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Selected AbstractsBlunted Hemodynamic Response and Reduced Oxygen Delivery With Exercise in Anemic Heart Failure Patients With Systolic DysfunctionCONGESTIVE HEART FAILURE, Issue 2 2007Jennifer Listerman MD Anemic heart failure patients with systolic dysfunction are known to have reduced exercise capacity. Whether this is related to poor hemodynamic adaptation to anemia is not known. Peak exercise oxygen consumption (VO2) and hemodynamics at rest and peak exercise were assessed among 209 patients and compared among those who were (n=90) and were not (n=119) anemic. Peak VO2 was significantly lower among anemic patients (11.7±3.3 mL/min/kg vs 13.4±3.1 mL/min/kg; P=.01). At rest, right atrial pressure was higher (10±5 mm Hg vs 8±4 mm Hg; P=.02) and venous oxygen saturation lower (62%±8% vs 58%±10%; P<.01) among anemic patients. At peak exercise, anemic patients had a higher wedge pressure (27±9 mm Hg vs 24±10 mm Hg; P=.04). No significant differences in stroke volume, cardiac index, systemic vascular resistance, or oxygen saturation were noted between the 2 groups. In conclusion, the relative hemodynamic response to exercise among anemic heart failure patients appears blunted and may contribute to worse exercise tolerance. [source] Low doses of isosorbide mononitrate attenuate the postprandial increase in portal pressure in patients with cirrhosisHEPATOLOGY, Issue 2 2003Lia Bellis Postprandial hyperemia is associated with a significant increase in portal pressure in cirrhosis, which may contribute to progressive dilation and rupture of gastroesophageal varices. In cirrhosis, an insufficient hepatic production of nitric oxide (NO) may impair the expected hepatic vasodilatory response to increased blood flow, further exaggerating the postprandial increase in portal pressure. This study was aimed at investigating whether low doses of an oral NO donor might counteract the postprandial peak in portal pressure. Twenty-three portal hypertensive cirrhotics, 8 of them under propranolol therapy, were randomized to receive orally 5-isosorbide mononitrate (ISMN; 10 mg; n = 11) or placebo (n = 12) and a standard liquid meal 15 minutes later. Hepatic venous pressure gradient (HVPG), mean arterial pressure (MAP), and hepatic blood flow (HBF) were measured at baseline and 15, 30, and 45 minutes after a meal. ISMN significantly attenuated the postprandial increase in portal pressure as compared with placebo (peak HVPG increase: 2.4 ± 1.4 mm Hg vs. 5.2 ± 2.1 mm Hg, P = .002). Percentual increases in HBF were similar in both groups. MAP decreased slightly in ISMN group (,7.5% ± .5%; P < .01 vs. baseline). These effects were also observed in patients on chronic propranolol therapy. In conclusion, hepatic NO supplementation by low doses of ISMN effectively reduces the postprandial increase of portal pressure in cirrhosis, with only a mild effect on arterial pressure. The same was observed in patients receiving propranolol. Our results suggest that therapeutic strategies based on selective hepatic NO delivery may improve the treatment of portal hypertension. [source] A Comparison of Morning Blood Pressure Surge in African Americans and WhitesJOURNAL OF CLINICAL HYPERTENSION, Issue 4 2005Donald C. Haas MD African Americans have twice the risk of suffering a stroke compared to whites, but the reasons for this disparity have yet to be elucidated. Recent data suggest that the morning blood pressure (BP) surge is an independent predictor of strokes. Whether African Americans and whites differ with respect to morning BP surge is unknown. African-American (n=183) and white (n=139) participants, age 18-65, were studied with 24-hour ambulatory BP monitoring. Morning surge was defined as morning BP minus the trough BP during sleep. The morning surge was significantly lower in African Americans than in whites (23 mm Hg vs. 27 mm Hg; both SEM=1.0; p=0.009). This relationship was no longer evident after adjusting for gender, age, and body mass index (23 mm Hg vs. 26 mm Hg; SE=1.0 and 1.1; p=nonsignificant). Morning BP surge is unlikely to account for differences in stroke incidence between African Americans and whites. [source] Hemodynamic profile and tissular oxygenation in orthotopic liver transplantation: Influence of hepatic artery or portal vein revascularization of the graftLIVER TRANSPLANTATION, Issue 11 2006Carlos 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] Improved lung function after thoracocentesis in patients with paradoxical movement of a hemidiaphragm secondary to a large pleural effusionRESPIROLOGY, Issue 5 2007Lee-Min WANG Background and objectives: Previous studies have shown little or no improvement in pulmonary function and arterial blood oxygenation after therapeutic thoracocentesis. This study investigated changes in pulmonary function, arterial blood gases and dyspnoea after therapeutic thoracocentesis in patients with paradoxical movement (PM) of a hemidiaphragm due to pleural effusion. Methods: Twenty-one patients with pleural effusion and PM of a hemidiaphragm and 41 patients with pleural effusion but without paradoxical movement (NPM) were studied before and 24 h after thoracocentesis. Lung function measurements included lung mechanics, blood gas exchange and the Borg dyspnoea scale. Results: At thoracocentesis a mean of 1220 mL of pleural fluid was removed from the PM group and 1110 mL from the NPM group. Post-thoracocentesis the PM group showed small but significant improvement (P < 0.05) in FEV1 (63% vs 73%), FVC (67% vs 77%), PaO2 (66 mm Hg vs 73 mm Hg), A-a O2 gradient (38 mm Hg vs 30 mm Hg), and the Borg scale (5.1 vs 2.1). The NPM group showed no significant change in any parameter. Conclusions: Statistically significant improvement in pulmonary function following thoracocentesis was observed in patients with pleural effusion and PM of the hemidiaphragm. Patient selection may therefore explain the different outcomes of thoracocentesis reported in previous studies. [source] Left Ventricle Afterload Impedance Control by an Axial Flow Ventricular Assist Device: A Potential Tool for Ventricular RecoveryARTIFICIAL ORGANS, Issue 9 2010Francesco Moscato Abstract Ventricular assist devices (VADs) are increasingly used for supporting blood circulation in heart failure patients. To protect or even to restore the myocardial function, a defined loading of the ventricle for training would be important. Therefore, a VAD control strategy was developed that provides an explicitly definable loading condition for the failing ventricle. A mathematical model of the cardiovascular system with an axial flow VAD was used to test the control strategy in the presence of a failing left ventricle, slight physical activity, and a recovering scenario. Furthermore, the proposed control strategy was compared to a conventional constant speed mode during hemodynamic changes (reduced venous return and arterial vasoconstriction). The physiological benefit of the control strategy was manifested by a large increase in the ventricular Frank,Starling reserve and by restoration of normal hemodynamics (5.1 L/min cardiac output at a left atrial pressure of 10 mm Hg vs. 4.2 L/min at 21 mm Hg in the unassisted case). The control strategy automatically reduced the pump speed in response to reduced venous return and kept the pump flow independent of the vasoconstriction condition. Most importantly, the ventricular load was kept stable within 1%, compared to a change of 75% for the constant speed. As a key feature, the proposed control strategy provides a defined and adjustable load to the failing ventricle by an automatic regulation of the VAD speed and allows a controlled training of the myocardium. This, in turn, may represent a potential additional tool to increase the number of patients showing recovery. [source] Variations in Aortic Pressure Affect the Mechanics of the Intra-Aortic Balloon: An In Vitro InvestigationARTIFICIAL ORGANS, Issue 7 2010Giovanni Biglino Abstract This study aims to investigate the mechanics of the intra-aortic balloon (IAB) under different aortic pressure (Pao) and inclination (0,75°). Pressure and flow were measured in an artificial aorta during IAB pumping with a frequency of 1:3. Volume displaced toward the "coronary arteries" during inflation (Vprox) and "intra-aortic" pressure reduction during deflation (Pr) were derived. IAB duration of inflation and deflation was determined with a high-speed camera visualization. When the aorta was horizontal, Pao raised from 45 mm Hg to 115 mm Hg, Vprox reduced by 18% (25.0 ± 1.0 mL vs. 30.4 ± 1.9 mL) and Pr increased by 117% (106.4 ± 0.3 mm Hg vs. 48.9 ± 0.6 mm Hg). When the aorta was inclined, at low Pao of 45 mm Hg, Vprox was reduced by 30% from 0° to 45° (19.8 ± 2.3 mL vs. 28.3 ± 1.7 mL) and Pr was reduced by 66% (16.5 ± 0.1 mm Hg vs. 48.9 ± 0.6 mm Hg). However, at high Pao of 115 mm Hg, Vprox remained unchanged with increasing angle (20.0 ± 1.0 mL) and Pr was reduced by 24% (80.6 ± 0.8 mm Hg vs. 106.4 ± 0.3 mm Hg). Increasing Pao increased duration of inflation. At low Pao, increasing angle resulted in increasing duration of inflation, but at high Pao, increasing angle had the opposite effect. Duration of deflation generally decreased with Pao and increased with increasing angle. The IAB pump is affected by both Pao and angle, indicating that non-normotensive patients or patients in the semi-recumbent position might not receive the full benefits of IAB counterpulsation. [source] Comparison of Two Types of Neonatal Extracorporeal Life Support Systems With Pulsatile and Nonpulsatile FlowARTIFICIAL ORGANS, Issue 11 2009Nikkole Haines Abstract We compared the effects of two neonatal extracorporeal life support (ECLS) systems on circuit pressures and surplus hemodynamic energy levels in a simulated ECLS model. The clinical set-up included the Jostra HL-20 heart,lung machine, either the Medtronic ECMO (0800) or the MEDOS 800LT systems with company-provided circuit components, a 10 Fr arterial cannula, and a pseudo-patient. We tested the system in nonpulsatile and pulsatile flow modes at two flow rates using a 40/60 glycerin/water blood analog, for a total of 48 trials, with n = 6 for each set-up. The pressure drops over the Medtronic ECLS were significantly higher than those over the MEDOS system regardless of the flow rate or perfusion mode (144.8 ± 0.2 mm Hg vs. 35.7 ± 0.2 mm Hg, respectively, at 500 mL/min in nonpulsatile mode, P < 0.001). The preoxygenator mean arterial pressures were significantly increased and the precannula hemodynamic energy values were decreased with the Medtronic ECLS circuit. These results suggest that the MEDOS ECLS circuit better transmits hemodynamic energy to the patient, keeps mean circuit pressures lower, and has lower pressure drops than the Medtronic Circuit. [source] Procedural results and acute complications in stenting native and recurrent coarctation of the aorta in patients over 4 years of age: A multi-institutional studyCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2007Thomas J. Forbes MD Abstract Background: We report a multi-institutional experience with intravascular stenting (IS) for treatment of coarctation of the aorta. Methods and Results: Data was collected retrospectively by review of medical records from 17 institutions. The data was broken down to prior to 2002 and after 2002 for further analysis. A total of 565 procedures were performed with a median age of 15 years (mean = 18.1 years). Successful reduction in the post stent gradient (<20 mm Hg) or increase in post stent coarctation to descending aorta (DAo) ratio of >0.8 was achieved in 97.9% of procedures. There was significant improvement (P < 0.01) in pre versus post stent coarctation dimensions (7.4 mm ± 3.0 mm vs. 14.3 ± 3.2mm), systolic gradient (31.6 mm Hg ± 16.0 mm Hg vs. 2.7 mm Hg ± 4.2 mm Hg) and ratio of the coarctation segment to the DAo (0.43 ± 0.17 vs. 0.85 ± 0.15). Acute complications were encountered in 81/565 (14.3%) procedures. There were two procedure related deaths. Aortic wall complications included: aneurysm formation (n = 6), intimal tears (n = 8), and dissections (n = 9). The risk of aortic dissection increased significantly in patients over the age of 40 years. Technical complications included stent migration (n = 28), and balloon rupture (n = 13). Peripheral vascular complications included cerebral vascular accidents (CVA) (n = 4), peripheral emboli (n = 1), and significant access arterial injury (n = 13). Older age was significantly associated with occurrence of CVAs. A significant decrease in the technical complication rate from 16.3% to 6.1% (P < 0.001) was observed in procedures performed after January 2002. Conclusions: Stent placement for coarctation of aorta is an effective treatment option, though it remains a technically challenging procedure. Technical and aortic complications have decreased over the past 3 years due to, in part, improvement in balloon and stent design. Improvement in our ability to assess aortic wall compliance is essential prior to placement of ISs in older patients with coarctation of the aorta. © 2007 Wiley-Liss, Inc. [source] End-tidal Carbon Dioxide Measurements in Children with Acute AsthmaACADEMIC EMERGENCY MEDICINE, Issue 12 2007Bridgette D. Guthrie MD Objectives A noninvasive method to assess ventilation may aid in management of children with acute asthma. The purpose of this study was to evaluate the association between end-tidal carbon dioxide (EtCO2) values and disease severity among children with acute asthma. Methods This was a prospective, blinded, observational study of children 3,17 years old treated for acute asthma in a pediatric emergency department (ED). EtCO2 measurements were taken before the initiation of therapy and after each nebulization treatment (maximum of three). Peak expiratory flow rate (PEFR), Pediatric Asthma Severity Score (PASS), oxygen saturation, and disposition were recorded. Treating physicians, unaware of the EtCO2 results, made all treatment decisions, including disposition. Results One hundred children were enrolled. The mean initial EtCO2 value was 35 mm Hg (95% confidence interval = 34.3 to 36.1 mm Hg). The mean disposition EtCO2 value was 33.3 mm Hg (95% confidence interval = 32.6 to 34.4 mm Hg). PEFR measures were completed on 43 patients and PASS recorded on 100 patients. There was an overall trend toward lower EtCO2 values during treatment (p < 0.01). Sixteen patients were admitted. Initial EtCO2 values were lower among children admitted to the hospital (35.6 mm Hg vs. 32.9 mm Hg; Mann-Whitney U test; p < 0.02). EtCO2 values at disposition did not differ between groups based on PEFR, PASS, or hospital admission. Conclusions Noninvasive bedside measurement of EtCO2 values among children with acute asthma is feasible. EtCO2 values did not distinguish children with mild disease from those with more severe disease. Further data are needed to clarify the association between EtCO2 values and other indicators of disease severity, particularly in children with more severe disease. [source] | ||||||||||