Decrease In Systolic Arterial Pressure Research Articles

Показатели суточного мониторинга артериального давления у лиц старческого возраста c хронической сердечной недостаточностью в зависимости от жесткости сосудов

INTRODUCTION: Measurement of arterial pressure (AP) is a standard method for assessing the risk of developing cardiovascular diseases. Analysis of systolic and diastolic pressure, as well as their ratio, can help determine the risk of developing cardiovascular diseases. One of the ways to diagnose elevatedarterial pressure is daily monitoring of arterial pressure (DMAP). An increase in AP in the elderly is usually associated with an increase in the stiffness of the vascular walls. This leads to an increase in systolic arterial pressure (SAP) and pulse pressure (PP), as well as a decrease in diastolic arterial pressure (DAP). Elevated arterial pressure enhances the load on the heart and can lead to its pathological alterations. A decrease in DAP impairs the blood supply to the heart, which can cause ischemia and fibrosis; the result isdevelopment of diastolic dysfunction, which is the main cause of chronic heart failure (CHF). Currently, a promising way to determine the arterial stiffness is measurement of a cardio-ankle vascular index.The prognostic and diagnostic value of this parameter has been confirmed by numerous studies. It is important to study the parameters of the daily AP profile and arterial stiffness in older patients with CHF. This permits to identify malignant forms of elevated blood pressure, which can lead to cardiovascular complications. AIM: To study the characteristics of the parameters of the daily arterial pressure profile in elderly patients with CHF, depending on the vascular stiffness determined by volume sphygmography. MATERIALS AND METHODS: One hundred and twenty elderly patients with CHF undergoing treatment in a cardiology hospital were examined. By the method of volume sphygmography, the patients were divided into groups with ‘vessels of normal stiffness’ (group 1) and ‘stiff vessels’ (group 2), with subsequentDMAP. A statistical analysis of the parameters of the daily AP profile in the groups was performed. RESULTS: In patients of group 1, both daytime and nighttime SAP, DAP and PP, were significantly higher than in patients of group 2. Besides, in group 1, there was a nighttime decrease in SAP and DAP, while the morning rise of SAP was statistically higher in group 2, and no differences were recorded between the groups in the morning rise of DAP. When assessing the ankle-brachial index in patients of group 2, daytime and nighttime SAP and DAP were statistically higher. In group 1 (with probable peripheral atherosclerosis), PP was higher both during the day and at night. The nocturnal decrease in SAP was statistically higher in group 2, while the nocturnal decrease in DAP prevailed in group 1. The morning rise of SAP and DAP was higher in group 1. CONCLUSION: The DMAP data may indicate to some extent the severity of hypertension in patients with CHF, and this probably depends on the ‘stiffness of the vessels’. In elderly patients with CHF with ‘normal stiffness’ of vessels, the parameters of the daily arterial pressure profile were higher than in patients with ‘stiff vessels’. However, the daily range of parameters of the daily arterial pressure profile was greater in the group of patients with ‘stiff vessels’ (group 2).

Prueba de volumen en el quirófano: subestudio planificado del estudio observacional Fluid Day

BackgroundIntraoperative fluid administration is a ubiquitous intervention in surgical patients. But inadequate fluid administration may lead to poor postoperative outcomes. Fluid challenges (FCs), in or outside the so-called goal-directed fluid therapy, allows testing the cardiovascular system and the need for further fluid administration. Our primary aim was to evaluate how anesthesiologists conduct FCs in the operating room in terms of type, volume, variables used to trigger a FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC. MethodsThis was a planned substudy of an observational study conducted in 131 centers in Spain in patients undergoing surgery. ResultsA total of 396 patients were enrolled and analyzed in the study. The median [interquartile range] amount of fluid given during a FC was 250mL (200-400). The main indication for FC was a decrease in systolic arterial pressure in 246 cases (62.2%). The second was a decrease in mean arterial pressure (54.4%). Cardiac output was used in 30 patients (7.58%), while stroke volume variation in 29 of 385 cases (7.32%). The response to the initial FC did not have an impact when prescribing further fluid administration. ConclusionsThe current indication and evaluation of FC in surgical patients is highly variable. Prediction of fluid responsiveness is not routinely used, and inappropriate variables are frequently evaluated for assessing the hemodynamic response to FC, which may result in deleterious effects.

Physiological benefits of lung recruitment in the semi-lateral position after laparoscopic surgery: a randomized controlled study

We evaluated the physiological benefits of performing lung recruitment maneuver (LRM) in the semi-lateral position compared in the supine position. Seventy-nine patients undergoing laparoscopic prostatectomy were randomly assigned to either the supine or semi-lateral group according to body position during the LRM. At the end of surgery, LRM (35 cmH2O for 20 s) was performed twice in the assigned posture. The primary outcome was the maximal decrease in systolic arterial pressure during LRM. Secondary outcomes were changes in PaO2/FiO2 and the regional lung volume distribution after LRM. The decrease in systolic arterial pressure during the LRM was significantly higher in the supine group than in the semi-lateral group (mean ± standard deviation, [−] 27.6 ± 14.6% vs. [−] 18.6 ± 9.9%, P = 0.001). Improvement in PaO2/FiO2 ratio after the LRM was evident in both groups but was more prominent in the semi-lateral group than in the supine group (median [interquartile range], 39.3% [20.2, 63.6] vs. 18.2% [8.4, 29.2], P = 0.001). Among the horizontal lung divisions, regional lung volume in the most dependent portion (the dorsal division) was significantly increased after the LRM only in the semi-lateral group (P = 0.024). Performing lung recruitment in a semi-lateral position protected against hemodynamic deterioration during the LRM and increased regional lung ventilation in the dependent portion of the lung, leading to an improvement in arterial oxygenation after laparoscopic procedures.Trial registration Clinical Research Information Service (https://cris.nih.go.kr/). Identifier: KCT0003756.

Relationship between Hepatic Venous Anatomy and Blood Loss: Proposal of Vena Cava Half-Clamp with Trendelenburg Posture to Control Hepatic Venous Bleeding during Hepatectomy

Introduction: Predicting increased blood loss based on anatomical intervascular relationships is essential in major hepatectomy to understand the mechanism of hepatic venous bleeding. Method: We assessed 63 consecutive patients undergoing anatomical hepatectomy exposing the hepatic vein (HV) trunk at two institutes. Correlations between anatomical alterations of the hepatic inferior vena cava (IVC), HV, hepatic IVC, or right atrium (RA) and the blood loss per standard weight (BLSW) or blood transfusion (n=18) were analyzed. The results of IVC partial clamping (PC) were additionally examined. Result: The BLSW in type V-up anatomical morphology was significantly higher than that in straight type (p<0.05). The parameters associated with an increased BLSW (>13.5 mL/kg) were tumour size (>4 cm), prothrombin activity (<87%), CVP (>7 mmHg), area of suprahepatic IVC (<360 mm2), IVC-RA gap (>28 mm), longitudinal angle of IVC (<160°), and axial angle of the MHV (<55°). Multivariate analysis revealed that a high IVC-RA gap was a significant independent risk factor (odds ratio; 4.3, p<0.05). Among 25 patients undergoing IVC-PC, only three showed a remarkable decrease in hepatic venous bleeding. Although IVC-PC led to a decrease in systolic arterial pressure and difficult to control systemic circulation in many cases, the combined Trenderenburg posture could solve this problem. Conclusions: The IVC-RA gap might be a promising novel predictive parameter reflecting increased blood loss leading to blood transfusion in anatomical hepatectomy. Further, in the case of increased IVC gap and hepatic venous bleeding is difficult, our proposal combined procedure is feasible、easy, safe and useful.

Associated factors with umbilical arterial pH after cesarean delivery under spinal anesthesia: a retrospective cohort study

BackgroundMaximum decrease of blood pressure and number of minutes of hypotension were independently associated with umbilical arterial pH. However, the impact of hypotension considering the duration of it on umbilical arterial pH is unknown. MethodsPregnant women aged ≥ 20 years who delivered a baby at full-term via a cesarean delivery under a single-shot spinal anesthesia between January 2017 and March 2019 were included. The main outcome was to predict umbilical arterial pH, based on the value of the time integral of hypotension. Patient demographics, patient comorbidities, and intraoperative data, including the total dose of ephedrine and phenylephrine by fetal delivery and cumulative duration of maternal hypotension, were evaluated. Maternal hypotension was reflected as a decrease in systolic arterial pressure and mean arterial pressure to < 80% of baseline values. The systolic arterial pressure and mean arterial pressure were independently included in a multiple regression analysis along with all other explanatory factors to predict the umbilical arterial pH. ResultsOf the 416 eligible patients, 381 were enrolled. When including the systolic arterial pressure or mean arterial pressure in the model, emergency cases, the total dose of ephedrine, hypertensive disorders of pregnancy, and systolic arterial pressure or mean arterial pressure values were found to be significant predictive factors of umbilical arterial pH. ConclusionOur results suggest that an elevated time integral of maternal hypotension may have a negative impact on umbilical arterial pH. Therefore, to minimize the risk of fetal acidosis, maternal hypotension should be prevented with the consideration of vasopressors selection.

Arterial stiffness as a risk factor for hypotension during induction of general anesthesia

IntroductionHypotension after induction of general anaesthesia is identified as an independent factor in predicting adverse clinical outcomes. Preoperative evaluation of arterial stiffness could identify patients with an impaired vascular function and an altered haemodynamic response to induction of general anaesthesia. The purpose of this study is to investigate the relationship between arterial stiffness and blood pressure variation during induction of general anaesthesia.Material and methodsThis was an observational study that included patients who underwent surgical procedures under general anaesthesia. We used several systolic arterial pressure and mean arterial pressure thresholds for defining hypotension. Both absolute thresholds and thresholds relative to a baseline blood pressure were chosen based on the most frequently used definitions. Patient carotid-femoral pulse wave velocity determination, preoperative preparation, and induction of general anaesthesia were standardized.ResultsOur study included 115 patients. Both univariate and multivariate analysis showed that carotid-femoral pulse wave velocity was significantly associated with post-induction hypotension when defined as a systolic arterial pressure decrease of &gt; 30% or &gt; 40% from baseline or as a mean arterial pressure decrease of &gt; 40% from baseline. Also, carotid-femoral pulse wave velocity was positively associated with duration of post-induction hypotension.ConclusionsPreoperative assessment of arterial stiffness identifies patients at risk of a pronounced decrease in blood pressure during induction of general anaesthesia.

Mental disorders in type 2 diabetes

To assess the prevalence of mental disorders in patients with type 2 diabetes mellitus (DM2) and their relationship with laboratory findings, somatic comorbidities and psychosocial consequences. In the frames of the INTERPRET-DD multicenter 200 T2DM patients from primary care (47 men and 153 women) from the Russian sample were studied. The psychometric assessment included MINI-6, HAMD-17, PHQ-9, PAID, WHO-5. One hundred and seventeen patients (58.5%) have mental disorders. Current mental disorders were diagnosed in 93 (46.5%) of patients. Depression (depressive episode, recurrent depressive disorder, bipolar affective disorder type II) was identified in 34 (17.0%), dysthymia in 26 (13.0%), and anxiety spectrum disorders in 39 (19.5%). In about half of the cases, anxiety disorders were combined with depression. The most severe problems were observed in the patients with depression and dysthymia. Patients with social phobia had significantly higher levels of glycated hemoglobin compared to patients without mental disorders. The significant decrease of systolic arterial pressure and body mass index was observed in patients with agoraphobia compared to patients without mental disorders. In addition, there was an increased prevalence of chronic ischemic heart disease in recurrent depression, dysthymia and generalized anxiety disorder, higher prevalence of neuropathy in depressive episode and recurrent depression and nephropathy in panic disorder. Depressive and anxiety disorders, as well as severe psychosocial problems, are consistently associated with T2DM. At the same time, concomitant somatic disorders and complications of DM2 are not just by chance comorbid to various forms of mental disorders, which allows for a new look at the problem of comorbidity/multimorbidity in T2DM.

Evaluation of arterial stiffness in patients with schizophrenia

The aim of this study was to evaluate arterial stiffness in schizophrenia patients. 28 male patients were included. The intima-media thickness (IMT) of the vessels were taken using high-resolution ultrasonography system. The mean carotid IMT and the mean femoral IMT values of the study group were found to be statistically significantly higher than the values of the control group. As the duration of the disease increased, there was an increase in the carotid IMT, carotid elastic modulus and femoral IMT, whereas there was a decrease in carotid and femoral diastolic wall stress in patients. No statistically significant differences were observed between the groups’ carotid and femoral compliance, distensibility and elastic modulus values. The mean systolic arterial blood pressure in the patient group was determined to be lower than that of the control group. The mean diastolic wall stress values in the carotid and femoral arteries were determined to be lower than those of the control group. There was no relationship between antipsychotic dose, blood pressure and arterial stiffness parameters. Schizophrenia patients are more prone to develop arterial stiffness by atherosclerosis either with the effect of the nature of the disease itself or antipsychotic treatment. But evaluation with more parameters (carotid and femoral compliance, distensibility and elastic modulus) did not indicate any difference from the control group in respect of arterial stiffness. Antipsychotic treatment may play a protective role in terms of arterial stiffness by causing a decrease in systolic arterial pressure and carotid and femoral diastolic wall stress.

P1249SEVERE HEMODYNAMIC INSTABILITY DURING DIALYSIS - DRY, STUNNED OR ALLERGIC? STATE OF THE ART ECHOCARDIOGRAPHY COMBINED WITH SIMULTANEOUS LUNG ULTRASOUND

Abstract Background and Aims Intradialytic hypotension is a fairly common and serious adverse phenomenon. Associated comorbidities include e.g. heart failure, hypovolemia, allergic reactions with the dialysis apparatus and electrolyte disturbancies. Excessive ultrafiltration may explain later onset hypotension, but early-onset hemodynamic collapse remains poorly understood. Preventive interventions may include incremental dialysis, increasing dry weight, increasing dialysis time and changing dialysis membranes/apparatus. This study combines Echocardiography (Echo) and Lung Ultrasound (LUS) for hemodynamic phenotyping of patients with severe, early onset intra-dialytic hypotension. The aim is to figure out possible preventive strategies depending on underlying abnormalities. Method We enrolled dialysis patients with a symptomatic decrease in systolic arterial pressure &amp;lt; 90 mmHg requiring norepinephrine during the first 60 minutes of at least two consecutive dialysis sessions in our dialysis department. Echo + LUS was done simultaneously to everyone at baseline, i.e. BEFORE dialysis begun, and later at onset of a hypotension episode during dialysis. Patients with active bleeding or any other obvious temporary etiology for hypotension were excluded. Echo concentrated especially on volemic state and filling pressures, while LUS evaluated the lungs and pleurae for signs of pulmonary congestion. Cardiac structure and function (e.g. valves, ejection fraction) was also evaluated. Results Between 1.10.2019 - 31.12.2019 10 patients were enrolled. All patients eventually required norepinephrine despite fluid challenge. No patients had signs or symptoms of an allergic reaction, such as urticaria or stridor/obstructive respiration, nor significant electrolyte disturbancies. 5/10 patients had severe systolic cardiac dysfunction at baseline (LVEF &amp;lt; 30 %) and these 5 patients also simultaneously showed signs of congestion and fluid overload on ultrasound. On the contrary, the other 5/10 patients without severe cardiac failure all had low left-sided filling pressures and a collapsed inferior vena cava on Echo ALREADY at baseline, i.e. before initiation of dialysis. All of these hypovolemic patients had an excellent residual diuresis (&amp;gt; 1500ml/d). All 10 patients in this study showed a significant drop in body volume measurement (BVM) -curves and left-sided filling pressures on Echo prior to onset of hypotension. Of the 5 patients with severe cardiac dysfunction, 2/5 were transmitted into palliative care without dialysis, while 3/5 could be managed without future norepinephrine by longer, more frequent dialysis sessions using more convective and less diffusive dialysis. Of the latter 5 “dry” patients without severe cardiac dysfunction, 3/5 had no more hypotensive episodes after increasing dry weight and using incremental dialysis programs, and the remaining 2 dry patients could be completely switched off dialysis due to vivid residual function. 3/5 of the “dry patients” had a baseline pulse pressure &amp;gt; 120 mmHg and 3 had coronary artery disease, both possibly predisposing to diastolic under-filling. No patients in this study presented with significant myocardial stunning, defined as a &amp;gt; 10 % decrease in LVEF compared to baseline. Conclusion Severe, intra-dialytic hypotension requiring vasopressors may be prevented by individual tailoring of dialysis prescription. Ultrasound may help phenotyping patients requiring different dialysis strategies, including stopping dialysis entirely. Stunning and allergic reactions seemed rare. At baseline, patients seemed to be mainly 1) either over-dialyzed (hypovolemic or hypo-osmotic) or 2) having significant cardiac disease, naturally requiring quite opposite preventive strategies. A decrease in left ventricular preload furthermore occurred in all patients at onset of hypotension, suggesting crossover of a patient-specific preload threshold.

A randomised double-blind dose–response study of weight-adjusted infusions of norepinephrine for preventing hypotension during combined spinal–epidural anaesthesia for Caesarean delivery

BackgroundNorepinephrine infusion has been suggested as an effective method for preventing hypotension during spinal anaesthesia for Caesarean delivery. However, optimal dosing regimens for norepinephrine have not been well established. This study aimed to determine the dose–response characteristics of a weight-adjusted fixed-rate infusion of norepinephrine to prevent hypotension during neuraxial anaesthesia for Caesarean delivery. MethodsIn a double-blind, randomised controlled trial, 80 parturients having elective Caesarean delivery received a prophylactic norepinephrine infusion at 0.025 μg kg−1 min−1 (Group N1), 0.05 μg kg−1 min−1 (Group N2), 0.075 μg kg−1 min−1 (Group N3), or 0.10 μg kg−1 min−1 (Group N4), starting immediately after induction of combined spinal–epidural anaesthesia. The primary outcome was non-occurrence of hypotension, defined as a decrease in systolic arterial pressure ≥20% below baseline value or to ≤90 mm Hg, before delivery. Values for 50% effective dose (ED50) and ED90 were calculated using probit regression. ResultsThe incidence of hypotension was 11/20 (55%), 6/20 (30%), 2/20 (10%), and 1/20 (5%) in Groups N1, N2, N3, and N4, respectively (P<0.0001). The ED50 and ED90 (95% confidence interval) of norepinephrine infusions for preventing hypotension were 0.029 (–0.002 to 0.043) and 0.080 (0.065–0.116) μg kg−1 min−1, respectively. The incidence of reactive hypertension increased with increasing norepinephrine dose (P=0.002). Other adverse effects were similar among groups. ConclusionsUnder the conditions of this study, an infusion of norepinephrine 0.08 μg kg−1 min−1 was effective for preventing hypotension in 90% of patients. This information should provide a guide for initiating norepinephrine infusions. Clinical trial registrationChiCTR1900022322 at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/enindex.aspx).

Energy-dependent effect trial of photobiomodulation on blood pressure in hypertensive rats.

The main purpose of this work was to construct an energy-dependent response curve of photobiomodulation on arterial pressure in hypertension animal model. To reach this objective, we have used a two-kidney one clip (2K-1C) rat model. Animals received acute laser light irradiation (660nm) on abdominal region using different energy (0.6, 1.8, 3.6, 7.2, 13.8, 28.2, 55.8, and 111.6J), the direct arterial pressure was measured by femoral cannulation, and systolic arterial pressure (SAP), diastolic arterial pressure (DAP), heart rate (HR), and time of effect were obtained. Our results indicated that 660nm laser light presents an energy-dependent hypotensive effect, and 28.2J energy irradiation reached the maximum hypotensive effect, inducing a decreased SAP, DAP, and HR (decrease in SAP: - 19.23 ± 1.82mmHg, n = 11; DAP: - 9.57 ± 2.23mmHg, n = 11; HR: - 39.15 ± 5.10bpm, n = 11; and time of hypotensive effect: 3068.00 ± 719.00s, n = 11). The higher energy irradiation evaluated (111.6J) did not induce a hypotensive effect and induced an increase in HR (21.69 ± 7.89bpm, n = 7). Taken together, our results indicate that red laser energy irradiation from 7.2 to 55.8J is the effective therapeutic window to reduce SAP, DAP, MAP, and HR and induce a long-lasting hypotensive effect in rats, with effect loss at higher energy irradiation (111.6J).

Renalase, Catecholamine and Nitric Oxide Changes Before and After Sodium Nitroprusside Administration to Patients who Develop Post-Coronary Artery By-Pass (CABG) Hypertension.

Hypertension develops at a rate of 33 to 70% after Coronary artery bypass grafting (CABG) operations. One of the most commonly used drugs to control hypertension is sodium nitroprusside (SNP). Additionally, renalase enzyme destroys catecholamines and mediates the regulation (reduction) of blood pressure. Thus, this clinical study aims to reveal how renalase, catecholamines and nitric oxide (NO) change and how certain hemodynamic parameters are affected in randomly and prospectively selected cases who are administered SNP for the treatment of blood pressure elevation within 6 to 8 hours after CABG surgery. The study included 26 patients who developed hypertension after CABG, 12 patients who had normal blood pressure after CABG, and 22 healthy individuals. Renalase and catecholamine levels of the patients were measured using ELISA method and NO levels were determined by spectrophotometry. Renalase and NO levels of the patients who developed hypertension after CABG were found statistically significantly lower than those of healthy controls and patients who did not develop hypertension after CABG, while catecholamine levels were significantly higher in the former. After SNP was started, renalase and NO levels increased, and a significant decrease was observed in the catecholamine levels. Additionally, administration of SNP produced a slight increase in the heart rate and a decrease in systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and means arterial pressure (MAP). SNP elevates NO and renalase levels; thus, administration of renalase preparations, which act in the destruction of catecholamines to contain persistent hypertension that develops in association with catecholamine elevation after CABG surgery, along with SNP and other medications used to lower blood pressure can be an effective therapeutic method to control hypertension.

Effect of omeprazole on antihypertensive efficacy of amlodipine in patients with comorbid pathology – arterial hypertension and acid-dependent disease

Objective:The problem of drug interactions is increasingly important today because they may induce serious adverse events as well as interfere with efficacy of pharmacotherapy. Combinations of drugs are most often prescribed to patients presenting with comorbid pathology. The incidence of a combination of arterial hypertension (AH) and acid-dependent diseases (ADDs) varies widely ranging from 11.6 to 50%. One of combinations of drugs prescribed to such patients is a combination of calcium channel blocker amlodipine and proton pump inhibitor omeprazole. The latter in the human body undergoes biotransformation mediated at the level of cytochrome P450 by isoenzymes CYP2C19 and CYP3A4. Amlodipine is a substrate of the isoenzyme CYP3A4, which increases the probability of the development of interaction between these drugs. The purpose of our study was to investigate antihypertensive efficacy of amlodipine in patients suffering from arterial hypertension combined with acid-dependent diseases and additionally taking omeprazole.Method:Study included a total of 150 patients with AH and ADD. Antihypertensive therapy was evaluated by means of office measuring of arterial pressure (AP) and circadian monitoring of AP (CMAP). The followed-up patients with AH and ADD were divided into 2 groups. Group One was composed of hypertensive patients undergoing pharmacotherapy with 10 mg amlodipine, whose condition required due to exacerbation of ADD administration of omeprazole at a dose of 20 mg for a period from 3 to 4 weeks. Group Two comprised hypertensive patients receiving antihypertensive therapy consisting of 10 mg amlodipine, who were found to have remission of acid-dependent diseases, with no additional medication taken.Results:The obtained findings demonstrated that one of the commonly used drug combinations in treatment of patients with AH and ADD in ambulatory conditions was a combination of omeprazole and amlodipine, accounting for 7.1%. The results of office measurement of arterial pressure (AP) 2 weeks after initiating pharmacotherapy with omeprazole in patients with AH and ADD demonstrated that the patients receiving omeprazole in addition to antihypertensive therapy were found to have a statistically significant decrease in systolic arterial pressure (SAP) and statistically significantly more pronounced dynamics of a decrease in diastolic arterial pressure (SAP) (p<0.05) compared with those not receiving therapy with omeprazole. Also, in the group of patients taking omeprazole, the findings of circadian monitoring of blood pressure (CMAP) showed a statistically significant decrease in average circadian SAP, average circadian DAP, mean value of daytime SAP and mean value of nighttime SAP (p<0.05).Conclusion:The obtained findings demonstrated that simultaneous prescription of amlodipine and omeprazole to patients with concomitant pathology, i.e., AH and ADD, turned out to enhance the antihypertensive affect of amlodipine, which probably resulted from substrate competition of amlodipine and omeprazole at the level isoenzyme CYP 3A4 of cytochrome P450.

Hypotensive acute effect of photobiomodulation therapy on hypertensive rats

The purpose of this study was to evaluate the acute effect of photobiomodulation therapy (PBM) on arterial pressure in hypertensive and normotensive rats with application in an abdominal region. Normotensive (2K) and hypertensive (2K-1C) wistar rats were treated with PBM. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP) and heart rate (HR) were measured before, during and after PBM application. The nitric oxide (NO) serum concentration was measured before and after PBM application. Vascular reactivity study was performed in isolated thoracic aortas. Aluminum gallium arsenide (GaAlAs) diode laser was used, at 660nm wavelength and 100mW optical output.The PBM application induced a decrease of SAP in 2K-1C rats. In 2K rats, the PBM application had no effect on SAP, DAP and MAP. Moreover, the magnitude of hypotensive effect was higher in 2K-1C than in 2K rats. The PBM application induced a decrease of HR in 2K-1C and 2K, with higher effect in 2K-1C rats. In 2K-1C, the hypotensive effect induced by PBM was longer than that obtained in 2K rats. PBM application induced an elevation of NO concentration in serum from 2K-1C and 2K rats, with higher effect in 2K-1C. In isolated aortic rings PBM effect is dependent of NO release, and is not dependent of nitric oxide synthase (NOS) activation. Our results indicate that the abdominal acute application of PBM at 660nm is able to induce a long lasting hypotensive effect in hypertensive rats and vasodilation by a NO dependent mechanism.

Cardiorespiratory parameters in the awake pigeon and during anaesthesia with isoflurane

ObjectiveTo determine baseline cardiovascular and respiratory variables in the awake pigeon, and to assess those variables during anaesthesia at the individual minimal anaesthetic concentration (MAC) of isoflurane during spontaneous breathing. Study designProspective, experimental trial. AnimalsSeven healthy adult pigeons weighing a mean ± standard deviation (SD) of 438 ± 38 g. MethodsHeart rate (HR), heart rhythm, respiratory rate (fR), end-expired carbon dioxide tension (Pe’CO2), indirect systolic arterial pressure (SAP) and cloacal temperature (T) were measured in birds in the awake state (after acclimatization to handling). Two weeks later, the pigeons were anaesthetized with isoflurane in order to determine their MAC and evaluate the same cardiovascular and respiratory variables during a further 40 minutes of isoflurane anaesthesia. ResultsIn the awake pigeon, mean ± SD HR, SAP, fR, Pe’CO2 and T were, respectively, 155 ± 28 beats minute−1, 155 ± 21 mmHg, 34 ± 6 breaths minute−1, 38 ± 8 mmHg (5.1 ± 1.1 kPa) and 41.8 ± 0.5 °C. Mean isoflurane MAC was 1.8 ± 0.4%. During maintenance of anaesthesia at MAC, although no significant decreases between values obtained in the awake and anaesthetized states emerged in HR or respiratory rate, significant decreases in SAP and cloacal temperature and an increase in Pe’CO2 were observed. No arrhythmia was identified in awake pigeons, whereas second- and third-degree atrioventricular blocks occurred under isoflurane. Conclusions and clinical relevanceIsoflurane MAC in pigeons appeared to be higher than in other avian species. Isoflurane anaesthesia in pigeons resulted in hypercapnia, hypotension, mild hypothermia and second- and third-degree atrioventricular blocks.

Abstract 18257: A Novel Portable Polyvinylidene Fluoride Based Sensor for Detection of Hemorrhage

Introduction: Hemorrhage (Hem) is one of the leading causes of mortality from trauma, and continuous monitoring for Hem using techniques such as traditional BP, especially in field conditions, poses significant challenges. We have built a portable low-powered noninvasive sensor for continuous vascular tone monitoring to detect significant Hem as an alternative to BP monitoring. The sensor, made of polyvinylidene fluoride (PVDF) material, can sense and record changes in the mechanical properties of arteries due to peripheral vasoconstriction caused by Hem. Methods: Nine pigs underwent Hem by femoral artery bleeding. Systolic arterial pressure (SAP) was used to select 16 instances of significant hemorrhage (SAP&gt;85mmHg pre-Hem and &gt;10mmHg drop in SAP post-Hem). The PVDF signal was measured from the animal’s distal forelimb. A piecewise linear estimation of the PVDF signal was computed using a newly developed Taut String algorithm such that the error was &lt;4% of the signal amplitude. The number of pieces in each period was used as a complexity score (CS) to detect Hem. Results: Arterial BP and the CS derived from the PVDF signal for one subject (Fig), as well as snapshots from the PVDF signal demonstrating morphology changes are shown. Maximum separation between pre- and post-Hem CS was achieved by a threshold of 5.5; 14 instances (87.5%) transitioned from CS≥6 to 5 within 5 minutes of the onset of HS (t0) while the remaining 2 instances transitioned from CS=5 to 3. The average detection delay was 1.95±1.2 min. These changes corresponded to &gt;10mmHg decrease in SAP from baseline. CS improved during subsequent resuscitations. Conclusions: The proposed low-powered portable sensor captures continuous vascular tone and can be used to detect significant Hem in a continuous manner that may offer diagnostic and therapeutic guidance as an alternative to traditional intermittent BP measures. The results indicate that the derived CS can effectively separate the signals pre- and post-Hem.

English

AIMS: In this study, we compared the effect of preloading with crystalloid, colloid and intravenous ephedrine against the hypotensive effects of propofol induction in ASA I-II patients scheduled for elective surgical procedures. MATERIAL AND METHODS: 120 patients aged 20yrs to 50yrs were randomly allocated to one of the four groups of 30patients each. Group-1 (control) did not receive any study medication, group-2 received degraded gelatin 10ml/kg over a period of 15min, group-3 received ringer lactate 20ml/kg over a period of 15 min and group-4 received intravenous ephedrine 0.2mg/kg prior to induction of anesthesia. Midazolam 1mg was given 1hour before induction of anesthesia. Anesthesia was induced with propofol 2.5mg/kg over 20 to 30 seconds. Heart rate and blood pressure were recorded before induction and then every minute for 5 minutes after induction of anesthesia. After the study period patients were intubated and anesthesia was continued as required. Hypotension was defined as a drop in systolic arterial pressure more than or equal to 20% of baseline. RESULTS: A significant decrease in systolic arterial pressure occurred in patients of group preloaded with ringer lactate as well as the control group. Less decrease in systolic arterial pressure was seen in the patients preloaded with degraded gelatine and ephedrine group. The incidence of hypotension was also lower in ephedrine group when compared with degraded gelatin group. CONCLUSION: We conclude that crystalloid preloading is not efficacious in preventing hypotension while as degraded gelatine and ephedrine markedly attenuates, but does not fully abolish the decrease in blood pressure caused by induction.

THE EFFECTS OF VIBROACOUSTICALLY-INDUCED MICROVIBRATIONS ON ARTERIAL BLOOD PRESSURE AND OXIDATIVE STRESS IN RATS

Abstract Vibroacoustics is a scientific field which has been intensively developed for the last thirty years; it uses the capabilities of sound (infrasound, ultrasound, noise and music) to induce vibrations, which, like a sound, may have useful or harmful effects. The aim of this paper was to examine the effects of vibroacoustically-induced microvibrations on arterial blood pressure and markers of oxidative stress in the rat blood. The experiments were done on Wistar male rats, 180-200 g body mass, divided into control and experimental groups (6 rats in each). In the experimental group, microvibrations were induced using vibroacoustic apparatus (the so-called phoning, Vitafon, St. Petersburg, Russian Federation ), with total of 60 min phoning time in 4 different application regimes, (5-minute-stabilization time, each 10-minute phoning regime each with 5-minute-breaks between single regimes, 30Hz-18000 kHz frequency rates and 2.8 μm-12.3 μm microwave amplitudes, kidney and liver phoning). After the completion of phoning experimental protocol, the animals were sacrificed and the values of oxidative stress markers were analyzed in blood samples (O 2 - , H 2 O 2 , nitrites, lipid peroxidation index, superoxide dismutase, catalase, glutathione) and compared with the values of markers in the control group. The analysis of values of systolic arterial pressure after acute application of different regimes of vibroacoustic microvibrations showed statistically significant decrease of systolic arterial pressure during the administration of the second regime in comparison to the control group. Systolic arterial pressure was found to return to nearly initial value after the application of vibrocoustic microvibrations in the third and fourth regimes. The analysis of values of diastolic arterial pressure after acute administration of vibroacoustic microvibrations in four different regimes did not show statistically significant decrease of diastolic arterial pressure in any regimes, although the pressure tended to decrease in the first and second regimes. Diastolic arterial pressure was found to return to nearly initial value after the administration of vibrocoustic microvibrations in the third and fourth regimes. The obtained results showed the occurrence of high statistically significant differences in catalase, while no statistically significant differences were found in relation to other analyzed parameters, although positive trend was observed after the phoning. Further research is necessary in order to define the applicative effects of low in regard to high frequencies of the vibroacoustically-induced microvibrations and physiological, i.e. possible therapeutic significance of the registered effects. Key words: vibroacoustics, arterial blood pressure, oxidative stress, microvibrations

ANG-(3–4) inhibits renal Na+-ATPase in hypertensive rats through a mechanism that involves dissociation of ANG II receptors, heterodimers, and PKA

The physiological roles of ANG-(3-4) (Val-Tyr), a potent ANG II-derived peptide, remain largely unknown. The present study 1)investigates whether ANG-(3-4) modulates ouabain-resistant Na(+)-ATPase resident in proximal tubule cells and 2) verifies whether its possible action on pumping activity, considered the fine tuner of Na(+) reabsorption in this nephron segment, depends on blood pressure. ANG-(3-4) inhibited Na(+)-ATPase activity in membranes of spontaneously hypertensive rats (SHR) at nanomolar concentrations, with no effect in Wistar-Kyoto (WKY) rats or on Na(+)-K(+)-ATPase. PD123319 (10(-7) M) and PKA(5-24) (10(-6) M), an AT2 receptor (AT2R) antagonist and a specific PKA inhibitor, respectively, abrogated this inhibition, indicating that AT2R and PKA are central in this pathway. Despite the lack of effect of ANG-(3-4) when assayed alone in WKY rats, the peptide (10(-8) M) completely blocked stimulation of Na(+)-ATPase induced by 10(-10) M ANG II in normotensive rats through a mechanism that also involves AT2R and PKA. Tubular membranes from WKY rats had higher levels of AT2R/AT1R heterodimers, which remain associated in 10(-10) M ANG II and dissociate to a very low dimerization state upon addition of 10(-8) M ANG-(3-4). This lower level of heterodimers was that found in SHR, and heterodimers did not dissociate when the same concentration of ANG-(3-4) was present. Oral administration of ANG-(3-4) (50 mg/kg body mass) increased urinary Na(+) concentration and urinary Na(+) excretion with a simultaneous decrease in systolic arterial pressure in SHR, but not in WKY rats. Thus the influence of ANG-(3-4) on Na(+) transport and its hypotensive action depend on receptor association and on blood pressure.

Midazolam, as a co-induction agent, has propofol sparing effects but also decreases systolic blood pressure in healthy dogs

ObjectiveTo evaluate the effects of the co-administration of midazolam on the dose requirement for propofol anesthesia induction, heart rate (HR), systolic arterial pressure (SAP) and the incidence of excitement. Study designProspective, randomized, controlled and blinded clinical study, with owner consent. AnimalsSeventeen healthy, client owned dogs weighing 28 ± 18 kg and aged 4.9 ± 3.9 years old. MethodsDogs were sedated with acepromazine 0.025 mg kg−1 and morphine 0.25 mg kg−1 intramuscularly (IM), 30 minutes prior to induction of anesthesia. Patients were randomly allocated to receive midazolam (MP; 0.2 mg kg−1) or sterile normal saline (CP; 0.04 mL kg−1) intravenously (IV) over 15 seconds. Propofol was administered IV immediately following test drug and delivered at 3 mg kg−1 minute−1 until intubation was possible. Scoring of pre-induction sedation, ease of intubation, quality of induction, and presence or absence of excitement following co-induction agent, was recorded. HR, SAP and respiratory rate (fR) were obtained immediately prior to, immediately following, and 5 minutes following induction of anesthesia. ResultsThere were no significant differences between groups with regard to weight, age, gender, or sedation. Excitement occurred in 5/9 dogs following midazolam administration, with none noted in the control group. The dose of propofol administered to the midazolam group was significantly less than in the control group. Differences in HR were not significant between groups. SAP was significantly lower in the midazolam group compared with baseline values 5 minutes after its administration. However, values remained clinically acceptable. Conclusions and clinical relevanceThe co-administration of midazolam with propofol decreased the total dose of propofol needed for induction of anesthesia in sedated healthy dogs, caused some excitement and a clinically unimportant decrease in SAP.