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Hemodynamic Variables (hemodynamic + variable)

Distribution by Scientific Domains

Medical Sciences	83%

Distribution within Medical Sciences

Anesthesia & Pain Management	49%
Cardiovascular Disease	30%

Selected Abstracts

Intensity modulation of TMS-induced cortical excitation: Primary motor cortex

HUMAN BRAIN MAPPING, Issue 6 2006
Peter T. Fox
Abstract The intensity dependence of the local and remote effects of transcranial magnetic stimulation (TMS) on human motor cortex was characterized using positron-emission tomography (PET) measurements of regional blood flow (BF) and concurrent electromyographic (EMG) measurements of the motor-evoked potential (MEP). Twelve normal volunteers were studied by applying 3 Hz TMS to the hand region of primary motor cortex (M1hand). Three stimulation intensities were used: 75%, 100%, and 125% of the motor threshold (MT). MEP amplitude increased nonlinearly with increasing stimulus intensity. The rate of rise in MEP amplitude was greater above MT than below. The hemodynamic response in M1hand was an increase in BF. Hemodynamic variables quantified for M1hand included value-normalized counts (VNC), intensity (z-score), and extent (mm3). All three hemodynamic response variables increased nonlinearly with stimulus intensity, closely mirroring the MEP intensity-response function. VNC was the hemodynamic response variable which showed the most significant effect of TMS intensity. VNC correlated strongly with MEP amplitude, both within and between subjects. Remote regions showed varying patterns of intensity response, which we interpret as reflecting varying levels of neuronal excitability and/or functional coupling in the conditions studied. Hum Brain Mapp, 2005. © 2005 Wiley-Liss, Inc. [source]

Efficacy of bupivacaine-neostigmine and bupivacaine-tramadol in caudal block in pediatric inguinal herniorrhaphy

PEDIATRIC ANESTHESIA, Issue 9 2010
REZA TAHERI MD
Summary Background:, Limited duration of analgesia is among the limitations of single caudal injection with local anesthetics. Therefore, the purpose of this study was to evaluate the effectiveness and safety of bupivacaine in combination with either neostigmine or tramadol for caudal block in children undergoing inguinal herniorrhaphy. Methods:, In a double-blinded randomized trial, sixty children undergoing inguinal herniorrhaphy were enrolled to receive a caudal block with either 0.25% bupivacaine (1 ml·kg,1) with neostigmine (2 ,g·kg,1) (group BN) or tramadol (1 mg·kg,1) (group BT). Hemodynamic variables, pain and sedation scores, additional analgesic requirements, and side effects were compared between two groups. Results:, Duration of analgesia was longer in group BT (17.30 ± 8.24 h) compared with group BN (13.98 ± 10.03 h) (P = 0.03). Total consumption of rescue analgesic was significantly lower in group BT compared with group BN (P = 0.04). There were no significant differences in heart rate, mean arterial pressure, and oxygen saturation between groups. Adverse effects excluding the vomiting were not observed in any patients. Conclusion:, In conclusion, tramadol (1 mg·kg,1) compared with neostigmine (2 ,g·kg,1) might provide both prolonged duration of analgesia and extended time to first analgesic in caudal block. [source]

The association between early hemodynamic variables and outcome in normothermic comatose patients following cardiac arrest

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2010
C. TORGERSEN
Background: Currently, few data exist on the association between post-cardiac arrest hemodynamic function and outcome. In this explorative, retrospective analysis, the association between hemodynamic variables during the first 24 h after intensive care unit admission and functional outcome at day 28 was evaluated in 153 normothermic comatose patients following a cardiac arrest. Methods: Medical records of a multidisciplinary intensive care unit were reviewed for comatose patients (Glasgow Coma Scale ,9) admitted to the intensive care unit after successful resuscitation from an in- or an out-of-hospital cardiac arrest. The hourly variable time integral of hemodynamic variables during the first 24 h after admission was calculated. At day 28, outcome was assessed as favorable or adverse based on a Cerebral Performance Category of 1,2 and 3,5, respectively. Bi- and multivariate regression models adjusted for relevant confounding variables were used to evaluate the association between hemodynamic variables and functional outcome. Results: One hundred and fifty-three normothermic comatose patients were admitted after a cardiac arrest, of whom 64 (42%) experienced a favorable outcome. Neither in the adjusted bivariate models (r2, 0.61,0.78) nor in the adjusted multivariate model (r2, 0.62,0.73) was the hourly variable time integral of any hemodynamic variable during the first 24 h after intensive care unit admission associated with functional patient outcome at day 28 in all patients as well as in patients after an in- or an out-of-hospital cardiac arrest. Conclusion: Commonly measured hemodynamic variables during the first 24 h following intensive care unit admission due to a cardiac arrest do not appear to be associated with the functional outcome at day 28. [source]

Identifying Left Ventricular Dysfunction in Pulmonary Hypertension

CONGESTIVE HEART FAILURE, Issue 5 2009
Navin Rajagopalan MD
The significance of left ventricular (LV) dysfunction in patients with pulmonary hypertension (PH) is unknown. Our purpose was to quantify LV function in PH patients by measuring LV myocardial performance index (MPI) and correlating it with invasively determined hemodynamic variables. The authors prospectively measured LV MPI via transthoracic echocardiography in 50 patients with PH (53±11 years; 35 women) who also underwent right heart catheterization within 1 day of echocardiography. For comparative purposes, LV MPI was also measured in 15 healthy volunteers who served as controls. LV MPI was significantly increased in the PH group compared with controls (0.62±0.27 vs 0.36±0.08; P<.001), indicating worse LV dysfunction despite that LV ejection fraction was not significantly different between the groups (58%±4% vs 60%±3%). LV MPI demonstrated significant correlations with invasively determined mean pulmonary artery pressure (r=.50; P<.001), pulmonary vascular resistance (r=.57; P<.001), and cardiac index (r=,.64; P<.001). By receiver operating characteristic analysis, LV MPI >0.75 predicted cardiac index <2 L/min/m2 with 89% sensitivity and 78% specificity (area under the curve, 0.89). In a multivariate model, LV MPI was independently associated with cardiac index (P<.01). Patients with PH demonstrate abnormal LV function as quantified by elevated LV MPI, which correlates significantly with pulmonary vascular resistance and cardiac index. [source]

Correlation of Tricuspid Annular Velocities With Invasive Hemodynamics in Pulmonary Hypertension

CONGESTIVE HEART FAILURE, Issue 4 2007
Navin Rajagopalan
The authors performed tissue Doppler imaging of the tricuspid annulus in patients with pulmonary hypertension to assess its correlation with invasive indices of right ventricular function. The study population consisted of 32 patients with suspected pulmonary hypertension who underwent pulsed tissue Doppler imaging of the tricuspid annulus and right heart catheterization. Peak systolic (Sa), early diastolic (Ea), and late diastolic (Aa) velocities of the lateral tricuspid annulus were measured and correlated with hemodynamic variables. Peak Sa demonstrated excellent correlation with hemodynamic variables, including cardiac index (r=0.78; P<.001), pulmonary vascular resistance (r=,0.79; P<.001), and transpulmonary gradient (r=,0.72; P<.001). Peak Sa <10 cm/s predicted cardiac index <2.0 L/min/m2 with 89% sensitivity and 87% specificity. In conclusion, tissue Doppler imaging of the tricuspid annulus is a complementary method to assess right ventricular function in pulmonary hypertensive patients. [source]

Stress-Induced Wall Motion Abnormalities with Low-Dose Dobutamine Infusion Indicate the Presence of Severe Disease and Vulnerable Myocardium

ECHOCARDIOGRAPHY, Issue 7 2007
Stephen G. Sawada M.D.
Background: Patients with left ventricular (LV) systolic dysfunction due to coronary artery disease (CAD) may develop stress-induced wall motion abnormalities (SWMA) with low-dose (10 ,g/kg/min) dobutamine infusion. The clinical significance of low-dose SWMA is unknown. Objective: We investigated the clinical, hemodynamic and angiographic correlates of low-dose SWMA in patients with chronic ischemic LV systolic dysfunction. Methods: Seventy patients with chronic ischemic LV systolic dysfunction who had dobutamine stress echocardiography were studied. Clinical, hemodynamic, and angiographic parameters at rest and low-dose were compared between 38 patients (mean ejection fraction (EF) of 30 ± 8%) with low-dose SWMA and 32 patients (EF 30 ± 11%) without low-dose SWMA. Results: Multivariate analysis showed that the number of coronary territories with severe disease (stenosis ,70%)(P = 0.001, RR = 6.3) was an independent predictor of low-dose SWMA. An increasing number of collateral vessels protected patients from low-dose SWMA (P = 0.011, RR = 0.25). A higher resting heart rate was a negative predictor of low-dose SWMA (P = 0.015, RR = 0.92) but no other hemodynamic variables were predictors. In the patients with low-dose SMA, regions with low-dose SWMA were more likely to be supplied by vessels with severe disease than regions without low-dose SWMA (92% vs 58%, P < 0.001). Conclusion: In patients with ischemic LV systolic dysfunction, the extent of severe disease and a lower numbers of collaterals predict the occurrence of low-dose SWMA. Low-dose SWMA is a highly specific marker for severe disease. [source]

Cardiovascular dialysis instability and convective therapies

HEMODIALYSIS INTERNATIONAL, Issue 2006
Antonio SANTORO
Abstract Acute hypotension is a frequent hemodialysis complication. Intratreatment vascular instability is a multifactorial process in which procedure-related and patient-related factors may influence the decrease in plasma volume and induce an impairment of cardiovascular regulatory mechanisms. Identification of the most susceptible patients and of the various risk factors may contribute to significantly improve cardiovascular stability during dialysis. In some high-risk patients, monitoring and biofeedback of the various hemodynamic variables, together with an extensive use of convection, can prevent the appearance of symptomatic hypotension and help in averting its onset. [source]

Hemodynamic analysis of intracranial aneurysms with moving parent arteries: Basilar tip aneurysms

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2010
Daniel M. Sforza
Abstract The effects of parent artery motion on the hemodynamics of basilar tip saccular aneurysms and its potential effect on aneurysm rupture were studied. The aneurysm and parent artery motions in two patients were determined from cine loops of dynamic angiographies. The oscillatory motion amplitude was quantified by registering the frames. Patient-specific computational fluid dynamics (CFD) models of both aneurysms were constructed from 3D rotational angiography images. Two CFD calculations were performed for each patient, corresponding to static and moving models. The motion estimated from the dynamic images was used to move the surface grid points in the moving model. Visualizations from the simulations were compared for wall shear stress (WSS), velocity profiles, and streamlines. In both patients, a rigid oscillation of the aneurysm and basilar artery in the anterio-posterior direction was observed and measured. The distribution of WSS was nearly identical between the models of each patient, as well as major intra-aneurysmal flow structures, inflow jets, and regions of impingement. The motion observed in pulsating intracranial vasculature does not have a major impact on intra-aneurysmal hemodynamic variables. Parent artery motion is unlikely to be a risk factor for increased risk of aneurysmal rupture. Copyright © 2010 John Wiley & Sons, Ltd. [source]

The association between early hemodynamic variables and outcome in normothermic comatose patients following cardiac arrest

Diagnosing acute lung injury in the critically ill: a national survey among critical care physicians

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2009
A. P. J. VLAAR
Background: Incidence reports on acute lung injury (ALI) vary widely. An insight into the diagnostic preferences of critical care physicians when diagnosing ALI may improve identification of the ALI patient population. Methods: Critical care physicians in the Netherlands were surveyed using vignettes involving hypothetical patients and a questionnaire. The vignettes varied in seven diagnostic determinants based on the North American European Consensus Conference and the lung injury score. Preferences were analyzed using a mixed-effects logistic regression model and presented as an odds ratio (OR) with a 95% confidence interval. Results: From 243 surveys sent to 30 hospitals, 101 were returned (42%). ORs were as follows: chest X-ray consistent with ALI: OR 1.7 (1.3,2.3), high positive end-expiratory pressure (PEEP) (15 cmH2O): OR 5.0 (3.9,6.6), low pulmonary artery occlusion pressures (PAOP) (<18 mmHg): OR 4.7 (3.6,6.1), low compliance (30 ml/cmH2O): OR 0.7 (0.5,0.9), low PaO2/FiO2 (<250 mmHg): OR 9.2 (6.9,12.3), absence of heart failure: OR 1.2 (0.9,1.5), presence of a risk factor for ALI (sepsis): OR 1.0 (0.8,1.3). The questionnaire revealed that critical care physicians with an anesthesiology background differed from physicians with an internal medicine background with regard to hemodynamic variables when considering an ALI diagnosis (P<0.05). Conclusions: Dutch critical care physicians consider the PEEP level, but not the presence of a risk factor for ALI, as an important factor to diagnose ALI. Background specialty of critical care physicians influences diagnostic preferences and may account for variance in the reported incidence of ALI. [source]

Biological Activity of Endogenous Atrial Natriuretic Peptide During Cardiopulmonary Bypass

ARTIFICIAL ORGANS, Issue 10 2000
Nobuhiko Hayashida
Abstract: To evaluate the effect of cardiopulmonary bypass (CPB) on atrial natriuretic peptide (ANP) biological activity in patients undergoing cardiac operations, we conducted a prospective study. Ten patients undergoing mitral valve surgery were enrolled. Plasma levels of ANP and cyclic guanosine monophosphate (cGMP), hemodynamic variables, and renal function parameters were assessed perioperatively. The molar ratio of cGMP to ANP (as a marker for ANP biological activity) decreased significantly (p < 0.05) during CPB despite similar plasma ANP levels. The ratio correlated inversely with the duration of CPB (r = ,0.85, p = 0.002). The ratio also correlated with fractional sodium excretion (r = 0.65, p = 0.04) and correlated inversely with pulmonary vascular resistance (r = ,0.79, p = 0.009) and atrial filling pressure (r = ,0.84, p = 0.003) postoperatively. CPB decreased the molar ratio of cGMP to ANP, which may represent ANP biological activity, such as vasodilation and natriuresis. The phenomenon may contribute to water,sodium retention and pulmonary hypertension after cardiac surgery. [source]