Non-invasive Blood Pressure Measurement Research Articles

An Evaluation of the NICCI Monitor in Providing Continuous, Noninvasive Blood Pressure Readings in Children During Intraoperative Anesthetic Care

BackgroundIn specific clinical scenarios or with patient comorbid conditions, continuous blood pressure (BP) monitoring may be required as it can be expected to provide superior physiologic monitoring to intermittent techniques. However, continuous BP monitoring requires an arterial cannula (AC) placement, which may be time-consuming, technically challenging, or associated with adverse events. Various noninvasive BP devices have been developed which provide a continuous BP reading. The current study evaluates the accuracy of a novel continuous BP device, the NICCI monitor (NM), in pediatric patients weighing 10 - 40 kg.MethodsThe study cohort included pediatric patients weighing between 10 and 40 kg, scheduled for surgery for which placement of an AC was planned. Systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressure readings were captured from the AC and the NM every second during anesthetic care.ResultsThe study cohort included 24 pediatric patients undergoing major orthopedic, cardiac, and neurosurgical procedures. A total of 146,562 pairs of SBP, DBP, and MAP values from the AC and NC were analyzed. The absolute difference for the NM and the AC’s SBP, DBP, and MAP values were 11 ± 9, 10 ± 7, and 10 ± 7 mm Hg, respectively. The difference between the BP values from the NM and the AC was ≤ 10 mm Hg for 57% of the SBP readings, 60% of the DBP readings, and 56% of the MAP readings. The bias was 4, 4, and 6 mm Hg for the SBP, DBP, and MAP, respectively.ConclusionsAlthough there were some technical limitations given patient size, potentially resulting in variation in accuracy, the NM provided a continuous noninvasive BP measurement within clinically useful limits during a significant portion of anesthetic care compared to values obtained from an AC. Ongoing modification of the technology to improve its application in pediatric patients will likely increase its accuracy.

Comparison of oscillometric, non-invasive and invasive arterial pressure monitoring in patients undergoing laparoscopic bariatric surgery \u2013 a secondary analysis of a prospective observational study

BackgroundOscillometric, non-invasive blood pressure measurement (NIBP) is the first choice of blood pressure monitoring in the majority of low and moderate risk surgeries. In patients with morbid obesity, however, it is subject to several limitations. The aim was to compare arterial pressure monitoring by NIBP and a non-invasive finger-cuff technology (Nexfin®) with the gold-standard invasive arterial pressure (IAP).MethodsIn this secondary analysis of a prospective observational, single centre cohort study, systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP) were measured at 16 defined perioperative time points including posture changes, fluid bolus administration and pneumoperitoneum (PP) in patients undergoing laparoscopic bariatric surgery. Absolute arterial pressures by NIBP, Nexfin® and IAP were compared using correlation and Bland Altman analyses. Interchangeability was defined by a mean difference ≤ 5 mmHg (SD ≤8 mmHg). Percentage error (PE) was calculated as an additional statistical estimate. For hemodynamic trending, concordance rates were analysed according to the Critchley criterion.ResultsSixty patients (mean body mass index of 49.2 kg/m2) were enrolled and data from 56 finally analysed. Pooled blood pressure values of all time points showed a significant positive correlation for both NIPB and Nexfin® versus IAP. Pooled PE for NIBP versus IAP was 37% (SAP), 35% (DAP) and 30% (MAP), for Nexfin versus IAP 23% (SAP), 26% (DAP) and 22% (MAP). Correlation of MAP was best and PE lowest before induction of anesthesia for NIBP versus IAP (r = 0.72; PE 24%) and after intraoperative fluid bolus administration for Nexfin® versus IAP (r = 0.88; PE: 17.2%). Concordance of MAP trending was 90% (SAP 85%, DAP 89%) for NIBP and 91% (SAP 90%, DAP 86%) for Nexfin®. MAP trending was best during intraoperative ATP positioning for NIBP (97%) and at induction of anesthesia for Nexfin® (97%).ConclusionAs compared with IAP, interchangeability of absolute pressure values could neither be shown for NIBP nor Nexfin®, however, NIBP showed poorer overall correlation and precision. Overall trending ability was generally high with Nexfin® surpassing NIBP. Nexfin® may likely render individualized decision-making in the management of different hemodynamic stresses during laparoscopic bariatric surgery, particularly where NIBP cannot be reliably established.Trial registrationThe non-interventional, observational study was registered retrospectively at (NCT03184285) on June 12, 2017.

The effect of heart rate on blood pressure measurement in patients with atrial fibrillation: a cross-sectional study.

This study explored the effect of heart rate (HR) on the stability and accuracy of blood pressure (BP) measurement and the optimal HR range for the most accurate blood pressure measurement in atrial fibrillation (AF) patients. A total of 583 patients (383 and 200 with AF and sinus rhythm (SR), respectively) were included in this study. The noninvasive blood pressure (NIBP), invasive blood pressure (IBP), and HR were repeatedly measured ten times at 30-second intervals for every patient. Both the AF and SR groups were then subdivided into five groups depending on the HR (i.e., < 60, 60-80, 80-100, 100-120, and ≥120 bpm). The difference between the IBP and NIBP (i.e., △SBP) and the coefficient of variation (CV) were calculated, and the stability and accuracy of NIBP measurements were analyzed. CV and △SBP were significantly higher in the AF group. In the AF group, the CV of NIBP was highest when the HR was ≥ 100 bpm; and △SBP was significantly lower in the HR groups with 60-80 and 80-100 bpm (< 60 bpm, △SBP 11.62 ± 2.64 mmHg; 60-80 bpm, △SBP 7.10 ± 1.92 mmHg; 80-100 bpm, △SBP 7.10 ± 2.95 mmHg; 100-120 bpm, △SBP 10.52 ± 2.72 mmHg; ≥120 bpm, △SBP 14.15 ± 3.61 mmHg, P < 0.05). The stability and accuracy of the NIBP in the SR groups were not affected by the HR. In AF patients, the NIBP stability was low when the HR was high, and the NIBP was often underestimated when the HR was high or low. Sixty to 100 bpm is the best HR range for measuring blood pressure in AF patients.

Echocardiographic and electrocardiographic effects of atenolol versus sotalol in dogs with severe subaortic stenosis

BackgroundSubaortic stenosis (SAS) is a commonly diagnosed canine congenital cardiac defect, with severe forms of carrying a poor long-term prognosis. To date, an effective treatment strategy has not been developed in veterinary medicine. This study sought to determine if sotalol, a class III antiarrhythmic, may have salient echocardiographic and antiarrhythmic benefits for medical management for dogs affected with severe SAS. MethodsTen dogs diagnosed with severe SAS were enrolled in this prospective, double-blinded, crossover study. Dogs underwent physical exam, non-invasive blood pressure measurement, electrocardiography, echocardiography, and 24-h Holter monitoring. Diagnostics were repeated 12–16 days following randomization to oral atenolol (0.5–1 mg/kg) or sotalol (1–2 mg/kg) twice daily. After a medication taper and four-day washout, dogs were crossed-over to the alternate study medication, and the diagnostics were repeated in 12–16 days. Linear and multinomial mixed models were developed to evaluate the effects of treatments on echocardiographic and electrocardiographic variables. ResultsIndices of left ventricular systolic function were reduced based on the volumetric assessment when dogs received sotalol compared to atenolol. No difference was noted between groups in left ventricular systolic function based on the linear assessment. No difference was observed in the reduction in left ventricular outflow tract velocity. No significant differences were observed between treatment groups for any variable on 24-h Holter monitor. ConclusionsSotalol may be a viable therapy to consider for dogs with severe SAS based on this pilot study. A larger, prospective study is necessary to investigate further.

Inflationary noninvasive blood pressure monitoring reduces lower-limb pain during measurement

Objective: This study aimed to investigate whether inflationary noninvasive blood-pressure measurement reduces pain during blood-pressure monitoring with the lower limbs compared to the conventional noninvasive measurement method.Methods: Healthy volunteers aged ≥ 18 years were recruited for the study. After seating the participants, a manchette was fitted onto each limb (upper limbs: YP-713T YAWARA CUFF2 13 cm; lower limbs: YP-715T YAWARA CUFF2 for thigh 19 cm, Nihon Kohden Tokyo, Japan). The inflationary and conventional noninvasive blood-pressure measurement devices (PVM-9901 and PVM-9901, Nihon Kohden, Tokyo, Japan) were connected, and the blood pressure was measured simultaneously at two points in the upper and lower limbs. After the measurement, the participants answered a questionnaire regarding the lower-limb pain, and the intensity of pain was evaluated using the visual analog scale.Results: The study included 111 healthy volunteers. The visual analog scale scores of the upper and lower limbs were significantly lower with the inflationary noninvasive blood pressure measurement device than with the conventional noninvasive blood pressure device (upper limbs: 25.6 ± 23.2 vs. 38.8 ± 27.5, p &lt; .001 and lower limbs: 42.2 ± 25.1 vs. 54.2 ± 26.1, p &lt; .01, respectively).Conclusions: We examined the effect of pain reduction on the lower limbs with inflationary noninvasive blood-pressure measurements in healthy volunteers. We conclude that inflationary noninvasive blood pressure measurement may reduce pain in the lower limbs during blood-pressure monitoring compared to a conventional noninvasive blood pressure measurement.

Continuous Noninvasive Remote Automated Blood Pressure Monitoring With Novel Wearable Technology: A Preliminary Validation Study.

BackgroundWearable continuous monitoring biosensor technologies have the potential to transform postoperative care with early detection of impending clinical deterioration.ObjectiveOur aim was to validate the accuracy of Cloud DX Vitaliti continuous vital signs monitor (CVSM) continuous noninvasive blood pressure (cNIBP) measurements in postsurgical patients. A secondary aim was to examine user acceptance of the Vitaliti CVSM with respect to comfort, ease of application, sustainability of positioning, and aesthetics.MethodsIncluded participants were ≥18 years old and recovering from surgery in a cardiac intensive care unit (ICU). We targeted a maximum recruitment of 80 participants for verification and acceptance testing. We also oversampled to minimize the effect of unforeseen interruptions and other challenges to the study. Validation procedures were according to the International Standards Organization (ISO) 81060-2:2018 standards for wearable, cuffless blood pressure (BP) measuring devices. Baseline BP was determined from the gold-standard ICU arterial catheter. The Vitaliti CVSM was calibrated against the reference arterial catheter. In static (seated in bed) and supine positions, 3 cNIBP measurements, each 30 seconds, were taken for each patient with the Vitaliti CVSM and an invasive arterial catheter. At the conclusion of each test session, captured cNIBP measurements were extracted using MediCollector BEDSIDE data extraction software, and Vitaliti CVSM measurements were extracted to a secure laptop through a cable connection. The errors of these determinations were calculated. Participants were interviewed about device acceptability.ResultsThe validation analysis included data for 20 patients. The average times from calibration to first measurement in the static position and to first measurement in the supine position were 133.85 seconds (2 minutes 14 seconds) and 535.15 seconds (8 minutes 55 seconds), respectively. The overall mean errors of determination for the static position were –0.621 (SD 4.640) mm Hg for systolic blood pressure (SBP) and 0.457 (SD 1.675) mm Hg for diastolic blood pressure (DBP). Errors of determination were slightly higher for the supine position, at 2.722 (SD 5.207) mm Hg for SBP and 2.650 (SD 3.221) mm Hg for DBP. The majority rated the Vitaliti CVSM as comfortable. This study was limited to evaluation of the device during a very short validation period after calibration (ie, that commenced within 2 minutes after calibration and lasted for a short duration of time).ConclusionsWe found that the Cloud DX’s Vitaliti CVSM demonstrated cNIBP measurement in compliance with ISO 81060-2:2018 standards in the context of evaluation that commenced within 2 minutes of device calibration; this device was also well-received by patients in a postsurgical ICU setting. Future studies will examine the accuracy of the Vitaliti CVSM in ambulatory contexts, with attention to assessment over a longer duration and the impact of excessive patient motion on data artifacts and signal quality.Trial RegistrationClinicalTrials.gov NCT03493867; https://clinicaltrials.gov/ct2/show/NCT03493867

Isolated systolic hypertension is associated with increased left ventricular mass index and aortic stiffness in adolescents: a cardiac magnetic resonance study.

Despite the high prevalence of isolated systolic hypertension (ISH) among hypertensive adolescents, its clinical significance is not determined. In addition, it is hypothesized that ISH with normal central blood pressure (BP) in young patients is a benign phenomenon and was hence labeled spurious hypertension (sHTN). Using cardiac magnetic resonance we evaluated a group of 73 patients with suspected primary hypertension, aged 13-17 years (median: 16.9, interquartile range 15.8-17.4; 13 girls), in whom, based on 24-h ambulatory BP monitoring either ISH (n = 30) or white-coat hypertension (WCH) (n = 43) was diagnosed. Based on noninvasive central BP measurement 13 participants in the ISH group were classified as having sHTN and 17 were diagnosed with true hypertension. Compared with WCH adolescents, ISH patients presented with higher indexed left ventricular mass index (LVMI) (P < 0.001), maximal left ventricular (LV) wall thickness (P < 0.001), LV concentricity (P = 0.001) and more often had LV hypertrophy (47 vs. 14%, P = 0.002). They had higher average pulse wave velocity (PWV) in the proximal aorta (P = 0.016) and the whole thoracic aorta (P = 0.008). In addition, we observed higher indexed LV stroke volume (P = 0.025) in patients with ISH. The sHTN subgroup had significantly higher LVMI and aortic PWV, and more often had LV hypertrophy compared with the WCH group. The sHTN and true hypertension subgroups did not differ in terms of aortic PWV, LVMI or LV geometry. Compared with adolescents with WCH patients with ISH, including the sHTN subtype, have more pronounced markers of cardiac end-organ damage, higher aortic stiffness and stroke volume.

Tracking Peripheral Artery Motion and Vascular Resistance With a Multimodal Wearable Sensor Under Pressure Perturbations.

The status of peripheral arteries is known to be a key physiological indicator of the body's response to both acute and chronic medical conditions. In this paper, peripheral artery deformation is tracked by wearable photoplethysmograph (PPG) and piezo-electric (polyvinylidene difluoride, PVDF) sensors, under pressure-varying cuff. A simple mechanical model for the local artery and intervening tissue captures broad features present in the PPG and PVDF signals on multiple swine subjects, with respect to varying cuff pressure. These behaviors provide insight into the robustness of cardiovascular property identification by noninvasive wearable sensing. This is found to help refine noninvasive blood pressure measurements and estimation of systemic vascular resistance (SVR) using selected features of sensor amplitude versus applied pressure.

Continuous Monitoring of Blood Pressure Using a Wrist-Worn Cuffless Device.

Measuring an accurate blood pressure (BP) in ambulatory patients is critical for therapeutic decisions. An accurate noninvasive device that measures BP continuously could provide a more comprehensive assessment of BP. The aim of this study was to determine whether the LiveOne device, a cuffless wristband that provides continuous BP measurements, is accurate in comparison to an invasive arterial line (A-line). We enrolled hospitalized patients and healthy volunteers in this multicenter study. All patients had an invasive A-line. Waveforms were simultaneously downloaded from the A-line and LiveOne device. The primary outcome was the correlation between the LiveOne device and the A-line for systolic BP (SBP) and diastolic BP (DBP). Thirty-four patients with 233 measurement periods were included. Mean age was 60.7 ± 15.2 years, and 15 (44%) were female. The correlation for SBP was 0.91 and for DBP was 0.85. The mean band error was 0.0 ± 6.9 mm Hg for SBP and 1.2 ± 5.7 mm Hg for DBP. The mean absolute error was 8.2 ± 5.8 mm Hg for SBP and 6.4 ± 3.9 mm Hg for DBP. For SBP, 98% of LiveOne measurements were within 15 mm Hg and for DBP, 92% of LiveOne measurements were within 10 mm Hg. The LiveOne device provides continuous, noninvasive BP measurements that are accurate in comparison to A-line measurements. The portability and unobtrusive nature of this device and the ability to provide continuous BP measurements may offer advantages over currently available BP monitors. Trial Number NCT03919136.

Cuffless Blood Pressure Measurement Using Linear and Nonlinear Optimized Feature Selection.

The cuffless blood pressure (BP) measurement allows for frequent measurement without discomfort to the patient compared to the cuff inflation measurement. With the availability of a large dataset containing physiological waveforms, now it is possible to use them through different learning algorithms to produce a relationship with changes in BP. In this paper, a novel cuffless noninvasive blood pressure measurement technique has been proposed using optimized features from electrocardiogram and photoplethysmography based on multivariate symmetric uncertainty (MSU). The technique is an improvement over other contemporary methods due to the inclusion of feature optimization depending on both linear and nonlinear relationships with the change of blood pressure. MSU has been used as a selection criterion with algorithms such as the fast correlation and ReliefF algorithms followed by the penalty-based regression technique to make sure the features have maximum relevance as well as minimum redundancy. The result from the technique was compared with the performance of similar techniques using the MIMIC-II dataset. After training and testing, the root mean square error (RMSE) comes as 5.28 mmHg for systolic BP and 5.98 mmHg for diastolic BP. In addition, in terms of mean absolute error, the result improved to 4.27 mmHg for SBP and 5.01 for DBP compared to recent cuffless BP measurement techniques which have used substantially large datasets and feature optimization. According to the British Hypertension Society Standard (BHS), our proposed technique achieved at least grade B in all cumulative criteria for cuffless BP measurement.

Assessment of pulmonary circulation unit during exercise in patients with ankylosing spondilitis and sporiatic arthritis

Abstract Funding Acknowledgements Type of funding sources: None. Background Ankylosing spondylitis (AS) and psoriatic arthritis (PsA) are chronic multisystem inflammatory disorders that present with articular and extra-articular features. Cardiac dysfunction and pulmonary disease are well-known and commonly reported extra-articular manifestations of AS and PsA. The inflammatory process can induce respiratory complications, including chest wall restriction, significantly impacting patients" cardiorespiratory status. We aimed to assess pulmonary circulation and right ventricle behaviour during exercise in patients with AS and PsA and to detect the possible effect of chest wall restriction on right heart function. Methods A total of 45 spondylarthritis patients were enrolled in the study (age 51.5 ± 12.3 years, 82.2% men): 27 of them were diagnosed with AS (20 of them had ankylosis at the time of the study), while 18 had PsA (2 of them in ankylosis). According to a standardized protocol, all subjects underwent resting and exercise stress echocardiography on a semi-recumbent cycle ergometer with an incremental workload up to the maximal tolerated workload. Basic echocardiographic measurements were taken, focusing on the right and left ventricular functions and the systolic pulmonary artery pressure (PASP) at rest, at 50 watts workload, and maximal exercise. During the examination, non-invasive blood pressure measurements, transcutaneous capillary oxygen saturation and continuous ECG recording were performed. Results PASP did not differ between the AS and PsA patients at rest (15.6 ± 6.7 mmHg vs 13.7 ± 8.3 mmHg; p = ns); however, PASP measured at the maximal workload was significantly higher among AS patients (31.4 ± 15.9mmHg vs 21.6 ± 12.7mmHg; p &amp;lt; 0.05; Figure 1). PASP did not correlate with the age or the time that passed since the diagnosis. Parameters describing the left and right ventricular systolic and diastolic function did not differ significantly between AS and PsA patients at rest and peak stress. Comparing the LV diastolic parameters of ankylosing patients with non-ankylosing patients irrespective of the underlying disease showed significantly different values in peak E/e"ratio (8.9 ± 3 vs 7.4 ± 1.6; p &amp;lt; 0,05; Figure 2). Conclusion Exercise stress echocardiography is a promising diagnostic modality in autoimmune diseases. In AS patients, the chest wall restriction may results in elevation of PASP during the exercise. The noninvasive indice of left ventricular filling pressure increases significantly in patients with ankylosis in both groups, explaining the effect of the rigid chest wall on the left ventricular filling. Abstract Figure. Abstract Figure.

Cross-sectional survey of non-invasive indirect blood pressure measurement practices in cats by veterinarians.

This survey of small animal veterinarians endeavored to: (1) determine current methods of indirect blood pressure measurement; (2) detail techniques used to reduce situational hypertension; and (3) better understand the obstacles to performing blood pressure measurement in cats. An online survey was produced and circulated to members of the Veterinary Information Network. A total of 733 veterinarians who saw cats in their practice and had access to at least one indirect blood pressure device completed the entirety of the survey. Ninety-six percent (703/733) of veterinarians who completed the survey reported measuring indirect blood pressure in cats in their practice, with veterinary technicians conducting most (600/703; 85.3%) of these measurements. Few veterinarians (30/733; 4.1%) did not measure blood pressure, with these veterinarians citing several obstacles including: difficulty interpreting results with the occurrence of fear, anxiety and stress in cats (20/30; 66.7%); difficulty performing measurements in cats (17/30; 56.7%); and technical staff being uncomfortable performing measurements (12/30; 40.0%). Most veterinarians (300/435; 69.0%) in this survey preferred an ultrasonic Doppler flow detector with sphygmomanometry, with many (272/300; 90.7%) perceiving that the results obtained with this device were more trustworthy compared with results obtained with oscillometry. Ninety percent (633/703) of veterinarians employed techniques to reduce situational hypertension in cats. Techniques perceived to be most helpful among veterinarians included: using a quiet location (454/633; 71.7%); minimizing restraint (316/633; 49.9%); performing blood pressure prior to other procedures (eg, phlebotomy, cystocentesis) (302/633; 47.7%); avoiding other animals (219/633; 34.6%); and allowing time for acclimation (167/633; 26.4%). This survey study of veterinarians helps clarify obstacles to routine blood pressure measurement in conscious cats. Veterinarians reported several strategies that they felt reduced situational hypertension in cats. The data inform modifications of techniques to increase the frequency and perceived reliability of blood pressure measurement in at-risk cats.

A non-invasive blood pressure prediction method based on pulse wave feature fusion

To study the non-invasive blood pressure prediction based on pulse wave feature fusion to achieve rapid blood pressure (BP) measurement and improve the measurement accuracy, which provides a new method for the non-invasive blood pressure measurement by wearable devices. From the pulse signals, 82 dimensional features were extracted, including time domain features extracted by the feature point method, ratio features of pulse wave amplitude and pulse-taking pressure fusion, and pulse wave velocity (PWV) features. Feature fusion is performed by feature importance analysis to reduce the dimensionality, and the fused features are used to build blood prediction models based on gradient boosting decision tree (GBDT) regression algorithm. The correlation coefficients between the predicted and actual values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 0.93 and 0.92, respectively, which had high correlation, and the mean absolute errors between the predicted and actual values of SBP and DBP were 3.75 mmHg and 3.10 mmHg, respectively, with standard deviations of 5.46 mmHg and 3.93 mmHg, all of which met the overall performance requirements of the association for the advancement of medical instrumentation (AAMI) and British hypertension society (BHS) International electronic blood pressure monitor. This blood pressure prediction model can be better used in the non-invasive blood pressure measurement of wearable devices, which is more convenient and has higher prediction accuracy compared with mercury sphygmomanometer.

Towards Robust Blood Pressure Estimation From Pulse Wave Velocity Measured by Photoplethysmography Sensors

In recent years, advances in biosensing devices have greatly increased the ability of sensing human biological vital signs. These advances have allowed physicians to better assess the health status of patients. Among them, blood pressure (BP) sensing has been the dominant one, showing the most potential for growth. Despite much progress, a rapid, robust, and easy-accessed way for BP sensing is still much needed for the emerging point-of-care market. To tackle this challenge, in this paper, we present a BP measurement unit that is developed based on two photoplethysmography (PPG) sensors from which pulse wave velocity (PWV) of blood flow can be derived. A robust time difference of collected two subsequent PPG waveforms between two heartbeats was used to calculate PWV. The systolic and diastolic BPs from 26 participants were estimated by using the derived PWV as the input of machine learning (ML) models. Upon testing multiple ML models, the Gaussian process regressor achieved the highest R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> score of >0.88 and >0.62 for the systolic BP and diastolic BP, respectively. These R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> scores are among the best that can be achieved with state-of-art non-invasive BP measurement devices. This work demonstrates that PPG-based sensors for PWV and BP estimation, combined with ML, have a great potential of becoming a complementary way to measure biological vital signs.

Glut5 Knockdown in the Nucleus Tractus Solitarii Alleviates Fructose-Induced Hypertension in Rats

BackgroundSeveral studies have suggested mechanisms whereby excessive fructose intake increases blood pressure (BP). Glucose transporter 5 (GLUT5) is a fructose transporter expressed on enterocytes, and its involvement in the nucleus tractus solitarius (NTS)–modulated increase in BP following fructose intake remains unclear. ObjectivesHerein, we investigated whether NTS Glut5 knockdown (KD) can alleviate fructose-induced hypertension in rat models. MethodsMale Wistar-Kyoto rats (6–8 weeks old; average weight: 230 g) were randomly assigned into 4 groups [control (Con), fructose (Fru), fructose + scrambled (Fru + S), and Fru + KD]. The Con group rats had ad libitum access to regular water, and the other 3 groups were provided 10% fructose water ad libitum for 4 weeks (2 weeks before lentiviral transfection in the Fru + S and Fru + KD groups). Glut5 short hairpin RNA was delivered into the NTS of rats using a lentivirus system. Fructose-induced hypertension was assessed via the tail-cuff technique, a noninvasive blood pressure measurement approach. GLUT5-associated and other insulin signaling pathways in the NTS of rats were assessed using immunofluorescence and immunoblotting analyses. We evaluated between-group differences using the Mann-Whitney U test or Kruskal-Wallis 1-way ANOVA. ResultsCompared with the Fru + S group, the Fru + KD group had reduced sympathetic nerve hyperactivity (48.8 ± 3.2 bursts/min; P < 0.05), improved central insulin signaling, upregulated protein kinase B (AKT; 3.0-fold) and neuronal NO synthase (nNOS; 2.78-fold) expression, and lowered BP (17 ± 1 mmHg, P < 0.05). Moreover, Glut5 KD restored signaling dependent on adenosine 5′-monophosphate–activated protein kinase and reduced fructose-induced oxidative stress 2.0-fold, and thus decreased NAD(P)H oxidase in p67-phox 1.9-fold within the NTS. ConclusionsFructose-induced reactive oxygen species generates in the NTS of rats through GLUT5 and receptor for advanced glycation end products signaling, thus impairing the AKT–nNOS–NO signaling pathway and ultimately causing hypertension.

Blood pressure nomograms for children undergoing general anesthesia, stratified by age and anesthetic type, using data from aretrospective cohort at a tertiary pediatric center.

Reference values for non-invasive blood pressure (NIBP) are available for children undergoing general anesthesia, but have not been analyzed by type of anesthetic. This study establishes age-specific pediatric NIBP reference values, stratified by anesthetic type: inhalational anesthesia (IHA), total intravenous anesthesia (TIVA), and mostly intravenous anesthesia (MIVA, an inhalational induction followed by intravenous maintenance of anesthesia). NIBP measurements were extracted from a de-identified vital signs database for children < 19years undergoing anesthesia between Jan/2013-Dec/2016, excluding cardiac surgery. We automatically rejected artifacts and randomly sampled 20 NIBP values per case. Anesthetic phase (induction/maintenance) was identified using operating room booking times for procedure start, and anesthetic types were identified based on intraoperative minimum alveolar concentration values in the different phases of the anesthetic. From 36,347 cases in our operating room booking system, we matched 24,457 cases with available vital signs. Of these, 20,613 (84%) had valid NIBP data and could be assigned to one anesthetic type: TIVA 11,819 [57%], IHA 4,752 [23%], and MIVA 4,042 [20%]. Mean NIBP during anesthesia increased with age, from median values of 48mmHg (TIVA), 45mmHg (IHA), and 41mmHg (MIVA) in neonates, to 70mmHg (TIVA), 68mmHg (IHA), and 64mmHg (MIVA) in 18-year-olds, respectively. In children < 1year, mean NIBP values were 4mmHg higher with TIVA than IHA (p < 0.001). These pediatric NIBP reference values contribute to ongoing debate about alarm limits based on age and anesthetic type, and may motivate prospective studies into the effects of different anesthesia regimes on vital signs.

A Novel Clustering-Based Algorithm for Continuous and Noninvasive Cuff-Less Blood Pressure Estimation.

Extensive research has been performed on continuous and noninvasive cuff-less blood pressure (BP) measurement using artificial intelligence algorithms. This approach involves extracting certain features from physiological signals, such as ECG, PPG, ICG, and BCG, as independent variables and extracting features from arterial blood pressure (ABP) signals as dependent variables and then using machine-learning algorithms to develop a blood pressure estimation model based on these data. The greatest challenge of this field is the insufficient accuracy of estimation models. This paper proposes a novel blood pressure estimation method with a clustering step for accuracy improvement. The proposed method involves extracting pulse transit time (PTT), PPG intensity ratio (PIR), and heart rate (HR) features from electrocardiogram (ECG) and photoplethysmogram (PPG) signals as the inputs of clustering and regression, extracting systolic blood pressure (SBP) and diastolic blood pressure (DBP) features from ABP signals as dependent variables, and finally developing regression models by applying gradient boosting regression (GBR), random forest regression (RFR), and multilayer perceptron regression (MLP) on each cluster. The method was implemented using the MIMIC-II data set with the silhouette criterion used to determine the optimal number of clusters. The results showed that because of the inconsistency, high dispersion, and multitrend behavior of the extracted features vectors, the accuracy can be significantly improved by running a clustering algorithm and then developing a regression model on each cluster and finally weighted averaging of the results based on the error of each cluster. When implemented with 5 clusters and GBR, this approach yielded an MAE of 2.56 for SBP estimates and 2.23 for DBP estimates, which were significantly better than the best results without clustering (DBP: 6.27, SBP: 6.36).

Direct Determination rather than Oscillometric Estimation of Systolic Blood Pressure in Patients with Severe Chronic Kidney Disease

Introduction: Although arterial hypertension is a major concern in patients with chronic kidney disease (CKD), obtaining accurate systolic blood pressure (SBP) measurement is challenging in this population for whom automatic oscillometric devices may yield erroneous results. Methods: This cross-sectional study was conducted in 89 patients with stages 4, 5, and 5D CKD, for whom we compared SBP values obtained by the recently described systolic foot-to-apex time interval (SFATI) technique which provides direct SBP determination, the standard technique (Korotkoff sounds), and oscillometry. We investigated the effects of age, sex, diabetes, CKD stage, and pulse pressure to explain measurement errors defined as biases or misclassification relative to the SBP thresholds of 110–130-mm Hg. Results: All 3 techniques showed satisfactory reproducibility for SBP measurement (CCC > 0.84 and >0.91, respectively, in dialyzed and nondialyzed patients). The mean ± SD from SBP as determined via Korotkoff sounds was 1.7 ± 4.6 mm Hg for SFATI (CCC = 0.98) and 5.9 ± 9.3 mm Hg for oscillometry (CCC = 0.88). Referring to the 110–130-mm Hg SBP range outside which treatment prescription or adaptation is recommended for CKD patients, SFATI underestimated SBP in 3 patients and overestimated it in 1, whereas oscillometry underestimated SBP in 12 patients and overestimated it in 3. Higher pulse pressure was the main explanatory factor for measurement and classification errors. Discussion/Conclusion: SFATI provides accurate SBP measurements in patients with severe CKD and paves the way for the standardization of automated noninvasive blood pressure measurement devices. Before prescribing or adjusting antihypertensive therapy, physicians should be aware of the risk of misclassification when using oscillometry.

Measurement of noninvasive blood pressure during general anesthesia in lateral decubitus position

Measurement of noninvasive blood pressure during general anesthesia in lateral decubitus position

Accuracy and precision of oscillometric noninvasive blood pressure measurement in critically ill patients: systematic review and meta-analysis.

Mean arterial pressure (MAP) is akey haemodynamic variable monitored in critically ill patients. The advantages of oscillometric noninvasive blood pressure (NIBP) measurement are its easy and fast methodology; however, the accuracy and the precision of this measurement in critically ill patients is constantly debated. We performed asystematic review and meta-analysis of observational studies comparing oscillometric NIBP methods with invasive arterial pressure (IAP) measurements. We included studies of adult critically ill patients, which evaluated MAP in the same patient by both NIBP and IAP at any site. We included only studies comparing simultaneous measurements of arterial pressure by NIBP and IAP, reporting their results using mean difference and SD of agreement. The main outcome was to define the bias of the MAP measured by NIBP over the IAP measurement. The quality of the studies was analysed by the QUADAS 2 tool. Seven studies and 1593 patients were included in the main analysis. The oscillometric NIBP method had amean value of -1.50 mmHg when compared with IAP (95% CI: -3.34 to 0.35; I2 = 96% for random effects model, P < 0.01). The limits of agreement for MAP varied between -14.6 mmHg and +40.3 mmHg. NIBP had an adequate accuracy regarding MAP measurements by oscillometry. Limits of agreement may thus narrow the clinical applicability in scenarios in which there is aneed for amore precise management of blood pressure.