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Hemodynamic Parameters (hemodynamic + parameter)

Distribution by Scientific Domains

Medical Sciences	97%

Distribution within Medical Sciences

Cardiovascular Disease	23%
Pharmacology & Pharmaceutical Medicine	8%

Selected Abstracts

Combination of B-Type Natriuretic Peptide Levels and Non-Invasive Hemodynamic Parameters in Diagnosing Congestive Heart Failure in the Emergency Department

CONGESTIVE HEART FAILURE, Issue 4 2004
Erin Barcarse BS
This study aimed to assess whether the combination of a B-type natriuretic peptide (BNP) level with various noninvasive hemodynamic parameters can help physicians more quickly and accurately diagnose congestive heart failure and determine the type of left ventricular dysfunction present in patients presenting to the emergency department with dyspnea. Subjects were 98 men (aged 64.57±1.23 years) that presented to the VA San Diego Healthcare System. Hemodynamic parameters were measured using impedance cardiography, and BNP levels were quantified using a rapid immunoassay. All patients with a BNP <100 pg/mL (n=37) had no evidence of congestive heart failure 97% of the time. In those with a BNP >100 pg/mL (601 ±55 pg/mL; n=61), a cardiac index of 2.6 L/min/m2 is 65% sensitive and 88% specific in determining systolic dysfunction. In patients with a BNP >100 pg/mL, a multivariate model consisting of noninvasive hemodynamic measurements was able to predict cardiac deaths, readmissions, and emergency department visits within 90 days with 83% accuracy. The authors conclude that, in patients presenting to an emergency department with dyspnea, the addition of impedance cardiography measurements to BNP level measurements will more effectively diagnose congestive heart failure and determine both the type of heart dysfunction and the severity of illness. [source]

Arterial blood gases in extraperitoneal laparoscopic urethrocystopexy

INTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2002
Hasan Kocoglu
Abstract Background: The aim of this study was to investigate the effects of extraperitoneal laparoscopy and carbon dioxide insufflation on hemodynamic parameters, arterial blood gases and complications in urethrocystopexy operations. Methods: Twenty-five female patients who underwent extraperitoneal laparoscopic mesh urethrocystopexy operation for the correction of urinary incontinence were allocated to the study. Hemodynamic parameters were noted and blood gas analyzes were performed before the induction of anesthesia, 10 min after induction, 5 and 10 min after the beginning of carbon dioxide insufflation, at the end of carbon dioxide insufflation and 30 min after exsufflation. Results: There was no significant change in mean arterial pressure, peripheral oxygen saturation, arterial carbon dioxide pressure, and arterial oxygen saturation compared to preinsufflation and preinduction values. End-tidal carbon dioxide pressure did not increase above 45 mm/Hg during carbon dioxide insufflation. Arterial oxygen saturation and partial oxygen pressure did not decrease. Subcutaneous emphysema, pneumothorax, pneumomediastinum and pleural effusion were not noted in any patient. Conclusion: We conclude that, extraperitoneal laparoscopic urethrocystopexy is not associated with hemodynamic and respiratory impairment. [source]

Myocardial Contractility and Cardiac Filling Measured by Impedance Cardiography in Patients with Nitroglycerine-Induced Vasovagal Syncope

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2006
PETER MITRO
Objective: Increased myocardial contractility and inadequate cardiac filling leading to activation of the Bezold-Jarisch reflex were proposed as possible triggering mechanisms of vasovagal syncope (VVS). In the present study noninvasive hemodynamic measurements were performed in order to examine the role of myocardial contractility and cardiac filling in pathogenesis of VVS. Methods: Hemodynamic parameters were measured during head-up tilt test (HUT) by impedance cardiography in 46 patients with unexplained syncope. Myocardial contractility was measured as index of contractility (IC), acceleration index (ACI), and ejection fraction (EF). Afterload was measured as systemic vascular resistance index (SVRI) and preload was expressed as end-diastolic index (EDI). Serial measurements were done 1 minute before HUT, during HUT at 1-minute intervals, and 1 minute after completion of HUT. Results: HUT was positive in 30 patients (10 men, 20 women, mean age 36 ± 16 years) and negative in 16 patients (8 men, 8 women, mean age 31 ± 14 years). No significant differences were observed between HUT(+) and HUT(,) groups in hemodynamic parameters at supine rest and during HUT until the development of syncope. SVRI was lower in HUT(+) than in HUT(,) group at syncope (122.7 + 66.3 vs 185.6 + 51.4 dyn sec cm,5/m2, P = 0.002) and after syncope (117.0 + 61.1 vs 198.0 + 95.7 dyn sec cm,5/m2, P = 0.007). ACI, IC, EF, and EDI did not differ between groups at syncope. After syncope EF was higher in HUT(+) group compared to HUT(,) group (59.2 + 6.1 vs 52.7 + 9.4%, P = 0.02). Conclusion: The role of increased myocardial contractility and decreased cardiac filling is not confirmed in the present study. [source]

Cardioprotective effect of sasanquasaponin preconditioning via bradykinin-NO pathway in isolated rat heart

PHYTOTHERAPY RESEARCH, Issue 8 2009
Zhangping Liao
Abstract Sasanquasaponin (SQS) is an effective component of Camellia oleifera Abel. This study was designed to investigate the cardioprotective effect of SQS against ischemia-reperfusion (I/R) injury and the possible mechanism in isolated rat hearts. These hearts were pretreated by SQS only or SQS and HOE140 in different groups, and then subjected to I/R injury. Hemodynamic parameters, oxidative injury, and NO level were measured. The results showed that SQS preconditioning could decrease the incidences of arrhythmias and improve the heart functions. In addition, SQS preconditioning could protect isolated I/R injured heart against lipid peroxidation, as evidenced by increases in SOD and GSH-Px activity, and by decreases in contents of MDA, ROS generation. However, HOE140 treatment reversed all these indexes. NO production was significantly decreased after a treatment with HOE140. So we can propose that SQS preconditioning could induce the cardioprotective effects and the possible mechanism was that the activation of bradykinin-NO system by SQS preconditioning had an inhibition effect on ROS generation in isolated heart. Copyright © 2009 John Wiley & Sons, Ltd. [source]

ORIGINAL RESEARCH,PHARMACOTHERAPY: Hemodynamic Effects of Sildenafil Citrate and Isosorbide Mononitrate in Men with Coronary Artery Disease and Erectile Dysfunction

THE JOURNAL OF SEXUAL MEDICINE, Issue 3 2005
Graham Jackson
ABSTRACT Introduction., Mild hemodynamic effects have been reported with sildenafil citrate therapy. Aim., To compare the hemodynamic effects of sildenafil and isosorbide mononitrate (ISMN) in men with coronary artery disease and erectile dysfunction. Methods., A total of 31 men aged 35 years or older with coronary artery disease (at least 50% narrowing of the left main stem or at least 70% narrowing of any other coronary artery) and erectile dysfunction (receiving medication for erectile dysfunction or scoring less than 26 out of a maximum score of 30 on the erectile function domain questions of International Index of Erectile Function) were randomized to sildenafil 100 mg (n = 10), ISMN 40 mg (n = 11), or placebo (n = 10) in this single-dose multicenter study. Main Outcome Measures., Hemodynamic parameters were measured at baseline, 1, 2, 4, and 6 hours post dose. Results., Compared with baseline, cardiac index increased slightly with sildenafil (0.29 L/min/m2 at 1 hour) and decreased slightly with placebo (,0.12 L/min/m2 at 4 hours) and ISMN (,0.14 L/min/m2 at 1 hour). The stroke volume index increased from baseline at each time point post dose with sildenafil (4.4 mL/m2 at 2 hours), but decreased with ISMN (,5.8 mL/m2 at 1 hour) and placebo (,2.8 mL/m2 at 4 hours). ISMN reduced mean arterial pressure more than sildenafil did (,22 vs. ,10 mm Hg at 2 hours, respectively). Both sildenafil and ISMN increased heart rate (4 vs. 7 beats/minute at 1 hour, respectively) and decreased systemic vascular resistance, but sildenafil produced greater reductions in pulmonary vascular resistance. There were no serious adverse events in the sildenafil group. Conclusions., Sildenafil 100 mg was well tolerated and induced smaller changes in central and peripheral hemodynamic pressures compared with ISMN 40 mg. Moreover, sildenafil selectively reduced pulmonary resistance, which may have clinical importance in pulmonary hypertension. [source]

Correlation of Plasma and Peritoneal Diasylate Clomipramine Concentration with Hemodynamic Recovery after Intralipid Infusion in Rabbits

ACADEMIC EMERGENCY MEDICINE, Issue 2 2009
MBChB, Martyn Harvey FACEM
Abstract Objectives:, Drug sequestration to an expanded plasma lipid phase has been proposed as a potential mechanism of action for lipid emulsions in lipophilic cardiotoxin overdose. The authors set out to document plasma and peritoneal diasylate clomipramine concentration after resuscitation with lipid emulsion in a rabbit model of clomipramine-induced hypotension. Methods:, Twenty sedated mechanically ventilated New Zealand White rabbits were allocated to receive either 12 mL/kg 20% Intralipid or 12 mL/kg saline solution, following clomipramine infusion to 50% baseline mean arterial pressure (MAP). Hemodynamic parameters and serum clomipramine concentration were determined to 59 minutes. Peritoneal dialysis with 20% Intralipid or saline solution was evaluated for clomipramine concentration. Results:, Mean arterial pressure was greater in lipid-treated animals as assessed by repeated-measures analysis of variance (F[1,14] = 6.84; p = 0.020). Lipid infusion was associated with elevated plasma clomipramine concentration and reduced initial volume of distribution (Vd; 5.7 [±1.6] L/kg lipid vs. 15.9 [±7.2] L/kg saline; p = 0.0001). Peritoneal diasylate clomipramine concentration was greater in lipid-treated animals (366.2 [±186.2] ,g/L lipid vs. 37.7 [±13.8] ,g/L saline; p = 0.002). Conclusions:, Amelioration of clomipramine-induced hypotension with lipid infusion is associated with reduced initial Vd and elevated plasma clomipramine concentration consistent with intravascular drug,lipid sequestration. Concomitant peritoneal dialysis with lipid emulsion enhances clomipramine extraction. [source]

An Alternative Hemostatic Dressing: Comparison of CELOX, HemCon, and QuikClot

ACADEMIC EMERGENCY MEDICINE, Issue 1 2008
Buddy G. Kozen MD
Abstract Objectives:, Uncontrolled hemorrhage remains a leading cause of traumatic death. Several topical adjunct agents have been shown to be effective in controlling hemorrhage, and two, chitosan wafer dressing (HemCon [HC]) and zeolite powder dressing (QuikClot [QC]), are being utilized regularly on the battlefield. However, recent literature reviews have concluded that no ideal topical agent exists. The authors compared a new chitosan granule dressing (CELOX [CX]) to HC, QC and standard dressing in a lethal hemorrhagic groin injury. Methods:, A complex groin injury with transection of the femoral vessels and 3 minutes of uncontrolled hemorrhage was created in 48 swine. The animals were then randomized to four treatment groups (12 animals each). Group 1 included standard gauze dressing (SD); Group 2, CX; Group 3, HC; and Group 4, QC. Each agent was applied with 5 minutes of manual pressure followed by a standard field compression dressing. Hetastarch (500 mL) was infused over 30 minutes. Hemodynamic parameters were recorded over 180 minutes. Primary endpoints included rebleed and death. Results:, CX reduced rebleeding to 0% (p < 0.001), HC to 33% (95% CI = 19.7% to 46.3%, p = 0.038), and QC to 8% (95% CI = 3.3% to 15.7%, p = 0.001), compared to 83% (95% CI = 72.4% to 93.6%) for SD. CX improved survival to 100% compared to SD at 50% (95% CI = 35.9% to 64.2%, p = 0.018). Survival for HC (67%) (95% CI = 53.7% to 80.3%) and QC (92%; 95% CI = 84.3% to 99.7%) did not differ from SD. Conclusions:, In this porcine model of uncontrolled hemorrhage, CX improved hemorrhage control and survival. CELOX is a viable alternative for the treatment of severe hemorrhage. [source]

The Utility of Heart Sounds and Systolic Intervals Across the Care Continuum

CONGESTIVE HEART FAILURE, Issue 2006
W. Frank Peacock MD
Acoustic cardiography is an exciting, new, easy-to-use, modernized technology that incorporates already proven techniques of phonocardiography. Application of acoustic cardiography to clinical practice can improve diagnosis and management of heart failure patients. Its clinical use should help address some of the need for robust, inexpensive, and widely accessible technology for proactive heart failure diagnosis and management. Acoustic cardiographically recorded measurements have been correlated with both cardiac catheterization and echocardiographically determined hemodynamic parameters. Heart sounds captured by acoustic cardiograms have proven to assist clinicians in assessing dyspneic patients in the emergency department by utilizing the strong specificity of an S3 for detecting acute decompensated heart failure. Acoustic cardiography offers a cost-efficient, easy-to-use method to optimize the devices used in cardiac resyncronization therapy. The rapidly and easily obtainable information gathered by acoustic cardiography should foster its more widespread use in diagnosis and treatment of heart failure, including cardiac resyncronization therapy device optimization. [source]

The Utility of Heart Sounds and Systolic Intervals Across the Care Continuum

Acute and Chronic Oral Magnesium Supplementation: Effects on Endothelial Function, Exercise Capacity, and Quality of Life in Patients With Symptomatic Heart Failure

CONGESTIVE HEART FAILURE, Issue 1 2006
Johanna C. Fuentes MD
Endothelial dysfunction is an important pathophysiologic mechanism in the progression of heart failure. The objective of the present study was to determine the effects of acute and chronic oral magnesium supplementation on endothelial function in patients with symptomatic heart failure. Twenty-two symptomatic chronic heart failure patients were randomized to receive 800 mg oral magnesium oxide daily or placebo for 3 months. Data collected included large and small arterial elasticity/compliance, hemodynamic parameters, exercise capacity, and quality-of-life score at baseline, 1 week, and 3 months. Patients who received magnesium had improved small arterial compliance at 3 months from baseline compared with placebo. This study suggests that chronic supplementation with oral magnesium is well tolerated and could improve endothelial function in symptomatic heart failure patients. [source]

Combination of B-Type Natriuretic Peptide Levels and Non-Invasive Hemodynamic Parameters in Diagnosing Congestive Heart Failure in the Emergency Department

Effects of Delaying Fluid Resuscitation on an Injury to the Systemic Arterial Vasculature

ACADEMIC EMERGENCY MEDICINE, Issue 4 2002
James F. Holmes MD
Abstract. Objectives: To determine the effects of delaying fluid on the rate of hemorrhage and hemodynamic parameters in an injury involving the arterial system. Methods: Twenty-one adult, anesthetized sheep underwent left anterior thoracotomy and transection of the left internal mammary artery. A chest tube was inserted into the thoracic cavity to provide a continuous measurement of blood loss. The animals were randomly assigned to one of three resuscitation protocols: 1) no fluid resuscitation (NR), 2) standard fluid resuscitation (SR) begun 15 minutes after injury, or 3) delayed fluid resuscitation (DR) begun 30 minutes after injury. All of the animals in the two resuscitation groups received 60 mL/kg of lactated Ringer's solution over 30 minutes. Blood loss and hemodynamic parameters were measured throughout the experiment. Results: Total hemorrhage volume (mean ± SD) at the end of the experiment was significantly lower (p = 0.006) in the NR group (1,499 ± 311 mL) than in the SR group (3,435 ± 721 mL) or the DR group (2,839 ± 1549 mL). Rate of hemorrhage followed changes in mean arterial pressure in all groups. Hemorrhage spontaneously ceased significantly sooner (p = 0.007) in the NR group (21 ± 14 minutes) and the DR group (20 ± 15 minutes) than in the SR group (54 ± 4 minutes). In the DR group, after initial cessation of hemorrhage, hemorrhage recurred in five of six animals (83%) with initiation of fluid resuscitation. Maximum oxygen (O2) delivery in each group after injury was as follows: 101 ± 34 mL O2/kg/min at 45 minutes in the DR group, 51 ± 20 mL O2/kg/min at 30 minutes in the SR group, and 35 ± 8 mL O2/kg/min at 60 minutes in the NR group. Conclusions: Rates of hemorrhage from an arterial injury are related to changes in mean arterial pressure. In this animal model, early aggressive fluid resuscitation in penetrating thoracic trauma exacerbates total hemorrhage volume. Despite resumption of hemorrhage from the site of injury, delaying fluid resuscitation results in the best hemodynamic parameters. [source]

A clinical prospective comparison of anesthetics sensitivity and hemodynamic effect among patients with or without obstructive jaundice

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2010
L.-Q. YANG
Background: To compare isoflurane anesthesia in patients with or without hyperbilirubinemia undergoing hepatobiliary surgery. Methods: Forty-two patients with obstructive jaundice and 40 control patients with normal liver function scheduled for hepatobiliary surgery under isoflurane anesthesia were studied. Anesthesia was induced with propofol (1.5,2 mg/kg) and remifentanil (2 ,g/kg). After tracheal intubation, anesthesia was titrated using isoflurane in oxygen-enriched air, adjusted to maintain a bispectral index (BIS) value of 46,54. Ephedrine, atropine and remifentanil were used to maintain hemodynamic parameters within 30% of the baseline. The mean arterial blood pressure (MAP), heart rate (HR), drug doses and the time taken to recover from anesthesia were recorded. Results: Demographic data, duration and BIS values were similar in both groups. Anesthesia induction and maintenance were associated with more hemodynamic instability in the patients with jaundice and they received more ephedrine and atropine and less remifentanil and isoflurane (51.1±24.2 vs. 84.6±20.3 mg/min; P for all <0.05) than control patients. Despite less anesthetic use, the time to recovery and extubation was significantly longer than that in control. Conclusion: Patients with obstructive jaundice have an increased sensitivity to isoflurane, more hypotension and bradycardia during anesthesia induction and maintenance and a prolonged recovery time compared with controls. [source]

Arterial blood gases in extraperitoneal laparoscopic urethrocystopexy

Strong relationship between NT-proXNP levels and cardiac output following cardiac surgery in neonates and infants

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2010
T. BREUER
Background: NT-proXNP, a new natriuretic peptide analyte, incorporates information about the concentrations of both N-terminal pro-atrial and pro-brain natriuretic peptides (NT-proANP, NT-proBNP). We aimed to investigate whether NT-proXNP is a reliable indicator of the cardiac index (CI) and the hemodynamic state in neonates and infants undergoing an open heart surgery. Methods: We enrolled 26 children under the age of 1 year into this prospective study. All patients underwent an elective cardiac operation with cardiopulmonary bypass (CPB) to achieve complete biventricular repair. Peri-operative hemodynamic parameters were assessed by transpulmonary thermodilution and natriuretic peptide levels were recorded. Results: The NT-proXNP level correlated significantly with the simultaneously measured NT-proANP level (r=0.60, P<0.001), but more strongly with the NT-proBNP level (r=0.89, P<0.001) and the arithmetic sum of both (r=0.88, P<0.001). NT-proXNP had a strong correlation with CI (r=,0.85, P<0.001), the stroke volume index (r=,0.80, P<0.001) and the global ejection fraction (r=,0.67, P<0.009) throughout the post-operative period. Conventionally measured parameters such as heart rate, mean arterial pressure and pulse-pressure product exhibited weaker correlations with CI than NT-proXNP. Among laboratory values, creatinine levels correlated significantly with CI (r=,0.77, P<0.001) and NT-proXNP (r=0.76, P<0.001) during the post-operative period. A post-operative NT-proXNP level of 3079 pmol/l was diagnostic for CI <3 l/min/m2 with 89% sensitivity and 90% specificity (area under the curve: 0.91 ± 0.05). Conclusion: NT-proXNP is a good marker of cardiac output following pediatric cardiac surgery and might be a useful tool in the recognition of a low output state. [source]

Temporary Epicardial Ventricular Stimulation in Patients with Atrial Fibrillation: Acute Effects of Ventricular Pacing Site on Bypass Graft Flows

JOURNAL OF CARDIAC SURGERY, Issue 4 2009
Navid Madershahian M.D.
This study aimed to evaluate the optimal epicardial ventricular pacing site in patients with AF following coronary artery bypass surgery (CABG). Methods: In 23 consecutive patients (mean age = 69.2 ± 1.9 years, gender = 62% male, ejection fraction [EF]= 50.4 ± 2.1%) monoventricular stimulations (VVI) were tested with a constant pacing rate of 100 bpm. The impact of ventricular pacing on bypass graft flow (transit-time flow probe) and pulsatility index (PI) were measured after lead placement on the mid paraseptal region of the right (RVPS) and the left (LVPS) ventricle, on the right inferior wall (RVIW), and on the right ventricular outflow tract (RVOT). In addition, hemodynamic parameters were measured. Patients served as their own control. Results: Comparison of all tested pacing locations revealed that RVOT stimulation provided the highest bypass grafts flows (59.9 ± 6.1 mL/min) and PI (2.2 ± 0.1) when compared with RVPS (51.3 ± 4.7 mL/min, PI = 2.6 ± 0.2), RVIW (54.0 ± 5.1 mL/m; PI = 2.4 ± 0.2), and LVPS (53.1 ± 4.5 mL/min; PI = 2.3 ± 0.1), respectively (p < 0.05). When analyzing patients according to their preoperative LV function (group I = EF > 50%; group II = EF < 50%), higher bypass graft flows were observed with RVOT pacing in patients with lower EF (p = n.s.). Conclusions: Temporary RVOT pacing facilitates optimal bypass graft flows when compared with other ventricular pacing sites and should be the preferred method of temporary pacing in cardiac surgery patients with AF. Especially in patients with low EF following CABG, RVOT pacing may improve myocardial oxygen conditions for the ischemic myocardium and enhance graft patency in the early postoperative period. [source]

Effects of pentoxifylline on coagulation profile and disseminated intravascular coagulation incidence in Egyptian septic neonates

JOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 3 2010
M. Adel Msc
Summary Background and objectives:, Neonatal sepsis is frequently associated with pathological activation of the coagulation system, leading to microcirculatory derangement and multiple organ dysfunction syndrome (MODS). The key role in the pathogenesis of sepsis has been attributed to proinflammatory cytokines. These trigger the development of disseminated intravascular coagulation (DIC) via the tissue factor-dependent pathway of coagulation. Pentoxifylline (PTX), a methylxanthine derivative that is used in peripheral vascular disease, has the potential to modify inflammatory response. The current work was designed to evaluate the potential protective effects of PTX against sepsis-induced microcirculatory derangement in Egyptian neonates. Methods:, A double-blind placebo-controlled quasi-randomized design was used. Thirty-seven neonates with sepsis were randomly allocated into two groups. Seventeen patients were given PTX (5 mg/kg/h for 6 h; for 6 successive days). Twenty patients received equivalent volume of normal saline and represented the placebo group. Prothrombin time (PT), Activated partial thromboplastin time (APTT), fibrinogen, d -dimer, C-reactive protein (CRP), complete blood count (CBC), also hemodynamic parameters comprising arterial blood pressure, heart rate, capillary refill and urinary output were assessed in both groups before and after treatment. Results:, Coagulation parameters in the two groups showed no significant differences. However, a higher incidence of DIC was observed in the placebo group neonates. PTX significantly lowered the percentage of bleeding (P = 0·0128) and less frequent use of FFP was observed in the PTX group (35·53% in PTX group vs. 80% in placebo group, P = 0·003). Incidence of MODS was significantly lower (P = 0·037) and hospital stay duration of survivors was significantly shorter (P = 0·044) in the PTX treated-infants. Conclusion:, Pentoxifylline protects against sepsis-induced microcirculatory derangement in neonates. It significantly lowered the incidence of bleeding and MODS and shortened the length of hospital stay. [source]

Magnetic resonance brain perfusion imaging with voxel-specific arterial input functions

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2006
Renate Grüner MSc
Abstract Purpose To propose an automatic method for estimating voxel-specific arterial input functions (AIFs) in dynamic contrast brain perfusion imaging. Materials and Methods Voxel-specific AIFs were estimated blindly using the theory of homomorphic transformations and complex cepstrum analysis. Wiener filtering was used in the subsequent deconvolution. The method was verified using simulated data and evaluated in 10 healthy adults. Results Computer simulations accurately estimated differently shaped, normalized AIFs. Simple Wiener filtering resulted in underestimation of flow values. Preliminary in vivo results showed comparable cerebral flow value ratios between gray matter (GM) and white matter (WM) when using blindly estimated voxel-specific AIFs or a single manually selected AIF. Significant differences (P , 0.0125) in mean transit time (MTT) and time-to-peak (TTP) in GM compared to WM was seen with the new method. Conclusion Initial results suggest that the proposed method can replace the tedious and difficult task of manually selecting an AIF, while simultaneously providing better differentiation between time-dependent hemodynamic parameters. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc. [source]

Pretreatment with melatonin exerts anti-inflammatory effects against ischemia/reperfusion injury in a rat middle cerebral artery occlusion stroke model

JOURNAL OF PINEAL RESEARCH, Issue 2 2004
Zhong Pei
Abstract:, Inflammatory response following cerebral ischemia/reperfusion plays a key pathogenic role in ischemic cerebral damage. Nitric oxide (NO), cyclooxygenase-2 (COX-2) and myeloperoxidase (MPO) are important inflammatory mediators. Neuronal NO synthase (nNOS) is a major initial source of excessive NO during ischemia/reperfusion. Induction of COX-2 and infiltration of polymorphonuclear cells expressing MPO are critical factors in delayed inflammatory damage. Previously, we demonstrated that administration of melatonin before ischemia significantly reduced the infarct volume in a rat middle cerebral artery occlusion (MCAO) stroke model. In this study, we examined the effect of pretreatment with melatonin at 5 mg/kg on the immunoreactivity (ir) for nNOS, COX-2, MPO, and glial fibrillary acidic protein (GFAP) at 24, 48, and 72 hr after right-sided endovascular MCAO for 1 hr in adult male Sprague,Dawley rats. Melatonin did not affect the hemodynamic parameters. When compared with rats with sham MCAO, ischemia/reperfusion led to an ipsilateral increase in cells with positive ir for nNOS (similar at all times) and in ir-GFAP (similar at all times). Ischemia/reperfusion led to appearance of cells with positive ir for COX-2 (greatest at 24 hr with a tendency to increase again at 72 hr) or MPO (greatest at 24 hr). A single dose of melatonin significantly lessened the ipsilateral increase in cells with positive ir for nNOS, COX-2 or MPO, but did not influence the ipsilateral change in ir-GFAP. Our results suggest that melatonin treatment mediates neuroprotection against ischemia/reperfusion injury partly via inhibition of the consequential inflammatory response. [source]

Divergent effects of ephedrine and phenylephrine on cardiovascular hemodynamics of near-term fetal sheep exposed to hypoxemia and maternal hypotension

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2007
T. Erkinaro
Background:, We hypothesized that the administration of ephedrine and phenylephrine for maternal hypotension modifies cardiovascular hemodynamics in near-term sheep fetuses. Methods:, At 115,136 days of gestation, chronically instrumented, anesthetized ewes with either normal placental function or increased placental vascular resistance after placental embolization were randomized to receive boluses of ephedrine (n = 12) or phenylephrine (n = 12) for epidural-induced hypotension after a short period of hypoxemia. Fetal cardiovascular hemodynamics were assessed by Doppler ultrasonography at baseline, during hypotension and after vasopressor treatment. Results:, During hypotension, fetal PO2 decreased and proximal branch pulmonary arterial and pulmonary venous vascular impedances increased. Additionally, in the embolized fetuses, the time-velocity integral ratio between the antegrade and retrograde blood flow components of the aortic isthmus decreased. These parameters were restored to baseline conditions by ephedrine but not by phenylephrine. With phenylephrine, weight-indexed left ventricular cardiac output and ejection force decreased in the non-embolized fetuses, and the proportion of isovolumetric contraction time of the total cardiac cycle was elevated in the embolized fetuses. Conclusions:, After exposure to hypoxemia and maternal hypotension, ephedrine restored all fetal cardiovascular hemodynamic parameters to baseline. Phenylephrine did not reverse fetal pulmonary vasoconstriction or the relative decrease in the net forward flow through the aortic isthmus observed in fetuses with increased placental vascular resistance. Moreover, fetal left ventricular function was impaired during phenylephrine administration. [source]

Hemodynamic profile and tissular oxygenation in orthotopic liver transplantation: Influence of hepatic artery or portal vein revascularization of the graft

LIVER TRANSPLANTATION, Issue 11 2006
Carlos Moreno
We performed a prospective, randomized study of adult patients undergoing orthotopic liver transplantation, comparing hemodynamic and tissular oxygenation during reperfusion of the graft. In 30 patients, revascularization was started through the hepatic artery (i.e., initial arterial revascularization) and 10 minutes later the portal vein was unclamped; in 30 others, revascularization was started through the portal vein (i.e., initial portal revascularization) and 10 minutes later the hepatic artery was unclamped. The primary endpoints of the study were mean systemic arterial pressure and the gastric-end-tidal carbon dioxide partial pressure (PCO2) difference. The secondary endpoints were other hemodynamic and metabolic data. The pattern of the hemodynamic parameters and tissue oxygenation values during the dissection and anhepatic stages were similar in both groups At the first unclamping, initial portal revascularization produced higher values of mean pulmonary pressure (25 ± 7 mm of Hg vs. 17 ± 4 mm of Hg; P < 0.05) and wedge and central venous pressures. At the second unclamping, initial portal revascularization produced higher values of cardiac output and mean arterial pressure (87 ± 15 mm of Hg vs. 79 ± 15 mm of Hg; P < 0.05) and pulmonary blood pressure. Postreperfusion syndrome was present in 13 patients (42.5%) in the arterial group and in 11 patients (36%) in the portal group. During revascularization, the values of gastric and arterial pH decreased in both groups and recovered at the end of the procedure, but were more accentuated in the initial arterial revascularization group. In conclusion, we found that initial arterial revascularization of the graft increases pulmonary pressure less markedly, so it may be indicated for those patients with poor pulmonary and cardiac reserve. Nevertheless, for the remaining patients, initial portal revascularization offers more favorable hemodynamic and metabolic behavior, less inotropic drug use, and earlier normalization of lactate and pH values. Liver Transpl, 2006. © 2006 AASLD. [source]

Predictive models of short- and long-term survival in patients with nonbiliary cirrhosis

LIVER TRANSPLANTATION, Issue 3 2003
Gérald Longheval
The limited number of donor organs has placed a burden on the medical community to improve patient selection and timing of liver transplantation (LT). We aim to evaluate short- and long-term survival of 124 consecutive patients with a diagnosis of nonbiliary cirrhosis. Seventeen clinical, biochemical, functional, and hemodynamic parameters were computed. Patient survival was evaluated in the short term (3 months) by logistic regression, and the predictive power of the model was evaluated using receiver operating characteristic curves and the log likelihood ratio. For the long-term (up to 5 years) prognosis, the Cox proportional model was used. During follow-up, 54 patients died and 20 patients underwent LT. In the short-term study, the Model for End-Stage Liver Disease score (including bilirubin level, international normalized ratio [INR], and creatinine level) was as predictive as our score, which contained only two independent indicators (bilirubin and creatinine levels). In the long-term study, three independent variables (albumin level, INR, and creatinine level) emerged from the Cox model, and patients were classified into three survival-risk groups according to a prognostic index (PI): ,1.039 × albumin (grams per deciliter) + 1.909 × loge INR + 1.207 × loge serum creatinine (milligrams per deciliter). Survival probabilities at 1 and 5 years were 89% and 80%, 63% and 52%, and 23% and 10% with a low, medium, and high PI, respectively. The validation study using the split-sample technique and data from independent patients confirmed that a high PI (>,2.5) identifies patients with a poor prognosis within 5 years. We thus have shown and validated that risk for death at the short and long term of patients with nonbiliary cirrhosis can be predicted with great accuracy using models containing a few simple and easily obtained objective variables, and these survival models are useful tools in clinical decision making, especially in deciding to list patients for LT and prioritization on the liver waiting list. [source]

Effect of acute acoustic stress on anorectal function and sensation in healthy humans,

NEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2005
S. Gonlachanvit
Abstract, Little is known about the effects of acute acoustic stress on anorectal function. To determine the effects of acute acoustic stress on anorectal function and sensation in healthy volunteers. Ten healthy volunteers (7 M, 3 F, mean age 34 ± 3 years) underwent anorectal manometry, testing of rectal compliance and sensation using a barostat with and without acute noise stress on separate days. Rectal perception was assessed using an ascending method of limits protocol and a 5-point Likert scale. Arousal and anxiety status were evaluated using a visual analogue scale. Acoustic stress significantly increased anxiety scores (P < 0.05). Rectal compliance was significantly decreased with acoustic stress compared with control (P < 0.000001). In addition, less intraballoon volume was needed to induce the sensation of severe urgency with acoustic stress (P < 0.05). Acoustic stress had no effect on hemodynamic parameters, anal sphincter pressure, threshold for first sensation, sensation of stool, or pain. Acute acoustic stimulation increased anxiety scores, decreased rectal compliance, and enhanced perception of severe urgency to balloon distention but did not affect anal sphincter pressure in healthy volunteers. These results may offer insight into the pathogenesis of stress-induced diarrhoea and faecal urgency. [source]

Myocardial Contractility and Cardiac Filling Measured by Impedance Cardiography in Patients with Nitroglycerine-Induced Vasovagal Syncope

Effect of oriental herbal prescription Guan-Xin-Er-Hao on coronary flow in healthy volunteers and antiapoptosis on myocardial ischemia-reperfusion in rat models

PHYTOTHERAPY RESEARCH, Issue 10 2007
Jianlei Zhao
Abstract Ischemic heart disease (IHD) is the main cause of death and a major public health problem in the world. The traditional herbal medicinal formula Guan-Xin-Er-Hao (GXEH) has been used in China and East Asia for the treatment of coronary heart disease, however, the underlying cardioprotection mechanisms remain unclear. To make clear the antiischemic mechanism involved, GXEH was orally administered to 15 healthy volunteers. Heart rates (HR), blood pressure and coronary flow (CF) velocity before and 1 h after a single oral dose of GXEH were observed and compared. It was demonstrated that the oral administration of GXEH increased CF acutely in a dose-dependent manner without modification of systemic hemodynamic parameters. Moreover, the myocardial protection function of GXEH was also experimentally examined in ischemia-reperfusion (I/R) rat models. Apoptosis was measured quantitatively by the terminal transferase UTP nick end-labeling (TUNEL) method and confirmed by caspase-3 activity. The infarct size and TUNEL-positive cells of GXEH-treated group (20 g/kg) were reduced significantly, which was consistent with the decreased caspase-3 activity. These suggest that GXEH protects hearts from ischemia injury by increasing CF and reduces infarct size by inhibiting myocardial apoptosis. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Numerical Simulation of Hemodynamic Changes During Beating-heart Surgery: Analysis of the Effects of Cardiac Position Alteration in an Animal Model

ARTIFICIAL ORGANS, Issue 1 2007
Gianfranco Ferrari
Abstract:, Hemodynamic instability, mostly due to vertical lifting of the heart, is usually observed during beating-heart surgical procedures. However, some hemodynamic parameters, such as coronary blood flow, are not routinely measured. A digital computer model of the circulation able to simulate and analyze the effects of heart lifting and the Trendelenburg maneuver, and thus supply detailed hemodynamic information to the clinicians would provide a useful analytical tool. A lumped parameters model of the circulation was applied to both ,-blocked and not ,-blocked pigs. The results confirmed a drop of cardiac output and coronary flow during heart lifting and a rise of both variables after the Trendelenburg maneuver for ,-blocked animals. In not ,-blocked pigs, the analysis was more complex but the model reproduced experimental data and permitted coronary flow to be estimated. These results showed the feasibility of numerical simulation for specific circulatory conditions encountered during beating-heart surgery. [source]

Hemodynamics of a Pulsatile Left Ventricular Assist Device Driven by a Counterpulsation Pump in a Mock Circulation

ARTIFICIAL ORGANS, Issue 4 2006
Ashraf William Khir
Abstract:, The BCM (CardialCare, Minneapolis, MN, U.S.A.) is a pusher-plate pulsatile left ventricular assist device (LVAD) that is operated by counterpulsation pumps. The purpose of this work was to assess the fluid dynamics associated with operating the BCM in a mock circulation, and also to examine the similarities between hemodynamic parameters produced by this device in vitro and those produced by the left ventricle (LV) in vivo. The BCM was connected to a true size silicon rubber aorta and operated by an intra-aortic balloon pump. We examined the performance of the device at two system pressures (6.5 and 8 kPa); at three heart rates (60, 80, and 100 bpm); and at three pumping frequencies (1:1, 1:2, 1:3). Pressure and flow were measured in the upper descending aorta, and wave intensity analysis was used to calculate the peak intensity and energy of the compression and expansion waves. Pressure and flow waveforms produced by the BCM LVAD in vitro under different loading conditions were similar to those observed in vivo under similar loadings. Pusher-plate-type LVADs can produce compression and expansion waves similar to those generated by healthy LV in vivo. [source]

Effect of Hemodiafiltration on Pulmonary Hemodynamics in Endotoxic Shock

ARTIFICIAL ORGANS, Issue 12 2003
B. Lambermont
Abstract:, Hemofiltration can improve pulmonary hemodynamics during septic shock. The main objective of the study was to determine whether hemodiafiltration (HDF) would also have beneficial effects on pulmonary hemodynamics during septic shock. In the Endo group, six anesthetized pigs received a 0.5 mg/kg endotoxin infusion over 30 min. In the HDF group (n = 6), HDF was started 30 min after the end of the endotoxin infusion, while in the Control group (n = 4) they received HDF but no endotoxin infusion. Pulmonary hemodynamics were analyzed in detail with a four-element windkessel model. Although in the Control group, HDF did not alter pulmonary hemodynamic parameters, in the HDF group, it was responsible for an amplification of the deleterious pulmonary vascular response to endotoxin insult. Our results show that HDF must be used cautiously in septic shock since it can precipitate right heart failure by increasing pulmonary vascular resistance. [source]

A New Approach to Assist Postoperative Heart Failure in an Animal Model: Juxta-Aortic Counterpulsation

ARTIFICIAL ORGANS, Issue 10 2002
Edmundo I. Cabrera Fischer
Abstract: Aortic counterpulsation is a useful technique frequently used in postcardiotomy heart failure. An acute heart failure model in open chest sheep was chosen to evaluate hemodynamic improvement with a counterpulsation balloon pump in juxta-aortic position. This was achieved with a manufactured Dacron prosthesis and a balloon pump placed between the prosthesis and the aorta. Juxta-aortic balloon pump counterpulsation in acute experimental heart failure resulted in a significant improvement of hemodynamic parameters: increase of cardiac output (from 0.86 ± 0.04 to 1.29 ± 0.09 L/min, p < 0.05) and cardiac index (from 0.03 ± 0.01 to 0.04 ± 0.01 L/min per kg, p < 0.05), and decrease of systemic vascular resistance (from 89.76 ± 6.69 to 66.56 ± 6.02 mm Hg/L per min, p < 0.05). The extent of aortic diastolic pressure change evaluated through the diastolic and systolic areas beneath the aortic pressure curve (DABAC/SABAC) index before cardiac failure induction showed a significant increase compared with unassisted values (from 0.81 ± 0.10 to 1.12 ± 0.09, p < 0.05). Assisted values of DABAC/SABAC index after heart failure induction also showed a significant increase compared with unassisted values (from 0.78 ± 0.21 to 1.17 ± 0.38, p < 0.05). Treatment of experimental acute heart failure by juxta-aortic balloon pump counterpulsation allows an effective hemodynamic improvement in open chest sheep. [source]

Tumor blood flow interruption after radiotherapy strongly inhibits tumor regrowth

CANCER SCIENCE, Issue 7 2008
Katsuyoshi Hori
To clarify the therapeutic significance of interrupting tumor blood flow after irradiation, we investigated X-irradiation-induced changes in hemodynamic parameters (blood flow, extravasation and washout of fluorescein isothiocyanate-dextran, and interstitial fluid pressure) in a variant of Yoshida sarcoma, LY80. Tumors in anesthetized male Donryu rats received local irradiation (10 Gy). At 48 h after irradiation, tumor blood flow increased significantly; at 72,96 h after irradiation, a 2,2.5-fold increase was observed. All parameters then consistently showed improved tumor microcirculation, which probably contributed to regrowth of cancer because certain cells survived irradiation. Rats received an intravenous dose (10 mg/kg) of a combretastatin derivative, AC7700 (AVE8062), which interrupts tumor blood flow and disrupts tumor vessels. At all times evaluated after irradiation, AC7700 completely stopped tumor blood flow. Radiotherapy efficacy was significantly enhanced when combined with AC7700: AC7700 given 48 h after irradiation, when tumor blood flow increased significantly, remarkably suppressed tumor regrowth compared with AC7700 given 48 h before irradiation. Also, postirradiation AC7700 completely inhibited not only primary tumor regrowth but also regional lymph node metastases in half of tumor-bearing rats and led to a significant improvement in survival. These results strongly suggest that the combination effect was enhanced via interruption of increased tumor blood flow after irradiation. This therapeutic combination and timing may have important benefits, even in tumors with low sensitivity to either treatment alone, because the effect was considerably greater than additive. Our data thus show that destruction of tumor microcirculation after irradiation is quite effective for preventing cancer recurrence. (Cancer Sci 2008; 99: 1485,1491) [source]