The Effects of Prostacyclin Aerosol and Infusion on Pulmonary Hypertension / 대한마취과학회지

BACKGROUND: Prostacyclin administered intravenously has demonstrated intermediate pulmonary specificity and its aerosol form has an even greater pulmonary selectivity. There have been few systematic analyses of the difference in response according to the route of administration and the dose of administration of prostacyclin. So we have compared prostacyclin infusion versus inhalation in various concentrations in an animal model. METHODS: Pulmonary hypertension was induced by continuous intravenous infusion of the vasoconstrictor U46619 and prostacyclin solutions of 10, 50, 100, 200 mcg/ml were inhaled using a jet nebulizer. Prostacyclin infusion was done at a rate of 100, 200, 400 ng/kg/min. RESULTS: With inhalation of 10, 50, 100, 200 mcg/ml prostacyclin, PVR fell to values of 85%, 76%, 64%, 55% of the preinhalation value and SVR fell to values of 94%, 80%, 76%, 64% of the preinhalation value, respectively (p<0.05). PVR/SVR ratios decreased significantly in all inhalation doses (p<0.05). With infusion of prostacyclin at a rate of 100, 200, 400 ng/kg/min, PVR fell to values of 73%, 60%, 50% of the preinfusion value and SVR fell to values of 68%, 54%, 38% of the preinfusion value, respectively (p<0.05). PVR/SVR ratios increased at an infusion rate of 400 ng/kg/min. CONCLUSION: Prostacyclin inhalation did not result in selective pulmonary vasodilation without causing any efects on the systemic vascular bed (absolute pulmonary selectivity). But it did cause more predominant vasodilation on the pulmonary vascular bed (relative pulmonary selectivity). By contrast, prostacyclin infusion caused more predominant vasodilation on the systemic vascular bed, creating the risk of severe systemic hypotension.

Acute Pulmonary Hypertension Associated with Protamine Neutralization of Systemic Heparinization during Open Heart Surgery / 대한마취과학회지

Protamine sulfate, a strong polycationic polypeptide, combined with acidic heparin to form a neutral salt, eliminates the anticoagulating properties of heparin. Heparin reversal with protamine after cardiopulmonary bypass may complicate with adverse hemodynamic effects including systemic hypotension, decreased cardiac output, changes in systemic and pulmonary vascular resistances, anaphylaxis and noncardiogenic pulmonary edema. We recently observed a case of severe pulmonary vasoconstriction with right ventricular failure after protamine administration in 37-year-old woman with mitral stenosis who underwent mitral valvuloplasty. After uneventful termination of cardiopulmonary bypass, administration of protamine was associated with sudden elevation of pulmonary arterial pressure with profound right ventricular distension and systemic hypotension by which heparin-protamine reaction is suspected. After intravenous epinephrine infusion and cardiac massage, these changes were reversed. Although the mechanism of this protamine-heparin induced response is unclear, complement activation and thromboxane release may play a role in the development of pulmonary vasoconstriction.

Effects of dietary magnesium on hypoxic pulmonary vasoconstriction and chronic hypoxic pulmonary hypertension in rats / 中国病理生理杂志

The effects of dietary magnesium on pulmonary vascular reactivity and chronic hypoxic pulmonary hypertension were assessed in rats. The rats were fed on a high magnesium diet or a regular diet begining 8 weeks before the start of normobaric hypoxia (10?1.0% O_2 Ventilation, 8 hours per day, 14 days). The plasma level of magnesium Was significantly increased in the high magnesium group as compared to the control. Mean pulmonary arterial pressure, pulmonary vascular resistance and pulmonary vascular reactivity to hypoxia in the rats fed on high magnesium diet were markedly lower than that in the rats fed on regular diet. Hypertrophy of the right ventricle in the rats fed on high magnesium diet were significantly lower as well. Blood viscosity and hematocrit had no difference between the high magnesium group and the control. These findings suggested that dietary magnesium can attenuate basic pulmonary vascular resistance and hypoxic pulmonary vasoconstriction, and therefore can prevent the development of chronic hypoxic pulmonary hypertension and right ventricular hypertrophy.