Search

ObjectivesPrevious studies relating nervous activity to blood lead (BL) levels have limited relevance, because over time environmental and occupational exposure substantially dropped. We investigated the association of heart rate variability (HRV) and median nerve conduction velocity (NCV) with BL using the baseline measurements collected in the Study for Promotion of Health in Recycling Lead (NCT02243904).MethodsIn 328 newly hired men (mean age 28.3 years; participation rate 82.7%), we derived HRV measures (power expressed in normalised units (nu) in the high-frequency (HF) and low-frequency (LF) domains, and LF/HF) prior to long-term occupational lead exposure. Five-minute ECG recordings, obtained in the supine and standing positions, were analysed by Fourier transform or autoregressive modelling, using Cardiax software. Motor NCV was measured at the median nerve by a handheld device (Brevio Nerve Conduction Monitoring System, NeuMed, West Trenton, NJ, USA). BL was determined by inductively coupled plasma mass spectrometry.ResultsMean BL was 4.54 µg/dL (IQR 2.60–8.90 µg/dL). Mean supine and standing values of LF, HF and LF/HF were 50.5 and 21.1 nu and 2.63, and 59.7 and 10.9 nu and 6.31, respectively. Orthostatic stress decreased HF and increased LF (pConclusionsAt the exposure levels observed in our study, autonomous nervous activity and NCV were not associated with BL.Trial registration numberNCT02243904

Objective: Measuring arterial pulse transit time (PTT) to estimate blood pressure (BP) without conventional brachial cuff-based measurement is not new, but is a focus of current wearable technologies research. Much research pertains to efficient, accurate sensing of artery-related waveforms, yet the relationship between PTT and BP receives less attention despite being key for accurate BP estimation. This study investigated BP/PTT calibration by quantifying anatomical site variability ( n = 10, 3 female, age 30 $\pm$ 9 years) and individual variability ( n = 103, 50 female, age 53 $\pm$ 22 years). Methods: BP and pulse wave velocity (PWV) were measured in both seated and supine. Carotid-femoral PWV (cfPWV), carotid-radial PWV (crPWV), and carotid-finger-volume PWV (cvPWV) were measured with the wrist and hand positioned at the level of the upper thigh to achieve the same hydrostatic pressure effect across all measurements. Results: The postural change invoked a small (4 $\pm$ 7 mmHg) change in brachial diastolic BP with an additional 27 $\pm$ 2 mmHg change in hydrostatic pressure. cfPWV decreased in the supine position ( $-$ 1.75 $\pm$ 0.17 m $\cdot$ s−1, p $\Delta$ BP/ $\Delta$ PWV) across the sample population varied from 6.6 to 98.3 mmHg $\cdot$ s $\cdot$ m−1 (mean 22 $\pm$ 14 mmHg $\cdot$ s $\cdot$ m−1) and was correlated with age, heart rate, diastolic and pulse pressure, and weight. These variables did not explain the majority of the variability ( R2 = 0.248). Conclusion: There is anatomical site and between-individual variability in the calibration term for BP estimation from PTT. Significance: Using and accurately calculating hydrostatic changes in BP within the individual may be one method to increase the accuracy of this calibration term.

Objective: Arterial pulse pressure variation (PPV) is widely used for predicting fluid responsiveness and supporting fluid management in the operating room and intensive care unit. Available PPV algorithms have been typically validated for fluid responsiveness during episodes of hemodynamic stability. Yet, little is known about the performance of PPV algorithms during surgery, where fast changes of the blood pressure may affect the robustness of the presented PPV value. This work provides a comprehensive understanding of how various existing algorithmic designs affect the robustness of the presented PPV value during surgery, and proposes additional processing for the pulse pressure signal before calculating PPV. Approach: We recorded arterial blood pressure waveforms from 23 patients undergoing major abdominal surgery. To evaluate the performance, we designed three clinically relevant metrics. Main results and Significance: The results show that all algorithms performed well during episodes of hemodynamic stability. Moreover, it is demonstrated that the proposed processing helps improve the robustness of PPV during the entire course of surgery.

Objective: We investigate the basic feasibility of estimating the brachial artery area-pressure relationship from MRI data obtained during pressure cuff inflations in-vivo. Methods: We acquired cross-sectional real-time MR images and cardiac-gated CINE MR images from the upper arm of a single male subject at rest during supra-systolic pressure cuff inflations and deflations. We estimate from the MR images the lumen area changes of the brachial artery, and, simultaneously, from the cuff pressure the systemic blood pressure of the subject. We reconstruct the area-pressure curve from two real-time and three CINE independent measurements. Results: The area-pressure curve can be reconstructed, and it is plausible and appears largely consistent with the literature using other methods. Conclusion: MR imaging during pressure cuff inflations is an easy to use, non-invasive candidate method to estimate the brachial artery pressure-area curve.

WOS: 000461755500005 PubMed: 30916122 Introduction: The aim of this study was to examine the association of inter-arm systolic blood pressure difference (IASBPD) with carotid artery stenosis, subclavian artery stenosis and vertebral artery stenosis in patients who underwent carotid endarterectomy. Methods: A total of 141 patients (29 females, 112 males; mean age 71.2 +/- 10.4 years; range 47 to 92 years) who underwent carotid endarterectomy between September 2010 and December 2017 were retrospectively evaluated. We classified patients into four groups according to the IASBPD. 10 mmHg, >= 10 mm Hg, >= 20 mmHg and >= 30 mmHg. The stenosis of both subclavian and ertebral arteries was considered as >= 50%. Results: Of the 141 patients, 44 (31.2%) had >= 10 mmHg, 29 (20.5%) had >= 20 mmHg and 4 (2.8%) had >= 30 mmHg of IASBPD. 26 patients (18.4%) were diagnosed with significant subclavian artery stenosis and 18 (69.2%) of them had more than 20 mmHg of IASBPD. Of the 29 patients with IASBPD = 20 mmHg, 19 patients (65.5%) had a significant subclavian artery stenosis. We found a significant correlation between preoperative symptoms and subclavian artery stenosis (P= 0.018) and overall perioperative stroke was seen more frequently in patients with subclavian artery stenosis (P= 0.041). A significant positive correlation was observed between vertebral artery stenosis and subclavian artery stenosis (P= 0.01). Conclusion: Patients who were diagnosed with both subclavian artery stenosis and IASBPD (>= 20 mmHg) had a higher risk of postoperative stroke and death, had higher total cholesterol, LDL-C, blood creatinine level, and were more symptomatic.

Background Currently, the decision to treat iliac artery stenoses is mainly based on visual inspection of digital subtraction angiographies. Intra‐arterial pressure measurements can provide clinicians with accurate hemodynamic information. However, pressure measurements are rarely performed because of their invasiveness and the time required. Therefore, the aim of the study was to test the feasibility of a computational model that can predict translesional pressure gradients across iliac artery stenoses on the basis of imaging data only. Methods and Results Patients (N=21) with symptomatic peripheral arterial disease and a peak systolic velocity ratio between 2.5 and 5.0 were included in the study. Patients underwent per‐procedural 3‐dimensional rotational angiography and hyperemic intra‐arterial translesional pressure measurements. Vascular anatomical features were reconstructed from the 3‐dimensional rotational angiography data into an axisymmetrical 2‐dimensional computational mesh, and flow was estimated on the basis of the stenosis geometry. Computational fluid dynamics were performed to predict the pressure gradient and were compared with the measured pressure gradients. A good agreement by overlapping error bars of the predicted and measured pressure gradients was found in 21 of 25 lesions. Stratification of the stenosis on the basis of the predicted pressure gradient into hemodynamic not significant ( Conclusions The feasibility of the patient‐specific computational model to predict the hyperemic translesional pressure gradient over iliac artery stenosis was successfully tested. Presented results suggest that, with further optimization and corroboration, the model can become a valuable aid to the diagnosis of equivocal iliac artery stenosis. Clinical Trial Registration URL : http://www.trialregister.nl . Unique identifier: NTR 5085.

Item does not contain fulltext OBJECTIVES: To investigate the effects of intensive blood pressure (BP) lowering according to baseline BP levels and optimal achieved BP levels in patients with acute intracerebral hemorrhage (ICH). METHODS: INTERACT2 was an open, blinded endpoint, randomized controlled trial in 2,839 patients with ICH within 6 hours of onset and elevated systolic BP (SBP) (150-220 mm Hg) who were allocated to receive intensive (target SBP /=190 mm Hg (p homogeneity = 0.790). Analyses of achieved BP showed linear increases in the risk of physical dysfunction for achieved SBP above 130 mm Hg for both hyperacute (1-24 hours) and acute (2-7 days) phases while modest increases were also observed for achieved SBP below 130 mm Hg. CONCLUSIONS: Intensive BP lowering appears beneficial across a wide range of baseline SBP levels, and target SBP level of 130-139 mm Hg is likely to provide maximum benefit in acute ICH. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that the effect of intensive BP lowering on physical function is not influenced by baseline BP.

Background: Recently, 2 randomized controlled trials showed that the instantaneous wave-free ratio (iFR), a resting coronary physiological index, is noninferior to fractional flow reserve for guiding revascularization. The resting distal to aortic coronary pressure (Pd/Pa) measured at rest is another adenosine-free index widely available in the cardiac catheterization laboratory; however, little is known about the agreement of Pd/Pa using iFR as a reference standard. Objectives: The goal of this study was to investigate the agreement of Pd/Pa with iFR. Methods: A total of 763 patients were prospectively enrolled from 12 institutions. iFR and Pd/Pa were measured under resting conditions. Using iFR ≤0.89 as a reference standard, the agreement of Pd/Pa and its best cutoff value were assessed. Results: According to the independent core laboratory analysis, iFR and Pd/Pa were analyzable in 627 and 733 patients (82.2% vs. 96.1%; p < 0.001), respectively. The median iFR and Pd/Pa were 0.90 (interquartile range: 0.85 to 0.94) and 0.92 (interquartile range: 0.88 to 0.95), and the 2 indices were highly correlated (R2 = 0.93; p < 0.001; iFR = 1.31 * Pd/Pa –0.31). According to the receiver-operating characteristic curve analysis, Pd/Pa showed excellent agreement (area under the curve: 0.98; 95% confidence interval: 0.97 to 0.99; p < 0.001) with a best cutoff value of Pd/Pa ≤0.91. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 93.0%, 91.4%, 94.4%, 93.3%, and 92.7%, respectively. These results were similar in patients with acute coronary syndrome and stable angina. Conclusions: Pd/Pa was analyzable in a significantly higher number of patients than iFR. Pd/Pa showed excellent agreement with iFR, suggesting that it could be applied clinically in a similar fashion. (Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology? [CONTRAST]; NCT02184117)

Background: Orthostatic hypotension (OH) is common in older adults and associated with increased morbidity and mortality, loss of independence and high health-care costs. Standing up slowly is a recommended non-pharmacological intervention. However, the effectiveness of this advice has not been well studied. Objectives: The aim of this study was to investigate whether standing up slowly antagonises posture-related blood pressure (BP) decrease in a clinically relevant population of geriatric outpatients. Methods: In this cross-sectional study, 24 community-dwelling older adults referred to a geriatric outpatient clinic and diagnosed with OH were included. BP was measured continuously during 3 consecutive transitions from supine to standing position during normal, slow and fast transition. Results: The relative BP decrease at 0-15 s after slow transition was significantly lower than after normal transition (p = 0.003 for both systolic BP and diastolic BP) and fast transition (p = 0.045 for systolic BP; diastolic BP: non-significant). The relative diastolic BP decrease at 60-180 s after normal transition was significantly lower than after fast transition (p = 0.029). Conclusion: Standing up slowly antagonises BP decrease predominantly during the first 15 s of standing up in a clinically relevant population of geriatric outpatients diagnosed with OH. Results support the non-pharmacological intervention in clinical practice to counteract OH.

Item does not contain fulltext

Preeclampsia is a pregnancy-related syndrome, which still represents one of the major causes of maternal-fetal mortality and morbidity. Diagnosis can be made difficult due to the complexity of the disorder and its wide spectrum of clinical manifestations. In order to provide an efficient diagnostic tool to the clinician, medical societies regularly rethink the definition criteria. However, there are still clinical presentations of preeclampsia that escape the frame of the definition. The present review will address atypical forms of preeclampsia, such as preeclampsia without proteinuria, normotensive preeclampsia, preeclampsia before 20 weeks of gestation and post-partum preeclampsia.

Blood pressure increases during acute exposure to high altitude in healthy humans. However, little is known on altitude effects in hypertensive subjects or on the treatment efficacy in this condition. Objectives of High Altitude Cardiovascular Research (HIGHCARE)–Andes Lowlanders Study were to investigate the effects of acute high-altitude exposure on 24-hour ambulatory blood pressure in hypertensive subjects and to assess antihypertensive treatment efficacy in this setting. One hundred untreated subjects with mild hypertension (screening blood pressure, 144.1±9.8 mm Hg systolic, 92.0±7.5 mm Hg diastolic) were randomized to double-blind placebo or to telmisartan 80 mg+modified release nifedipine 30 mg combination. Twenty-four–hour ambulatory blood pressure monitoring was performed off-treatment, after 6 weeks of treatment at sea level, on treatment during acute exposure to high altitude (3260 m) and immediately after return to sea level. Eighty-nine patients completed the study (age, 56.4±17.6 years; 52 men/37 women; body mass index, 28.2±3.5 kg/m 2 ). Twenty-four–hour systolic blood pressure increased at high altitude in both groups (placebo, 11.0±9 mm Hg; P P P Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01830530.

The prevalence of hypertension in elderly is extremely high. Because of the burden of ageing of population, this condition considered as the most important risk factor for mortality is supposed to increase. There are some specific pitfalls in the diagnosis and management of hypertension in elderly. The definition of hypertension is the same in all age groups, however the phenotype is different in the elderly: white coat effect, non-dipping pattern, orthostatic hypotension, dysautonomia and pseudohypertension. The hallmark of hypertension in the elderly is pure systolic hypertension and an increased variability of blood pressure. The diagnosis is often difficult to establish. The elderly can be overtreated with undesirable effects of falls or hypoperfusion, particularly when there is frailty, or polymedication.

Dear Editor, Critically ill patients are transferred more safely with a mobile intensive care unit (MICU) and specialised retrieval team [1, 2], although incidents still occur [3]. However, transports are becoming more challenging [4]. During MICU transports, we repeatedly observed arterial blood pressure variations, concurrent with ambulance accelerations and decelerations. We aimed to evaluate whether the observed influence of acceleration on blood pressure is a real blood pressure change or a physical measurement artefact. Usually, the pressure transducer is positioned at the rear end of the trolley and the distance to the arterial cannula varies between 100 and 150 cm. In an experimental setting, pressure lines (Edwards Lifesciences, Irvine, USA) were positioned on the trolley. At the site of normal catheter insertion, the line was connected to a pressurised bag to simulate a static mean arterial pressure (MAP). The length of the pressure line and the baseline pressure were varied (0, 50, 100, 150 cm and 50, 75, 100 mmHg). To simulate acceleration and deceleration the trolley was moved forward and backward in several test runs. Pressures and accelerations (accelerometer, University of Twente, Enschede, the Netherlands) were measured for the different pressures and different pressure line lengths. Pressure data were plotted against acceleration data (Fig. 1). The Pearson’s correlation coefficients r, p values, R and the slopes of the linear regression lines (b) and their 95 % confidence intervals are listed in Table 1. In this experimental setting both an increase in the baseline pressure and in pressure line length were associated with significant increases in pressure variations during accelerations. To confirm the findings that pressure variations may be a physical phenomenon, MAP and acceleration data were collected during six transports. The medical ethics committee approved this study and the need for consent was waived. The pressure transducer was initially positioned at the rear end of the trolley and halfway changed to directly on top of the arterial cannula so that patients served as their own control. The effect of acceleration on MAP was analysed for both positions of the transducer. In patient transfers, a weak correlation was observed between acceleration and blood pressure with the transducer positioned on top of the arterial cannula. The mean Pearson’s r significantly increased from 0.09 to 0.50 when the transducer changed position to the rear end of the trolley. The inertial mass effect of the fluid column in the tubing explains most of the blood pressure variation. The

Objective To determine and to analyze the theoretical and practical knowledge of Nursing professionals on indirect blood pressure measurement. Methods This cross-sectional study included 31 professionals of a coronary care unit (86% of the Nursing staff in the unit). Of these, 38.7% of professionals were nurses and 61.3% nurse technicians. A validated questionnaire was used to theoretical evaluation and for practice assessment the auscultatory technique was applied in a simulation environment, under a non-participant observation. Results To the theoretical knowledge of the stages of preparation of patient and environment, 12.9% mentioned 5-minute of rest, 48.4% checked calibration, and 29.0% chose adequate cuff width. A total of 64.5% of professionals avoided rounding values, and 22.6% mentioned the 6-month deadline period for the equipment calibration. On average, in practice assessment, 65% of the steps were followed. Lacks in knowledge were primary concerning lack of checking the device calibration and stethoscope, measurement of arm circumference to choose the cuff size, and the record of arm used in blood pressure measurement. Conclusion Knowledge was poor and had disparities between theory and practice with evidence of steps taken without proper awareness and lack of consideration of important knowledge during implementation of blood pressure measurement. Educational and operational interventions should be applied systematically with institutional involvement to ensure safe care with reliable values. Objetivo Determinar e analisar o conhecimento teórico e prático de profissionais de Enfermagem sobre a medida indireta da pressão arterial. Métodos Estudo descritivo, transversal, com profissionais de Enfermagem de uma unidade coronariana. Participaram do estudo 31 sujeitos (86% da população), sendo 38,7% enfermeiros e 61,3% técnicos em enfermagem. A avaliação teórica ocorreu por meio de questionário validado, e a prática, com técnica auscultatória, em simulação, sob observação não participativa. Resultados Sobre o conhecimento teórico do preparo do cliente e ambiente, 12,9% citaram repouso de 5 minutos, 48,4% conferiram calibração e 29,0% escolheram o manguito correto. Já 64,5% evitaram o arredondamento dos valores, e 22,6% citaram o prazo semestral para a calibração dos aparelhos. Na avaliação prática, em média, 65% das etapas foram cumpridas. Dentre as lacunas desse conhecimento, destacaram-se a ausência de checagem da calibração do aparelho e do estetoscópio, a medida da circunferência braquial para escolher o manguito, e o registro do braço usado na medida. Conclusão: O conhecimento foi insatisfatório, com discrepâncias entre a teoria e a prática, com indícios de etapas cumpridas sem a devida consciência, e conhecimentos importantes negligenciados na execução da medida da pressão arterial. Intervenções educativas e operacionais devem ser sistematicamente aplicadas, com o envolvimento institucional, para garantir segurança da assistência com valores fidedignos.

Recently a new method has been proposed as a tool to measure arterial pulse wave velocity (PWV), a measure of the stiffness of the large arteries and an emerging parameter used as indicator of clinical cardiovascular risk. The method is based on measurement of brachial blood pressure during supra-systolic pressure inflation of a simple brachial cuff [the device is known as the Arteriograph (Tensiomed, Budapest, Hungary)]. This occlusion yields pronounced first and secondary peaks in the pressure waveform, the latter ascribed to a reflection from the aortic bifurcation, and PWV is calculated as the ratio of twice the jugulum-symphysis distance and the time difference between the two peaks. To test the validity of this working principle, we used a numerical model of the arterial tree to simulate pressures and flows in the normal configuration, and in a configuration with an occluded brachial artery. A pronounced secondary peak was indeed found in the brachial pressure signal of the occluded model, but its timing was only related to brachial stiffness and not to aortic stiffness. We also compared PWV's calculated with three different methods: PWVATG (approximately Arteriograph principle), PWVcar-fem (approximately carotid-femoral PWV, the current clinical gold standard method), and PWVtheor (approximately Bramwell-Hill equation). Both PWVATG (R2=0.94) and PWVcar-fem (R2=0.95) correlated well with PWVtheor, but their numerical values were lower (by 2.17+/-0.42 and 1.08+/-0.70 m/s for PWVATG and PWVcar-fem, respectively). In conclusion, our simulations question the working principle of the Arteriograph. Our data indicate that the method picks up wave reflection phenomena confined to the brachial artery, and derived values of PWV rather reflect the stiffness of the brachial arteries.

PubMed: 16935627 Background: The aim of this study is to measure and compare the in vivo intraaneurysmal pressures of experimental lateral wall aneurysms, before and after onyx embolization. The data of this experiment will carry an important role in forming the scientific basis for the clinical endovascular applications. Materials and Methods: Five experimental lateral wall aneurysms were created by microsurgical techniques in 5 New Zealand rabbits' right common carotid arteries. Onyx embolization was applied to the aneurysms. Intraaneurysmal dome pressure and parent artery measurements before and after the procedure were recorded. Results: The mean arterial pressure recording in parent artery was 69.2 ± 2.588 mm Hg under anesthesia. Mean heart rate was 131 beats per minute. The values were in physiologic limits. Meanwhile, aneurysm intradomal pressure recording showed a mean value of 59.2 ± 5.069 mm Hg. Although there was incomplete occlusion of the aneurysm, intradomal mean pressure was recorded to be 24.4 ± 8.876 mm Hg. After complete occlusion by onyx, mean intradomal aneurysm pressure was found to be 1.8 ± 0.836 mm Hg. Discussion: This study is the first study reporting on intraaneurysmal pressure measurements before and after onyx embolization. The results in this experiment tend to show the adequate intraaneurysmal pressure control of onyx. This is important in the stabilization of the aneurysm to prevent rupture and rerupture. When compared with the findings of GDC coil, onyx embolization seems to be superior in intraaneurysmal pressure control. Conclusion: In this study, it has been shown that onyx embolization decreases the intradomal aneurysmal pressure effectively. © 2006 Elsevier Inc. All rights reserved.

Twenty-four-hour ambulatory blood pressure (AMBP) was performed in microalbuminuric (micro.) type 1 diabetic patients, with the aim of comparison with a matched group of normoalbuminuric patients (normo.) and healthy controls. Thirty-four patients without antihypertensive medication were investigated in each group. Urinary albumin excretion (UAE) for micro. was (geometric mean, tolerance factor microgram/min) 51.7 x/divided by 1.94, 5.1 x/divided by 1.88 for normo. and 5.2 x/divided by 1.75 for controls. Twenty-four-hour AMBP (mean systolic/diastolic mm Hg +/- SD) was significantly higher in micro. (131 +/- 10/78 +/- 7) than in normo. (122 +/- 8/73 +/- 6; P less than 0.001/P less than 0.01). No 24-hour AMBP difference between normo. and controls (120 +/- 9/71 +/- 7) was found. No difference in the night/day ratio of blood pressure was found between the diabetic groups. Coefficient of variation for day time systolic measurements did not show any intergroup difference. Systolic day time blood pressure for the pooled diabetic group correlated significantly with UAE (r = 0.45, P less than 0.001), whereas no significant correlation with auscultatory systolic values in the clinic was found (r = 0.21; P = 0.09). In conclusion, blood pressure in micro. as compared to normo. is not more labile but is elevated day and night without significant alteration of the diurnal rhythm. AMBP reflects the association between UAE and blood pressure more precisely than clinical measurements and may be preferable for identifying candidates for antihypertensive treatment.

Pressure-volume (p-V) relationships of a segment of the forearm circulation have been measured in nine male healthy subjects. Forearm volume was measured using electrical impedance plethysmography, arterial transmural pressure by subtracting mean arterial pressure measured contralaterally in a finger from the pressure in a cuff placed over the sensing electrodes of the plethysmograph. A special two-phase measurement waveform was designed with which cuff pressure was first increased step wise to a suprasystolic level and held at that level for 120 s, then ramped down to zero pressure in another 300 s. The step phase inflation allowed us to estimate the parameters of the interstitial liquids and total blood compartments. The total blood compartment amounted to 6.2 ml per 100 ml of tissue. The ramp phase deflation allowed us to discriminate between a first phase in which only the arteries refilled and a second phase in which the veins also distended. An arctangent function was fitted to the first phase arterial p-V relationship, describing it in model form. Total arterial volume per 100 ml of tissue amounted to 3.8 ml at physiological pressures, total arterial compliance of the forearm per centimetre length to 19.5 microliter kPa-1 cm-1 (2.6 microliter mmHg-1 cm-1) at physiological pressures, and to 340 microliter kPa-1 cm-1 (45 microliter mmHg-1 cm-1) maximum compliance at the lower, inflection point pressures. These values are in general agreement with the literature. Pulse wave velocity cannot be computed reliably from these data.

Pressure-volume (p-V) relationships of a segment of the forearm circulation have been measured in nine male healthy subjects. Forearm volume was measured using electrical impedance plethysmography, arterial transmural pressure by subtracting mean arterial pressure measured contralaterally in a finger from the pressure in a cuff placed over the sensing electrodes of the plethysmograph. A special two-phase measurement waveform was designed with which cuff pressure was first increased step wise to a suprasystolic level and held at that level for 120 s, then ramped down to zero pressure in another 300 s. The step phase inflation allowed us to estimate the parameters of the interstitial liquids and total blood compartments. The total blood compartment amounted to 6.2 ml per 100 ml of tissue. The ramp phase deflation allowed us to discriminate between a first phase in which only the arteries refilled and a second phase in which the veins also distended. An arctangent function was fitted to the first phase arterial p-V relationship, describing it in model form. Total arterial volume per 100 ml of tissue amounted to 3.8 ml at physiological pressures, total arterial compliance of the forearm per centimetre length to 19.5 microliter kPa-1 cm-1 (2.6 microliter mmHg-1 cm-1) at physiological pressures, and to 340 microliter kPa-1 cm-1 (45 microliter mmHg-1 cm-1) maximum compliance at the lower, inflection point pressures. These values are in general agreement with the literature. Pulse wave velocity cannot be computed reliably from these data.

BACKGROUND: Hypertension is very common in older people and a number of trials of antihypertensives have demonstrated benefit from treatment in even the oldest old. However, people with dementia were significantly under-represented in these studies and as a population are more likely to be physically frail, to suffer orthostatic hypotension and to experience adverse effects from polypharmacy at a lower drug count. It may be that different thresholds for commencement and cessation of treatment should be considered and may already be used for this group. Against this background this review sets out to describe the prevalence of hypertension in people with dementia, its treatment, change in treatment over time and the achievement of blood pressure (BP) control.METHODS: The PubMed, Cochrane, Embase and PsychINFO databases were searched for observational studies involving people with dementia and a diagnosis of hypertension. The search was limited to English language articles involving adults and humans published from 1990 onwards. Abstracts and titles were then reviewed with eligible articles read in full. Bibliographies were examined for further relevant studies. The final selection of studies was then analysed and appraised.RESULTS: Thirteen articles were identified for analysis. The prevalence of hypertension in people with dementia was 45% (range 35%-84%). 73% of these were on at least one antihypertensive, with diuretics being the most common. The reported prevalence of hypertension in study populations remained unchanged over time. ACEi/ARBs and calcium channel blockers were prescribed more frequently in more recent studies whilst use of β-blockers and diuretics remained unchanged. Target blood pressure was achieved in 55% of those on treatment.CONCLUSION: Hypertension is as common in people with dementia as in other populations and is as commonly treated with antihypertensive drugs. The findings presented here will support further work to establish the risk-benefit of antihypertensive treatment in patients with dementia and, if differing ratios are identified, to establish dementia-specific guidelines for management.