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Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pulmonary vascular tone was investigated by the construction of pulmonary arterial pressure (PAP)/cardiac output (Q) plots, and gas exchange, by the multiple inert gas elimination technique, in 24 anesthetized dogs before and after pulmonary embolization of autologous clots. Three PAP/Q plots were obtained by a manipulation of venous return at baseline and 60 min and 110 min after embolization. Before the third PAP/Q plot, the dogs were randomly allocated to one of the following iv treatments: 1) placebo (n = 6); 2) prostaglandin E1 (PGE1) 0.4 microgram.kg-1.min-1 (n = 6); 3) hydralazine 2 mg/kg (n = 6); and 4) nitroprusside 10 microgram.kg-1.min-1 (n = 6). These vasodilators decreased systemic arterial pressure by a mean of 44%. Ventilation-perfusion (VA/Q) distributions were determined at the same Q (2.4 +/- 0.1 l.min-1.m-2, mean +/- SE) of each PAP/Q plot. Embolization increased the intercept and the slope of the PAP/Q plots (P less than 0.001). Distributions of VA/Q were only moderately impaired, with an increased dispersion of both VA and Q and a shift of VA distributions to higher VA/Q. PaO2 changed from 208 +/- 5 to 172 +/- 8 mmHg (P less than 0.01) (fraction of inspired O2 was 0.4). None of the treatments had any effect on VA/Q distributions. Placebo and PGE1 had no effect on PAP/Q plots. Hydralazine and nitroprusside reduced the slope of the PAP/Q plots. Thus, in this canine model of acute pulmonary embolism: 1) VA/Q distributions were moderately impaired accounting for only slight hypoxemia, and 2) pulmonary hypertension was partially reversible by hydralazine and by nitroprusside without associated non-flow-dependent change in VA/Q distributions and arterial oxygenation.
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PMID:Effects of vasodilators on gas exchange in acute canine embolic pulmonary hypertension. 229 36

The acute pulmonary and systemic haemodynamic response to low (0.15 mg/kg) and high (0.30 mg/kg) doses of intravenous hydralazine was evaluated in 26 consecutive patients with severe pulmonary hypertension due to cor pulmonale (nine patients), primary pulmonary hypertension (11 patients), or pulmonary embolism (six patients). Hydralazine did not cause a significant change in pulmonary arterial resistance or pressure in any group but produced a significant reduction in systemic resistance, which correlated with plasma concentration, and a significant increase in pulmonary blood flow index in all groups. Ten patients who experienced a reduction in pulmonary arterial resistance of at least 5 U X m2 after administration of hydralazine had higher initial values for pulmonary arterial resistance and systemic resistance and a lower pulmonary blood flow index than those who did not respond. Maintenance oral hydralazine treatment during nine to 36 months of follow up did not seem to affect symptoms or mortality. These results indicate that hydralazine has limited value in acutely reducing pulmonary arterial pressure or affecting clinical outcome in patients with pulmonary hypertension.
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PMID:Haemodynamic response to intravenous hydralazine in patients with pulmonary hypertension. 665

Shortly after pelvic surgery, massive bilateral pulmonary emboli and shock developed in an elderly woman. Despite fluids, dopamine hydrochloride, and heparin sodium, her condition steadily deteriorated. Two trials of hydralazine hydrochloride were given and each was associated with pronounced clinical and hemodynamic improvements. Ninety minutes and 24 hours after the first trial, her pulmonary vascular resistance decreased 44% and 67%, respectively, and cardiac index increased 40% and 90%, respectively. There were insignificant changes in heart rate and blood pressure. The hemodynamic improvements reversed when the hydralazine therapy was stopped but improved again during the second trial. Hydralazine may be of substantial benefit to patients with hemodynamic compromise secondary to pulmonary embolism.
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PMID:Oral hydralazine therapy for acute pulmonary embolism and low output state. 728 69