Increase In Arterial Blood Pressure Research Articles

Exaggerated postnatal surge of orexin neurons and the effects of elimination of excess orexin on blood pressure and exaggerated chemoreflex in spontaneously hypertensive rats.

An overactive orexin (OX) system is associated with neurogenic hypertension and an exaggerated chemoreflex in spontaneously hypertensive rats (SHRs). However, the chronology and mechanism of this association is unclear. We hypothesized that increased postnatal neurogenesis of OX neurons in SHRs precedes and contributes to the aberrant increase in mean arterial blood pressure (MAP) and the exaggerated response to hypercapnia during postnatal development. Using immunohistochemical methods and bromodeoxyuridine, we mapped the timeline of orexin neuron neurogenesis and maturation during early postnatal development. We then used whole-body plethysmography with EEG and EMG to map the development of mean arterial pressure (MAP) and state regulation. Finally, we used OX-targeted saporin toxin to determine the effects of eliminating excess OX neurons on the elevated MAP and exaggerated chemoreflex in adult SHRs. We found that both SHRs and Wistar-Kyoto (WKY) rats experienced postnatal increases in OX neurons. However, SHRs experienced a greater increase than WKY rats before P15, which led to significantly more OX neurons in SHRs than age-matched WKY controls by P15-16 (3,720 ± 780 vs. 2,406 ± 363, p = 0.005). We found that neurogenesis, as evidenced by BrdU staining in OX-positive neurons, was the primary contributor to the excess OX neurons in SHRs during early postnatal development. While SHRs develop more OX neurons by P15-16, SHRs and normotensive WKY control rats have similar MAP during postnatal development until P25 in wakefulness (81.6 ± 6.6 vs. 67.5 ± 6.8mmHg, p = 0.006) and sleep (79.3 ± 6.1 vs. 66.6 ± 6.5, p = 0.009), about 10 days after the surge of OX neurons. By selectively eliminating excess (∼30%) OX neurons in SHRs, we saw a significantly lowered MAP and hypercapnic ventilatory chemoreflex compared to non-lesioned SHRs at P40. Additionally, we found unique signatures in state indicative of the attention defecit phenotype commonly associated with this model. We suggest that the postnatal increase of OX neurons, primarily attributed to exaggerated postnatal OX neurogenesis, may be necessary for the development of higher MAP and exaggerated chemoreflex in SHRs, and modulation of the overactive OX system may have a potential therapeutic effect during the pre-hypertensive period.

Vascular Aging Entails Arterial Dilatation in Addition to Increased Arterial Stiffness

Introduction: The increase in arterial blood pressure occurring with aging is considered an important risk factor for end-organ damage in, among others, the brain. How exactly this risk emerges is largely unknown. Methods: We investigated the effect of aging on middle cerebral flow velocity (MCAFV) and noninvasive arterial blood pressure (NIBP) in 105 healthy volunteers aged 18 to 82 years. Both pulsatile signals were analyzed determining the first (Sys1) and second systolic peak (Sys2) and the diastolic flow velocity 560 ms after stroke onset (D560). Results: For NIBP, a linear increase was found with aging for Sys2 and D560 (0.72 and 0.14 mm Hg/year, respectively) but not for Sys1. For MCAFV, a linear decrease was found with aging for all variables, being more rapid for Sys1 than for Sys2 or D560 (−0.94, −0.41, and −0.54 cm/s/year, respectively). Both signals change from Sys1 dominant in young adults to increasingly Sys2 dominant in the elderly. Discussion: That MCAFV decreases with aging, whereas NIBP increases can best be explained by assuming arterial dilatation. Apart from the generally accepted increase in arterial stiffness, arterial dilatation may be an important additional factor in vascular aging: the loss of elastin allows arteries to dilate until restricted by arterial collagen. Conclusion: Normal values collected in this study support protocols for non-invasive monitoring that require a correction for age.

Characterization of Mild Delayed Gestational Hypertension in Rats Following Ozone Exposure.

The contribution of air pollution-induced cardiopulmonary damage on the development of hypertensive disorders of pregnancy and other adverse outcomes of pregnancy has gained increased attention as epidemiological data continue to highlight spatiotemporal pregnancy trends related to air pollution exposure. However clinical mechanistic data surrounding gestational complications remain sparse, necessitating the need for the use of animal models to study these types of complications of pregnancy. The current study seeks to examine the real-time effects of mid-gestational ozone exposure on maternal blood pressure and body temperature through the use of radiotelemetry in a rat model. The exposure resulted in acute depression of heart rate and core body temperature as compared to control animals. Ozone-exposed animals also presented with a slight but significant increase in arterial blood pressure which was perpetuated until term. The data presented here illustrates the feasibility of murine models to assess cardiovascular complications caused by inhaled toxicants during the window of pregnancy.

Policy Evaluation Of Minimum Service Standards For Hypertension Health Services At Mabelopura Health Center

Hypertension is a chronic medical condition in which arterial blood pressure increases, causing the heart to work harder. At Puskesmas Mabelopura, hypertension has not yet reached the Minimum Service Standard (MSS) target with an achievement of only 68.61% of the 95% target. This study evaluated the SPM policy on hypertension services at the Mabelopura Health Center using a descriptive qualitative method with informants from Key Informants and Triangulated Informants. The results showed that the implementation of SPM Hypertension only reached 68.61% of the 95% target, indicating that the target has not been achieved. Health services are in accordance with SPM standards but not optimal, due to differences in central target data with Puskesmas data and limited human resources. The low number of community visits for hypertension screening, due to the community's lack of perceived importance of routine control, was also a major factor. This study concluded that to achieve SPM targets, intensive efforts are needed from Puskesmas Mabelopura and the Health Office of Palu City to establish better communication with Pusdasten and increase community awareness of the importance of routine check-ups. Thus, it is expected that Puskesmas Mabelopura can be more effective in achieving SPM targets and improving the quality of life of people with hypertension in the area.

The protective effect of bergamot polyphenolic fraction on reno-cardiac damage induced by DOCA-salt and unilateral renal artery ligation in rats

Abstract Funding Acknowledgements None. The complex pathological interactions between renal and cardiovascular systems represent a real global epidemic and renovascular hypertension remains among the most prevalent, but also potentially reversible, risk factor for numerous reno-cardiac diseases in humans and pets. Here, we investigated the anti-inflammatory and reno-cardiac protective effects of a polyphenol-rich fraction of citrus bergamot (BPF) in an experimental model of hypertension induced by unilateral renal artery ligation (RAL). Adult male Wistar rats underwent unilateral renal artery ligation and treatment with 20 mg/kg deoxycorticosterone acetate (DOCA), twice a week for a period of 4 weeks, and 1% sodium chloride water. A subgroup of hypertensive rats received 100 mg/kg/day of BPF for 28 days, by gavage. Another group of animals was treated with a sub-cutaneous injection of vehicle (CTRL). RAL DOCA-Salt rats showed a significant increase in mean arterial blood pressure (MAP; p<0.05 vs CTRL) which strongly increased the resistive index (RI; p<0.05 vs CTRL) of contralateral renal artery flow and kidney volume after 4 weeks (p<0.001 vs CTRL). Renal dysfunction also led to a dysfunction of cardiac tissue strain associated with overt dyssynchrony in cardiac wall motion, as shown by the increased time-to-peak (T2P; p<0.05) and the decreased whole peak capacity (Pk; p<0.01) in displacement and strain rate (p<0.05) in longitudinal motion. The hearts of RAL DOCA-Salt rats showed a larger time delay between the fastest and the lowest region (Maximum Opposite Wall Delay-MOWD) (p<0.05 in displacement and p<0.01 in strain rate vs CTRL). A significant increase in the levels of the circulating pro-inflammatory cytokines and chemokines (p<0.05 for IL-12(40), p<0.01 for GM-CSF, KC, IL-13, and TNF- α) and in the NGAL expression of the ligated kidney (p<0.001) was observed.This pathological condition was prevented by BPF treatment, by reducing the increase of blood pressure in RAL DOCA-Salt rats (p<0.05) and exerting a protective effect on the volume of the contralateral kidney (p<0.01). BPF ameliorates cardiac tissue strain dysfunction by increasing Pk in displacement (p<0.01) and reducing the T2P in strain rate motion (p<0.05). These effects significantly improve MOWD (p<0.05) preventing the overt dyssynchrony in cardiac wall motion. The reno-cardiac protective effect of BPF was associated with a significant reduction in serum level of the pro-inflammatory cytokines and chemokines (p<0.05 for KC and IL-12(40), p<0.01 for GM-CSF, IL-13, and TNF- α)restoring physiological levels of NGAL (p<0.05) protein of the tethered kidney. In conclusion, the present results show that BPF promotes an efficient renovascular protection preventing the progression of inflammation and reno-cardiac damage, suggesting the potential clinical and veterinary role of dietary supplementation with the polyphenol-rich fraction of citrus bergamot in counteracting hypertension-induced reno-cardiac syndrome.

Estrogen stimulates fetal vascular endothelial growth factor expression and microvascularization.

We recently showed that the ratio of capillaries to myofibers in skeletal muscle, which accounts for 80% of insulin-directed glucose uptake and metabolism, was reduced in baboon fetuses in which estrogen was suppressed by maternal letrozole administration. Since vascular endothelial growth factor (VEGF) promotes angiogenesis, the present study determined the impact of estrogen deprivation on fetal skeletal muscle VEGF expression, capillary development, and long-term vascular and metabolic function in 4- to 8-year-old adult offspring. Maternal baboons were untreated or treated with letrozole or letrozole plus estradiol on days 100-164 of gestation (term = 184 days). Skeletal muscle VEGF protein expression was suppressed by 45% (P < 0.05) and correlated (P = 0.01) with a 47% reduction (P < 0.05) in the number of capillaries per myofiber area in fetuses of baboons in which serum estradiol levels were suppressed 95% (P < 0.01) by letrozole administration. The reduction in fetal skeletal muscle microvascularization was associated with a 52% decline (P = 0.02) in acetylcholine-induced brachial artery dilation and a 23% increase (P = 0.01) in mean arterial blood pressure in adult progeny of letrozole-treated baboons, which was restored to normal by letrozole plus estradiol. The present study indicates that estrogen upregulates skeletal muscle VEGF expression and systemic microvessel development within the fetus as an essential programming event critical for ontogenesis of systemic vascular function and insulin sensitivity/glucose homeostasis after birth in primate offspring.

THE SENOLYTIC QUERCETIN PREVENTS AGE-ASSOCIATED VASCULAR STIFFENING, REDUCES BLOOD PRESSURE AND IMPROVES COGNITIVE FUNCTION IN DAHL SALT-SENSITIVE RATS CONSUMING A NORMAL SALT DIET

Objective: Quercetin (QRC), a flavonoid with anti-oxidant, anti-inflammatory and senolytic effects, reduced BP in salt-induced hypertension in Dahl salt-sensitive (DSS) rats. The increases in central arterial stiffness (CAS) and blood pressure (BP) occur, as manifestation of early vascular aging (EVA), in DSS rats even consuming a normal salt (NS) diet, moreover, EVA is associated with cognitive impairment in humans. We hypothesized that as age advances, a decline in cognitive function will accompany EVA in DSS rats consuming a NS diet, and that QRC will not only retard EVA, but also will improve cognitive function. Design and method: A NS diet (0.5% NaCl), supplemented with QRC (100 mg/kg BW/day) was administered to male DSS rats at 6-mo of age (n=24) for a 3-month period. DSS without QRC supplementation served as a control group (n=12). Systolic and diastolic BP (SBP, DBP), pulse wave velocity (PWV, an index of CAS), echocardiography, and a visuospatial attention test were assessed prior to and following QRC treatment. Results: At 6-mo of age none of the measured parameters differ between control and QRC rats. During aging from 6- to 9-mo in the control group, SBP, DBP and PWV significantly increased, ESLV.vol showed a statistically borderline trend to increase, HR and EF showed a statistically borderline trend to decrease, and attention behavior did not change. QRC treatment reduced SBP, PWV, and ESLV.vol, and increased EF and attention (Table). The QRC effect to increase the number of correct attention test responses was inversely correlated with PWV (Pearson r=-0.420, P=0.02) but not with BP or cardiac parameters, indicating that CAS but not BP is linked to cognitive function. Conclusions: QRC reduces EVA and improves cognition assessed as an attention behavior. Although both BP and CAS are manifestations of EVA, a positive association between attention decline with PWV, but not BP, suggests that CAS is linked to cognitive function via mechanisms that are not directly related to BP. Further studies are required to determine whether the effects of QRC on EVA in DSS rats, consuming a NS diet, are linked to its anti-oxidant, anti-inflammatory or senolytic properties.

Evaluation of the inter-arm blood pressure difference in subjects with hypertension in Nnewi North Local Government Area, Anambra state

Hypertension is defined as a sustained elevated blood pressure with a systolic blood pressure (SBP) of 140mmHg or more and a diastolic blood pressure of 90mmHg or more. The evaluation of the inter-arm blood pressure difference in subjects with hypertension in Nnewi North Local Government Area, Anambra state was done via sampling techniques. The study population was obtained using convenience sampling method and comprised of male and female hypertensive patients aged 25 to 90 years, from the cardiology unit NAUTH Nnewi. Normotensive subjects of the same age range and gender were used as control. The sample size was determined to be 70 subjects using this formula: n= (z2pq)/d2). The result of the finding showed that there was a significant increase in the mean age when the control was compared to the hypertensive group, and no significant difference in their weight, height and BMI. Furthermore, the findings of this research also supported a significant increase in the left arterial systolic and diastolic blood pressure in the control compared to the hypertensive groups. Also, the mean right systolic and diastolic blood pressure showed a significant increase when the control was compared to the hypertensive group. The inter-arm systolic and diastolic blood pressure had no significant difference when control was compared to the hypertensive group.

Estimation of Systolic and Diastolic Blood Pressure for Hypertension Identification from Photoplethysmography Signals

Continuous monitoring plays a crucial role in diagnosing hypertension, characterized by the increase in Arterial Blood Pressure (ABP). The gold-standard method for obtaining ABP involves the uncomfortable and invasive technique of cannulation. Conversely, ABP can be acquired non-invasively by using Photoplethysmography (PPG). This non-invasive approach offers the advantage of continuous BP monitoring outside a hospital setting and can be implemented in cost-effective wearable devices. PPG and ABP signals differ in scale values, which creates a non-linear relationship, opening avenues for the utilization of algorithms capable of detecting non-linear associations. In this study, we introduce Neural Model of Blood Pressure (NeuBP), which estimates systolic and diastolic values from PPG signals. The problem is treated as a binary classification task, distinguishing between Normotensive and Hypertensive categories. Furthermore, our research investigates NeuBP’s performance in classifying different BP categories, including Normotensive, Prehypertensive, Grade 1 Hypertensive, and Grade 2 Hypertensive cases. We evaluate our proposed method by using data from the publicly available MIMIC-III database. The experimental results demonstrate that NeuBP achieves results comparable to more complex models with fewer parameters. The mean absolute errors for systolic and diastolic values are 5.02 mmHg and 3.11 mmHg, respectively.

The use of dexmedetomidine in suppressing cardiovascular response due to intubation in general anesthesia

Endotracheal intubation is commonly used to maintain a safe airway during general anesthesia. This intubation action can trigger a dangerous response for the patient, one of which is the cardiovascular system. Increases in arterial blood pressure, plasma catecholamine levels, and heart rate are responses that can occur during intubation. Therefore, various methods and treatments have been used to control this cardiovascular response, including dexmedetomidine. Dexmedetomidine is a highly selective α2-adrenergic receptor agonist that has analgesic, sympatholytic, and sedative effects with minimal depression of ventilation. Much research has been done on how well dexmedetomidine works to stop the cardiovascular response to intubation. Dexmedetomidine was significantly associated with reductions in heart rate, systolic blood pressure, and MAP.

Interindividual variability in cold-pressor pain sensitivity is not explained by peripheral vascular responding and generalizes to a C-nociceptor-specific pain phenotype.

Pain sensitivity of healthy subjects in the cold-pressor (CP) test was proposed to be dichotomously distributed and to represent a pain sensitivity trait. Still, it has not been systematically explored which factors influence this pain sensitivity readout. The aim of this study was to distinguish potential contributions of local tissue-related factors such as perfusion and thermoregulation or gain settings in nociceptive systems. Cold-pressor-sensitive and CP-insensitive students screened from a medical student laboratory course were recruited for a CP retest with additional cardiovascular and bilateral local vascular monitoring. In addition, comprehensive quantitative sensory testing according to Deutscher Forschungsverbund Neuropathischer Schmerz standards and a sustained pinch test were performed. Cold pressor was reproducible across sessions (Cohen kappa 0.61 ± 0.14, P < 0.005). At 30 seconds in ice water, CP-sensitive subjects exhibited not only more pain (78.6 ± 26.3 vs 29.5 ± 17.5, P < 0.0001) but also significantly stronger increases in mean arterial blood pressure (12.6 ± 9.3 vs 5.6 ± 8.1 mm Hg, P < 0.05) and heart rate (15.0 ± 8.2 vs 7.1 ± 6.2 bpm, P < 0.005), and lower baroreflex sensitivity, but not local or vasoconstrictor reflex-mediated microcirculatory responses. Cold-pressor-sensitive subjects exhibited significantly lower pain thresholds also for cold, heat, and blunt pressure, and enhanced pain summation, but no significant differences in Aδ-nociceptor-mediated punctate mechanical pain. In conclusion, differences in nociceptive signal processing drove systemic cardiovascular responses. Baroreceptor activation suppressed pain and cardiovascular responses more efficiently in CP-insensitive subjects. Cold-pressor sensitivity generalized to a pain trait of C-fiber-mediated nociceptive channels, which was independent of local thermal and vascular changes in the ice-water-exposed hand. Thus, the C-fiber pain trait reflects gain setting of the nociceptive system.

Antihypertensive Medications Can Prevent Fostamatinib-Induced Blood Pressure Elevation

Fostamatinib is a tyrosine kinase inhibitor that has been shown in clinical trials to be effective against spleen tyrosine kinase in patients suffering from rheumatoid arthritis. Fostamatinib medication was linked in clinical trials to a slight increase in systemic arterial Blood Pressure (BP). This observation is consistent with other kinase inhibitors, particularly those that obstruct VEGFR2 signaling. In conscious rats, we examined the relationship between the elevation of blood pressure caused by fostamatinib and the plasma levels of the fostamatinib-active metabolite R940406. We discovered that there was a strong correlation between changes in R940406 plasma concentration and the time course of the blood pressure effect, suggesting a direct pharmacological relationship. The experiments yielded free plasma levels of R940406 up to 346 nmol/L, which is greater than the mean peak free plasma concentration of 49 nmol/L that has been recorded in clinical settings. We beyond the clinically noted mean peak free plasma concentration of 49 nmol/L, up to 346 nmol/L. We’ve shown that there are several effective ways to reduce the blood pressure elevation caused by fostamatinib dosing, including simple drug withdrawal or condoning with a variety of common antihypertensive medications like atenolol, captopril, and nifedipine. These results provide credence to prospective strategies for preserving patient safety during fostamatinib therapy. Additionally, we have shown—using nifedipine as an example drug—that this blood pressure control was not brought about by a decrease in R940406’s plasma exposure, indicating that potential pharmacological benefits of the investigational drug may be preserved while blood pressure control is managed with the use of conventional medications.

Hypertension effects of the COVID-19 lockdowns: Evidence from a repeated cross-sectional survey in Peru

Using data from Peru and a quasi-experimental approach, we document significant increases in arterial blood pressure and in the incidence of arterial hypertension caused by the restrictive measures employed by the Peruvian authorities during the COVID-19 pandemic. The effects are more pronounced for women, older respondents, and urban residents. The effects are statistically significant and high in magnitude relative to the pre-pandemic incidence of disease in the Peruvian population. A main channel of disease propagation seems to be the changes in dietary habits and physical activity imposed by the COVID-19 lockdowns, which affected several anthropometric measurements that are common risk factors for hypertension.

Activation of orexin-A (hypocretin-1) receptors in the Raphe Pallidus at different ambient temperatures in the rat: effects on thermoregulation, cardiovascular control, sleep, and feeding behavior.

The Raphe Pallidus (RPa) is a brainstem nucleus containing sympathetic premotor neurons that control thermogenesis and modulate cardiovascular function. It receives inputs from various hypothalamic areas, including the Lateral Hypothalamus (LH), a heterogeneous region intricately involved in several autonomic and behavioral functions. A key subpopulation of neurons in the LH expresses orexin/hypocretin, a neuropeptide which is crucially involved in the regulation of the wake-sleep states and feeding behavior. The RPa receives orexinergic projections from the LH and orexinergic signalling in the RPa has been shown to enhance thermogenesis in the anaesthetized rat, but only in the presence of an already existing thermogenic drive, without significantly affecting cardiovascular function. The present work was aimed at exploring the effects on thermoregulation and autonomic function and the possible role in the modulation of the wake-sleep states and feeding behavior of orexin injection in the RPa in the free-behaving rat. In order to assess the influence of an already present thermogenic drive on orexinergic signalling in the RPa, animals were studied at three different ambient temperatures (Ta, 10°C, 24°C, and 32°C). We found that orexin injection into the RPa variably affected the wake-sleep states, autonomic functions, motor activity, and feeding behavior, at the different Tas. In particular, in the first post-injection hour, we observed an increase in wakefulness, which was large at Ta 24°C and Ta 10°C and rather mild at Ta 32°C. Deep brain temperature was increased by orexin injection at Ta 10°C, but not at either Ta 24°C or Ta 32°C. Moreover, an increase in mean arterial blood pressure occurred at Ta 24°C, which was probably masked by the high baseline levels at Ta 10°C and was completely absent at Ta 32°C. Finally, an enhancement in feeding behavior was observed at Ta 24°C and 10°C only. In accordance with what observed in anaesthetized rats, orexinergic signalling in the RPa seems to be ineffective in the absence of any thermogenic drive. Moreover, the effects observed on the wake-sleep states and feeding behavior introduce the RPa as a novel player in the central neural network promoting wakefulness and feeding.

Split Nasopharyngeal Airway, a Tracking Tool for Fibreoptic Nasotracheal Intubation: A Randomised Controlled Study

Introduction: Managing a challenging airway in awake, sedated, or anaesthetised patients has made Fibreoptic Intubation (FOI) using a flexible Fibreoptic Bronchoscope (FOB) a mainstay in clinical practice. Aim: To evaluate and compare fibreoptic nasotracheal intubation with or without Split Nasopharyngeal Airway (SNPA) as a conduit, focusing on time taken, ease of insertion, and haemodynamic changes. Materials and Methods: This randomised controlled study was conducted at the Department of Anaesthesiology and Critical Care, Pt. B.D. Sharma, PGIMS, Rohtak, Haryana, India, on 80 patients who were randomly allocated into two groups: Group CL (the control group without SNPA) and Group NP (with SNPA). Both groups were induced with general anaesthesia, and nostrils were prepared for FOB. In Group CL, a well-lubricated FOB was inserted into the selected nostril without using SNPA, and endotracheal intubation was performed. In Group NP, an appropriately sized SNPA was lubricated and inserted into the selected nostril. The fiberscope was passed through the SNPA, the vocal cords were visualised, and the SNPA was removed before railroading the preloaded tube through the vocal cords to confirm correct placement. The time taken for bronchoscopy and intubation, ease of insertion, haemodynamic parameters, and bleeding were recorded in both groups. The data was coded, entered, and analysed using Statistical Package for the Social Sciences (SPSS) version 20.0. A significance level was set at a p-value ≤0.05. Results: Demographic data, including age and gender distribution, mean weight, height, Body Mass Index (BMI), and airway parameters such as Mallampati grading, neck circumference, inter-incisor distance, and ASA grading, were standardised. There was no significant difference between the CL and NP groups regarding these parameters. The time taken for FOB and intubation in Group CL was 2.59±0.96 minutes and 3.61±1.04 minutes, respectively, compared to 1.87±0.91 minutes and 2.51±0.86 minutes in Group NP (p-value=0.001). The time taken to visualise the glottis was also shorter in the NP group (6.70±13.97 minutes) compared to the CL group (24.02±13.06 minutes), which was significant. Fibreoptic bronchoscopy was considered easy in 16 patients (40%) in Group CL and 27 patients (67.5%) in Group NP (p-value=0.04). The increase in mean arterial blood pressure was significantly higher in Group CL than in Group NP just after the insertion of the FOB into the nasopharynx (p-value=0.05). Conclusion: Fibreoptic nasotracheal intubation through an SNPA is less time-consuming and results in easier intubation. It causes less trauma to the nasal passage and leads to fewer haemodynamic variations in terms of mean arterial pressure and heart rate. Hence, SNPA is a better method for facilitating FOI compared to intubation without it.

Changes in Cardiac Structure and Function Following Fistula Ligation in Kidney Transplant Recipients (Cohort Study)

Purpose: International guidelines recommend that haemodialysis access is provided by an arteriovenous fistula (AVF), which enables frequent, reliable access to the circulation, but there are no guidelines to suggest whether these AVFs need to be ligated after kidney transplantation. Cardiovascular morbidity and mortality remain high in recipients of a kidney transplant, the persistence of a patent arteriovenous fistula (AVF) after transplantation may contribute to ongoing maladaptive cardiovascular remodelling. The ability to reverse this maladaptive remodelling by ligation of this AVF is unknown. We conducted this trial to evaluate the effect of AVF ligation on cardiac structure and function in stable kidney transplant recipients. Also we studied the ability of preoperative echocardiographic and non-invasive hemodynamic measurements, including the effects of acute temporary occlusion of the fistula, to predict postoperative left ventricular diameter and mass reduction, by the closure of the fistula.&#x0D; Materials and Methods: Nonrandomized controlled trial. kidney transplant recipients (&gt;12 months after transplantation with stable graft function) were divided into 2 groups. The first referred for surgical arteriovenous fistula closure. The second group didn’t receive Fistula closure (control). Standard echocardiographic parameters, heart rate, and blood pressure were assessed preoperatively (fistula closure) at baseline. These measurements were repeated 6 months after surgical closure.&#x0D; Findings: Seventeen kidney transplant patients were prospectively studied with 11 case and 6 controls with no fistula closure. Surgical fistula closure decreased left ventricular end-diastolic diameter and mass indexes (29.9_2.4to 27.4_2.1 mm/m2, P&lt;0.001, and 141_37 to 132_39 g/m2, P&lt;0.05, respectively), whereas no changes were seen in controls after a similar delay. Postoperative left ventricular end-diastolic diameter and mass reductions correlated best with the increases in total peripheral resistance (r_0.85, P&lt;0.0001) and mean arterial blood pressure (r_0.64, P_0.006), respectively.&#x0D; Conclusions. Surgical closure of arteriovenous fistula reduces left ventricular diameter and mass in kidney transplant recipients. The best predictors of those morphological changes are the rise in blood pressure and total peripheral resistance induced by temporary occlusion of the fistula.&#x0D; Implications to Theory, Practice and Policy: Surgical closure of persistent AV fistula after renal transplantation to correct LV geometry and improve symptoms in terms of exertional dyspnea and palpitations.

Deep Parasternal Intercostal Plane Block for Intraoperative Pain Control in Cardiac Surgical Patients for Sternotomy: A Prospective Randomized Controlled Trial

Sternotomy pain is common after cardiac surgery. The deep parasternal intercostal plane (DPIP) block is a novel technique that provides analgesia to the anterior chest wall. The aim of this study was to investigate the analgesic effect of bilateral DPIP blocks on intraoperative pain control in cardiac surgery. This is a double-blinded, prospective randomized controlled trial (Oct 2020-Dec 2022). This study was conducted in a single institution, which is an academic university hospital. Eighty-six elective cardiac surgical patients with median sternotomy were recruited. Patients were randomly divided into DPIP or control group. Either 20ml 0.25% levobupivacaine or 0.9% normal saline was injected for the DPIP under ultrasound guidance after induction of general anaesthesia. The primary outcome was intraoperative opioids consumption and hemodynamic changes at sternotomy. Secondary outcomes included postoperative morphine consumption, postoperative pain and time to tracheal extubation. Intraoperative opioids requirement was reduced from a median (IQR) intravenous morphine equivalence of 21.4mg (13.8-24.3mg) in control group to 9.5mg (7.3-11.2mg) in the DPIP group (P<0.001). Hemodynamic parameters were more stable in DPIP group at sternotomy, as evidenced by lower percentage increase in systolic, diastolic and mean arterial blood pressure from baseline. No difference was observed in time to tracheal extubation, postoperative morphine consumption, postoperative pain score and spirometry. Bilateral DPIP block provides effective intraoperative analgesia and opioid-sparing. It may be included as part of the multimodal analgesia for enhanced recovery in cardiac surgery.

Functional knockout of the TRPV1 channel has no effect on the exercise pressor reflex in rats.

The role played by the transient receptor potential vanilloid 1 (TRPV1) channel on the thin fibre afferents evoking the exercise pressor reflex is controversial. To shed light on this controversy, we compared the exercise pressor reflex between newly developed TRPV1+/+ , TRPV1+/- and TRPV1-/- rats. Carotid arterial injection of capsaicin (0.5μg), evoked significant pressor responses in TRPV1+/+ and TRPV1+/- rats, but not in TRPV1-/- rats. In acutely isolated dorsal root ganglion neurons innervating the gastrocnemius muscles, capsaicin evoked inward currents in neurons isolated from TRPV1+/+ and TRPV1+/- rats but not in neurons isolated from TRPV1-/- rats. The reflex was evoked by stimulating the tibial nerve in decerebrated rats whose femoral artery was either freely perfused or occluded. We found no difference between the reflex in the three groups of rats regardless of the patency of the femoral artery. For example, the peak pressor responses to contraction in TRPV1+/+ , TRPV1+/- and TRPV1-/- rats with patent femoral arteries averaged 17.1 ± 7.2, 18.9 ± 12.4 and 18.4 ± 8.6mmHg, respectively. Stimulation of the tibial nerve after paralysis with pancuronium had no effect on arterial pressure, findings which indicated that the pressor responses to contraction were not caused by electrical stimulation of afferent tibial nerve axons. We also found that expression levels of acid-sensing ion channel 1 and endoperoxide 4 receptor in the L4 and 5 dorsal root ganglia were not upregulated in the TRPV1-/- rats. We conclude that TRPV1 is not needed to evoke the exercise pressor reflex in rats whose contracting muscles have either a patent or an occluded arterial blood supply. KEY POINTS: A reflex arising in contracting skeletal muscle contributes to the increases in arterial blood pressure, cardiac output and breathing evoked by exercise. The sensory arm of the reflex comprises both mechanoreceptors and metaboreceptors, of which the latter signals that blood flow to exercising muscle is not meeting its metabolic demand. The nature of the channel on the metaboreceptor sensing a mismatch between supply and demand is controversial; some believe that it is the transient receptor potential vanilloid 1 (TRPV1) channel. Using genetically engineered rats in which the TRPV1 channel is rendered non-functional, we have shown that it is not needed to evoke the metaboreflex.

Increased Oxygen Saturation in Retinal Venules During Isometric Exercise Is Accompanied With Increased Peripheral Blood Flow in Normal Persons.

A recent study has shown that an increase in the arterial blood pressure of approximately 10 mm Hg in healthy persons can increase the oxygen saturation in venules from the retinal periphery but not from the macular area. The purpose of the present study was to investigate whether a higher increase in blood pressure has further effects on oxygen saturations and whether this is accompanied with changes in retinal blood flow. In 30 healthy persons, oxygen saturation, diameter, and blood flow were measured in arterioles to and venules from the retinal periphery and the macular area. The experiments were performed before and during an experimental increase in arterial blood pressure of (mean ± SD) 18.3 ± 6.2 mm Hg. A higher number of venules than arterioles branching from the temporal vascular arcades to the macular area was balanced by a smaller diameter of the venules. Isometric exercise induced significant contraction of both peripheral and macular arterioles (P<0.01 for both comparisons) and significant increase in oxygen saturation in both peripheral and macular venules (P<0.001 for both comparisons). This was accompanied with a significant increase in the blood flow in the peripheral arterioles and venules (P=0.4 for both comparisons), but not in their macular counterparts (P>0.06 for both comparisons). Increased systemic blood pressure leading to arterial contraction and increased venous oxygen saturation in the retina in normal persons can increase peripheral blood flow without significant effects on macular blood flow. This may contribute to explaining regional differences in the response pattern of retinal vascular disease.

TCD assessment in fulminant hepatic failure: Improvements in cerebral autoregulation after liver transplantation

Introduction and ObjectivesAcute liver failure, also known as fulminant hepatic failure (FHF), includes a spectrum of clinical entities characterized by acute liver injury, severe hepatocellular dysfunction and hepatic encephalopathy. The objective of this study was to assess cerebral autoregulation (CA) in 25 patients (19 female) with FHF and to follow up with seventeen of these patients before and after liver transplantation. Patients and MethodsThe mean age was 33.8 years (range 14–56, SD 13.1 years). Cerebral hemodynamics was assessed by transcranial Doppler (TCD) bilateral recordings of cerebral blood velocity (CBv) in the middle cerebral arteries (MCA). ResultsCA was assessed based on the static CA index (SCAI), reflecting the effects of a 20–30 mmHg increase in mean arterial blood pressure on CBv induced with norepinephrine infusion. SCAI was estimated at four time points: pretransplant and on the 1st, 2nd and 3rd posttransplant days, showing a significant difference between pre- and posttransplant SCAI (p = 0.005). SCAI peaked on the third posttransplant day (p = 0.006). Categorical analysis of SCAI showed that for most patients, CA was reestablished on the second day posttransplant (SCAI > 0.6). ConclusionsThese results suggest that CA impairment pretransplant and on the 1st day posttransplant was re-established at 48–72 h after transplantation. These findings can help to improve the management of this patient group during these specific phases, thereby avoiding neurological complications, such as brain swelling and intracranial hypertension.