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At least 109 records · Page 6Linked to original sources
PubMed2003

Usefulness of a new Doppler index for assessing both ventricular functions and pulmonary circulation in newborn piglet with hypoxic pulmonary hypertension.

Persistent pulmonary hypertension of the newborn is a clinical syndrome associated with a variety of cardiopulmonary diseases. Serial evaluation of pulmonary circulation and cardiac function is important, but available imaging techniques have been limited. A new Doppler index combining systolic and diastolic time intervals (the Tei index, which is a simple and noninvasive measurement) has been reported to be useful for the assessment of global cardiac function in adults and children. The purpose of this study was to test the effectiveness of the Tei index in prospectively assessing ventricular function and pulmonary circulation in a newborn piglet model with hypoxic pulmonary hypertension. One-day-old piglets (1.1-1.6 kg) were intubated and prepared for the experiments under room air and hypoxia. A complete two-dimensional Doppler echocardiographic examination was performed. Common hemodynamic variables were measured continuously throughout the study. The right ventricle (RV) Tei index under hypoxia (fraction of inspired oxygen = 0.10) was significantly higher than the value under air ventilation (medians, 0.38 versus 0.56; p < 0.05). Moreover, there was a significant correlation between RV Tei index and mean pulmonary artery pressure and positive linear correlation between individual changes in RV Tei index and changes in mPAP (r2 = 0.799, p < 0.05). We conclude that the Tei index is useful for assessing the function of the RV and the left ventricle and pulmonary circulation in a newborn piglet model with hypoxic pulmonary hypertension. These results suggest that the Tei index will become an objective method of assessing patients with persistent pulmonary hypertension of the newborn.

Animals↗
PubMed1993

Effects of dobutamine and/or nitroprusside on the pulmonary circulation in patients with pulmonary hypertension secondary to end-stage heart failure.

Nine NYHA class III-IV patients awaiting heart transplantation (HTx) were studied with a right ventricular ejection fraction (RVEF) catheter. The first aim of the study was to explore the pulmonary and systemic circulatory effects of dobutamine (D) and/or nitroprusside (N) in these patients. The second aim was to search for the parameter(s) among those usually measured that best predicted RVEF. Baseline data were recorded after 30 minutes of stabilization. Then, three drug regimens were administered in a randomized order for 30 minutes each: D, 4 micrograms/kg/min; N, 0.25 to 1.0 micrograms/kg/min; and their combination. Significant changes in RV loading and function were observed with all three therapies. The combination of both drugs was superior to either drug alone. The best predictor of RVEF was pulmonary arterial elastance. The second best was pulmonary capillary wedge pressure (PCWP). Pulmonary artery pressures, pulmonary vascular resistances, and transpulmonary gradient (TPG) were of less predictive value, as shown by a multiple regression analysis. None of the drugs showed any selectivity for the pulmonary vasculature, because the ratio PVRI/SVRI was never changed significantly. Selective pulmonary arterial vascular smooth muscle relaxation is probably not the most important mechanism to explain the unloading and improvement in function of the RV with D and/or N. Improved myocardial pump function appears to be the major factor in unloading the RV via reduction of PCWP and mean pulmonary artery pressure with essentially no change in TPG. The RVEF catheter provides valuable additional information in the screening of HTx candidates for pulmonary hypertension.

Blood Pressure↗
PubMed1996

[Correlation of selected hemodynamic parameters of pulmonary circulation and indices of pulmonary function in patients with mitral stenosis].

The aim of this study was to test if the lung compliance and other indices of pulmonary function correlated with hemodynamic parameters in patients with secondary pulmonary hypertension due to mitral stenosis. 36 patients (mean age 50 years) with mitral stenosis (mean mitral valve area-1.2 cm2), without history of lung diseases were analyzed in the study. 16 patients (group A) were in the II-nd and 20 patients (group B) were in the III-rd and IV-th NYHA class. All patients underwent Swan-Ganz catheterization with evaluation of pulmonary pressures, resistances and pulmonary veins compliance. Pulmonary function tests (spirometry, plethysomography, lung compliance) were also performed. In both analyzed groups the pulmonary artery pressure and pulmonary vein compliance correlated significantly with pulmonary compliance.

Adult↗
PubMedDate not supplied

[Utility of echo enhancers in the study of pulmonary circulation time].

UNLABELLED: Pulmonary circulation time (PCT) varies under different clinical conditions. To evaluate the PCT, the persistence of contrast in both ventricles and the digital arterial saturation of oxygen with peripheral intravenous injection of microbubbles, were examined 14 patients. Groups: I normals, II left ventricular hypertrophy (EF > 50%), III with mitral stenosis and IV in congestive heart failure. In seven patients, isosorbide S/L was administered after the first injection. The transpulmonary transit in beats was 7.3 in normals, and larger in the others. The persistence of echo contrast in right chambers was 31 beats in group I, and larger in the other groups. In left chambers it was 20.6 beats in group I, and larger in others. There were no alterations with regards to peripheral arterial saturation of oxygen. AII patients with isosorbide presented shorter PCT and persistence of contrast in right chambers. CONCLUSIONS: There are differences in PCT among normals, patients with mitral stenosis and those with congestive heart failure. Prolonged persistence contrast in right chambers indicates abnormally slow transpulmonary transit. Patients with congestive heart failure and ventricular damage, have longer persistence of echo contrast. PCT studied with contrast is an easy means of evaluating some aspects of pulmonary circulation.

Contrast Media↗
PubMed2004

Modulating the pulmonary circulation: an update.

Pulmonary hypertension is a common finding in pulmonary circulatory disorders of different origin. Chronic pulmonary hypertension may develop due to either cardiopulmonary or systemic diseases whereas acute and acute-on-chronic pulmonary hypertension often occur in the course of cardiothoracic surgery. Right heart failure is the major risk particularly in the course of acute pulmonary hypertension. Thus, besides basic treatment of the underlying disease the use of vasodilators is a valuable therapeutic option to decrease right ventricular afterload, but intravenous vasodilators may provoke systemic arterial hypotension and impair gas exchange due to vasodilation of pulmonary shunt areas. Therefore, inhaled vasodilators such as nitric oxide and prostacyclin have been suggested for the treatment of pulmonary hypertension especially when concomitant hypoxemia is present due to a ventilation-perfusion mismatch. However, randomised controlled trials performed to evaluate long-term effects revealed different results: thus, in chronic pulmonary hypertension inhaled vasodilators improved outcome whereas the results for the treatment of the acute respiratory distress syndrome revealed beneficial effects only when used as a rescue and/or bridging therapy in severe hypoxemia. In cardiothoracic surgery, inhaled vasodilators have been shown to improve pulmonary circulation when severe pulmonary hypertension is present. Although effective in experimental studies no clear recommendation can be made in view to the use of other vasodilators such as phosphodiesterase inhibitors or endothelin antagonists. Likewise, the combination of different vasodilators merit further investigations to prove efficacy in randomised controlled trials.

Humans↗
PubMed1989

Sympathetic innervation of pulmonary circulation and its role in hypoxic pulmonary vasoconstriction.

The purposes of this study were to localize the position of spinal center of sympathetic nerve which controls the pulmonary circulation, and to evaluate the role of pulmonary sympathetic nerve in hypoxic pulmonary vasoconstriction (HPV) in pithed rat model. The sympathetic preganglionic fibers arising from C7-T10 segments were stimulated electrically in succession. During stimulation the pulmonary vascular resistance (PVR) was increased in all segments tested, most significantly in C7-T4 (about 28% above control value), obviously higher than that in T5-T10. The higher the stimulated spinal segments, the larger the ratio of delta PVR/ delta SVR. Alveolar hypoxia (12% O2-88% N2) could induce HPV in pithed rat. In the presence of hypoxia, stimulation of T1-T3 segments caused a double increment in PVR and Ppa as compared with those during normoxia (P less than 0.05). The data show that 1) the spinal center of sympathetic nerve regulating the vasomotion of pulmonary circulation is located in the C7-T4 segments; 2) the excitation of sympathetic nervous system during hypoxia could enhance HPV.

Animals↗
PubMed1990

[Significance of the arrest of pulmonary circulation in the genesis of postperfusion pulmonary complications in open heart surgery].

The purpose of the work is to elucidate the importance of pulmonary circulation arrest during extracorporeal circulation in the development of microcirculatory disorders in the pulmonary tissue. Experiments showed that temporary arrest of pulmonary circulation under conditions of extracorporeal circulation is attended by the development of ischemia of the respiratory pulmonary tissue. The systemic blood flow in the arterio-arterial anastomoses between the pulmonary and bronchial arteries is incapable of providing the pulmonary tissue with blood. Ischemia of the parenchyma leads to disorders in the microvessels of the organ, the manifestation of which in the ischemic and postischemic, periods is determined by the duration of the pathologic effect. The data gained indicate the importance of developing methods for the prevention and treatment of ischemic and postischemic pulmonary microcirculatory disorders and determining the safe terms of pulmonary artery ischemia.

Animals↗
PubMed2005

Noninvasive assessment and monitoring of the pulmonary circulation.

In pulmonary vascular disease, changes in the pulmonary vascular bed will lead to altered pulmonary haemodynamics. This review describes the application of several physiological principles to measure these changes noninvasively by means of novel techniques. Flow characteristics of blood through the pulmonary vascular bed alter in pulmonary vascular disease. Recent developments in magnetic resonance imaging and computed tomography make it possible to visualise and quantify these abnormal flow patterns. Information regarding pulmonary perfusion can also be obtained by measuring the electrical impedance changes in the lung by electrical impedance tomography. A more indirect approach to measure the pulmonary blood flow is the measurement of the absorption of acetylene, a perfusion limited gas. Information on the pulmonary vascular bed can also be obtained by the measurement of exhaled products of the pulmonary vascular endothelium, such as nitric oxide. Although all the techniques described offer new ways to diagnose or monitor pulmonary vascular disease, clinical data on these techniques are limited. Further improvement and evaluation of the clinical value of these techniques are therefore obligatory before they can be used in clinical practice.

Diagnostic Techniques, Cardiovascular↗
PubMed2006

Role of NO and EDHF-mediated endothelial function in the porcine pulmonary circulation: comparison between pulmonary artery and vein.

OBJECTIVE: To compare electrophysiological measurement of nitric oxide (NO) release and endothelium-derived hyperpolarizing factor (EDHF)-mediated endothelial function in porcine pulmonary arteries and veins. METHODS: Isolated pulmonary interlobular arteries (PA) and veins (PV) were obtained from a local slaughterhouse. By using a NO-specific electrode and a conventional intracellular microelectrode, the amount of NO released from endothelial cells and hyperpolarization of smooth muscle cells were investigated. The bradykinin (BK)-induced relaxation in the precontraction by U(46619) was examined in the absence or presence of N(G)-nitro-l-arginine (l-NNA), indomethacin (INDO) plus oxyhemoglobin (HbO). RESULTS: The basal release of NO was 7.0+/-1.2 nmol/L in PA (n=8) and 5.5+/-1.6 nmol/L in PV (n=8, p<0.01). BK-induced release of NO was 160.4+/-10.3 nmol/L in PA (n=8) and 103.0+/-14.7 nmol/L in PV (n=8, p<0.001) with longer releasing duration in PA than in PV (14.3+/-1.3 vs. 12.1+/-0.8 min, p<0.01). BK evoked an endothelium-dependent hyperpolarization and relaxation that were reduced by l-NNA, INDO, and HbO (hyperpolarization: 12.8+/-1.3 vs. 8.0+/-1.4 mV in PA, n=6, p<0.001 and 8.3+/-1.4 vs. 3.0+/-0.8 mV in PV, n=6, p<0.001; relaxation: 92.8+/-3.1% vs. 19.6+/-11.1% in PA n=8, p<0.001 and 70.3+/-7.9% vs. 6.0+/-6.8% in PV, n=8, p<0.001). Both hyperpolarization (8.0+/-1.4 vs. 3.0+/-0.8 mV, p<0.001) and relaxation (19.6+/-11.1% vs. 6.0+/-6.8%, p<0.01) were greater in PA than in PV. CONCLUSIONS: Both NO and EDHF play an important role in regulation of porcine pulmonary arterial and venous tones. The more significant role of NO and EDHF is revealed in pulmonary arteries than in veins.

Animals↗