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PubMed2003

Effect of hemodiafiltration on pulmonary hemodynamics in endotoxic shock.

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.

Animals↗
PubMed2005

The relation between vascular access flow and different types of vascular access with systemic hemodynamics in hemodialysis patients.

Access flow (Qa) has an important effect on systemic hemodynamics in dialysis patients. A Qa : cardiac output (CO) ratio higher than 0.3 is considered a risk factor for high-output cardiac failure. However, the effect of different types of vascular access in hemodialysis patients has not yet been studied. The aim of the present study was to assess the relationship between Qa and systemic hemodynamics and to compare systemic hemodynamics between patients with elbow/upperarm access with forearm access types. Qa, CO, cardiac index (CI), central blood volume (CBV), and peripheral vascular resistance (PVR) were studied by the saline dilution technique in 58 hemodialysis patients (18 with elbow/upperarm access; 40 with forearm access types). This article found that Qa was significantly and positively related to CO and CI, and inversely related to PVR. CBV, Qa, and presence of cardiac failure were independent determinants of CI. Qa and the Qa : CO ratio were significantly higher, and PVR significantly lower, in patients with elbow/upperarm access compared to patients with forearm access types. When patients with cardiac failure were excluded, CO and CI were also significantly higher in patients with elbow/upperarm access types. Eleven percent of patients with elbow/upperarm fistula had a Qa : CO ratio above 0.3. In conclusion, Qa is strongly related to systemic hemodynamics in dialysis patients. In patients without cardiac failure, CO and CI are significantly higher in patients with elbow/upperarm access compared to patients with forearm access types. However, only a small percentage of patients with elbow/upperarm fistulae appeared to be in the risk zone for development of high-output cardiac failure.

Aged↗
PubMedDate not supplied

Use of noninvasive hemodynamics to aid decision making in the initiation and titration of neurohormonal agents.

Angiotensin-converting enzyme inhibitors, beta adrenergic blockers, and nesiritide are pharmacologic agents for heart failure with both short- and long-term neurohormonal and hemodynamic effects. Angiotensin-converting enzyme inhibitors and beta adrenergic blockers reduce morbidity and mortality in chronic heart failure. Higher doses may result in better outcomes than lower doses, but concern about hemodynamic tolerance is a major barrier to the initiation and up-titration of these agents. Nesiritide is a newer neurohormonal agent with proven efficacy and safety for use in decompensated heart failure, but appropriate patient selection has been challenging for clinicians. Like vasodilators, nesiritide may be underutilized in heart failure treatment. Impedance cardiography is a newer, noninvasive monitoring technology that can accurately measure hemodynamic parameters. Impedance cardiography is being used with increasing frequency by clinicians to guide therapy in patients with heart failure and has been proposed in heart failure treatment algorithms. Three case reports are presented to illustrate how hemodynamic data using impedance cardiography can be utilized in the initiation and titration of neurohormonal agents.

Adrenergic beta-Antagonists↗
PubMed1988

Hemodynamic responses to rapid pacing: a model for tachycardia differentiation.

The hemodynamic responses to rapid atrial and ventricular pacing were examined in 10 closed-chest anesthetized dogs in an attempt to distinguish hemodynamically stable from unstable tachycardias. Pressure monitoring catheters were placed in the femoral artery, right atrium, and right ventricle to measure mean arterial pressure, mean right atrial pressure, and mean right ventricular pressure at baseline heart rate and after rapid high right atrial and right ventricular apex pacing. Pressures recorded during rapid pacing (average of the pressures at 30 and 60 seconds of pacing) at pacing rates of 180, 250, and 280/minute were compared to those recorded initially at baseline heart rates. Rapid right ventricular apex pacing resulted in significant increases in mean right atrial pressure (from 6 +/- 1 mmHg (mean +/- standard error) to 12 +/- 1 mmHg, a 100% increase, P less than 0.001) and mean right ventricular pressure (from 11 +/- 1 mmHg to 16 +/- 1 mmHg, a 45% increase, p less than 0.02) with marked hemodynamic compromise (mean arterial pressure decreased from 85 +/- 6 mmHg to 50 +/- 6 mmHg, a 41% decrease, P less than 0.01). These parameters remained stable (no statistically significant difference from baseline) during high right atrial pacing. In half of the dogs high right atrial pacing at rates greater than or equal to 250 resulted in atrioventricular Wenckebach. Thus, it is concluded that mean right atrial pressure and mean right ventricular pressure may be useful in distinguishing hemodynamically significant tachycardias, and in the future design of antitachycardia devices.

Animals↗
PubMed1990

Atrial natriuretic peptide during different pacing modes in a comparison with hemodynamic changes.

The study investigates the response of atrial natriuretic peptide (ANP) to different cardiac pacing modes in comparison with hemodynamic changes. Ten patients underwent Swan-Ganz catheterization during pacemaker implant. Atrioventricular and ventricular pacing were performed consecutively at three pacing rate levels (80, 100, and 110 ppm). Blood samples were taken from the pulmonary artery for ANP determination, both basally and at the end of each pacing period. Concomitantly, mean pulmonary capillary wedge pressure (PCWP) and mean pulmonary artery pressure (PAP) were measured. Cardiac output (CO) was determined by thermodilution both basally and during the 110 ppm steps. During atrioventricular pacing, whereas no significant changes were observed for ANP, PCWP and PAP, CO increased significantly (P less than 0.0005). At the beginning of ventricular pacing hemodynamic parameters and ANP levels were comparable with those of baseline conditions. During subsequent ventricular pacing PCWP and ANP increased significantly at the 110 ppm rate step (P less than 0.05). PAP did not change significantly, whereas CO decreased in all cases (P less than 0.01). A positive correlation was observed between ANP and PCWP during ventricular (P less than 0.001), but not atrioventricular pacing. The results, while confirming the hemodynamic advantages of atrioventricular pacing, point to a major stimulation of ANP secretion during ventricular pacing. This fact, together with the observed drop in CO and the correlation between ANP and PCWP, suggest that the increase of ANP in ventricular pacing may be the expression of a compensatory mechanism to the hemodynamic disadvantages of atrioventricular asynchrony.

Aged↗
PubMed2000

Hemodynamic assessment of right, left, and biventricular pacing by peak endocardial acceleration and echocardiography in patients with end-stage heart failure.

Multisite ventricular pacing acutely improves the hemodynamic status in heart failure, though longer-term observations require invasive procedures. The hemodynamics of multisite ventricular pacing were assessed by echocardiography and peak endocardial acceleration (PEA) measured by a pacemaker sensor. PEA variations are highly correlated with those of dP/dt. Thirteen end-stage heart failure patients (left ventricular ejection fraction < 0.30) with a QRS > or = 140 ms received a DDD PEA sensor-driven pacemaker allowing right (RV), left (LV) and biventricular (BV) pacing. Ten days after implantation, standard echocardiographic parameters and variations in PEA were measured after 20 minutes at each pacing mode. The aortic systolic preejection time interval was statistically comparable between RV and LV pacing (218 +/- 24 vs 219 +/- 34 ms; P = NS), and significantly shorter with BV pacing (198 +/- 27 ms; P = 0.013). Aortic ejection duration was nonsignificantly shorter during BV pacing than during LV pacing (-.061, P = 0.09). The aortic velocity time integer increased during LV pacing versus RV pacing (+21%, P < 0.05) and during BV pacing versus RV pacing (+37%, P = 0.05). As a result, the values of the PEA variations over a 15-minute period were significantly greater during LV pacing and BV pacing versus RV pacing (+43%, P < 0.05, and +38%, P = 0.05, respectively) and were statistically comparable between BV pacing and LV pacing (9% for LV pacing, P = NS). During various ventricular pacing configurations, PEA measurements were consistent with echocardiographic data, showing comparable hemodynamic effects of BV and LV pacing. The PEA sensor is a promising tool for long-term hemodynamic monitoring and serial evaluation of the effects of multisite ventricular pacing in heart failure patients.

Cardiac Pacing, Artificial↗
PubMed2005

Late hemodynamic changes during a negative passive head-up tilt predict the symptomatic outcome to a nitroglycerin sensitized tilt.

BACKGROUND: Sublingual nitroglycerin is advocated to sensitize the passive 70 degrees head-upright tilt test (HUTT) of patients with unexplained syncope. We hypothesized that a detailed analysis of hemodynamic responses recorded during a negative HUTT could predict the outcome to a subsequent nitroglycerin sensitized HUTT (NTG-HUTT). METHODS: Thirty-two patients (46 +/- 3 years, 17 males) with recurrent unexplained syncope but a negative HUTT were included. Heart rate, arterial blood pressure, and central hemodynamics assessed by transthoracic impedance (preejection and rapid left ventricular ejection time, slow ejection time, peak amplitude of first derivative, and cardiac index) were recorded during supine rest and 45 minutes HUTT. Changes from supine rest of the variables were retrospectively compared between patients with a negative (n = 15, NTG-HUTT(-)) and positive (n = 17, NTG-HUTT(+)) outcome to 10 minutes subsequent NTG-HUTT. RESULT: Significant differences between groups were observed during the 15th-20th minutes (Italian protocol) and during the last 5 minutes of passive HUTT (Westminster protocol). The combination of cutoff values, determined by receiver operating curves, on hemodynamic variables changes during the last 5 minutes predicted the outcome to a NTG-HUTT with a sensitivity of 76% and a specificity of 87%. The cutoff values determined during 15th-20th minutes gave an attractive sensitivity (85%) but a too weak specificity (53%) to shorten the 45 minutes passive HUTT at 20 minutes. CONCLUSION: Outcome to a NTG-HUTT can be reliably predicted by selected criteria determined from multiple hemodynamic variables recorded during a passive 70 degrees HUTT.

Analysis of Variance↗
PubMed1999

Systemic hemodynamic changes in mansonic schistosomiasis with portal hypertension treated by azygoportal disconnection and splenectomy.

OBJECTIVE: The aim of this study was to assess systemic hemodynamic changes in patients with Manson's schistosomiasis and portal hypertension during azygoportal disconnection and splenectomy. METHODS: Sixteen patients with portal hypertension secondary to hepatosplenic schistosomiasis with indication for surgery were studied prospectively. All underwent invasive hemodynamic monitoring with pulmonary artery catheter. The first systemic hemodynamic assessment was performed preoperatively. In the intraoperative period new hemodynamic data were collected as follows: a) after laparotomy; b) 15-30 min after splenic artery ligature; c) 15-30 min after splenectomy; and d) after ligation of the collateral circulation. RESULTS: The results indicated preoperatively that the patients presented with an increased cardiac index (4.40 +/- 0.94 L/min/m2) together with a reduction in the systemic vascular resistance index (1692.25 +/- 434.91 dyne.s/cm5.m2). The stroke index (53.74 +/- 10.40 ml/beat/m2) and both left (5.71 +/- 1.50 kg.m/m2) and right heart work indexes (1.12 +/- 0.74 kg.m/m2) were also elevated. The mean pulmonary artery pressure was increased (17.81 +/- 9.00 mm Hg) and the pulmonary vascular resistance index decreased (164.31 +/- 138.69 dyne.s/cm5.m2). From the moment that the splenic artery was ligated until the end of the procedure, the cardiac index (3.45 +/- 0.90 L/min/m2) was reduced and the systemic vascular resistance index (2059.50 +/- 590.05 dyne.s/cm5.m5) increased. The systolic index (44.25 +/- 11.01 ml/beat/m2) and the left ventricle work index (4.33 +/- 1.29 kg.m/m2) also reduced. The mean pulmonary artery pressure (19.18 +/- 9.21 mm Hg) and the right ventricle work index (0.94 +/- 0.62 mm Hg) remained elevated after the surgical procedure. CONCLUSIONS: The data allowed us to conclude that hepatosplenic schistosomiasis induces a hyperdynamic circulatory state that was corrected after splenectomy and azygoportal disconnection, remaining a mild pulmonary hypertension. Therefore, these changes are correlated with the portosystemic collateral circulation, especially as a consequence of splanchnic hyperflow.

Adolescent↗
PubMed2000

Nitric oxide may contribute to nocturnal hemodynamic changes in cirrhotic patients.

OBJECTIVE: Patients with liver cirrhosis have a nocturnal worsening of hemodynamic parameters that has been associated with an increased risk of variceal bleeding at nighttime. The aim of this study was to investigate whether nitric oxide and cytokines are implicated in these hemodynamic changes. METHODS: Ten cirrhotic patients and eight controls were studied. Mean blood pressure, heart rate, plasma norepinephrine, tumor necrosis factor alpha and interleukin-6 levels, and serum nitrite + nitrate levels were determined at 0800, 1600, and 2400 h. All determinations were performed in supine rest and at least 4 h after meals. In a second study, nitrite + nitrate levels were assessed in 10 cirrhotic patients before and after eating a standard meal. RESULTS: Mean arterial pressure levels that were always lower in the patient group showed a nocturnal decrease in both groups of subjects. Heart rate values that were always higher in cirrhotic patients showed a nocturnal fall in controls, whereas cirrhotics maintained elevated values at nighttime. Norepinephrine levels were higher in cirrhotics and maintained similar values during the study, whereas controls had a significant nocturnal decrease. Nitrite + nitrate levels that were higher in cirrhotic patients showed a significant mean increase of 40% from morning (0800 h) to night (2400 h) in the patient group, whereas in controls no change was observed (p < 0.05). Tumor necrosis factor alpha and interleukin-6 levels did not change either in patients or controls during the entire period. Cirrhotic patients with or without ascites maintained a pattern of hemodynamic and biochemical changes similar to the pattern observed in the entire group of patients. Finally, no changes in serum nitrite + nitrate levels were observed in patients before and after eating the standard meal. CONCLUSION: An increased nocturnal nitric oxide production might contribute to the hemodynamic changes observed in cirrhotic patients during nighttime.

Aged↗
PubMed2003

Measuring the hemodynamic response to primary pharmacoprophylaxis of variceal bleeding: a cost-effectiveness analysis.

OBJECTIVES: The hemodynamic response to ss-blockers alone or with nitrates is highly predictive of efficacy in prevention of variceal bleeding. Hemodynamic monitoring (HDM) requires catheterization of the hepatic vein and measurement of the hepatic venous pressure gradient, the difference between wedged and free hepatic venous pressure. The aim of this study was to compare HDM with no HDM in patients considered for primary pharmacoprophylaxis of esophageal variceal bleeding. METHODS: A decision model was constructed to compare HDM with no HDM in cirrhotic patients with moderate to large esophageal varices. Patients intolerant to beta-blocker therapy would undergo endoscopic variceal ligation; those with an inadequate hemodynamic response (HDR) to beta-blocker therapy could have nitrates added before ligation was considered. Variceal bleeding was treated with ligation, with transjugular intrahepatic portosystemic shunt (TIPS) reserved for refractory bleeding. Probabilities of treatment responses as well as risks of bleeding and mortality were based on published literature. Only direct costs were considered during the 5-yr time horizon. Outcomes were cost in United States dollars, survival length in life-years, and proportions of patients who experienced variceal bleeding, TIPS insertion, and mortality from any cause. RESULTS: In the base case analysis, HDM was either cost-saving ($2,523 US dollars /life-year gained) or cost-effective (incremental cost-effectiveness ratio of $5,200 US dollars/life-year saved) compared with no HDM, depending on whether nitrates were added to beta-blocker therapy. HDM reduced variceal bleeding by nearly 60% and had a small effect on all-cause mortality. In the sensitivity analysis, HDM was sensitive to the time horizon, as it was not cost-effective for a time horizon of <22 months and was not cost-saving before 49 months. The cost-effectiveness of HDM was not sensitive to reasonable variation in the probability of HDR to beta-blocker therapy, risk of bleeding, risk reduction with pharmacotherapy, or to the costs of HDM, bleeding, ligation, or TIPS. Probabilistic sensitivity analysis indicated that HDM was more effective and less costly 100% and 57% of the time, respectively. CONCLUSIONS: Compared with the current standard of no HDM, measuring the hemodynamic response of primary pharmacoprophylaxis substantially reduces the number of bleeding episodes and is cost-effective or cost-saving over a wide range of sensitivity analyses. A randomized trial of HDM is needed to verify its efficacy in clinical practice.

Adrenergic beta-Antagonists↗
PubMed1996

Systemic and splanchnic hemodynamic changes in patients with hepatic schistosomiasis.

Although hepatic schistosomiasis is a common cause of portal hypertension, only a few hemodynamic studies, in humans, have been published on this subject. The aim of this study was to determine the systemic and splanchnic hemodynamic changes in hepatic schistosomiasis and to evaluate the influence of liver fibrosis on these changes. A retrospective analysis of a series of 13 patients with hepatic schistosomiasis who had undergone hemodynamic studies was performed. Portal or perisinusoidal fibrosis was present at liver biopsy in 8 patients. The control group included 22 patients with chronic hepatitis and normal hepatic venous pressure gradients. Patients with schistosomiasis exhibited high cardiac index (4.11 +/- 1.15 l.min-1.m-2 vs 2.99 +/- 0.85 l.min-1.m-2; p < 0.05) and low systemic vascular resistance (1039 +/- 316 dyn.s.cm-5 vs 1334 +/- 336 dyn.s.cm-5; p < 0.05). The hepatic venous pressure gradient and hepatic blood flow were normal. Azygos blood flow was markedly increased (0.90 +/- 0.66 l.min-1 vs 0.13 +/- 0.04 l.min-1; p < 0.05). Hemodynamic values were not significantly different between patients with liver fibrosis and those without fibrosis at liver biopsy. In conclusion, patients with hepatic schistosomiasis had a hyperkinetic systemic and splanchnic circulation. In patients with esophageal varices, a normal hepatic venous pressure gradient confirmed presinusoidal portal hypertension. The presence of portal or perisinuoidal fibrosis did not influence hyperdynamic splanchnic state.

Adult↗
PubMed2005

Hemodynamic effects of sildenafil citrate and isosorbide mononitrate in men with coronary artery disease and erectile dysfunction.

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.

Adult↗
PubMed2002

Hemodynamic aspects of Alzheimer's disease.

Neuroradiological functional imaging techniques demonstrate the patterns of hypoperfusion and hypometabolism that are thought to be useful in the differential diagnosis of Alzheimer's disease (AD) from other dementing disorders. Besides the distribution patterns of perfusion or energy metabolism, vascular transit time (VTT), vascular reactivity (VR), and oxygen extraction fraction (OEF), which can be measured with positron emission tomography (PET), provide hemodynamic aspects of brain pathophysiology. In order to evaluate the hemodynamic features of AD, PET studies were carried out in 20 patients with probable AD and 20 patients with vascular dementia (VaD). The PET findings were not included in their diagnostic process of AD. Using oxygen-15-labeled compounds, cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO(2)), OEF, cerebral blood volume, and VTT were measured quantitatively during resting state. To evaluate VR, CBF was also measured during CO(2) inhalation. There was a significant increase in OEF in and around the parietotemporal cortices, but both VTT and VR were well preserved in patients with AD. By contrast, VR was markedly depressed and VTT was mildly prolonged in patients with VaD. Thus, from the hemodynamic point of view, the preservation of vascular reserve may be a distinct difference between AD and VaD. Furthermore, this indicates a hemodynamic integrity of the vasculature in the level of arterioles in AD.

Aged↗
PubMedDate not supplied

Method for assessing the need for case-specific hemodynamics: application to the distribution of vascular permeability.

A common approach to understanding the role of hemodynamics in atherogenesis is to seek relationships between parameters of the hemodynamic environment, and the distribution of tissue variables thought to be indicative of early disease. An important question arising in such investigations is whether the distributions of tissue variables are sufficiently similar among cases to permit them to be described by an ensemble average distribution. If they are, the hemodynamic environment needs be determined only once, for a nominal representative geometry; if not, the hemodynamic environment must be obtained for each case. A method for classifying distributions from multiple cases to answer this question is proposed and applied to the distributions of the uptake of Evans blue dye labeled albumin by the external iliac arteries of swine in response to a step increase in flow. It is found that the uptake patterns in the proximal segment of the arteries, between the aortic trifurcation and the ostium of the circumflex iliac artery, show considerable case-to-case variability. In the distal segment, extending to the deep femoral ostium, many cases show very little spatial variation, and the patterns in those that do are similar among the cases. Thus the response of the distal segment may be understood with fewer simulations, but the proximal segment has more information to offer.

Animals↗
PubMedDate not supplied

Hemodynamic effect of cerebral vasospasm in humans: a modeling study.

A mathematical model of cerebral hemodynamics during vasospasm is presented. The model divides arterial hemodynamics into two cerebral territories: with and without spasm. It also includes collateral circulation between the two territories, cerebral venous hemodynamics, cerebrospinal fluid circulation, intracranial pressure (ICP) and the craniospinal storage capacity. Moreover, the pial artery circulation in both territories is affected by cerebral blood flow (CBF) autoregulation mechanisms. In this work, a numerical value to model parameters was given assuming that vasospasm affects only a single middle cerebral artery (MCA). In a first stage, the model is used to simulate some clinical results reported in the literature, concerning the patterns of MCA velocity, CBF and pressure losses during vasospasm. The agreement with clinical data turns out fairly good. In a second stage, a sensitivity analysis on some model parameters is performed (severity of caliber reduction, longitudinal extension of the spasm, autoregulation gain, ICP, resistance of the collateral circulation, and mean systemic arterial pressure) to clarify their influence on hemodynamics in the spastic territory. The results suggest that the clinical impact of vasospasm depends on several concomitant factors, which should be simultaneously taken into account to reach a proper diagnosis. In particular, while a negative correlation between MCA velocity and cross sectional area can be found until CBF is well preserved, a positive correlation may occur when CBF starts to decrease significantly. This might induce false-negative results if vasospasm is assessed merely through velocity measurements performed by the transcranial Doppler technique.

Blood Flow Velocity↗
PubMed2000

Near-infrared study of fluctuations in cerebral hemodynamics during rest and motor stimulation: temporal analysis and spatial mapping.

We have noninvasively studied the motor cortex hemodynamics in human subjects under rest and motor stimulation conditions using a multichannel near-infrared tissue spectrometer. Our instrument measures optical maps of the cerebral cortex at two wavelengths (758 and 830 nm), with an acquisition time of 160 ms per map. We obtained optical maps of oxy- and deoxy-hemoglobin concentration changes in terms of amplitudes of folding average, power spectrum and coherence at the stimulation repetition frequency, and the phase synchronization index. Under periodic motor stimulation conditions, we observed coherence and frequency or phase synchronization of the local hemodynamic changes with stimulation. Our main findings are the following: (1) The amplitude of the hemodynamic response to the motor stimulation is comparable to the amplitude of the fluctuations at rest. (2) The spatial patterns of the oxy- and deoxy-hemoglobin responses to the stimulation are different. (3) The hemodynamic response to stimulation shows a spatial localization and a level of phase synchronization with the motor stimulation that depends on the stimulation period.

Adult↗
PubMed1996

Platelet-aggregation inhibition and hemodynamic effects of beraprost sodium, a new oral prostacyclin derivative: a study in healthy male subjects.

The antiaggregation and hemodynamic effects of the new prostacyclin analogue beraprost sodium were investigated in a randomized, placebo-controlled, double-blind clinical trial of Latin-square design. Twelve healthy Caucasian males randomly received 8-day oral treatments of 20, 40, and 60 micrograms of beraprost sodium and a placebo. One-week washout periods followed each treatment. Pharmacokinetic and pharmacodynamic measurements were performed on days 1 and 8 for each period of treatment. All three doses of beraprost sodium significantly inhibited platelet aggregation on day 8 (compared with placebo) during the 1st h after drug intake. Incubation of the 60-micrograms beraprost sodium samples with ADP (2, 5, and 10 microM) and collagen (1.25 micrograms/mL) decreased platelet aggregation by 10, 19, 16, and 6 +/- 4% (mean +/- SE), respectively, compared with placebo. No significant hemodynamic effects on blood pressure, heart rate, and digital pulse were observed. The 60-micrograms dose of beraprost sodium did significantly decrease the IRZ index (which may reflect the left ventricular pre-ejection period) on days 1 and 8. Some subjects experienced headache and facial flushing, effects that were dose dependent and reversible. Beraprost sodium at 20- to 60-micrograms doses exerts platelet antiaggregation (day 8 of therapy) and slight hemodynamic (days 1 and 8 of treatment) effects in Caucasian males. Beraprost sodium hemodynamic effects and potential benefits in patients with cardiovascular disease should be explored further.

Administration, Oral↗
PubMed1992

Hemodynamic effects of bolus injection of gadodiamide injection and gadopentetate dimeglumine as contrast media at MR imaging in rats.

The trend to administer contrast agents for magnetic resonance (MR) imaging by rapid injection and to use higher doses necessitates additional safety assessments with regard to potential hemodynamic effects. The current study was designed to evaluate the hemodynamic effects or rapid injection of increasing doses of gadodiamide injection (gadolinium diethylenetriaminepentaacetic acid bismethylamide) and gadopentetate dimeglumine. Each animal received incremental doses (0.1, 0.3, and 0.5 mmol/kg) of either contrast agent via the left jugular vein as a rapid bolus (1-2 seconds). Gadodiamide injection caused no hemodynamic alterations; however, gadopentetate dimeglumine caused dose-dependent cardiodepressive effects. At a dose of 0.5 mmol/kg, gadopentetate dimeglumine transiently decreased left ventricular end-systolic pressure by 25%, systolic arterial pressure by 34%, and positive peak differential quotient of pressure change against time by 43% of preinjection values. All hemodynamic parameters returned to baseline in the first 3-5 minutes.

Animals↗