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2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Ali Farki ◽  
Reza Baradaran Kazemzadeh ◽  
Elham Akhondzadeh Noughabi

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).


PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262263
Author(s):  
Yoichiro Kitajima ◽  
Nana Sato Hashizume ◽  
Chikako Saiki ◽  
Ryoji Ide ◽  
Toshio Imai

Purpose We examined the cardiorespiratory effect of dexmedetomidine, an α2- adrenoceptor/imidazoline 1 (I1) receptor agonist, in spontaneously breathing adult rats. Methods Male rats (226−301 g, n = 49) under isoflurane anesthesia had their tail vein cannulated for drug administration and their tail artery cannulated for analysis of mean arterial pressure (MAP), pulse rate (PR), and arterial blood gases (PaO2, PaCO2, pH). After recovery, one set of rats received normal saline for control recording and was then divided into three experimental groups, two receiving dexmedetomidine (5 or 50 μg·kg−1) and one receiving normal saline (n = 7 per group). Another set of rats was divided into four groups receiving dexmedetomidine (50 μg·kg−1) followed 5 min later by 0.5 or 1 mg∙kg−1 atipamezole (selective α2-adrenoceptor antagonist) or efaroxan (α2-adrenoceptor/I1 receptor antagonist) (n = 6 or 8 per group). Recordings were performed 15 min after normal saline or dexmedetomidine administration. Results Compared with normal saline, dexmedetomidine (5 and 50 μg·kg−1) decreased respiratory frequency (fR, p = 0.04 and < 0.01, respectively), PR (both p < 0.01), and PaO2 (p = 0.04 and < 0.01), and increased tidal volume (both p = 0.049). Dexmedetomidine at 5 μg·kg−1 did not significantly change minute ventilation (V′E) (p = 0.87) or MAP (p = 0.24), whereas dexmedetomidine at 50 μg·kg−1 significantly decreased V′E (p = 0.03) and increased MAP (p < 0.01). Only dexmedetomidine at 50 μg·kg−1 increased PaCO2 (p < 0.01). Dexmedetomidine (5 and 50 μg·kg−1) significantly increased blood glucose (p < 0.01), and dexmedetomidine at 50 μg·kg−1 increased hemoglobin (p = 0.04). Supplemental atipamezole or efaroxan administration similarly prevented the 50 μg·kg−1 dexmedetomidine-related cardiorespiratory changes. Principal conclusion These results suggest that dexmedetomidine-related hypoventilation and hypertension are observed simultaneously and occur predominantly through activation of α2-adrenoceptors, but not I1 receptors, in spontaneously breathing adult rats.


Nutrients ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 328
Author(s):  
Patrícia Dias ◽  
Jana Pourová ◽  
Marie Vopršalová ◽  
Iveta Nejmanová ◽  
Přemysl Mladěnka

Regular intake of polyphenol-rich food has been associated with a wide variety of beneficial health effects, including the prevention of cardiovascular diseases. However, the parent flavonoids have mostly low bioavailability and, hence, their metabolites have been hypothesized to be bioactive. One of these metabolites, 3-hydroxyphenylacetic acid (3-HPAA), formed by the gut microbiota, was previously reported to exert vasorelaxant effects ex vivo. The aim of this study was to shed more light on this effect in vivo, and to elucidate the mechanism of action. 3-HPAA gave rise to a dose-dependent decrease in arterial blood pressure when administered i.v. both as a bolus and infusion to spontaneously hypertensive rats. In contrast, no significant changes in heart rate were observed. In ex vivo experiments, where porcine hearts from a slaughterhouse were used to decrease the need for laboratory animals, 3-HPAA relaxed precontracted porcine coronary artery segments via a mechanism partially dependent on endothelium integrity. This relaxation was significantly impaired after endothelial nitric oxide synthase inhibition. In contrast, the blockade of SKCa or IKCa channels, or muscarinic receptors, did not affect 3-HPAA relaxation. Similarly, no effects of 3-HPAA on cyclooxygenase nor L-type calcium channels were observed. Thus, 3-HPAA decreases blood pressure in vivo via vessel relaxation, and this mechanism might be based on the release of nitric oxide by the endothelial layer.


Author(s):  
В.П. Нестеров ◽  
А.И. Бурдыгин ◽  
К.Б. Иванов ◽  
С.В. Нестеров ◽  
С.И. Сороко

Описаны результаты применения нового метода артериальной пьезопульсометрии для неинвазивной оценки функционального состояния и физиологических механизмов автономной регуляции сердечно-сосудистой системы (ССС) у пожилого человека при острой боли, связанной с неожиданной физической травмой. Такое воздействие в первый же день вызвало негативную стресс-реакцию в мышечных эффекторах (МЭ) ССС, провоцируя аномальное усиление и ускорение сократимости миокарда ЛЖ сердца. Анализ графиков волн пульсового АД крови (ПАДК) показал, что максимальная скорость прироста ПАДК - VmaxPP, отражающая сократительную способность миокарда, выросла с 625±74 перед травмой до 2 117±173 мм рт. ст./с после травмы, исказив контур нормального графика. Причиной этого роста могло быть быстрое суммарное воздействие трансмиттеров нейроэндокринной симпатико-адреналовой системы на адренорецепторы кардиомиоцитов. Результаты спектрального анализа вариабельности параметров волн ПАДК подтвердили такую возможность. Было показано, что при стрессе норадреналин из активированных симпатических эфферентов добавляется к характерному для пожилых людей уже повышенному содержанию гуморальных катехоламинов в межклеточной среде миокарда вблизи адренорецепторов кардиомиоцитов. При этом существенно возрастает активность парасимпатических эфферентов, выделяющих ацетилхолин, ингибирующий контрактильную реакцию миокарда и тем самым выполняющий сдерживающую кардиопротекторную функцию. При исследовании механизмов автономной регуляции МЭ ССС в условиях стрессорного воздействия использовали персонализированный подход. The article describes the results of using the method of arterial piezopulsometry for non-invasive assessment of the functional state and physiological mechanisms of autonomous regulation of the cardiovascular system (CVS) in an elderly person with acute pain associated with unexpected physical trauma. On the first day, such an effect caused a negative stress reaction in the muscle effectors (ME) of the CVS, provoking an abnormal increase and acceleration of the contractility of the left ventricular myocardium. Analysis of the arterial blood pressure (PP) pulse wave graphs showed that the maximum rate of PP growth - VmaxPP, which reflects myocardial contractility, increased from 625±74 before injury to 2 117±173 mm Hg/s after injury, distorting the contour of the normal PP waveform. The reason for this growth could be the rapid cumulative effect of transmitters of the neuroendocrine sympathoadrenal system on adrenergic receptors (AR) of cardiomyocytes (CM). The results of the spectral analysis of the variability of the parameters of the PP waves confirmed this possibility. It was shown that under stress, norepinephrine from activated sympathetic efferents is added to the already increased content of humoral catecholamines in the extracellular environment of the myocardium near the AR of the CM, which is characteristic of the elderly. At the same time, the activity of parasympathetic efferents, releasing acetylcholine, which inhibits the contractile reaction of the myocardium and, thereby, performs a restraining cardioprotective function, significantly increases. A personalized approach was used for piezopulsometric study of the mechanisms of autonomous regulation of ME CVS under specific conditions of stress.


Author(s):  
Michael M. Tymko ◽  
Christopher K. Willie ◽  
Connor A. Howe ◽  
Ryan L. Hoiland ◽  
Rachel Stone ◽  
...  

High-altitude exposure results in a hyperventilatory-induced respiratory alkalosis followed by renal compensation (bicarbonaturia) to return arterial blood pH(a) toward sea-level values. However, acid-base balance has not been comprehensively examined in both lowlanders and indigenous populations - where the latter are thought to be fully adapted to high-altitude. The purpose of this investigation was to compare acid-base balance between acclimatizing lowlanders, and Andean and Sherpa highlanders at various altitudes (~3,800, ~4,300, and ~5,000 m). We compiled data collected across five independent high-altitude expeditions and report the following novel findings: 1) at 3,800 m, Andeans (n=7) had elevated pHa compared to Sherpas (n=12; P<0.01), but not to lowlanders (n=16; nine days acclimatized; P=0.09); 2) at 4,300 m, lowlanders (n=16; 21 days acclimatized) had elevated pHa compared to Andeans (n=32) and Sherpas (n=11; both P<0.01), and Andeans had elevated pHa compared to Sherpas (P=0.01); and 3) at 5,000 m, lowlanders (n=16; 14 days acclimatized) had higher pHa compared to both Andeans (n=66) and Sherpas (n=18; P<0.01, and P=0.03, respectively), and Andean and Sherpa highlanders had similar blood pHa (P=0.65). These novel data characterize acid-base balance acclimatization and adaptation to various altitudes in lowlanders and indigenous highlanders.


2022 ◽  
Vol 2022 ◽  
pp. 1-10
Author(s):  
Vasileios Panoulas ◽  
Charles Ilsley

Introduction. We aimed to identify the independent “frontline” predictors of 30-day mortality in patients with acute coronary syndromes (ACS) and propose a rapid cardiogenic shock (CS) classification and management pathway. Materials and Methods. From 2011 to 2019, a total of 11439 incident ACS patients were treated in our institution. Forward conditional logistic regression analysis was performed to determine the “frontline” predictors of 30 day mortality. The C-statistic assessed the discriminatory power of the model. As a validation cohort, we used 431 incident ACS patients admitted from January 1, 2020, to July 20, 2020. Results. Independent predictors of 30-day mortality included age (OR 1.05; 95% CI 1.04 to 1.07, p < 0.001 ), intubation (OR 7.4; 95% CI 4.3 to 12.74, p < 0.001 ), LV systolic impairment (OR severe_vs_normal 1.98; 95% CI 1.14 to 3.42, p = 0.015 , OR moderate_vs_normal 1.84; 95% CI 1.09 to 3.1, p = 0.022 ), serum lactate (OR 1.25; 95% CI 1.12 to 1.41, p < 0.001 ), base excess (OR 1.1; 95% CI 1.04 to 1.07, p < 0.001 ), and systolic blood pressure (OR 0.99; 95% CI 0.982 to 0.999, p = 0.024 ). The model discrimination was excellent with an area under the curve (AUC) of 0.879 (0.851 to 0.908) ( p < 0.001 ). Based on these predictors, we created the SAVE (SBP, Arterial blood gas, and left Ventricular Ejection fraction) ACS classification, which showed good discrimination for 30-day AUC 0.814 (0.782 to 0.845) and long-term mortality p log − rank < 0.001 . A similar AUC was demonstrated in the validation cohort (AUC 0.815). Conclusions. In the current study, we introduce a rapid way of classifying CS using frontline parameters. The SAVE ACS classification could allow for future randomized studies to explore the benefit of mechanical circulatory support in different CS stages in ACS patients.


2022 ◽  
Vol 12 ◽  
Author(s):  
Agnieszka Uryga ◽  
Nathalie Nasr ◽  
Magdalena Kasprowicz ◽  
Karol Budohoski ◽  
Marek Sykora ◽  
...  

Introduction: Common consequences following aneurysmal subarachnoid hemorrhage (aSAH) are cerebral vasospasm (CV), impaired cerebral autoregulation (CA), and disturbance in the autonomic nervous system, as indicated by lower baroreflex sensitivity (BRS). The compensatory interaction between BRS and CA has been shown in healthy volunteers and stable pathological conditions such as carotid atherosclerosis. The aim of this study was to investigate whether the inverse correlation between BRS and CA would be lost in patients after aSAH during vasospasm. A secondary objective was to analyze the time-trend of BRS after aSAH.Materials and Methods: Retrospective analysis of prospectively collected data was performed at the Neuro-Critical Care Unit of Addenbrooke's Hospital (Cambridge, UK) between June 2010 and January 2012. The cerebral blood flow velocity (CBFV) was measured in the middle cerebral artery using transcranial Doppler ultrasonography (TCD). The arterial blood pressure (ABP) was monitored invasively through an arterial line. CA was quantified by the correlation coefficient (Mxa) between slow oscillations in ABP and CBFV. BRS was calculated using the sequential cross-correlation method using the ABP signal.Results: A total of 73 patients with aSAH were included. The age [median (lower-upper quartile)] was 58 (50–67). WFNS scale was 2 (1–4) and the modified Fisher scale was 3 (1–3). In the total group, 31 patients (42%) had a CV and 42 (58%) had no CV. ABP and CBFV were higher in patients with CV during vasospasm compared to patients without CV (p = 0.001 and p &lt; 0.001). There was no significant correlation between Mxa and BRS in patients with CV, neither during nor before vasospasm. In patients without CV, a significant, although moderate correlation was found between BRS and Mxa (rS = 0.31; p = 0.040), with higher BRS being associated with worse CA. Multiple linear regression analysis showed a significant worsening of BRS after aSAH in patients with CV (Rp = −0.42; p &lt; 0.001).Conclusions: Inverse compensatory correlation between BRS and CA was lost in patients who developed CV after aSAH, both before and during vasospasm. The impact of these findings on the prognosis of aSAH should be investigated in larger studies.


2022 ◽  
Vol 9 ◽  
Author(s):  
Rachel L. Leon ◽  
Eric B. Ortigoza ◽  
Noorjahan Ali ◽  
Dimitrios Angelis ◽  
Joshua S. Wolovits ◽  
...  

Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.


Author(s):  
Robert Weir ◽  
Jeffery Lee ◽  
Shelly Almroth ◽  
Jodie Taylor

Abstract Background: Using Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) during air and ground transport requires coordination among the responding clinical team, transport team, and receiving surgical team. Here, we describe the development of a REBOA transport program in a civilian medical system that demonstrates the value of REBOA as part of the toolkit for safe casualty transport. Methods: The regional REBOA program was developed at St. Anthony Summit Medical Center in a multi-step planning and training process to ensure coordination among the facilities and transport resources during trauma patient care. Retrospective record review was performed on all patients (n=5) that received REBOA for transport from the Level 3 Trauma Center to the Level 1 Trauma Center, since inception of the program in March 2019. Data were gathered from hospital electronic medical records. Results: SASMC has transported five trauma patients under the REBOA program; all successfully arrived at the Level 1 Trauma Center to receive definitive care. The integrated arterial blood pressure monitoring capability in the REBOA catheter provided robust physiologic data to enable data-driven interventions during transport. Conclusion: The REBOA program described here is a model of how REBOA can be used to enable safe transport between levels of care, when, without REBOA, such transport might not be possible. The model is applicable during care of civilian trauma patients and combat casualties, where injured patients are initially treated in a prehospital or Role1/2 environment but require transport to a Level 1 Trauma Center or Role 3+ for definitive care.  Keywords: REBOA, non-compressible hemorrhage, patient transport


Critical Care ◽  
2022 ◽  
Vol 26 (1) ◽  
Author(s):  
Marta Martín-Fernández ◽  
María Heredia-Rodríguez ◽  
Irene González-Jiménez ◽  
Mario Lorenzo-López ◽  
Estefanía Gómez-Pesquera ◽  
...  

Abstract Background Despite growing interest in treatment strategies that limit oxygen exposure in ICU patients, no studies have compared conservative oxygen with standard oxygen in postsurgical patients with sepsis/septic shock, although there are indications that it may improve outcomes. It has been proven that high partial pressure of oxygen in arterial blood (PaO2) reduces the rate of surgical-wound infections and mortality in patients under major surgery. The aim of this study is to examine whether PaO2 is associated with risk of death in adult patients with sepsis/septic shock after major surgery. Methods We performed a secondary analysis of a prospective observational study in 454 patients who underwent major surgery admitted into a single ICU. Patients were stratified in two groups whether they had hyperoxemia, defined as PaO2 > 100 mmHg (n = 216), or PaO2 ≤ 100 mmHg (n = 238) at the day of sepsis/septic shock onset according to SEPSIS-3 criteria maintained during 48 h. Primary end-point was 90-day mortality after diagnosis of sepsis. Secondary endpoints were ICU length of stay and time to extubation. Results In patients with PaO2 ≤ 100 mmHg, we found prolonged mechanical ventilation (2 [8] vs. 1 [4] days, p < 0.001), higher ICU stay (8 [13] vs. 5 [9] days, p < 0.001), higher organ dysfunction as assessed by SOFA score (9 [3] vs. 7 [5], p < 0.001), higher prevalence of septic shock (200/238, 84.0% vs 145/216) 67.1%, p < 0.001), and higher 90-day mortality (37.0% [88] vs. 25.5% [55], p = 0.008). Hyperoxemia was associated with higher probability of 90-day survival in a multivariate analysis (OR 0.61, 95%CI: 0.39–0.95, p = 0.029), independent of age, chronic renal failure, procalcitonin levels, and APACHE II score > 19. These findings were confirmed when patients with severe hypoxemia at the time of study inclusion were excluded. Conclusions Oxygenation with a PaO2 above 100 mmHg was independently associated with lower 90-day mortality, shorter ICU stay and intubation time in critically ill postsurgical sepsis/septic shock patients. Our findings open a new venue for designing clinical trials to evaluate the boundaries of PaO2 in postsurgical patients with severe infections.


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