Continuous Blood Pressure Monitoring Research Articles

Аптечный рынок тонометров: ключевые тренды

Arterial hypertension is the most common non-infectious disease in the world [1]. According to the foreign studies, about 35-40% of the adult population suffer from arterial hypertension, and the prevalence of it increases with ageing, accounting for 50-65% in people over 65 years old [2]. In Russia, at least 40% of the population are diagnosed hypertensive [2, 3]. At the same time, hypertension may also be diagnosed in childhood, accounting for about 3.5% of children and adolescents in Russia [3]. Continuous blood pressure monitoring using home-use blood pressure monitors, which are presented in this review by key market trends, is one of the most important measures for the prevention of complications of hypertension.

Maternal haemodynamics during labour epidural analgesia with and without adrenaline.

Labour is one of the most painful experiences in a woman's life. Epidural analgesia using low-concentration local anaesthetics and lipophilic opioids is the gold standard for pain relief during labour. Pregnancy in general, particularly labour, is associated with changes in maternal haemodynamic variables, such as cardiac output and heart rate, which increase and peak during uterine contractions. Adrenaline is added to labour epidural solutions to enhance efficacy by stimulating the α2-adrenoreceptor. The minimal effective concentration of adrenaline was found to be 2μgmL-1 for postoperative analgesia. The addition of adrenaline may also produce vasoconstriction, limiting the absorption of fentanyl into the systemic circulation, thereby reducing foetal exposure. However, adrenaline may influence the haemodynamic fluctuations, possibly adding to the strain on the circulatory system. The aim of this study was to compare the haemodynamic changes after application of labour epidural analgesia with or without adrenaline 2μgmL-1. This was a secondary analysis of a single-centre, randomised double-blind trial. Forty-one nulliparous women in labour requesting epidural analgesia were randomised to receive epidural solution of bupivacaine 1mgmL-1, fentanyl 2μgmL-1 with or without adrenaline 2μgmL-1. The participants were monitored using a Nexfin CC continuous non-invasive blood pressure and cardiac output monitor. The primary outcomes were changes in peak systolic blood pressure and cardiac output during uterine contraction within 30min after epidural activation. The effect of adrenaline was tested statistically using a linear mixed-effects model of the outcome variables' dependency on time, adrenaline, and their interaction. After excluding three patients due to poor data quality and two due to a malfunctioning epidural catheter, 36 patients (18 in each group) were analysed. The addition of adrenaline to the solution had no significant effect on the temporal changes in peak systolic blood pressure (p=0.26), peak cardiac output (0.84), or heart rate (p=0.91). Furthermore, no significant temporal changes in maternal haemodynamics (peak systolic blood pressure, p=0.54, peak cardiac output, p=0.59, or heart rate p=0.55) were associated with epidural analgesia during 30min after epidural activation in both groups despite good analgesia. The addition of 2μgmL-1 adrenaline to the epidural solution is not likely to change maternal haemodynamics during labour.

Arrhythmia incidence and associated factors during volatile induction of general anesthesia with sevoflurane: a retrospective analysis of 950 adult patients

BackgroundSevoflurane has been used to induce anaesthesia in adults due to its suitability for airway management and haemodynamic stability. Few studies have reported arrhythmia during volatile induction with sevoflurane in adults. Here, we investigated the incidence of arrhythmia and risk factors associated with its occurrence during sevoflurane induction of anaesthesia in adults. Patients and MethodsWe retrospectively analysed 950 adult patients who underwent elective ear nose and throat surgery with volatile induction using sevoflurane between May and December 2015. The incidence of arrhythmia and the factors associated with its development were analysed. ResultsArrhythmia was observed in 164 (17.3%) of 950 adult patients. The most frequently observed arrhythmia was sinus tachycardia (heart rate > 120 bpm) (77 patients, 47.0%). The multivariable logistic analysis showed four independent risk factors: age (odds ratio [OR] = 0.984, 95% confidence interval [CI] = 0.973−0.996, p = 0.006), coronary artery disease (OR = 3.749, 95% CI = 1.574–8.927, p = 0.003), maximal concentration (8 vol%) of sevoflurane from the start of induction (OR = 2.696, 95% CI = 1.139–6.382, p = 0.024), and maintenance of 8 vol% sevoflurane concentration after eyelash reflex loss (OR = 1.577, 95% CI = 1.083–2.296, p = 0.018). The risk of hypotension was greater in patients in whom arrhythmia occurred, although blood pressure recovered to baseline after the concentration of sevoflurane was adjusted. ConclusionsWe recommend that the sevoflurane concentration be gradually increased with continuous and vigilant electrocardiogram and blood pressure monitoring. The sevoflurane concentration should be adjusted after sufficient unconsciousness is reached.

Wireless, Skin‐Interfaced Devices for Pediatric Critical Care: Application to Continuous, Noninvasive Blood Pressure Monitoring

Indwelling arterial lines, the clinical gold standard for continuous blood pressure (BP) monitoring in the pediatric intensive care unit (PICU), have significant drawbacks due to their invasive nature, ischemic risk, and impediment to natural body movement. A noninvasive, wireless, and accurate alternative would greatly improve the quality of patient care. Recently introduced classes of wireless, skin-interfaced devices offer capabilities in continuous, precise monitoring of physiologic waveforms and vital signs in pediatric and neonatal patients, but have not yet been employed for continuous tracking of systolic and diastolic BP-critical for guiding clinical decision-making in the PICU. The results presented here focus on materials and mechanics that optimize the system-level properties of these devices to enhance their reliable use in this context, achieving full compatibility with the range of body sizes, skin types, and sterilization schemes typically encountered in the PICU. Systematic analysis of the data from these devices on 23 pediatric patients, yields derived, noninvasive BP values that can be quantitatively validated against direct recordings from arterial lines. The results from this diverse cohort, including those under pharmacological protocols, suggest that wireless, skin-interfaced devices can, in certain circumstances of practical utility, accurately and continuously monitor BP in the PICU patient population.

High Salt Diet Increases Renal Oxygen Consumption in Sprague‐Dawley Rats

The physiological relationships between kidney O2 delivery and consumption and metabolism have been studied only under conditions of anesthesia and stressful surgical procedures. We report here techniques developed in our laboratory enabling determination of kidney O2 utilization over many days in instrumented unanesthetized rats in which the effects of a high salt diet were determined in normal Sprague Dawley (SD) rats. Male SD rats (10 weeks of age) fed a 0.4% NaCl diet were instrumented with a left renal artery flow probe (Transonic) for continuous (24 hr/day) measurement of renal blood flow (RBF). An indwelling intra-renal vein catheter (MRE 025) was inserted through the femoral vein and tip fixed close to the renal pelvis. An aortic catheter inserted though the femoral artery was implanted to sample blood and continuously (24 hr/day) measure arterial blood pressure (BP). Catheters and flow probe cables which exited from the neck were attached to a custom designed swivel and a servo-controlled circular cage system (BASi cage) enabling the rat to move freely throughout the study. Following 7 days of recovery from surgery, continuous monitoring of RBF and BP began and continued throughout the study. Following a 3 day control period with rats fed a 0.4% NaCl diet, renal venous and arterial blood were samples (250 ul) and blood gas was measured immediately by a radiometer (ABL800 FLEX). The diet was switch to 4% NaCl and blood sampling was performed at days 7, 14 and 21 of the high salt diet. O2 content, O2 consumption, and O2 extraction were determined as: O2 content (mL/dL): 0.31 × Hemoglobin (Hb) (g/dL) × HbO­2 (%) + 0.003 × PaO2 (mmHg). O2 consumption (ml/min): RBF (ml/min) × (arterial-renal venous O2 content difference). O2 extraction (% of arterial supply): 1-(renal venous O2 content/arterial O2 content) × 100. Daily average mean arterial pressure (MAP) increased moderately soon after switching to the 4% NaCl diet from 113 ± 2 to 120 ± 2 mmHg by day 3 (p=0.03, n=9) and remain elevated at this level throughout the study (120 ± 3 mmHg at day 13). Renal blood flow also rose soon after switching to the 4% salt diet from 9.4 ± 0.8 to 10.3 ± 0.8 ml/min during day 2 (p=0.03, n=9) . Thereafter, it also remained elevated throughout the study (10.7 ± 0.8 ml/min at day 13). Changes in O2 consumption occurred more gradually increasing from 0.21 ± 0.04 and rising to 0.27 ± 0.03 (ml/min) at day 14 of 4% salt diet (p=0.02, n=5). The calculated O2 extraction ratio remained unchanged ranging from 12.1 ± 0.1 (%) to 12.8 ± 0.1 (%) (p=0.48, n=5) throughout the study. It appears that in normal SD rats, the increased tubular metabolic work associated with a high salt diet is initially accommodated by increased perfusion (RBF) and a gradual increase of O2 consumption while extraction remains unchanged for a two-week period.

Evaluation of Cardiovascular Functions during the Practice of Different Types of Yogic Breathing Techniques.

Introduction: Yoga is the science of right living practice to promote health. Many studies have documented the cardiovascular effects of various yogic breathing techniques (YBTs), comparing the cardiovascular changes before and after the practice. However, there is a lack of study reporting the cardiovascular changes during the practice of YBT.Materials and Methods: Twenty healthy individuals performed four different YBTs (Bhastrika, Bhramari, Kapalbhati, and Kumbhaka) in four different orders. Cardiovascular variables such as systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), pulse interval (PI), and total peripheral resistant (TPR) were assessed using a continuous noninvasive blood pressure monitoring system, before, during, and immediately after each YBT. Data were analyzed using repeated measures analysis of variance followed by post hoc analysis with Bonferroni adjustment for multiple comparisons using Statistical Package for the Social Sciences, Version 16.0.Results: Results of this study showed a significant increase in DBP, MAP, HR, and CO along with a reduction in PI during Bhastrika; a significant increase in DBP, MAP, HR, and TPR with a reduction in SV, CO, and PI during Bhramari pranayama; a significant increase in SBP, DBP, MAP, HR, and CO with a reduction in PI during Kapalbhati; and a significant increase in SBP, DBP, MAP, and TPR with a reduction in SV and CO during Kumbhaka practice.Conclusion: In healthy individuals, cardiovascular changes during the practice of Bhastrika and Kapalbhati are more or less similar to each other and are different from those of Bhramari and Kumbhaka in most of the variables.

Blockade of Trpm7 in the Carotid Body area reversed Obesity‐Induced Hypertension

Rationale Obesity leads to cardiovascular morbidity and mortality acting via multiple mechanisms including hypertension. One of the mechanisms of obesity-induced hypertension is an adipocyte-produced hormone leptin, which activates the sympathetic nervous system. We have recently reported that acute leptin infusion induces hypertension acting via the TRPM7 cation channel in the carotid bodies (CB). Here, we examined the relevance of TRPM7 signaling in CB for the pathogenesis of hypertension in diet-induced obesity (DIO) with high circulating leptin levels. We hypothesize that DIO causes hypertension acting on CB TRPM7. Methods DIO male mice (n =11) were implanted with telemetry in the left femoral artery for continuous blood pressure monitoring. Trpm7 was silenced in the carotid body areas by transfection with Ad-Trpm7 shRNA (n = 6); control mice (N = 5) were transfected with Ad-CON-shRNA. Plasma leptin level were measured by ELISA before and after tranfection; RT-PCR was performed to confirm Trpm7 knockdown. Result Trpm7 shRNA group induced a decrease in Trpm7 mRNA expression in the CB compared to control (0.089±0.02 vs 0.416±0.08 relatively to a house-keeping gene Rpl19 respectively, p<0.01). In Trpm7 shRNA treated group, blood pressure decreased from 119.0±2.2 mmHg to 109.6±1.4 mmHg (p<0.01), whereas scrambled shRNA had no effect (from 114.8±0.9 mmHg to 116.3±2.6 mmHg) (Fig. 1). Both groups had similar levels of plasma leptin at baseline, which did not change after transfection. Conclusion Our study has shown that downregulation of Trpm7 in carotid bodies abolished hypertension in obese mice.

Evidence of Early Diabetic Nephropathy in Pediatric Type 1 Diabetes.

BackgroundDiabetic nephropathy (DN) is one of the most common microvascular complications in type 1 diabetes Mellitus (T1D). Urinary markers of renal damage or oxidative stress may signal early stages of DN. The association of these markers with blood pressure (BP) patterns and glycemic variability (GV) in children is yet to be explored.MethodsSubjects between the ages of 10 and 21 years with T1D were enrolled. Continuous glucose monitoring (CGM) and ambulatory blood pressure monitoring (ABPM) were performed on each subject. Urine samples were collected and analyzed for albumin, creatinine, neutrophil gelatinase-associated lipocalin (NGAL) and pentosidine.ResultsThe study included 21 subjects (62% female) with median age of 16.8 (IQR: 14.5, 18.9). Median HbA1C was 8.4 (IQR: 7.5, 9.3). While microalbuminuria was negative in all but one case (4.8%), urinary NGAL/Cr and pentosidine/Cr ratios were significantly elevated (P<0.001) in diabetic patients despite having normal microalbuminuria, and they correlated significantly with level of microalbumin/Cr (r=0.56 [CI: 0.17, 0.8] and r=0.79 [CI: 0.54, 0.91], respectively). Using ABPM, none had hypertension, however, poor nocturnal systolic BP dipping was found in 48% of cases (95% CI: 28-68%). Urinary NGAL/Cr negatively correlated with nocturnal SBP dipping (r=-0.47, CI: -0.76, -0.03). Urine NGAL/Cr also showed a significant negative correlation with HbA1c measurements, mean blood glucose, and high blood glucose index (r=-0.51 [CI: -0.78, -0.09], r=-0.45 [CI: -0.74, -0.03], and r=-0.51 [CI: -0.77, -0.1], respectively). Median urinary NGAL/Cr and pentosidine/Cr ratios were higher in the high GV group but were not significantly different.DiscussionThis pilot study explores the role of ABPM and urinary markers of tubular health and oxidative stress in early detection of diabetic nephropathy. GV may play a role in the process of this diabetic complication.

Effect of Intravenous Acetaminophen on Mean Arterial Blood Pressure: A Post Hoc Analysis of the EFfect of Intravenous ACetaminophen on PosToperative HypOxemia After Abdominal SurgeRy Trial.

Acetaminophen is commonly used as part of multimodal analgesia for acute pain. The intravenous formulation offers a more predictable bioavailability compared to oral and rectal acetaminophen. There have been reports of hypotension with intravenous acetaminophen attributable to centrally mediated and vasodilatory effects. We tested the hypothesis that in adults having abdominal surgery the use of intravenous acetaminophen versus placebo for postoperative pain management is associated with a decrease in mean arterial pressure (MAP) after its administration. This is a substudy of eFfect of intravenous ACetaminophen on posToperative hypOxemia after abdominal surgeRy (FACTOR) trial (NCT02156154). FACTOR trial randomly assigned adults undergoing abdominal surgery to either 1 g of acetaminophen or placebo every 6 hours during the first postoperative 48 hours. Continuous monitoring of blood pressure was obtained by noninvasive ViSi Mobile device (Sotera Wireless, Inc, San Diego, CA) at 15-second intervals during initial 48 hours postoperatively. We excluded patients without continuous monitoring data available. The primary outcome was the MAP difference between MAP 5 minutes before study drug administration (baseline) and MAP 30 minutes poststudy drug administration initiation. We used a linear mixed effects model to assess the treatment effect on MAP change. The secondary outcome was MAP area under baseline (AUB) during the 30 minutes after treatment. In a sensitivity analysis of change in MAP from predrug to postdrug administration, we instead used postdrug MAP as the outcome adjusting for the baseline MAP in the model. Among 358 patients analyzed, 182 received acetaminophen and 176 placebo. The mean (standard deviation [SD]) of average MAP change was -0.75 (5.9) mm Hg for the treatment and 0.32 (6.3) mm Hg for the placebo. Acetaminophen was found to decrease the MAP from baseline more than placebo after drug administration. The estimated difference in mean change of MAP was -1.03 (95% confidence interval [CI] -1.60 to -0.47) mm Hg; P < .001. The sensitivity analysis showed postoperative MAP in the acetaminophen group was 1.33 (95% CI, 0.76-1.90) mm Hg lower than in the placebo group (P < .001). The median of MAP AUB was 33 [Q1 = 3.3, Q3 = 109] mm Hg × minutes for the treatment and 23 [1.6, 79] mm Hg × minutes for the placebo. Acetaminophen was found to increase the AUB with an estimated median difference of 15 (95% CI, 5-25) mm Hg × minutes (P = .003). Intravenous acetaminophen decreases MAP after its administration. However, this decrease does not appear to be clinically meaningful. Clinicians should not refrain to use intravenous acetaminophen for acute pain management because of worries of hypotension.

An advanced double intravenous vasopressor automated system to treat hypotension during spinal anaesthesia for caesarean section: A pilot study.

During spinal anaesthesia for caesarean section, haemodynamic instability may lead to maternal and foetal complications. We developed a novel advanced double intravenous vasopressor automated system (ADIVA) by using a continuous blood pressure and heart rate monitor. Treatment of hypotension was based on three criteria: the drug (phenylephrine or ephedrine) according to the heart rate; the dose of vasopressor determined by the degree of hypotension; a fast or slow bolus of vasopressor administered depending on whether there was a negative or positive gradient of SBP changes, respectively. The aim of this pilot study was to investigate the feasibility of the ADIVA algorithm. A prospective pilot study. Single obstetrics and gynaecology centre in Singapore. Women undergoing elective caesarean delivery under spinal anaesthesia. Automated administration of ephedrine or phenylephrine based on changes in blood pressure and heart rate (via the ADIVA algorithm) detected on continuous noninvasive haemodynamic monitoring using noninvasive continuous haemodynamic monitor (Nexfin). The primary outcome was the incidence of hypotension, defined as SBP less than 80% of baseline. The secondary outcome measures were reactive hypertension, total vasopressor requirement, maternal and neonatal outcomes and system performance. Forty-five women were recruited. Thirty-one women (69.9%) had at least one reading of hypotension. SBP was within ±20% of the baseline in a mean ± SD of 79.7 ± 17.6% of measurements. Forty-four (97.8%) women required phenylephrine before delivery, while 15 (33.3%) required ephedrine. No rescue medications were required. Three women (6.7%) had nausea and two (4.4%) vomiting. All neonates had APGAR scores of 9 at 5 min. The ADIVA system, with noninvasive continuous haemodynamic monitoring, was able to maintain maternal SBP within ±20% of baseline for the vast majority of the measurements. This system had good maternal and foetal outcomes with minimal intervention from the attending anaesthetist. NCT03620942.

Off label use of PICC as umbilical arterial catheter: Clinical case series.

Umbilical arterial catheters are often placed at birth in critical ill neonates. Advantages of umbilical arterial catheterization include continuous blood pressure monitoring, accurate blood gas and frequent blood samplings. We described the off-label use of a third generation polyurethane power injectable 3 Fr single lumen peripheral inserted central catheter as umbilical arterial catheter. This clinical case series opens new scenarios about the off-label use of power PICC in newborns. Prospective studies are needed to evaluate the safety and advantages of PICCs as umbilical catheters over the conventional old generation polyurethane neonatal catheters.

PULSE ARRIVAL TIME CAN TRACK CHANGES IN SYSTOLIC BLOOD PRESSURE

Objective: Automated cuff-based blood pressure (BP) monitoring is limited to intermittent measurements vulnerable to movement. Pulse arrival time (PAT), calculated using electrocardiography (ECG) and photo plethysmography (PPG), has shown promise for non-invasive, continuous BP monitoring. The precise relationship between BP parameters and PAT under varying conditions remains to be fully understood. This study aimed to investigate the correlation between PAT and BP under different exercise modalities. Design and method: Data was analyzed on 33 volunteers aged 18 years or older with and without hypertension. The test protocol consisted of isometric leg exercise, an incremental ergometer bicycle test and seated periods of rest before, in-between and after. PAT was measured with an easy-to-use chest belt consisting of a 1-channel ECG and PPG sensor. PAT was calculated and averaged using a gliding average over 200 cycles from the R-wave in the ECG signal to the foot of the PPG waveform. Reference BP was measured every minute manually with an aneroid sphygmomanometer. Systolic- and diastolic BP was recorded to the nearest second for optimal synchronicity. Results: Subjects were aged 42.3 ± 13.3 years, ranging from 18–70. 48.5% were males, 18.2% had a prior diagnosis of hypertension and 15.2 % used antihypertensive medication. Systolic- and diastolic BP at inclusion were 123.6 ± 16.1 and 76.4 ± 8.4 mmHg with ranges from 98–168 and 66–100 mmHg respectively. Pearson's correlation between systolic BP and PAT was -0.86 ± 0.08, -0.84 ± 0.14 and -0.81 ± 0.14 for the full protocol, isometric exercise and dynamic exercise respectively. Corresponding correlation for diastolic BP was 0.43 ± 0.31, -0.75 ± 0.20 and 0.39 ± 0.35. For diastolic BP, correlation with PAT was positive in most subjects for the full protocol (94%) and dynamic exercise (79%), and negative in all subjects for isometric exercise. Systolic BP showed negative correlation inn all subjects for all analyses. Figure 1 shows test protocol and results for one subject. Conclusions: The results suggest that pulse arrival time can track changes in systolic blood pressure. The relationships between diastolic blood pressure and pulse arrival time varied between exercise modalities and remains to be further elucidated.

CIRCADIAN VARIABILITY AND CIRCADIAN HYPER AMPLITUDE TENSION AS A EARLY PREDICTIVE MARKER OF CHEMOTHERAPHY INDUCED CARDIOTOXICITY

Objective: Chemotherapeutic Medicines like Anthracycline antibiotics are effectively being used for breast cancer treatment in India. Despite of close clinical monitoring, the use of serological markers, such as troponins and BNP, and finally by using standard and novel imaging techniques like, nuclear imaging, echocardiograms etc some patients still develop severe left ventricular dysfunction. Also there are certain limitations of these techniques as these techniques can predict CV damages only after Cardiac function deterioration has become irreversible. Design and method: Therefore in this study Seven day continuous ambulatory blood pressure monitoring and CHAT (circadian hyper amplitude tension) have been evaluated to find out the variability in blood pressure and heart rate as a marker for cardiac function. Subjects who were fulfilling the inclusion criteria were enrolled for study. 24 hour /7days Ambulatory blood pressure monitoring, Left ventricular Ejection Fraction ratio (LVEF), Heart rate variability (HRV) and Cardiotoxicity Biomarkers viz Brain Natruitic peptide (BNP) and C- Reactive Protein (Hs CRP) and Troponin T were analyzed before receiving first Cycle of Antracycline Chemotherapy. All the parameters were repeated after first and Second Cycle of Chemotherapy. Results: Results shows significant increase in MESOR and Double Amplitude and Hyperbaric indexes of SBP, DBP and HR after Chemotherapy. Number of subjects diagonosed with CHAT (Circadian Hyper Amplitude Tension) increased after Chemotherapy while No Significant Changes were noted in LVEF (Left Ventricular ejection fraction) and serum biomarkers (i.e Troponin T, Hs CRP, and BNP). These data suggest that Anthracyclines Chemotheraphy treatment in Breast Cancer Subjects produces variations in 7 day circadian pattern of blood pressure and heart rate which can result into disturbed vascular events and thus are at greater risk of cardiovascular morbidity. Conclusions: long term monitoring of circadian pattern of blood pressure and heart rate in cancer patients will be an effective measure to prevent chemotherapy induced cardiotoxicity. Chronobiological screening parameters will be a novel approach in the context of chemotherapy induced cardiotoxity in order to identify or stratify risk in cancer patients that would potentially benefit from early cardio protective or other precautionary measures.

Blood Pressure Monitoring System Using a Two-Channel Ballistocardiogram and Convolutional Neural Networks.

Hypertension is a chronic disease that kills 7.6 million people worldwide annually. A continuous blood pressure monitoring system is required to accurately diagnose hypertension. Here, a chair-shaped ballistocardiogram (BCG)-based blood pressure estimation system was developed with no sensors attached to users. Two experimental sessions were conducted with 30 subjects. In the first session, two-channel BCG and blood pressure data were recorded for each subject. In the second session, the two-channel BCG and blood pressure data were recorded after running on a treadmill and then resting on the newly developed system. The empirical mode decomposition algorithm was used to remove noise in the two-channel BCG, and the instantaneous phase was calculated by applying a Hilbert transform to the first intrinsic mode functions. After training a convolutional neural network regression model that predicts the systolic and diastolic blood pressures (SBP and DBP) from the two-channel BCG phase, the results of the first session (rest) and second session (recovery) were compared. The results confirmed that the proposed model accurately estimates the rapidly rising blood pressure in the recovery state. Results from the rest sessions satisfied the Association for the Advancement of Medical Instrumentation (AAMI) international standards. The standard deviation of the SBP results in the recovery session exceeded 0.7.

Cuff-less continuous blood pressure measurement based on multiple types of information fusion

Non-invasive and cuff-less real-time continuous blood pressure monitoring plays an important role in both intensive care unit (ICU) and the management of chronic diseases such as hypertension and cardiovascular disease. Although pulse wave transit time (PTT) and pulse waveform parameters (PWPs) can be extracted from photoplethysmography (PPG) and electrocardiographic (ECG) to estimate blood pressure, the value of blood pressure is also constrained by personal characteristics parameters (PCPs). For example, the blood pressure may vary with height, weight and age. In this paper, we present a cuff-less continuous blood pressure measurement method based on multiple types of information fusion. First, we recruited 186 volunteers and measured their personal data (PPG signal, ECG signal, height, age, weight, gender). Second, extract the PTT and PWPs from the PPG signal and ECG signal. Then, according to the extracted parameters, the blood pressure models of control group and experimental group were established respectively (the experimental group uses the multiple types of information fusion method to model, the control group only considers PTT and PWPs). Experiments show that, comparing with the control group, the experimental group systolic blood pressure (SBP) correlation was increased from 0.9355 to 0.9948, root mean square error (RMSE) was reduced from 5.2 mmHg to 1.5 mmHg, while the diastolic blood pressure (DBP) correlation was improved from 0.9331 to 0.9931, RMSE was reduced from 2.9 mmHg to 0.9 mmHg. Therefore, the modeling method proposed in this paper can get more accurate blood pressure values. Further promotion, to achieve the measurement with the "modeling" method, all "restriction" elements must be taken into account in order to obtain a more accurate and stable model.

Effect of essential fatty acid blend on circadian variations of ambulatory blood pressure in patients with essential hypertension and coronary artery disease risk markers.

Flaxseed oil is an excellent source of alpha-linolenic acid ALA known for its antihypertensive action. Flaxseed oil is unstable and its dose is not achievable in our conventional diet hence blending of natural flaxseed oil with palm oil, containing high flavonoids may be a better strategy, to stabilize the blend and provide proper balance of essential fatty acids and potential antioxidant effects. Aim of this study was to access the effect of blended flaxseed oil on 24 h 7-day circadian variations of blood pressure in subjects with essential hypertension. Assessment of CHAT (circadian hyper amplitude tension) using ABPM is the best marker for cardiovascular function. We registered 50 subjects with CAD (Group 1) and 50 subjects with Essential hypertension HT (Group 2) and 52 control subjects with CAD/Hypertension. Group 1 and 2 participant was supplemented with blended flaxseed oil (BFO) (30 ml/day) for the period of 24 weeks, while control group administered available oils sunflower in identical containers, for a follow-up period of 24 weeks. Twenty four hour seven days continuous ambulatory blood pressure monitoring was done initially and after six months of BFO supplementation. There were significant changes noted in lipid profile along with Ambulatory blood pressure parameters like MESOR, ACROPHASE, Hyperbaric Indexes, and CHAT. Circadian hyper amplitude tension (CHAT) incidence decreased after BFO supplementation. Study results suggest that blended flaxseed oil administration can be a potent natural vegetarian antihypertensive supplement which helps in synchronization of cardiac rhythms, and can be used as a preventive treatment of hypertension and as effective vegetarian source of maintaining Omega 3 and omega 6 ratios of essential fatty acids in the body.

Design and Fabrication of a New Wearable Pressure Sensor for Blood Pressure Monitoring.

In recent years, research into the field of materials for flexible sensors and fabrication techniques directed towards wearable devices has helped to raise awareness of the need for new sensors with healthcare applicability. Our goal was to create a wearable flexible pressure sensor that could be integrated into a clinically approved blood pressure monitoring device. The sensor is built from a microfluidic channel encapsulated between two polymer layers, one layer being covered by metal transducers and the other being a flexible membrane containing the microfluidic channel, which also acts as a sealant for the structure. The applied external pressure deforms the channel, causing changes in resistance to the microfluidic layer. Electrical characterization has been performed in 5 different configurations, using alternating current (AC) and (DC) direct current measurements. The AC measurements for the fabricated pressure sensor resulted in impedance values at tens of hundreds of kOhm. Our sensor proved to have a high sensitivity for pressure values between 0 and 150 mm Hg, being subjected to repeatable external forces. The novelty presented in our work consists in the unique technological flow for the fabrication of the flexible wearable pressure sensor. The proposed miniaturized pressure sensor will ensure flexibility, low production cost and ease of use. It is made of very sensitive microfluidic elements and biocompatible materials and can be integrated into a wearable cuffless device for continuous blood pressure monitoring.

Agreement between continuous noninvasive finger cuff-derived and invasive arterial blood pressure measurements: Effect of data sampling and data processing.

The effect of different methods for data sampling and data processing on the results of comparative statistical analyses in method comparison studies of continuous arterial blood pressure (AP) monitoring systems remains unknown. We sought to investigate the effect of different methods for data sampling and data processing on the results of statistical analyses in method comparison studies of continuous AP monitoring systems. Prospective observational study. University Medical Center Hamburg-Eppendorf, Hamburg, Germany, from April to October 2019. 49 patients scheduled for neurosurgery with AP measurement using a radial artery catheter. We assessed the agreement between continuous noninvasive finger cuff-derived (CNAP Monitor 500; CNSystems Medizintechnik, Graz, Austria) and invasive AP measurements in a prospective method comparison study in patients having neurosurgery using all beat-to-beat AP measurements (Methodall), 10-s averages (Methodavg), one 30-min period of 10-s averages (Method30), Method30 with additional offset subtraction (Method30off), and 10 30-s periods without (Methodiso) or with (Methodiso-zero) application of the zero zone. The agreement was analysed using Bland-Altman and error grid analysis. For mean AP, the mean of the differences (95% limits of agreement) was 9.0 (-12.9 to 30.9) mmHg for Methodall, 9.2 (-12.5 to 30.9) mmHg for Methodavg, 6.5 (-9.3 to 22.2) mmHg for Method30, 0.5 (-9.5 to 10.5) mmHg for Method30off, 4.9 (-6.0 to 15.7) mmHg for Methodiso, and 3.4 (-5.9 to 12.7) mmHg for Methodiso-zero. Similar trends were found for systolic and diastolic AP. Results of error grid analysis were also influenced by using different methods for data sampling and data processing. Data sampling and data processing substantially impact the results of comparative statistics in method comparison studies of continuous AP monitoring systems. Depending on the method used for data sampling and data processing, the performance of an AP test method may be considered clinically acceptable or unacceptable.

Abstract MP36: Blood Pressure Reductions in the Hyperacute Phase of Large Vessel Occlusion Ischemic Stroke Are Associated With Infarct Progression and Poor Functional Outcome

Introduction: Decreases in blood pressure (BP) during endovascular therapy (EVT) have been associated with infarct progression and worse outcome after large vessel occlusion (LVO) stroke. However, BP trajectories in the hyperacute phase prior to EVT have not been well characterized. We used high-frequency BP and hemodynamic monitoring to study the timing of BP reductions during the hyperacute period of stroke and evaluated their relation to infarct progression and functional outcome. Methods: We prospectively enrolled patients with anterior circulation LVO stroke undergoing EVT. BP and cardiac hemodynamic variables were recorded every 20 seconds from ER admission until the end of EVT using non-invasive finger plethysmography. Patients underwent initial CT perfusion imaging and a follow-up MRI at 24 hours to calculate infarct growth. The following hemodynamic parameters were defined as exposure variables: the difference between admission MAP and lowest MAP (ΔMAP), MAP drop&gt; 20% from admission, MAP&lt;70 mmHg, and SBP&lt;140 mmHg. Functional outcome was measured with the modified Rankin Scale (mRS) at 90 days. Core associations between BP reductions and outcomes were studied using linear regression and logistic regression models. Results: 45 patients underwent continuous BP monitoring (age 72±17; 58% female; NIHSS 13±6). Aggregated time series data revealed a marked BP reduction around the time of imaging from which patients recovered (mean SBP 33 mmHg, duration 18 min). A sustained decrease in BP was observed after groin puncture without return to baseline BP levels. A linear regression analysis revealed a 13ml infarct growth for every 10 mmHg reduction in ΔMAP (p=0.054). Patients were divided into two groups based on median ΔMAP = 29. Those with ΔMAP ≤29 had better functional outcome at 90 days (34.78% vs. 9.09%, p = 0.038). Conclusion: Marked and frequently iatrogenic BP reductions occur around the time of initial imaging and may present a potential target for therapeutic intervention. Decrease in blood pressure before reperfusion may increase the risk of infarct progression and poor functional outcome. Changes in cardiac hemodynamic variables throughout the acute stroke period suggest a potential role for fluid resuscitation for hemodynamic optimization.

Bio-Impedance Measurement Optimization for High-Resolution Carotid Pulse Sensing.

Continuous hemodynamic monitoring is important for long-term cardiovascular healthcare, especially in hypertension. The impedance plethysmography (IPG) based carotid pulse sensing is a non-invasive diagnosis technique for measuring pulse signals and further evaluating the arterial conditions of the patient such as continuous blood pressure (BP) monitoring. To reach the high-resolution IPG-based carotid pulse detection for cardiovascular applications, this study provides an optimized measurement parameter in response to obvious pulsation from the carotid artery. The influence of the frequency of excitation current, electrode cross-sectional area, electrode arrangements, and physiological site of carotid arteries on IPG measurement resolution was thoroughly investigated for optimized parameters. In this study, the IPG system was implemented and installed on the subject’s neck above the carotid artery to evaluate the measurement parameters. The measurement results within 6 subjects obtained the arterial impedance variation of 2137 mΩ using the optimized measurement conditions, including excitation frequency of 50 kHz, a smaller area of 2 cm2, electrode spacing of 4 cm and 1.7 cm for excitation and sensing functions, and location on the left side of the neck. The significance of this study demonstrates an optimized measurement methodology of IPG-based carotid pulse sensing that greatly improves the measurement quality in cardiovascular monitoring.