Invasive Blood Pressure Measurements Research Articles

Characterization and progression of heart failure with preserved ejection fraction in SDT fatty rats

Abstract Background Heart failure with preserved ejection fraction (HFpEF) is a complex clinical phenotype associated with the presence of multiple comorbidities including diabetes, obesity, and metabolic syndrome. A major challenge in the search of new therapies for HFpEF is the development of relevant animal models. The Spontaneously Diabetic Torii (SDT) fatty rat is a well-established type2 diabetic model with multiple diabetes-related comorbidities such as nephropathy, neuropathy, and retinopathy. However, the onset and spontaneous progression of cardiac dysfunction is not yet reported in this model. Purpose To validate the SDT fatty rat as a type2 diabetes related HFpEF model, we assessed the natural evolution, i.e., without any diet or surgical intervention, of cardiac function in SDT fatty at different ages starting at 7-week of age. Methods The cardiovascular phenotyping of male SDT fatty rats was assessed by echocardiography at 7, 12 and 17-week of age and invasive left intraventricular and blood pressure measurements at 17-week of age. Vascular function of isolated thoracic aortas was also evaluated at 17-week of age. Renal function was investigated by measuring the Glomerular Filtration Rate (GFR) and urine parameters at 7, 12 and 17-week of age. A group of Sprague Dawley (SD) rats was included as a negative control. Results Compared to SD rats, echocardiography in SDT fatty showed cardiac remodeling starting at 7 weeks and persistent with age. Systolic function and ejection fraction were preserved, while diastolic function was impaired as early as 7-week of age and worsened with time. E/A was comparable in SDT fatty and SD rats at 7-week of age and then increased with age to reach 1.8±0.1 vs 1.2±0.05 in SD (p<0.001) at 17 weeks, while E’/A’ was already inverted at 7 weeks (0.9± 0.02 vs 1.3±0.03 in SD, p<0.001), and lasted with age which is a sign of relaxation default and suggestive of a restrictive filling pattern. E/E’ was significantly higher at 7-week of age (16.1± 0.9 vs 12.1±0.6 in SD, p<0.01) and further increased at 17 weeks (23.1± 0.8 vs 12.1±0.8 in SD, p<0.001) indicating higher filling pressure. Intraventricular and arterial pressure were also increased (p<0.05). As well, SDT fatty rats showed altered endothelium vasodilating properties. As expected, SDT fatty rats were hyperglycemic and showed renal impairment expressed by higher proteinuria, urine albumin/creatinine ratio, KIM-1 and cystatin-C levels and a hyperfiltration state (80% higher GFR, p<0.05). Conclusions The present data demonstrate that the SDT fatty rats developed diastolic dysfunction characterized by a restrictive profile combining compliance and relaxation impairments as well as higher filling pressure along with hypertension. This type2 diabetic model seems as a very promising model to translate the hypertension/kidney dysfunction and cardiometabolic clinical HFpEF phenogroups and is consequently a relevant model to evaluate drugs targeting HFpEF.

Intraoperative hypotension in children-Measurement and treatment

Intraoperative hypotension is acommon perioperative complication in pediatric anesthesia. Oscillometric blood pressure measurement is therefore an essential part of standard perioperative monitoring in pediatric anesthesia. The optimum measurement site is the upper arm. Attention must be paid to the correct cuff size. Blood pressure should be measured before induction. In children undergoing major surgery or in critically ill children, invasive blood pressure measurement is still the gold standard. Continuous noninvasive measurement methods could be an alternative in the future.Threshold values to define hypotension remain unknown, even in awake children. There are also little data on hypotension thresholds in the perioperative setting. The most reliable measurement parameter for estimating hypotension is the mean arterial pressure. The threshold values for intraoperative hypotension are 40 mm Hg in newborns, 45 mm Hg in infants, 50 mm Hg in young children and 65 mm Hg in adolescents. Treatment should be initiated at adeviation of 10% and intensified at adeviation of 20%.Bolus administration of isotonic balanced crystalloid solutions, vasopressors and/or catecholamines are used as treatment options. Consistent and rapid intervention in the event of hypotension appears to be crucial. So far there is no evidence as to whether this leads to an improvement in outcome parameters.

Comparison of the ClearSight™ finger cuff monitor versus invasive arterial blood pressure measurement in elective cardiac surgery patients: a prospective observational study.

To determine the acceptability of the ClearSight™ system (Edwards Lifesciences Corp., Irvine, CA, USA) for continuous blood pressure monitoring during elective cardiac surgery compared with arterial catheterization. We enrolled 30 patients undergoing elective cardiac surgery in a prospective observational study. Blood pressure measurements were recorded every 10 sec intraoperatively. We determined agreement based on the Association for the Advancement of Medical Instrumentation (AAMI) recommendations. Statistical analysis included fixed bias (difference of measurements between methods), percentage error (accuracy between ClearSight measurement and expected measurement from arterial line), and interchangeability (ability to substitute ClearSight monitor without effecting overall outcome of analysis). We used a paired samples t test to compare the time required for placing each monitor. We found fixed bias in the differences between the ClearSight monitor and invasive arterial blood pressure measurement in systolic blood pressure (SBP; mean difference, 8.7; P < 0.001) and diastolic blood pressure (DBP; mean difference, -2.2; P < 0.001), but not in mean arterial pressure (MAP; mean difference, -0.5; P < 0.001). Bland-Altman plots showed that the means of the limits of agreement were greater than 5mm Hg for SBP, DBP, and MAP. The percentage errors for SBP, DBP, and MAP were lower than the cutoff we calculated from the invasive arterial blood pressure measurements. Average interchangeability rates were 38% for SBP, 50% for DBP, and 50% for MAP. Placement of the ClearSight finger cuff was significantly faster compared with arterial catheterization (mean [standard deviation], 1.7 [0.6] min vs 5.6 [4.1] min; P < 0.001). In this prospective observational study, we did not find the ClearSight system to be an acceptable substitute for invasive arterial blood pressure measurement in elective cardiac surgery patients according to AAMI guidelines. Nevertheless, based on statistical standards, there is evidence to suggest otherwise. ClinicalTrials.gov ( NCT05825937 ); first submitted 11 April 2023.

Independent Factors Influencing Changes in Baroreceptor Sensitivity after Carotid Endarterectomy

ObjectiveCarotid endarterectomy (CEA) is a well-established standard therapy for patients with symptomatic or asymptomatic high-grade carotid stenosis. The aim of carotid endarterectomy is to decrease the risk of stroke and avoid relevant functional loss. However, carotid endarterectomy is known to be associated with haemodynamic dysregulation. In this study we compared eversion CEA (E-CEA) and conventional CEA (C-CEA) regarding postoperative blood pressure values as well as preoperative and postoperative baroreceptor sensitivity in the first 7 days after surgery. The aim was to find possible factors influencing changes in baroreceptor sensitivity. MethodsPatients (111 patients were enrolled, of which 50 patients received C-CEA and 61 patients E-CEA) were prospectively enrolled in this study. For the measurement of baroreceptor sensitivity, a non-invasive Finometer measuring device from Finapres Medical System B.V. (Amsterdam, The Netherlands) was used. Measurements were performed one day before surgery (PRE), directly after surgery (F1), on day 1 (F2), day 2 (F3) and on day 7 (F4) postoperatively. ResultsPostoperative blood pressure values were significantly higher in the E-CEA group on the day of surgery (F1) (p<0.001) and on day 1 (F2) (p<0.001). From day 2 (F3, F4) postoperatively, no significant difference was found between the two groups. The invasive blood pressure measurement in the postoperative recovery room showed significantly higher systolic blood pressure values in the E-CEA group (p=0.001). The need of acute antihypertensive therapy was significantly higher in the recovery room in the E-CEA group (p=0.020). With regard to changes in baroreceptor sensitivity, significantly lower baroreceptor sensitivity (BRS) values were recorded in the E-CEA group at 1 day (F2) postoperatively (p=0.005). The regression analysis showed that the applied surgical technique and the patients age were significant factors influencing changes in baroreceptor sensitivity. ConclusionsIn this study we could confirm higher blood pressure levels after E-CEA in the first two days after surgery. Additionally, we identified two factors possibly influencing baroreceptor sensitivity: surgical technique and age. Based on the data obtained in this study, haemodynamic dysregulation after CEA (E-CEA, C-CEA) is temporary and short-term. Already after the second postoperative day there was no significant difference between the E-CEA and E-CEA groups, this effect remained stable after 7 days.

Cerebrovascular Autoregulation in Preterm Infants Using Heart Rate or Blood Pressure: A Pilot Study.

Cerebrovascular autoregulation (CAR) is often impaired in preterm infants but requires invasive mean arterial blood pressure (MABP) measurements for continuous assessment. We aimed to assess whether using heart rate (HR) results in different CAR assessment compared with using MABP. We compared CAR (moving window correlation-coefficient with cerebral oxygenation saturation (rcSO2)), and percentage of time with impaired CAR (%timeCARi) calculated by either HR (TOHRx, tissue oxygenation heart rate reactivity index) or MABP (COx, cerebral oximetry index) during the first 72 h after birth, and its association with short-term cerebral injury. We included 32 infants, median gestational age of 25 + 5/7 weeks (interquartile range 24 + 6/7-27 + 5/7). COx and TOHRx correlation coefficients (cc) were significantly different in the first two days after birth (individual means ranging from 0.02 to 0.07 and -0.05 to 0.01). %TimeCARi using MABP (cc cut-off 0.3), was higher on day 1 (26.1% vs. 17.7%) and day 3 (23.4% vs. 16.9%) compared with HR (cc cutoff -0.3). During 65.7-69.6% of the time, both methods indicated impaired CAR simultaneously. The aforementioned calculations were not associated with early cerebral injury. In conclusion, HR and MABP do not seem interchangeable when assessing CAR in preterm infants.

Comparison of invasive blood pressure monitoring vs. non-invasive blood pressure monitoring in critically ill children receiving vasoactive agents-a prospective observational study.

The primary aim of this study was to compare non-invasive blood pressure (NIBP) measurement using the automated oscillometric method with invasive blood pressure (IBP) measurement using peripheral arterial line insertion in critically ill children receiving vasoactive agents. Single-centre, prospective cohort study. Tertiary care 15 bedded Pediatric ICU in Urban Indian city. All critically ill children between the ages of 1 month to 16 years with shock on vasoactive medications and with IBP monitoring. Forty children with 1,072 paired BP measurements were incorporated in the final analysis. Among all normotensive children (Total number of paired measurements = 623) receiving vasoactive agents, Bland-Altman analysis revealed an acceptable agreement between Invasive mean blood pressure (MBP) and non-invasive MBP with a bias of -2.10 mmHg (SD 11.35). The 95% limits of agreement were from -24.34 to 20.14 mmHg. In children with hypotension (Total number of paired measurements = 449), Bland-Altman analysis showed disagreement between Invasive MBP and non-invasive MBP i.e., a bias of -8.44 mmHg (SD 9.62). The 95% limits of agreement were from -27.29 to 10.41 mmHg. A limited agreement exists between invasive blood pressure (IBP) and non-invasive blood pressure (NIBP) measurements in critically ill children requiring vasoactive agents. This discrepancy can lead to either an underestimation or an overestimation of blood pressure. While NIBP can serve as a screening tool for hemodynamically stable children, those who are hemodynamically unstable and necessitate the initiation of vasoactive agents should undergo IBP monitoring.

LVSP and LBBP result in similar or improved LV synchrony and hemodynamics compared to biventricular pacing

Abstract Background The effect of left ventricular myocardial septal pacing (LVSP) and left bundle branch pacing (LBBP) on ventricular synchrony and LV hemodynamics is poorly understood in unselected cardiac resynchronization therapy (CRT) patients. Aim To investigate the impact of LBBP and LVSP on ultra-high-frequency ECG (UHF-ECG) ventricular synchrony and hemodynamics in CRT patients. Methods In consecutive CRT patients with LBBB, ventricular synchrony was assessed using UHF-ECG. LV hemodynamics was assessed using invasive systolic blood pressure measurement during multiple transitions between LBBP, LVSP, and biventricular pacing (BVP). LV synchrony was assessed by LV lateral wall delay (LVLWd) from the first to the last from V5-V8 activations. Hemodynamic effects were expressed as relative changes in systolic blood pressure. Results Thirty patients with an LVEF of 29 ± 6% and mean QRSd of 169 ± 24 ms were included. Twenty had non-ischemic cardiomyopathy. QRSd during BVP, LVSP, and LBBP was the same, but LBBP provided shorter LVLWd than BVP (-9 ms (-16; -4), p = 0.004); the difference between LVSP and BVP was not significant (-4 ms (-10;2), p = 0.2). LBBP was associated with higher systolic blood pressure than BVP (4% (2; 5) p &amp;lt; 0.001), while LVSP was not (1% (1; 2), p = 0.1. LV hemodynamic improvements during LBBP and LVSP vs. BVP were more pronounced in non-ischemic than ischemic patients. Conclusion The differences in ventricular synchrony between LBBP, LVSP, and BVP were demonstrated using UHF-ECG but not QRSd. LBBP, but not LVSP, was associated with better LV synchrony and hemodynamics than BVP.Local activation times in V1–V8Ventricular dyssynchrony and hemodynamic

LVSP and LBBP Result in Similar or Improved LV Synchrony and Hemodynamics Compared to BVP

BackgroundThe effect of left ventricular septal myocardial pacing (LVSP) and left bundle branch pacing (LBBP) on ventricular synchrony and left ventricular (LV) hemodynamic status is poorly understood. ObjectivesThe aim of this study was to investigate the impact of LVSP and LBBP vs biventricular pacing (BVP) on ventricular electrical synchrony and hemodynamic status in cardiac resynchronization therapy patients. MethodsIn cardiac resynchronization therapy candidates with LV conduction disease, ventricular synchrony was assessed by measuring QRS duration (QRSd) and using ultra-high-frequency electrocardiography. LV electrical dyssynchrony was assessed as the difference between the first activation in leads V1 to V8 to the last from leads V4 to V8. LV hemodynamic status was estimated using invasive systolic blood pressure measurement during multiple transitions between LBBP, LVSP, and BVP. ResultsA total of 35 patients with a mean LV ejection fraction of 29% and a mean QRSd of 168 ± 24 ms were included. Thirteen had ischemic cardiomyopathy. QRSd during BVP, LVSP, and LBBP was the same, but LBBP provided shorter LV electrical dyssynchrony than BVP (−10 ms; 95% CI: −16 to −4 ms; P = 0.001); the difference between LVSP and BVP was not significant (−5 ms; 95% CI: −12 to 1 ms; P = 0.10). LBBP was associated with higher systolic blood pressure than BVP (4%; 95% CI: 2%-5%; P < 0.001), whereas LVSP was not (1%; 95% CI: 0%-2%; P = 0.10). Hemodynamic differences during LBBP and LVSP vs BVP were more pronounced in nonischemic than ischemic patients. ConclusionsUltra-high-frequency electrocardiography allowed the documentation of differences in LV synchrony between LBBP, LVSP, and BVP, which were not observed by measuring QRSd. LVSP provided the same LV synchrony and hemodynamic status as BVP, while LBBP was better than BVP in both.

Short-Chain Fatty Acid Butyrate Is an Inotropic Agent With Vasorelaxant and Cardioprotective Properties.

The heart can metabolize the microbiota-derived short-chain fatty acid butyrate. Butyrate may have beneficial effects in heart failure, but the underlying mechanisms are unknown. We tested the hypothesis that butyrate elevates cardiac output by mechanisms involving direct stimulation of cardiac contractility and vasorelaxation in rats. We examined the effects of butyrate on (1) invivo hemodynamics using parallel echocardiographic and invasive blood pressure measurements, (2) isolated perfused hearts in Langendorff systems under physiological conditions and after ischemia and reperfusion, and (3) isolated coronary arteries mounted in isometric wire myographs. We tested Na-butyrate added to injection solutions or physiological buffers and compared its effects with equimolar doses of NaCl. Butyrate at plasma concentrations of 0.56 mM increased cardiac output by 48.8±14.9%, stroke volume by 38.5±12.1%, and left ventricular ejection fraction by 39.6±6.2%, and lowered systemic vascular resistance by 33.5±6.4% without affecting blood pressure or heart rate invivo. In the range between 0.1 and 5 mM, butyrate increased left ventricular systolic pressure by up to 23.7±3.4% in isolated perfused hearts and by 9.4±2.9% following ischemia and reperfusion, while reducing myocardial infarct size by 81.7±16.9%. Butyrate relaxed isolated coronary septal arteries concentration dependently with an EC50=0.57 mM (95% CI, 0.23-1.44). We conclude that butyrate elevates cardiac output through mechanisms involving increased cardiac contractility and vasorelaxation. This effect of butyrate was not associated with adverse myocardial injury in damaged hearts exposed to ischemia and reperfusion.

Asphyxial Circulatory Arrest with a Complex of Resuscitation Measures in an Experimental Model

The majority of asphyxial circulatory arrest (CA) models have a number of disadvantages, such as the lack of uniform criteria for fixing CA and recovery of spontaneous circulation, short duration of CA episode and limited volume of post-resuscitation intensive care, poor similarity with resuscitation measures in current clinical anesthesiology/intensive care settings.The aim of the study: to improve the experimental model of asphyxicial CA by standardizing experimental procedures and using a complex of resuscitation measures replicating current CA management in clinical anesthesiology-intensive care.Materials and methods. The experiments were conducted on 34 male Wistar rats, distributed into 2 groups: Group I included animals subjected to sham procedure (SP, N=12) and Group II – animals subjected to asphyxial circulatory arrest (CA, N=22) and subsequent resuscitation. Asphyxia in anesthetized rats was induced by rocuronium bromide injection, followed by recording of electrocardiogram (ECG), parameters of invasive blood pressure (BP) measurement and laser Doppler fluxmetry (LDF) to assess skin perfusion. CA episode was maintained for 2 min, followed by a series of resuscitation measures and intensive therapy for 2 h. Circulatory parameters (ECG, BP, LDF), gas composition and arterial blood acid-base state (ABS) dynamics were evaluated.Results. Monitored parameters were comparable in both groups at baseline after stabilization period. After exclusion criteria were applied 11 animals from SP group and 18 — from CA were included in the analysis. Tachycardia (heart rate, beats/min–1, SP vs CA) was documented in the CA group: 218 [205; 236] vs 286 [272; 305], P⩽0.0001), as well as recovery of skin perfusion to subnormal parameters in the first minutes after successful resuscitation. At minute 10 in the post-resuscitation period worsening of skin perfusion (M, perfusion units, SP vs CA): 14.7 [12.1; 16.5] vs 10.1 [7.0; 12.5], P=0.0014), and decompensated mixed acidosis (pH, SP vs CA): 7.42 [7.40; 7.43] vs 7.20 [7.13; 7.23], P⩽0.0001) were documented in the CA group, however BP values were comparable (BP, mmHg, SP vs CA): 60 [58; 72] vs 67 [62; 82], P=0.482). At minute 120 post-resuscitation and at the end of intensive care period, both groups demonstrated similar values of the monitored parameters. Three out of 18 animals in the CA group died after resuscitation.Conclusion. Electromechanical dissociation underlies CA in rats subjected to asphyxia. The use of LDF to assess peripheral blood flow makes it possible to standardize the severity of ischemic reperfusion injuries and improve reproducibility of the model. Series of resuscitation measures in experimental setting is justified from a bioethical point of view, and makes it possible to improve repeatability of preclinical research results in clinical practice.

Case Report: Sympathetic crashing acute pulmonary edema – only “NIV and nitroglycerin”?

Introduction An 84-year-old male patient alerted EMS because of severe dyspnea and subsequently presented with respiratory failure due to sympathetic crashing acute pulmonary edema (SCAPE.) The term SCAPE was coined outside Europe, with guidance on treatment only reflecting drugs available in the US and omitting potentially effective options, as highlighted in this report.[1] Diagnostic findings The patient presented sweating, pale and tachypneic with auscultatory crackles, radial pulse was palpable. He was able to follow commands, but unable to communicate verbally due to dyspnea. Initial SpO2 showed 80%, NIBP 185/105mmHg. The patient described sudden onset dyspnea as the only symptom. An ECG showed sinus tachycardia and LBBB (SGARBOSSA negative.) ABG showed hypoxemia and acidosis due to hypercapnia and lactatemia. Main diagnosis In absence of other causes for flash pulmonary edema, SCAPE was suspected. Therapeutic interventions The patient was supported in sitting position, oxygen applied, a total of 25mg urapidil and 7mg morphine administered intravenously, non-invasive ventilation (CPAP+ASB, PEEP 5mbar, ΔASB 5mbar) initiated and an arterial line placed for invasive blood pressure measurement and ABG. Outcome While RSI was considered multiple times, the patient improved rapidly during transport and a short NIV duration at the emergency department and was transferred to the ward without further interventions. Discussion With reducing afterload as main goal of pharmacological therapy, urapidil could be as effective as high-dose i.v. nitroglycerine, which is currently recommended.[2,3] While lacking the effect of venous vasodilation and thus not reducing preload, its effect on sympathetic tone via 5-HT1A-receptors supplemental to affecting arterial vasodilation via α-receptors might make it equally effective while being easier to administer. No data is available comparing urapidil to high-dose nitroglycerin, while it has proven more effective than low-dose nitroglycerin.[4]

MFAP4-Deficiency Aggravates Age-Induced Changes in Resistance Artery Structure, While Ameliorating Hypertension.

Abnormalities of resistance arteries may play essential roles in the pathophysiology of aging and hypertension. Deficiency of the vascular extracellular matrix protein MFAP4 (microfibrillar-associated protein 4) has previously been observed as protective against aberrant arterial remodeling. We hypothesized that MFAP4-deficiency would reduce age- and hypertension-dependent arterial changes in extracellular matrix composition and stiffening. Mesenteric arteries were isolated from old (20-23 months) littermate Mfap4+/+ and Mfap4-/- mice, and 2-photon excitation microscopy imaging was used to quantify elastin and collagen volumes and dimensions in the vascular wall. Ten-week-old littermate Mfap4+/+ and Mfap4-/- mice were subjected to 20 days of continuous Ang II (angiotensin II) infusion and hypertension was monitored using invasive blood pressure measurements. Arterial stiffness, responses to vascular constrictors, and myogenic tone were monitored using wire- or pressure-myography. Collagen contents were assessed by Western blotting. MFAP4-deficiency significantly increased collagen volume and elastin fragmentation in aged mesenteric arteries without affecting arterial stiffness. MFAP4-deficient mice exhibited reduced diastolic pressure in Ang II-induced hypertension. There was no significant effect of MFAP4-deficiency on mesenteric artery structural remodeling or myogenic tone, although collagen content in mesenteric arteries was tendentially increased in hypertensive Mfap4+/+ mice relative to Mfap4-/- mice. Increased efficacy of vasoconstrictors (phenylephrine, thromboxane) and reduced stiffness were observed in Ang II-treated Mfap4-/- mouse mesenteric arteries in ex vivo myography recordings. MFAP4-deficiency reduces the elastin/collagen ratio in the aging resistance artery without affecting arterial stiffness. In contrast, MFAP4-deficiency reduces the stiffness of resistance arteries and ameliorates Ang II-induced hypertension.

Cardiovascular Protective Effect of Garcinia dulcis Flower Acetone Extract in 2-Kidney-1-Clip Hypertensive Rats.

Morelloflavone and camboginol are bioactive compounds purified from Garcinia dulcis (GD), which has anti-inflammatory and antihypertensive properties. The objective of this study was to examine the cardiovascular protective effect of GD flower acetone extract in 2-kidney-1-clip (2K1C) hypertensive rats. Male Wistar rats underwent 2K1C or sham operation (SO) and were housed for 4 weeks. Each group of rats, then, was further divided into 2 subgroups receiving oral administration of either 50 mg/kg BW GD extract or corn oil (vehicle) daily for 4 weeks. Noninvasive blood pressure (BP) and body weight were measured weekly throughout the study. Subsequently, the invasive measurement of arterial BP and the heart rate were determined in all anesthetized rats. The baroreceptor reflex sensitivity (BRS) was investigated by injection of either phenylephrine or sodium nitroprusside for bradycardia or tachycardia response, respectively. Histological examination of the heart and thoracic aorta was also performed in order to investigate the general morphology and the tumor necrosis factor alpha (TNF-α) expression. We found that the GD flower extract significantly diminished the BP and restored the impaired BRS. Moreover, it also decreased the TNF-α expression in the cardiac muscle and thoracic aorta of 2K1C when compared to the SO group. Taken together, our data showed that GD flower extract exhibits the cardiovascular protective effect in the 2K1C hypertensive rats.

Comparison between invasive and oscillometric blood pressure measurements in a controlled hemorrhage model in dorsally-recumbent isoflurane-anesthetized horses

Comparison between invasive and oscillometric blood pressure measurements in a controlled hemorrhage model in dorsally-recumbent isoflurane-anesthetized horses

A comparison of invasive arterial blood pressure measurement with oscillometric non-invasive blood pressure measurement in patients with sepsis.

This study aimed to compare non-invasive oscillometric blood pressure (NIBP) measurement with invasive arterial blood pressure (IBP) measurement in patients with sepsis. We conducted a retrospective study to evaluate the agreement between IBP and NIBP using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Paired blood pressure measurements of mean arterial pressure (MAP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were compared using Bland-Altman analysis and paired Student's t test. We also focus on the effect of norepinephrine (NE) on the agreement between the two methods and the association between blood pressure and mortality during intensive care unit (ICU) stay. A total of 96,673 paired blood pressure measurements from 6060 unique patients were analyzed in the study. In Bland-Altman analysis, the bias (± SD, 95% limits of agreement) was 6.21mmHg (± 12.05mmHg, -17.41 to 29.83mmHg) for MAP, 0.39mmHg (± 19.25mmHg, -37.34 to 38.12mmHg) for SBP, and 0.80mmHg (± 12.92mmHg, -24.52 to 26.12mmHg) for DBP between the two techniques. Similarly, large limits of agreement were shown in different groups of NE doses. NE doses significantly affected the agreement between IBP and NIBP. SBP between the two methods gave an inconsistent assessment of patients' risk of ICU mortality. IBP and NIBP were not interchangeable in septic patients. Clinicians should be aware that non-invasive MAP was clinically and significantly underestimated invasive MAP.

Blood Pressure Estimation Based on PPG and ECG Signals Using Knowledge Distillation.

Easy access bio-signals are useful for alleviating the shortcomings and difficulties associated with cuff-based and invasive blood pressure (BP) measurement techniques. This study proposes a deep learning model, trained using knowledge distillation, based on photoplethysmographic (PPG) and electrocardiogram (ECG) signals to estimate systolic and diastolic blood pressures. The estimation model comprises convolutional layers followed by one bidirectional recurrent layer and attention layers. The training approach involves knowledge distillation, where a smaller model (student model) is trained by leveraging information from a larger model (teacher model). The proposed multistage model was evaluated on 1205 subjects from Medical Information Mart for Intensive Care (MIMIC) III database using the Association for the Advancement of Medical Instrumentation (AAMI) and the standards of the British Hypertension Society (BHS). The results revealed that our model performance achieved grade A in estimating both systolic blood pressure (SBP) and diastolic blood pressure (DBP) and met the requirements of the AAMI standard. After training with knowledge distillation (KD), the model achieved a mean absolute error and standard deviation of 2.94 ± 5.61mmHg for SBP and 2.02 ± 3.60mmHg for DBP. Our results demonstrate the benefits of the knowledge distillation training method in reducing the number of parameters and improving the predictive accuracy of the blood pressure regression model.

Effectiveness of the preventive administration of vasoactive amines in counterbalancing significant patient blood pressure drops following nimodipine administration during mechanical thrombectomy procedures

Background Focal vasospasm (FV) of the occluded vessel can occur during the endovascular treatment of acute ischemic stroke (AIS). Nimodipine is commonly used to treat vasospasm and can play a role in distinguishing it from artery narrowing due to iatrogenic dissection or residual clot. However, nimodipine administration can result in arterial hypotension and subsequent enlargement of the ischemic core. Objective To assess the efficacy of preventive and continuous vasoactive amine infusion to counterbalance nimodipine-induced hypotension. Methods We reviewed data from a prospective registry of patients treated for AIS between January 2019 and January 2022 who were administered nimodipine. All patients were equipped with an arterial cannula for invasive blood pressure measurement and given vasoactive amines preemptively before general anesthesia and throughout the procedure. Data obtained from invasive monitoring of mean arterial blood pressure (MABP) in a time-lapse of 25 min before and after nimodipine administration were analyzed. Results MABP significantly decreased after nimodipine administration but remained within the recommended range (81.79 ± 0.49 mmHg). Nimodipine was effective in reducing FV caused by stent retriever passage in 76.3% of cases. Furthermore, it proved valuable in diagnosing iatrogenic dissection (9.2%), residual clot (10.5%), or intracranial stenosis (4%). Conclusions Infusion of vasoactive amines effectively counteracted the intraarterial nimodipine effect, thus avoiding frank arterial hypotension during endovascular treatment. Nimodipine has been useful in differentiating the diagnosis of FV resulting from mechanical thrombectomy and other potential causes, such as iatrogenic dissection or residual clot.

History of blood pressure measurement in newborns and infants.

The development of methods for measuring blood pressure (BP) in newborns and small children has a rich history. Methods for BP measuring in adults had to be adapted to this age group. For measuring BP in direct invasive way, a suitable approach had to be found to access the arterial circulation through the umbilical and later radialis artery. Currently, results obtained from direct invasive BP measurement are considered the "gold standard". The development of non-invasive methods for BP measuring in newborns and children began with the use of von Basch's sphygmomanometer (1880). In 1899, Gustav Gärtner constructed the device, which was the basis for the flush method. After the discovery of the palpation and auscultation methods, these methods were also used for BP measurement in newborns and children, however, the BP values obtained in these ways were typically underestimated using excessively wide cuffs. From the auscultation method, methods utilizing ultrasound and infrasound to detect arterial wall movement and blood flow were later developed. The oscillometric method for BP measurement was introduced by E. J. Marey so early as in 1876. In 1912, P. Balard used the oscillometric technique to measure blood pressure in a large group of newborns. Through different types of oscillometers using various methods for detecting vascular oscillations (such as xylol method, impedance and volume plethysmography, etc.), the development has continued to assessment of vascular oscillations by modern sensor technology and software. For continuous non-invasive blood pressure measurement, the volume-clamp method, first described by Jan Peňáz in 1968, was developed. After modification for use in newborns, application of the cuff to the wrist instead of the finger, it is primarily used in clinical physiological studies to evaluate beat-to-beat BP and heart rate pressure variability, such as in the determination of the baroreflex sensitivity.

Prehospital hemodynamic instability: invasive blood pressure measurement—the future?

Prehospital hemodynamic instability: invasive blood pressure measurement—the future?

Abstract 18759: Reliability and Accuracy of Non-Invasive versus Invasive Blood Pressure Monitoring During Atrial Fibrillation Ablation

Introduction Patients with atrial fibrillation (AF) have multiple confounders that could affect the reliability of non-invasive blood pressure (NIBP). We sought to investigate if AF and paced rhythms (PR) modify the reliability of NIBP and accuracy against an invasive blood pressure (IBP) reference, as compared to sinus rhythm (SR), and impact NIBP validity for procedural monitoring. Hypothesis Changes in heart rhythm between AF, SR and PR, within a patient would not alter the reliability and accuracy of NIBP. Methods We conducted an observational study in patients undergoing an AF ablation procedure under general anesthesia with paired IBP, NIBP, and heart rhythm measurements available. Results We evaluated 91 patients ( Table 1 ) with 1,179 usable NIBP vs. IBP pairs; 547 (46.4%) during SR, 376 during AF (31.9%), and 256 (21.7%) during PR. In the entire sample, the average difference (standard error) between systolic NIBP and IBP was 2.9 (1.8) mmHg (P=0.10 against H0=0) with a within-subject standard deviation (SD) for the difference of 11.6 mmHg and intraclass correlation coefficient of 0.76 ( Fig. 1 ). Systolic NIBP was higher on average vs. IBP when in SR (6.2 [1.1] mmHg; P&lt;0.001), but not when in AF (1.5 [2.6] mmHg; P=0.55) or in PR (-2.0 [3.3] mmHg; P=0.54). However, the within-patient SD of the difference was high in SR, AF, and PR (SD 10.5, 12.9, and 11.9 mmHg, respectively). Results were similar for diastolic and mean NIBP vs. IBP. Conclusion AF or PR, as compared to SR, did not materially change the reliability and accuracy of NIBP vs. IBP. However, the high within-patient variation in systolic NIBP versus IBP raises concerns on the validity of NIBP for systolic blood pressure monitoring.