Measurement Of Arterial Pressure Research Articles

Feasibility and Accuracy of Noninvasive Continuous Arterial Pressure Monitoring during Transcatheter Atrial Fibrillation Ablation

Transcatheter atrial fibrillation (AF) ablation is still carried out with continuous invasive radial arterial blood pressure (IBP) monitoring in many centers. Continuous noninvasive blood pressure (CNBP) measurement using the volume-clamp method is a noninvasive alternative method used in ICU. No data on CNBP reliability are available in the electrophysiology lab during AF ablation, where rhythm variations are common. The objective of the present study was to compare continuous noninvasive arterial pressure measured with the ClearSight device (Edwards Lifesciences, Irvine, CA, USA) with invasive radial artery pressure used as the reference method during AF ablation. We prospectively enrolled 55 consecutive patients (age 62 ± 11 years, 80% male) undergoing transcatheter AF ablation (62% paroxysmal, 38% persistent) at our center. Standard of care IBP monitoring via a radial cannula and a contralateral noninvasive finger volume-clamp CNBP measurement device were positioned simultaneously in all patients for the entire procedure. Bland-Altman analysis was used to analyze the agreement between the two techniques. A total of 1219 paired measurements for systolic, diastolic, and mean arterial pressure were obtained in 55 subjects, with a mean (SD) of 22 (9) measurements per patient. The mean bias (SD) was -12.97 (13.89) mmHg for systolic pressure (level of agreement -14.24-40.20; correlation coefficient 0.84), -1.85 (8.52) mmHg for diastolic pressure (level of agreement -18.54-14.84; correlation coefficient 0.77) and 2.31 (8.75) mmHg for mean pressure (level of agreement -14.84-19.46; correlation coefficient 0.85). In patients undergoing AF ablation, CNBP monitoring with the ClearSight device showed acceptable agreement with IBP monitoring. Larger studies are needed to confirm the potential clinical implications of continuous noninvasive BP monitoring during AF ablation.

Discussion on the zero-calibration and the zero line in the measurement of central venous pressure and invasive arterial blood pressure

To figure out the timing of zeroing and the location of the zero line in the central venous pressure (CVP) monitoring and invasive arterial blood pressure (IBP) monitoring, and to provide scientific and accurate data for patients management. The liquid vessel models were used to simulate the pressure measurement process of the continuous pressure monitoring system. Based on the theory of fluid mechanics and the knowledge of blood pressure physiology and cardiovascular anatomy, the composition and influencing factors of the pressure in the fluid-filled catheter system during the zeroing and placing the transducer in the zero line of CVP and IBP, were analyzed. The pressure in the liquid-filled catheter system was composed of atmospheric pressure, the pressure of pumping bag, the gravity of the water column (the vertical distance between the liquid level of Murphy's dropper and pressure transducer, ΔH), and the resistance of tube wall. This pressure value is set as a pressure of 0 mmHg (1 mmHg ≈ 0.133 kPa). In the process of pressure measurement, when the pressure transducer was placed at a horizontal position of 10 cm below the highest liquid level of the vessel, the pressure measured at different catheter tip positions was all 10 cmH2O (1 cmH2O ≈ 0.098 kPa); When the pressure transducer was placed at the horizontal position of the highest liquid level of the vessel, the measured pressure is 0 mmHg. Zeroing should repeatedly be performed only when one or more conditions (atmospheric pressure, pressure of pumping bag, gravity of ΔH water column and resistance of tube wall) are changed. In the measurement process, the pressure transducer should be placed at the zero line position at any time to eliminate the influence of hydrostatic pressure and to ensure the objective and accurate value.

Uretero-pelvic junction obstruction in children: Is vascular hitch an effective and safe solutions in very long term outcome? Report of 25 years follow-up

Vascular (VH) according to Hellstrom-Chapman technique is considered a safe and effective alternative approach to pure extrinsic Ureteropelvic Junction Obstruction (UPJO) with good results in short and medium term, but few data are available on long and verylong term outcomes. Our aim is to evaluate VH long and very-long term outcomes in patients treated in pediatric age focusing on relapse, development of hypertension and/or inferior polar kidney hypotrophy during puberty and adulthood. From 1990 to 2015 in our Department 76 children were treated by open or laparoscopic VH for pure extrinsic-UPJO. We were able to contact 54 of 76. 41 patients (25 males, 16 females) accepted to be studied. Mean follow- up time was 12.7 years (range 6-27 years); mean age at the assessment was 22.2 years. We excluded patients who were younger than 13 (if females) or 14 (if males) at the assessment (upper limits of physiological puberty onset). Patients were followed with US, MAG-3-scan and arterial blood pressure measurement. Collected data were compared with the preoperative ones by Student t-test. 95% of US images and MAG-3-scan reports were compatible with complete resolution of obstruction with good renal functionality. 87% of patients were completely healthy. We recorded 3 cases of hypertension (7%) not secondary to renovascular origin; 2 cases with recurrent flank pain (5%) with slightly dilated pelvis at the US and sub-obstructive pattern at MAG-3-scan with preserved renal function. Our experience confirms that VH, (open/laparoscopic) is a safe and effective procedure with good outcomes at very longterm follow-up. No patients at puberty and in adulthood required reoperation or presented polar hypotrophy and related vascular hypertension. VH is an alternative approach to pure extrinsic-UPJO. There were few data about long and very-long term outcomes in patients after this kind of surgery. We followed-up 41 patients confirming that VH (open/laparoscopic) is safe and effective with good long-term outcomes.

The effect of successful lower extremity revascularization on aortic stiffness in patients with peripheral arterial disease.

Peripheral arterial disease (PAD) is a global health problem and associated with poor outcomes. It causes increased arterial stiffness. The association of PAD with aortic arterial stiffness was investigated in previous studies. However, there is limited data regarding the effect of peripheral revascularization on arterial stiffness. The aim of our study is to investigate the effect of peripheral revascularization on aortic stiffness parameters in patients with symptomatic PAD. A total of 48 patients with PAD who underwent peripheral revascularization were included in the study. Echocardiography was performed before and after the procedure, and aortic stiffness parameters were obtained by using aortic diameters and arterial blood pressure measurements. Post-procedural aortic strain (5.1 [1.3-14] vs. 6.3 [2.8-6.3], p = 0.009) and aortic distensibility (0.2 [0.0-0.9] vs. 0.3 [0.1-1.1], p = 0.001) measurements were significantly increased compared to pre-procedural values. Patients were also compared according to the lesion laterality, site and treatment methods. It was found that the change in aortic strain (p = 0.031) and distensibility (p = 0.043) were significantly higher in unilateral lesion compared to bilateral lesion. Also, the change in aortic strain (p = 0.042) and distensibility (p = 0.033) were significantly higher in iliac site lesion compared to superficial femoral artery (SFA) site lesion. Moreover, the change in aortic strain was significantly higher (p = 0.013) in patients treated with stent compared to only balloon angioplasty. Our study showed that successful percutaneous revascularization significantly reduced aortic stiffness in PAD. The change in aortic stiffness was significantly higher in unilateral lesions, iliac site lesions and stent-treated lesions.

Effect on Pulmonary Atery Presssres after Transcatheter Occlusion of Patent Ductus Arteriosus with Severe Pulmonary Artery Hypertension

Objective: The purpose of this study was to ascertain how the patent ductus arteriosus will respond to trans catheter closure on the pulmonary artery pressure. Methods: All patients having clinical and echocardiographic evidence of hemodynamically significant isolated PDA and patients with PASP > 20 mmHg will be labelled as PDA with PAH, while patients with mean PASP > 60 mmHg will be labelled as PDA with severe PAH. These patients were all included in the research. Both pulmonary artery pressure measurements and echocardiography were done. Once the patient has been assessed, the viability of a transcatheter closure PDA has been confirmed. Results: The Mean age of the patients were 10.6±8.18 years. Out 40 participants 35% were males and 65% were females. A significant variation (p=0.003) in MPA pressure was observed in patients after balloon occlusion. A significant variation in RV higher (0.007) and lower (0.003) pressure was observed in patients after balloon occlusion. A significant variation (p=0.005) in LV Higher pressure was observed in patients after balloon occlusion. A significant variation (p=0.003) in higher Aorta pressure was observed in patients after balloon occlusion. Conclusion: After PDA closure, some individuals with borderline hemodynamic data with PDA and PAH may get worse or continue to have PAH. Care must be taken while providing these individuals with permanent closure.

Kidney dysfunction: prevalence and associated risk factors in a community-based study from the North West Province of South Africa

BackgroundGlobally, the World Health Organization ranks chronic kidney disease (CKD) as one of the top 10 causes of mortality. In South Africa, where noncommunicable diseases have become leading causes of mortality, the true population prevalence of CKD is unknown and associated risk factors remain understudied. This study aimed to describe the prevalence of kidney dysfunction and associated risk factors in a community from the North West province of South Africa.MethodsThis cross-sectional study included 1999 participants older than 30 years. Kidney dysfunction was defined as (i) estimated glomerular filtration rate (eGFR) < 90 ml/min/1.73m2, or (ii) urine albuminuria-to-creatinine ratio (uACR) ≥ 3.0 mg/mmol, or a combination (i and ii). Risk factors included age, sex, urban/rural locality, body mass index (BMI), blood pressure (BP), lipid profile, haemoglobin A1c (HbA1C), C-reactive protein (CRP), gamma-glutamyl transferase (GGT), tobacco use, and HIV status.ResultsMean age of participants was 48 (42;56) years, and 655/1999 (33%) had eGFR < 90 ml/min/1.73m2 and/or uACR ≥ 3.0 mg/mmol. Compared to those with normal kidney function, participants with eGFR < 90 ml/min/1.73m2 and/or uACR ≥ 3.0 mg/mmol were older, female, had higher measures of adiposity, systolic, diastolic, and mean arterial blood pressure, serum lipids and C-reactive protein (CRP) (all p ≤ 0.024). In multiple regression analyses eGFR was associated with systolic BP (β = 0.11) and HIV infection (β = -0.09), and albuminuria was associated with elevated CRP (β = 0.12) and HIV infection (β = 0.11) (all p < 0.026). In both groups (individuals with and without kidney dysfunction respectively), eGFR was associated with age (β = -0.29, β = -0.49), male sex (β = 0.35, β = 0.28), BMI (β = -0.12, β = -0.09), low-density/high-density lipoprotein cholesterol ratio (β = -0.17, β = -0.09) and CRP (β = 0.10, β = 0.09) (all p < 0.005); and uACR was associated with female sex (β = 0.10, β = -0.14), urban locality (β = -0.11, β = -0.08), BMI (β = -0.11, β-0.11), and systolic BP (β = 0.27, β = 0.14) (all p < 0.017).ConclusionIn this study from the North West province, South Africa, eGFR < 90 ml/min/1.73m2 and/or uACR ≥ 3.0 mg/mmol was prevalent and associated with modifiable risk factors. The findings may inform screening strategies for kidney disease prevention, focusing on women, obesity, blood pressure control, dyslipidaemia, identifying and treating inflammation, and HIV diagnosis and treatment.

Thyroid hormone disorder and the heart: The role of cardiolipin in calcium handling.

What is the central question of this study? Do alterations in thyroid status affect haemodynamic parameters and echocardiographic measurements in the rat postnatal heart, and calcium handling, contractility, relaxation and cardiolipin content in isolated rat cardiomyocytes? What is the main finding and its importance? An imbalance in phospholipids of the mitochondrial membrane such as cardiolipin is related to defects in mitochondrial function. T3 -dependent cardiolipin signals contribute to the maintenance of mitochondrial homeostasis and involve Ca2+ handling, this pathway being more important in hypothyroidism. The objective of this study was to evaluate whether alterations in thyroid status affect (1) haemodynamic parameters and echocardiographic measurements in the rat postnatal heart, and (2) calcium handling, contractility, relaxation and cardiolipin content in isolated rat cardiomyocytes. Sprague-Dawley rats aged 2months treated with T3 (hyperthyroid, 20μg/100g body weight) or 0.02% methimazole (hypothyroid, w/v) for 28 days. Heart function was evaluated by echocardiography. Measurements of mean arterial pressure (MAP), heart rate, Ca2+ transients, cardiomyocyte shortening, number of spontaneous contractions per minute and cardiolipin (CL) content were performed. Thyroid disorders were associated with changes in pacemaker activity without modifications of MAP. Thyroid disorder induced changes in left ventricular diameter which were correlated with modifications of cardiac contractility (altered cell shortening and sarcoplasmic reticulum Ca2+ content). Endocrine disorders altered cardiomyocyte relaxation (reduction in the time to 50% re-lengthening and the time to 50% Ca2+ decay). Thyroid disorder increased the number of spontaneous contractions per minute (an index of pro-arrhythmogenic behaviour). CL content was increased only in hypothyroid rats. Changes in CL content, CL composition and CL-protein interaction in mitochondria from hypothyroid animals are responsible for alterations of contractile and relaxation cardiac function. This mechanism may be not be involved in T3 -treated rats. Maintenance of euthyroidism is of crucial importance to preserve cardiac performance. An imbalance in relation to phospholipids of the mitochondrial membrane such as CL is related to defects in mitochondrial function. T3 -dependent CL signals contribute to the maintenance of mitochondrial homeostasis and involve Ca2+ handling, this pathway being more important in hypothyroidism.

Catheterization of Pulmonary and Carotid Arteries for Concurrent Measurement of Mean Pulmonary and Systemic Arterial Pressure in Rat Models of Pulmonary Arterial Hypertension.

Pulmonary hypertension (PH) is a group of pulmonary vascular disorders in which mean pulmonary arterial pressure (mPAP) becomes abnormally high because of various pathological conditions, including remodeling of the pulmonary arteries, lung and heart disorders, or congenital conditions. Various animal models, including mouse and rat models, have been used to recapitulate elevated mPAP observed in PH patients. However, the measurement and recording of mPAP and mean systemic arterial pressure (mSAP) in small animals require microsurgical procedures and a sophisticated data acquisition system. In this paper, we describe the surgical procedures for right heart catheterizations (RHC) to measure mPAP in rats. We also explain the catheterization of the carotid artery for simultaneous measurement of mPAP and mSAP using the PowerLab Data Acquisition system. We enumerate the surgical steps involved in exposing the jugular vein and the carotid artery for catheterizing these two blood vessels. We list the tools used for microsurgery in rats, describe the methods for preparing catheters, and illustrate the process for inserting the catheters in the pulmonary and carotid arteries. Finally, we delineate the steps involved in the calibration and setup of the PowerLab system for recording both mPAP and mSAP. This is the first protocol wherein we meticulously explain the surgical procedures for RHC in rats and the recording of mPAP and mSAP. We believe this protocol will be essential for PH research. Investigators with little training in animal handling can reproduce this microsurgical procedure for RHC in rats and measure mPAP and mSAP in rat models of PH. Further, this protocol is likely to help master RHC in rats that are performed for other conditions, such as heart failure, congenital heart disease, heart valve disorders, and heart transplantation.

Efficacy of the intracamerally administered mydriatics for cataract surgery in patients with primary open-angle glaucoma.

To compare Mydrane®, mydriatic eye drops, and Mydriasert® in terms of pupil site stability, surgical time, visual field, and anterior chamber configuration modifications among patients with primary open-angle glaucoma (POAG) during cataract extraction surgery. Retrospective analysis of sixty patients with POAG and cataract who underwent elective cataract extraction. All patients underwent routine ophthalmic examinations, including automatic visual field examination, anterior chamber configuration, specular microscopy, and arterial blood pressure measurement prior to surgery, and 24 h and 30 days postoperatively. All cataract surgeries were video-recorded and all measurements were performed using a media player. Patients divided into groups 1, 2, and 3 (n = 20 in each group) received topical mydriatic eye drops, Mydriasert®, and an intracameral injection of Mydrane®, respectively, immediately after the first incision. The mean change in pupil size from just before capsulorhexis to the end of surgery was 0.43 ± 0.09, 0.42 ± 0.08, and 0.36 ± 0.02 mm in groups 1, 2, and 3, respectively. The mean surgery duration was similar among all the groups. The baseline main cell density slightly decreased at 24 h and remained stable for 30 days postoperatively. The mean deviation and pattern standard deviation remained stable at 1 month after surgery. At 24 h after surgery, the nasal irido-corneal angle, temporal-iridocorneal angle, and anterior chamber depth increased compared with the baseline, remaining stable for 30 days after surgery. Mydrane® produced adequate and stable mydriasis as effectively as produced by Mydriasert® and topical eye drops.

The impact of nitroglycerine and volume on gastric tube microperfusion assessed by indocyanine green fluorescence imaging

The influence of hypervolemia and intraoperative administration of nitroglycerine on gastric tube microperfusion remains unclear The present study aimed to investigate the impact of different hemodynamic settings on gastric tube microperfusion quantified by fluorescence imaging with Indocyanine green (ICG-FI) as a promising tool for perfusion evaluation. Three groups with seven pigs each were formed using noradrenaline, nitroglycerin, and hypervolemia for hemodynamic management, respectively. ICG-FI, hemodynamic parameters, and transit-time flow measurement (TTFM) in the right gastroepiploic artery were continuously assessed. Fluorescent microspheres (FM) were administered, and the partial pressure of tissue oxygen was quantified. The administration of nitroglycerine and hypervolemia were both associated with significantly impaired microperfusion compared to the noradrenaline group quantified by ICG-FI. Even the most minor differences in microperfusion could be sufficiently predicted which, however, could not be represented by the mean arterial pressure measurement. Histopathological findings supported these results with a higher degree of epithelial damage in areas with impaired perfusion. The values measured by ICG-FI significantly correlated with the FM measurement. Using tissue oxygenation and TTFM for perfusion measurement, changes in microperfusion could not be comprehended. Our results support current clinical practice with restrictive volume and catecholamine administration in major surgery. Hypervolemia and continuous administration of nitroglycerine should be avoided.

Effectiveness of the First Trimester Samrakshan Protocol for the Identification of Pregnant Women at High Risk for Preterm Pre-eclampsia.

Aim To determine the effectiveness of the first trimester Samrakshan protocol for the identification of pregnant women at high risk for preterm pre-eclampsia (PE). Methods Samrakshan uses a protocol that integrates routine first-trimester ultrasound assessment at 11 to 14 gestation weeks with the measurement of mean arterial blood pressure and mean uterine artery pulsatility index assessment to determine a customized risk for preterm PE and fetal growth restriction. Based on the risk assessment, pregnant women are classified as high or low risk. Results The protocol had a high specificity (90.4%, 95% CI: 89.4%, 91.2%) and negative predictive value (98.1%, 95% CI: 97.6%, 99%) for preterm PE. The odds ratio and positive likelihood ratio for preterm PE were 16.7 (95% CI: 12.3, 22.6) and 6.64 (95% CI: 5.77, 7.63), respectively. Conclusions The positive likelihood ratio and odds ratios indicate that pregnant women identified as high risk for preterm PE using the first-trimester protocol of Samrakshan are significantly more likely to develop preterm PE than low-risk women.

Arterial site selection for measurement of mean arterial pressure in septic shock patients on high-dose norepinephrine.

The guidelines of the Surviving Sepsis Campaign suggest using invasive blood pressure (IBP) measurement in septic shock patients, without specifying for a preferred arterial site for accuracy in relation to the severity of septic shock. The objective of this study was to determine the mean arterial pressure (MAP) gradient between the femoral and radial artery sites in septic shock patients. This prospective study was carried out at a 20-bed ICU in a university hospital. Simultaneous MAP measurements at femoral and radial arterial sites were obtained in septic shock patients receiving norepinephrine (≥0.1 μg/kg/min), with a pre-planned subgroup analysis for those receiving a high dose of norepinephrine (≥0.3 μg/kg/min). The median norepinephrine dose across all 80 patients studied, including 59 patients on a high dose, was 0.4 (0.28-0.7) μg/kg/min. Overall, simultaneous measurement of MAP (mmHg) at the femoral and radial arterial sites produced mean (95% CI) MAP values of 81 (79-83) and 78 (76-80), respectively, with a mean difference of 3.3 (2.67-3.93), p < 0.001. In Bland-Altman analysis of MAP measurements, the detected effect sizes were 1.14 and 1.04 for the overall and high-dose cohorts, respectively, which indicates a significant difference between the measurements taken at each of the two arterial sites. The Pearson correlation coefficient indicated a weak but statistically significant correlation between MAP gradient and norepinephrine dose among patients receiving a high dose of norepinephrine (r = 0.289; p = 0.026; 95% CI 0.036-0.508). In septic shock patients, MAP readings were higher at the femoral site than at the radial site, particularly in those receiving a high dose of norepinephrine. [ClinicalTrials.gov], identifier [NCT03475667].

First-trimester preterm preeclampsia prediction with metabolite biomarkers: differential prediction according to maternal body mass index

Prediction of preeclampsia risk is key to informing effective maternal care. Current screening for preeclampsia at 11 to 13 weeks of gestation using maternal demographic characteristics and medical history with measurements of mean arterial pressure, uterine artery pulsatility index, and serum placental growth factor can identify approximately 75% of women who develop preterm preeclampsia with delivery at <37 weeks of gestation. Further improvements to preeclampsia screening tests will likely require integrating additional biomarkers. Recent research suggests the existence of distinct maternal risk profiles. Therefore, biomarker evaluation should account for the possibility that a biomarker only predicts preeclampsia in a specific maternal phenotype. This study aimed to verify metabolite biomarkers as preterm preeclampsia predictors early in pregnancy in all women and across body mass index groups. Observational case-control study drawn from a large prospective study on the early prediction of pregnancy complications in women attending their routine first hospital visit at King's College Hospital, London, United Kingdom, in 2010 to 2015. Pregnant women underwent a complete first-trimester assessment, including the collection of blood samples for biobanking. In 11- to 13-week plasma samples of 2501 singleton pregnancies, the levels of preselected metabolites implicated in the prediction of pregnancy complications were analyzed using a targeted liquid chromatography-mass spectrometry method, yielding high-quality quantification data on 50 metabolites. The ratios of amino acid levels involved in arginine biosynthesis and nitric oxide synthase pathways were added to the list of biomarkers. Placental growth factor and pregnancy-associated plasma protein A were also available for all study subjects, serving as comparator risk predictors. Data on 1635 control and 106 pregnancies complicated by preterm preeclampsia were considered for this analysis, normalized using multiples of medians. Prediction analyses were performed across the following patient strata: all subjects and the body mass index classes of <25, 25 to <30, and ≥30 kg/m2. Adjusted median levels were compared between cases and controls and between each body mass index class group. Odds ratios and 95% confidence intervals were calculated at the mean ±1 standard deviation to gauge clinical prediction merits. The levels of 13 metabolites were associated with preterm preeclampsia in the entire study population (P<.05) with particularly significant (P<.01) associations found for 6 of them, namely, 2-hydroxy-(2/3)-methylbutyric acid, 25-hydroxyvitamin D3, 2-hydroxybutyric acid, alanine, dodecanoylcarnitine, and 1-(1Z-octadecenyl)-2-oleoyl-sn-glycero-3-phosphocholine. Fold changes in 7 amino acid ratios, all involving glutamine or ornithine, were also significantly different between cases and controls (P<.01). The predictive performance of some metabolites and ratios differed according to body mass index classification; for example, ornithine (P<.001) and several ornithine-related ratios (P<.0001 to P<.01) were only strongly associated with preterm preeclampsia in the body mass index of <25 kg/m2 group, whereas dodecanoylcarnitine and 3 glutamine ratios were particularly predictive in the body mass index of ≥30 kg/m2 group (P<.01). Single metabolites and ratios of amino acids related to arginine bioavailability and nitric oxide synthase pathways were associated with preterm preeclampsia risk at 11 to 13 weeks of gestation. Differential prediction was observed according to body mass index classes, supporting the existence of distinct maternal risk profiles. Future studies in preeclampsia prediction should account for the possibility of different maternal risk profiles to improve etiologic and prognostic understanding and, ultimately, clinical utility of screening tests.

Assessing the measurement error of different methods used to calculate Pulse Pressure Variation

Objective: To assess the measurement error of different methods used to calculate Pulse Pressure Variation. Background: Many studies have demonstrated the use of pulse pressure variation (PPV) as a predictor of fluid responsiveness as long as the limitations to its use are understood and respected. These limitations have proven a constraint in the use of PPV and various researchers have published methods of overcoming these constraints in daily practice. Different methods also exist to calculate PPV. This study aims to systematically calculate the measurement error of the different methods used to calculate PPV and compare them. Methods: After approval of the institutional trial board and ethics committee of Ghent University Hospital, Ghent, Belgium, and registration with the local code number B670201629642 (intern:EC/2016/1113), postoperative measurements of invasive arterial pressure and ECG were simultaneously recorded over 1 minute between 29/11/2016 to 16/11/2018. Data was then analyzed using different methods, namely (i) individual PPV averaged over fixed number of respiratory cycles (iPPV family), (ii) pooled PPV over fixed number of respiratory cycles (pPPV family) and (iii) methods over fixed window in terms of time (Aboy and Lansdorp).The Taffe extension of the Bland Altman method was used to compare and determine the measurement error of these four different methods. IPPV1 was chosen as the common reference. Differential en proportional bias and precision are reported as the intercept and the slope respectively of the models studied. Results: Data from 27 subjects were collected. The iPPV showed minimal bias and improved precision. pPPV showed increasing bias (0.879 - 1.999) with the increase in the respiratory cycles as well as precision (0.633-1.08). The Aboy algorithm model showed reduction in bias (-0.473 - -0.139) and precision (0.235-0.146) by the larger fixed windows. Bias increases from the smaller windows to the larger windows in the Lansdorp method. Precision improves over the same range. Conclusions: Every method has its own measurement error. There is a proportionality in the measurement error in the methods we compared for calculating PPV. The bias is variable by each method we studied.

Effects of intrarenal angiotensin 1-7 infusion on renal haemodynamic and excretory function in anaesthetised two-kidney one-clip and deoxycorticosterone acetate-salt hypertensive rats.

What is the central question of this study? Are renal functional responses to intrarenal angiotensin 1-7 (Ang (1-7)) infusion dependent on the level of the endogenous renin-angiotensin system (RAS) in the two-kidney one-clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt animal models of hypertension? What is the main finding and its importance? The renal actions of Ang (1-7) are dependent on the relative endogenous levels of each arm of the classical angiotensin II-angiotensin II type 1 receptor (AT1 R) axis and those of the Ang (1-7)-Mas receptor axis. These findings support the hypothesis that a balance exists between the intrarenal classical and novel arms of the RAS, and in particular the relative abundance of AT1 R to Mas receptor, which may to a large extent determine the renal excretory response to Ang (1-7) infusion. This study investigated the action of angiotensin 1-7 (Ang (1-7)) on renal haemodynamic and excretory function in the two-kidney one-clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt rat models of hypertension, in which the endogenous renin-angiotensin system (RAS) activity was likely to be raised or lowered, respectively. Rats were anaesthetised and prepared for the measurement of mean arterial pressure and kidney function during renal interstitial infusion of Ang (1-7) or saline. Kidney tissue concentrations of angiotensin II (Ang II) and Ang (1-7) were determined. Intrarenal infusion of Ang (1-7) into the clipped kidney of 2K1C rats increased urine flow (UV), absolute (UNa V) and fractional sodium (FENa ) excretions by 110%, 214% and 147%, respectively. Renal Ang II concentrations of the clipped kidney were increased with no major changes in Ang (1-7) concentration. By contrast, Ang (1-7) infusion decreased UV, UNa V, and FENa by 27%, 24% and 21%, respectively in the non-clipped kidney in which tissue Ang (1-7) concentrations were increased, but renal Ang II concentrations were unchanged compared to sham animals. Ang (1-7) infusion in DOCA-salt rats had minimal effects on glomerular filtration rate but significantly decreased UV, UNa V and FENa by ∼30%. Renal Ang (1-7) concentrations were higher and Ang II concentrations were lower in DOCA-salt rats compared to sham rats. These findings demonstrate that the intrarenal infusion of exogenous Ang (1-7) elicits different renal excretory responses the magnitude of which is dependent on the balance between the endogenous renal Ang II-AT1 receptor axis and Ang (1-7)-Mas receptor axis.

Perioperative Validation of the TensorTip™ MTX Device for Noninvasive Arterial Pressure Measurement: A Method Comparison Study.

The noninvasive TensorTip™ MTX measures blood pressure by interpreting blood diffusion color of the finger skin. In addition to blood pressure, the device is able to measure various vital signs: heart rate, oxygen saturation, stroke volume, and cardiac output. Studies about accuracy and precision thus far available have only been conducted by the manufacturer. The aim of our study was to investigate the accuracy and precision of the TensorTip MTX in comparison to invasive radial artery blood pressure values. Forty-one patients scheduled for elective surgery were enrolled in this study. Placement of the arterial catheter had to be part of the standard of care. Once hemodynamic stable conditions were achieved, blood pressure was measured. Three measurements with the TensorTip MTX were averaged and compared with one invasive blood pressure measurement using Bland-Altman plot and error grid analysis. Systolic, diastolic, and mean blood pressure had a bias of respectively 6.2, -6.9 and 4.4 mm Hg. Corresponding standard deviation were respectively 30.1, 17.0 and 22.2. Calculated percentage errors were 47.6%, 52.9% and 52.3%. Proportional bias was present in all Bland-Altman analyses. Error grid analysis showed 61.0% of systolic blood pressure measurements, and 46.3% of mean blood pressure measurements were in the clinical acceptable zone. The TensorTip MTX was not able to reliably measure blood pressure compared to blood pressure obtained with an arterial catheter and therefore, the measurement performance is not clinically acceptable. Moreover, a high malfunction rate makes the device unsuitable for use in perioperative period.

The Implementation of Preeclampsia Screening and Prevention (IMPRESS) Study

Preeclampsia affects between 2% and 5% of pregnancies and is one of the leading causes of perinatal morbidity and mortality worldwide. Despite strong evidence that the combination of systematic preeclampsia screening based on the Fetal Medicine Foundation preeclampsia risk calculation algorithm with treatment of high-risk patients with low-dose aspirin reduces the incidence of preterm preeclampsia more than currently used risk-factor-based screening, real-world implementation studies have not yet been done in Canada. This study aimed to assess the operational feasibility of implementing first-trimester screening and prevention of preterm preeclampsia (<37 weeks) alongside a publicly funded first-trimester combined screening program for aneuploidies. This was a prospective implementation study. Consecutive pregnant patients referred for first-trimester combined screening (11-13+6 weeks) were offered screening for preeclampsia based on the Fetal Medicine Foundation algorithm concomitantly with their aneuploidy screen. Consenting participants were screened using maternal risk factors, mean arterial pressure, uterine artery Doppler pulsatility index, pregnancy-associated plasma protein-A, and placental growth factor. Risk for preterm preeclampsia (<37 weeks) was calculated using the Fetal Medicine Foundation algorithm, and individuals with a risk score ≥1 per 100 were recommended to use aspirin (162 mg once daily at bedtime, <16-36 weeks). Implementation metrics assessed included: acceptability, operational impact, proportion of aspirin initiation, quality and safety measures, and screen performance. Between December 1, 2020 and April 23, 2021, 1124 patients consented to preeclampsia screening (98.3% uptake), and 92 (8.2%) screened positive. Appointments for patients receiving first-trimester combined screening aneuploidy and preeclampsia screening averaged 6 minutes longer than first-trimester combined screening alone, and adding uterine artery Doppler pulsatility index averaged 2 minutes. Of the 92 patients who screened as high-risk for preeclampsia, 72 (78.3%) were successfully contacted before 16 weeks' gestation. Of these, 62 (86.1%) initiated aspirin, and 10 (13.9%) did not. Performance audit identified a consistent negative bias with mean arterial pressure measurements (median multiple of the median <1 in 10%); other variables were satisfactory. There were 7 cases of preterm preeclampsia (0.69%): 5 and 2 in the high- and low-risk groups, respectively. Screening detected 5 of 7 (71.4 %) preterm preeclampsia cases, with improved performance after adjustment for aspirin treatment effect. This study confirms the operational feasibility of implementing an evidence-based preeclampsia screening and prevention program in a publicly funded Canadian setting. This will facilitate implementation into clinical service and the scaling up of this program at a regional and provincial level.

Abstract 187: Synergy Of Elevation Of The Head And Thorax And Resuscitative Endovascular Balloon Occlusion Of The Aorta In A Porcine Model Of Prolonged Cardiac Arrest: A Pilot Study

Background: Two new approaches to improve cardiac arrest outcomes, active compression-decompression (ACD) with an impedance threshold device (ITD) CPR with automated Head Up Positioning, (AHUP-CPR), and resuscitative endovascular balloon occlusion (REBOA) have been studied separately but never together. This was a pilot animal study exploring potential hemodynamic synergy of AHUP+ REBOA after prolonged CPR. Methods: Farm pigs (~40 kg) were sedated, intubated, and anesthetized. Central venous, and intracranial pressures were measured. Bilateral femoral arterial access was obtained for arterial pressure measurement and REBOA placement in the proximal thoracic aorta. Hemodynamics were measured with solid state pressure catheters. The arterial pressure catheter was placed in the thoracic aorta and confirmed via fluoroscopy. After 35 minutes of AHUP CPR, animals underwent two-minute epochs of AHUP-CPR, AHUP+REBOA CPR, ACD+ITD CPR flat + REBOA, and ACD+ITD CPR flat. Pressures are reported as mean (mmHg) ± standard deviation. Comparison testing was not performed in this pilot study. Results: In 4 pigs after 35 minutes, the AHUP CPR cerebral perfusion pressure (CerPP) was 21.1 ± 10.4, aortic compression (AOC) and decompression (AOD) pressures were 43.4 ± 9.1 and 14.1 ± 9.4, and intracranial compression (ICP) and decompression (DIP) pressures were 9.2 ± 2.7 and 6.5 ± 3.6, respectively. With AHUP+REBOA, CerPP was 39.0 ± 8.7, AOC and AOD pressures were 69.2 ± 10.7 and 21.0 ± 8.9, and ICP and DIP 9.7 ± 2.6 and 5.8 ± 2.9. The ACD+ITD CPR flat + REBOA CerPP was 21.7 ± 11.8, AOC and AOD pressures were 57.1 ± 9.5, and ICP and DIP were 20.5 ± 4.1 and 15.9 ± 3.2. The ACD+ITD CPR flat CerPP was 11.2 ± 7.5, AOC and AOD pressures were 38.8 ± 6.7 and 15.9 ± 6.6, and ICP and DIB were 17.4 ± 1.1 and 15.0 ± 1.6. A representative study tracing is shown. Conclusions: The combination of AHUP CPR with REBOA is feasible and may work synergistically after prolonged resuscitation in this ongoing animal study.

Impact of Rapid Weight Loss after Bariatric Surgery in Systemic Inflammatory Response and Pulmonary Hemodynamics in Severely Obese Subjects with Pulmonary Hypertension.

Pulmonary hypertension (PH) can be associated with obesity. The excessive production of proinflammatory mediators by dysfunctional adipocytes may enhance remodeling of the pulmonary vasculature and worsen pulmonary hemodynamics. This study aimed to describe the changes in pulmonary arterial pressures and systemic inflammation in patients with obesity with PH after bariatric surgery (BaS). In this retrospective cohort study, we compared patients with PH who underwent BaS from 2008 to 2018 at our institution (group 1) to a group of severely obese patients with PH (group 2). Echocardiographic right ventricular systolic pressure (RVSP) was used as an indirect measurement of pulmonary arterial pressures. Red blood cell distribution width (RDW) was used as a marker of systemic inflammation. A total of 40 patients were included, 20 per group. In group 1, the RVSP decreased from 44.69 ± 7.12 mmHg to 38.73 ± 12.81 mmHg (p = 0.041), and the RDW decreased from 15.22 ± 1.53 to 14.41 ± 1.31 (p = 0.020). In group 2, the RVSP decreased from 60.14 ± 18.08 to 59.15 ± 19.10 (0.828), and the RDW increased from 15.37 ± 1.99 to 15.38 ± 1.26 (0.983). For both groups, we found a positive correlation between RVSP and RDW changes, although the correlation was not statistically significant. Previous studies suggest BaS could be a safe and effective procedure to achieve weight loss in obese patients with PH, with an additional modest improvement in pulmonary hemodynamics. The results of this study reinforce this observation and suggest that such improvement could be related to a decrease in systemic inflammation. Further prospective studies with bigger samples are needed to better understand these findings.

ODP238 RELATIONSHIP BETWEEN BODY COMPOSITION, POST PRANDIAL GLUCOSE AND INSULIN FOR EARLY PREDICTION OF TYPE 2 DIABETES AND CARDIOVASCULAR RISK.

Abstract Different studies report that visceral fat percentage, visceral adiposity index (VAI) and body mass index (BMI) are considered markers of dysfunction and adipose tissue distribution, which are considered early detection tools and indirect expression of cardio metabolic risk; however it is also reported that post prandial glucose and insulin are abnormalities that detect early type 2 diabetes and cardiovascular risk, due to their toxic effect on the vascular endothelium. The objective of the research was to evaluate the association of body composition, glucose and insulin postprandial for early prediction of diabetes and cardiovascular risk. It is a non-experimental study of cross-sectional design, in a total population of 271 adults between the ages 19 and 65 years, without diabetes, in a non-random sample calculated with 95% confidence level of patients attending outpatient clinics of private and IESS hospitals of Riobamba. Descriptive statistics were performed for all variables. With the variables related to cardio metabolic risk such as age, sex, abdominal circumference, mean arterial pressure, BMI, visceral fat and biochemical measures of HbA1c, fasting glucose, postprandial glucose and insulin, HOMA-IR index, and HDLC, triglycerides, cardio vascular risk index given by the ratio triglycerides/HDLc cholesterol over 3.5. These variables were grouped by a multivariate cluster analysis, kmeans, and two homogeneous groups were obtained, different from each other and different from the others, and then the average cardiovascular risk in each group was calculated. A 9: 1 ratio of women/men was found, for cluster 1 the average age was 49, and in cluster 2 it was 48 years, TAM: 87.5 mmHg, BMI: 27.12, PAB: 109 cm, visceral fat 12.79 and cardiovascular risk 4.78. In group 2 with predominance in cluster 2 the average values of the variables studied were significantly higher with a statistically significant p value for the differences between groups of postprandial glucose and insulin (p less than 0. 05). Conclusions postprandial glucose and insulin are early predictors of cardiovascular risk and diabetes. Key words: postprandial glucose, postprandial insulin, cardiovascular risk, body composition. Presentation: No date and time listed