21.7 ± 2.3; 31 women: 22.0 ± 2.0 years) were included in this study. Arm circumference, resting BP, and AOP were taken in the seated position. Multiple linear regression analysis was used to determine whether the relationship of AOP with arm circumference and resting BP differed between sexes. Prediction accuracy was assessed with the mean absolute percent error and Bland-Altman plots. Men had higher systolic BP and larger arm circumference than women (p < 0.05). Nevertheless, AOP was similar between sexes. Arm circumference, systolic BP, and sex were all significant predictors of AOP (p < 0.05), explaining 42% of its variance. The absolute percent error was similar in both sexes (men: -0.55 ± 7.12; women: -0.39 ± 6.31%, p > 0.05). Bland-Altman plots showed that the mean difference between actual and estimated AOP was nearly zero in both groups, with no systematic overestimation or underestimation. In conclusion, arm circumference, systolic BP, and sex are all significant predictors of upper-limb-seated AOP. Their measurement allows for the indirect estimation of BFR pressure within the context of exercise training.

Epidemiological and clinical implications of blood pressure measured in seated versus supine position

The evidence concerning how posture influences blood pressure is not consistent. The aim of this cross-sectional study was to consider the clinical and epidemiological implications of blood pressure measured in seated versus supine position, and to investigate the impact of age, sex, body mass index (BMI), and diabetes on these differences.This study included 1298 individuals (mean age 58.6 ± 11.8 years) from the Vara-Skövde cohort at the 10 years' follow-up visit in 2014. Physical examination included blood pressure measurements in seated and supine position. Self-reported information on diabetes status, hypertension, ongoing medication, leisure time physical activity, and smoking habits were obtained. Linear regression models accounted for differences in age, sex, BMI, and known diabetes.Both systolic and diastolic blood pressure were significantly higher in the seated position [1.2 mm Hg, P < .001, 95% confidence interval (95% CI) 0.79-1.54 and 4.2 mm Hg, P < .001, 95% CI 4.08-4.71, respectively]. The prevalence of high blood pressure in seated position was higher (19.9%) than in supine position (13.5%). Linear regression analysis showed that age (β = -0.215, P < .001) and diabetes (β = -0.072, P = .012) were associated with smaller differences in postural diastolic blood pressure and BMI (β = 0.124, P < .001) with greater difference.This study showed substantial postural differences in blood pressures measured in office. Measuring blood pressure in the supine position shows lower blood pressure readings when compared with the seated position. Clinicians should be aware of how age, BMI, and diabetes influence these differences.

Reliability of oscillometric central blood pressure and central systolic loading in individuals over 50 years: Effects of posture and fasting

BACKGROUND AND AIMS

The between-day reliability of oscillometric pulse wave analysis has been demonstrated in a young, healthy population but not in an older sample. This study examined the between-day reliability of the SphygmoCor XCEL in individuals over 50 years. As blood pressure is measured in a range of postures and fasting states (supine/seated, fasted/non-fasted), this study also investigated the effect of these variables on central blood pressure and central systolic loading.

METHODS

Fifty-one adults (m = 21; age 57 ± 6.4 y) were tested on three mornings in supine and seated conditions and in fasted and non-fasted states. Data was analysed as a whole and for normotensive (n = 25) and hypertensive participants (n = 26).

RESULTS

SphygmoCor XCEL demonstrated strong reliability in the whole sample for central systolic and diastolic blood pressures, augmentation index (AIx) and AIx75 (ICC = 0.77-0.95). Significant interaction effects were observed in central diastolic blood pressure, central pulse pressure, augmentation index (AIx) and AIx75 (p < 0.05; η_p² = 0.10-0.23). Fasting state had a greater influence on central pressures in a seated than supine posture, but a greater effect on central systolic loading measures in a supine posture.

CONCLUSIONS

The SphygmoCor XCEL is a reliable tool to assess central haemodynamic variables in an older population. It would be pertinent for clinicians and researchers to record central measures in a supine posture to minimise the effects of food consumption. Conversely, the assessment of central systolic loading should occur in a seated condition to minimise the influence of varying fasting states.

Sources of inaccuracy in the measurement of adult patients' resting blood pressure in clinical settings: a systematic review

BACKGROUND

To interpret blood pressure (BP) data appropriately, healthcare providers need to be knowledgeable of the factors that can potentially impact the accuracy of BP measurement and contribute to variability between measurements.

METHODS

A systematic review of studies quantifying BP measurement inaccuracy. Medline and CINAHL databases were searched for empirical articles and systematic reviews published up to June 2015. Empirical articles were included if they reported a study that was relevant to the measurement of adult patients' resting BP at the upper arm in a clinical setting (e.g. ward or office); identified a specific source of inaccuracy; and quantified its effect. Reference lists and reviews were searched for additional articles.

RESULTS

A total of 328 empirical studies were included. They investigated 29 potential sources of inaccuracy, categorized as relating to the patient, device, procedure or observer. Significant directional effects were found for 27; however, for some, the effects were inconsistent in direction. Compared with true resting BP, significant effects of individual sources ranged from -23.6 to +33 mmHg SBP and -14 to +23 mmHg DBP.

CONCLUSION

A single BP value outside the expected range should be interpreted with caution and not taken as a definitive indicator of clinical deterioration. Where a measurement is abnormally high or low, further measurements should be taken and averaged. Wherever possible, BP values should be recorded graphically within ranges. This may reduce the impact of sources of inaccuracy and reduce the scope for misinterpretations based on small, likely erroneous or misleading, changes.

[Orthostatic hypotension; that great unknown]

Orthostatic hypotension is an anomaly of growing interest in scientific research. Although certain neurogenic diseases are associated with this phenomenon, it can also be associated with non-neurological causes. Although orthostatic hypotension is defined by consensus as a decrease in the systolic blood pressure of at least 20mmHg, or a decrease in diastolic blood pressure of at least 10mmHg, within 3min of standing, the studies differ on how to diagnose it. Orthostatic hypotension is associated with certain cardiovascular risk factors and with drug treatment, but the results are contradictory. The purpose of this review is to update the knowledge about orthostatic hypotension and its treatment, as well as to propose a method to standardise its diagnosis.