Search results for "HEMODYNAMICS"
showing 10 items of 511 documents
Ventilation-Perfusion Ratio in Perflubron During Partial Liquid Ventilation
2010
BACKGROUND: Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detec…
Quantification of pulmonary blood flow (PBF): validation of perfusion MRI and nonlinear contrast agent (CA) dose correction with H(2)15O positron emi…
2009
Validation of quantification of pulmonary blood flow (PBF) with dynamic, contrast-enhanced MRI is still missing. A possible reason certainly lies in difficulties based on the nonlinear dependence of signal intensity (SI) from contrast agent (CA) concentration. Both aspects were addressed in this study. Nine healthy pigs were examined by first-pass perfusion MRI using gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) and HO positron emission tomography (PET) imaging. Calculations of hemodynamic parameters were based on a one-compartment model (MR) and a two-compartment model (PET). Simulations showed a significant error when assuming a linear relation between MR SI and CA dose in the …
Zum Einflu� der pr�isch�mischen Blutzuckerkonzentration auf H�modynamik und regionale Organdurchblutung w�hrend und nach kardiopulmonaler Reanimation…
1996
Gegenstand der vorliegenden Untersuchung im Schweinemodell ist der Einflus einer pra-ischamischen Normo-, Hyper- oder Hypoglykamie auf Hamodynamik, regionale Organdurchblutung und Reanimierbarkeit nach 3minuti-gem unbehandelten Herz-Kreislauf-Stillstand und anschliesender kardiopulmonalen Reanimation (CPR). Hypoglykamie (Blutzuckerkonzentration von 34±2 mg/dl) war bereits vor der Reanimation mit einer deutlichen Beeintrachtigung hamodynamischer Parameter assoziiert. Keines der hypoglykamischen Tiere konnte erfolgreich reanimiert werden, im Gegensatz zu den hyper- (Blutzucker 319±13 mg/dl) bzw. normoglykamischen Tieren, die keinen Unterschied hinsichtlich der Erfolgsrate der Reanimation aufw…
H�modynamische Untersuchungen zur blutdrucksteigernden Wirkung von Mineralocorticoiden
1979
Bei 6 gesunden freiwilligen Probanden wurde der Einflus einer langerfristigen hochdosierten Mineralocorticoid-Applikation auf die Hamodynamik untersucht. Die Versuchspersonen erhielten das synthetische Mineralocorticoid 9α-Fluorhydrocortison in einer Dosierung von 0,8 mg p.o. taglich. Vor der Gabe des Steroids sowie nach 1- und 6wochiger Steroidbehandlung wurden der zentrale Venendruck und der arterielle Blutdruck direkt gemessen, das Herzzeitvolumen wurde mittels Farbstoffverdunnungsmethode bestimmt.
Reduced inotropic support after aprotinin therapy during pediatric cardiac operations
1999
Several reports indicate that aprotinin treatment before and during cardiopulmonary bypass (CPB) might have a protective effect on the myocardium. We evaluated the hemodynamic effects of perioperative aprotinin treatment.We conducted a randomized, double-blind, placebo-controlled trial in 34 infants (mean age, 2.5 years) who had cardiac operations. Half of the patients received high-dose aprotinin therapy. There were no significant differences between the aprotinin and placebo groups with respect to age, weight, sex, aortic cross-clamp time, and CPB time. The following data were recorded at arrival in the intensive care unit 6, 12, 24, and 48 hours after termination of CPB: heart rate, bloo…
Adjustable tourniquet to manipulate pulmonary blood flow after Norwood operations
2000
Abstract Background . Survival after first-stage palliative Norwood operations for single ventricle with systemic outflow obstruction is mainly dependent on a balanced ratio of pulmonary blood flow to systemic blood flow. Here we report the clinical results using a modified technique that allows a controlled systemic-to-pulmonary shunt flow to prevent pulmonary overcirculation. Methods . From 1995 to 1998, of 26 infants undergoing first-stage palliative Norwood operations, 7 had placement of an adjustable tourniquet around a modified right Blalock-Taussig shunt. Results . Hospital survival was 20 of 26 patients (77%). All 7 patients in whom snaring of the shunt was indicated survived. Two p…
Cardiorenal Syndrome in Acute Heart Failure: Revisiting Paradigms
2015
A B S T R A C T Cardiorenal syndrome has been defined as the simultaneous dysfunction of both the heart and the kidney. Worsening renal function that occurs in patients with acute heart failure has been classified as cardiorenal syndrome type 1. In this setting, worsening renal function is a common finding and is due to complex, multifactorial, and not fully understood processes involving hemodynamic (renal arterial hypoperfusion and renal venous congestion) and nonhemodynamic factors. Traditionally, worsening renal function has been associated with worse outcomes, but recent findings have revealed mixed and heterogeneous results, perhaps suggesting that the same phenotype represents a dive…
Natural and modified history of isolated ventricular septal defect: A 17-year study
1992
We studied 882 cases of isolated ventricular septal defect (VSD) diagnosed from 1971 to 1988 with a mean follow-up period of 9.5 years. They represent 22.5% of all congenital heart defects diagnosed in this period. Six hundred eighty-three children (77.4%) did not develop symptoms, had small defects, and the rate of spontaneous closure was high (40.2%). The remaining 199 children presented symptoms; at the initial catheterization 25, 65, 107, and 2 cases were grouped in hemodynamic groups 2, 3, 4, and 5-6, respectively, on the basis of pulmonary flow and resistance. Only seven patients (0.7%) developed aortic regurgitation, and only five patients (0.5%) developed infective endocarditis. Com…
Early cardiac unloading with ImpellaCP™ in acute myocardial infarction with ventricular septal defect
2020
Abstract Despite a relative contraindication, mechanical support with Impella™ left ventricular assist device has already been described for ischaemic ventricular septal defect treatment, either as a bridge to surgery, as intraoperative mechanical haemodynamic support, or to ensure intraprocedural haemodynamic stability during device closure. We describe two cases of ventricular septal defect complicating acute myocardial infarction, where the percutaneous ImpellaCP was implanted early (differently than previously described) with the aim of preventing haemodynamic instability, while deferring surgical repair. We present a report of haemodynamic, echocardiographic, biochemical, and clinical …
Impact of Prosthesis-Patient Mismatch after Mitral Valve Replacement
2016
Background and aim of the study: The study aim was to determine the impact of prosthesis-patient mismatch (PPM) on early and late clinical outcomes, left atrial and ventricular remodeling, late tricuspid valve regurgitation and pulmonary hypertension (PH) in patients after mitral valve replacement (MVR). Methods: A total of 46 patients (mean age 66 ± 9.3 years) with mitral valve diseases and undergoing isolated MVR was enrolled in the study. The mitral valve effective orifice area (EOA) was determined using the continuity equation and indexed for the patient’s body surface area (EOAi). PPM was defined as EOAi ≤1.2 cm2/m2. PH was defined as a systolic pulmonary artery pressure (sPAP) >40 mmH…