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Biomedical subjects

E A Kopman

Publications and source records attributed to E A Kopman.

At least 19 recordsLinked to original sources
PubMed1985

Interaction of right and left ventricular filling pressures at the termination of cardiopulmonary bypass. Central venous pressure/pulmonary capillary wedge pressure ratio.

In 50 patients who underwent coronary bypass grafting, the interaction of left- and right-sided filling pressures were prospectively evaluated to determine whether restoration and/or maintainance of a normal central venous pressure/pulmonary capillary wedge pressure (CVP/PCWP) ratio could improve biventricular performance. In 40 patients, the CVP/PCWP ratio was normal (less than 1) and termination of cardiopulmonary bypass was uneventful. In 10 patients, during loading at the termination of extracorporeal circulation, CVP exceeded PCWP and the ratio was reversed (less than 1). Cardiac index and systolic arterial pressure were low. Restoration of normal ratio by emptying the right heart helped in the improvement of systolic arterial pressure and cardiac index. Thus, in the presence of reversed CVP/PCWP ratio at the termination of cardiopulmonary bypass, restoration of the ratio may prevent unnecessary pharmacologic and/or mechanical intervention, such as inotropic agents, balloon pumps, or assist devices.

Adult↗
PubMed1983

Scavenging of cardioplegic solution from right heart to prevent hyperkalemia.

The present study was designed to test the hypothesis that hyperkalemia can be prevented if the cardioplegic solution returning to the right heart from the coronary sinus is aspirated. In the control group (15 patients without aspiration), the potassium concentration rose from 3.5 +/- 1 (SD) mEq/L to 6.3 +/- 0.4 mEq/L (p less than 0.001) 10 minutes after the administration of cardioplegic solution and was still high before the patient was weaned from cardiopulmonary bypass (5.2 +/- 0.3 mEq/L (p less than 0.001). Electromechanical recovery time was delayed. In the second group (15 patients with aspiration), serum potassium did not change. Our data indicate that scavenging of cardioplegic solution may prevent hyperkalemia in most patients.

Heart Arrest, Induced↗
PubMed1982

Bolus intravenous nitroglycerin for ST-segment depression not associated with increased myocardial oxygen demand.

Ischaemic ST-segment changes may occur in patients with coronary artery disease when myocardial oxygen consumption is increased as a result of hypertension, tachycardia or increased contractility. Ischaemia can also occur as the result of decreased coronary perfusion pressure caused by hypotension or coronary artery spasm. We report ST-segment depression in the absence of hypertension, tachycardia or hypotension. The response to bolus intravenous nitroglycerin suggested coronary artery spasm as the cause.

Adult↗
PubMed1980

Mechanism of nitroglycerin-induced hypoxemia.

We and others have previously demonstrated a consistent significant decline in arterial oxygen tension (PaO2) after sublingual nitroglycerin in premedicated and unpremedicated patients both with and without coronary artery disease and/or obstructive ventilatory disease. Thus, in our 19 patients, PaO2 fell by an average of 17% (12 mm Hg), mean systemic arterial pressure by 19% (17 mm Hg), pulmonary arterial pressure by 38% (6 mm Hg), pulmonary arterial occlusive pressure by 62% (5.3 mm Hg), and cardiac index by 16% (0.37 liter/min/m2) [P less than 0.001 for each] after nitroglycerin. Previous experimental studies suggest that the mechanism for the reduction of PaO2 may be relief of hypoxic pulmonary vasoconstriction with an increase in perfusion to poorly ventilated or nonventilated regions of the lungs. To examine this possibility, pulmonary vasodilatation was precluded by administration of a pulmonary vasoconstrictor (phenylephrine) simultaneously with nitroglycerin in nine patients with coronary artery disease. No significant change was observed in systemic or pulmonary arterial pressure, pulmonary arterial occlusive pressure, or systemic and pulmonary vascular resistance, and PaO2 did not decline. In ten other patients with coronary artery disease, the intrapulmonary right-to-left shunt fraction was determined before and after sublingual nitroglycerin; only a minimal increase in shunt fraction of 1.4% was observed, quantitatively insufficient to account for the observed decline in PaO2, thus excluding a predominant effect of nitroglycerin on nonventilated alveoli as a cause of the hypoxemia. We conclude that the reduction of PaO2 after nitroglycerin administration is attributable to pulmonary vasodilatation with a relative increase in perfusion of poorly ventilated lung units.

Cardiac Catheterization↗
PubMed1980

Arterial hypoxaemia following premedication in patients with coronary artery disease.

The effect of premedication with morphine and scopolamine, morphine alone, and scopolamine alone on arterial oxygen tension has been studied in patients with coronary artery disease undergoing bypass operations. Control arterial blood samples were obtained with the patients in the supine position breathing room air the day before operation. A second arterial blood sample was taken in the induction room with the patient breathing room air in the supine position. In the first group (scopolamine only) and second group (morphine only) cH+ (pH), PaCO2 and PaO2 did not change. In the third group (morphine and scopolamine), however, PaO2 decreased, while PaCO2 and cH+ increased (pH decreased). The changes in cH+ and PaCO2 were statistically significant, but of no clinical importance. The present study suggests that, when morphine and scopolamine premedication is used for patients with coronary artery disease, simultaneous administration of oxygen is important in helping to eliminate a possible cause of preoperative myocardial ischaemia.

Adult↗
PubMed1979

Hemodynamic effects of head-down lithotomy position in patients with coronary artery disease.

The hemodynamic effect of the head-down lithotomy (HDL) position was studied in 12 anesthetized patients with documented coronary artery disease. Data were collected in patients in supine position and then 10 minutes after placement in a 10-degree HDL position. Systolic arterial pressure (SP), mean arterial pressure (AP), mean right atrial pressure (RAP), mean pulmonary artery pressure (PAP), mean pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and heart rate-systolic pressure product (HRSP) increased significantly. Heart rate (HR), systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were unchanged. In 2 patients with very low ejection fractions (EF), CO was decreased. The increase in HRSPP and PCWP suggests that all patients had increased myocardial oxygen demand. This increased demand may not be met because of impaired coronary circulation, potentially causing myocardial ischemia. This study suggests that patients with significant coronary artery disease should not be placed in the HDL position for extended periods without appropriate monitoring.

Blood Pressure↗
PubMed1978

Arterial hypoxemia following the administration of sublingual nitroglycerin.

The effect of nitroglycerin on arterial blood gases and cardiovascular hemodynamics were studied in patients with coronary artery disease. In 13 premedicated patients blood gases and cardiovascular hemodynamics were studied before and 10 minutes after sublingual nitroglycerin (0.6 mg). In eight unpremedicated patients only blood gases were determined before and 10 minutes after sublingual nitroglycerin 0.6 mg. All studies were performed before induction of anesthesia with the patients in the supine position breathing room air. In both groups, arterial PO2 decreased significantly (p less than 0.001); pH and pCO2 did not change. In the 13 patients on which hemodynamic studies were performed, the mean arterial pressure (p less than 0.001), cardiac index (p less than 0.001), central venous pressure (p less than 0.001), pulmonary artery (p less than 0.001) and pulmonary artery wedge pressure (p less than 0.001) decreased. Calculated values for systemic and pulmonary vascular resistance were not significantly altered (p greater than 0.4). This study gives conclusive evidence that nitroglycerin reduces arterial PO2 in most patients with coronary artery disease breathing room air in the supine position. The possible mechanisms and clinical implications are discussed.

Administration, Oral↗