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Biomedical subjects

R N Edie

Publications and source records attributed to R N Edie.

At least 37 records · Page 2Linked to original sources
PubMed1982

Platelet function during cardiac operation: comparison of membrane and bubble oxygenators.

The effects of cardiopulmonary bypass with bubble and membrane oxygenator systems on platelet function were studied in 26 patients who had elective coronary arterial bypass grafts. Fourteen patients were perfused with spiral coil membrane oxygenator systems, 12 with bubble oxygenator systems. During and after bypass, platelet counts decreased in both groups; however, when corrected for dilution, platelet counts did not change significantly in patients perfused with membrane oxygenators and increased slightly but significantly in those perfused with membrane oxygenators and increased slightly but significantly in those perfused with bubble oxygenator systems. During and 1 hour after bypass, the concentration of adenosine diphosphate (ADP) required to cause complete aggregation increased in both groups. Plasma low affinity platelet factor 4 (LA-PF4) increased significantly during and after bypass in both groups. However, the concentration of platelet adenine nucleotides and LA-PF4, measured only in patients perfused with membrane oxygenator systems, did not change. Bleeding times increased postoperatively in both groups and 18 hour blood losses were similar. Cardiopulmonary bypass with membrane and bubble oxygenator systems causes qualitatively similar losses in sensitivity to ADP and similar increases in bleeding times. The mechanism by which platelets are altered during cardiopulmonary bypass in obscure but is not due to partial depletion of granule contents in patients perfused with membrane oxygenators.

Adenosine Diphosphate↗
PubMed1979

Right atrial ultrastructure in congenital heart disease. II. Atrial septal defect: effects of volume overload.

Portions of operatively resected right atrium from 15 patients with atrial septal defect were studied ultrastructurally to determine whether the cell hypertrophy in the right atrium of patients with increased right atrial blood flow and increased right atrial pressure is caused by the increased blood flow. In 12 patients with normal right atrial mean pressure but increased right atrial blood flow the atrium was dilated but no atrial arrhythmias were noted clinically. Ultrastructurally, the atrial myocardial cells in these patients were normal, measuring 6 to 10 mu in diameter, and there was no evidence of cell hypertrophy or degeneration. The remaining three patients had elevated right atrial mean pressure and increased right atrial blood flow. Ultrastructurally, the atrial myocardial cells in all three patients were hypertrophied, and two patients had evidence of focal cell degeneration; the atrium was markedly dilated, but atrial arrhythmias were not noted. The lack of cell hypertrophy in the right atrium of the 12 patients with increased blood flow but normal mean pressure suggests that in congenital heart disease volume overload alone does not lead to cell hypertrophy of the right atrial myocardium.

Adult↗
PubMed1979

Comparison of intraoperative nitroprusside unloading in mitral and aortic regurgitation.

To compare the hemodynamic effect of vasodilator therapy on different regurgitant lesions, we infused sodium nitroprusside intraooperatively in 12 patients with mitral regurgitation and 15 with aortic regurgitation. During the critical period preceding establishment of cardiopulmonary bypass, both groups had developed intense vasoconstriction and cardiac decompensation. All demonstrated improved cardiac function with vasodilator therapy; however, the degree of improvement with nitroprusside differed in the two groups. Stroke volume increased 10 ml. per beat per meter squared in those patients with aortic regurgitation and only 6 ml. per beat per meter squared in those with mitral regurgitation (p less than 0.05). The percent increase in stoke volume induced by nitroprusside was inversely correlated to the preoperative left ventricular ejection fraction (r = 0.44, p less than 0.02). Patients with aortic regurgitation had lower preoperative left ventricular ejection fractions than those with mitral regurgitation (0.53 versus 0.63, p less than 0.02). Therefore, we conclude that patients with aortic regurgitation derived greater intraoperative hemodynamic benefit from unloading with nitroprusside, because they came to surgery with greater impairment of left ventricular contractility. Although nitroprusside improved cardiac function in both groups, only the patients with aortic regurgitation achieved normal pulmonary artery pressure (17 torr) and pulmonary vascular resistance (2.1 units) as a result of unloading. Those with mitral regurgitation continued to have pulmonary hypertension (28 torr) and increased pulmonary vascular resistance (3.9 units) despite vasodilator therapy. Thus the data suggest that patients with mitral regurgitation derived less hemodynamic benefit from intraoperative nitroprusside therapy because they were also limited by right ventricular dysfunction and a less responsive pulmonary vasculature.

Adult↗
PubMed1979

Pulmonary atresia with intact ventricular septum. Sixteen-year experience.

Infants with pulmonary atresia and intact ventricular septum (PA-IVS) usually require urgent surgical intervention. Thirty patients with this anomaly, seen at the Columbia-Presbyterian Medical Center between 1962 and 1978, had palliative operations, 26 within the first 3 days of life. Six underwent a closed pulmonary valvotomy alone, with no survivors; six had only a systemic--pulmonary artery shunt, with three early survivors. Because of this experience, 17 had a combined procedure of valvotomy and shunt, with 14 early survivors. One patient recently underwent a definitive right ventricular outflow patch procedure with cardiopulmonary bypass. Eight patients subsequently have had corrective open-heart procedures, with five patients surviving from 2 to 10 years. A unicusp aortic homograft was used for repair in five and a Hancock valved conduit in three. Four patients are presently awaiting operation. We conclude that the initial surgical management of these critically ill infants must not only increase pulmonary blood flow but in addition provide an opportunity for right ventricular growth. Thus we continue to advocate the combined procedure of a valvotomy plus a shunt to provide adequate palliation. Repeat catheterization should be performed within a year to confirm the adequacy of the valvotomy, since this is essential to maximal right ventricular enlargement and to allow for definitive correction at a later date.

Adolescent↗
PubMed1978

The cellular electrophysiologic effects of digitalis on human atrial fibers.

We used microelectrode techniques to study the indirect and direct actions of ouabain on human atrial fibers (HAF) obtained from patients with congenital heart disease undergoing open heart surgery. At 15 min of superfusion ouabain, 2 X 10(-7) M, induced an increase in maximum diastolic potential (MDP), action potential (AP) amplitude and upstroke velocity of phase 0 depolarization (Vmax) and a decrease in AP duration. Spontaneously beating HAF showed a decrease in automaticity. Acetylcholine (3 X 10(-6) M) induced identical effects on AP characteristics and automaticity. Prior treatment with atropine (1 X 10 (-6) M) blocked these effects of ouabain and acetylcholine. Superfusion with ouabain (2 X 10 (-7) M) for 30 to 90 min resulted in decreased MDP, AP amplitude and Vmax, and a further decrease in AP duration. Phase 4 depolarization and spontaneous rate increased and delayed afterdepolarization and tachyarrythmia occurred. The ACh-like effects of digitalis decrease automaticity and increase MDP of HAF; the direct effects decrease MDP, increase automaticity, and induce tachyarrythmias.

Acetylcholine↗
PubMed1978

Delirium after coronary artery bypass surgery.

The incidence of postoperative delirium following coronary artery bypass surgery was 28%. This rate is comparable to that after open-heart surgery. However, of those variables which were previously found to correlate with delirium in the open-heart group, only severity of postoperative illness in the recovery room significantly correlated with delirium in patients having bypass. The relationship between personality type and delirium, previously found to be signficant, was suggestively associated in these patients. A history of myocardial infarction prior to surgery was significantly associated with delirium.

Adult↗
PubMed1978

Surgical management of ventricular septal defects in infants.

Infants with ventricular septal defect (VSD) who are symptomatic despite intensive medical therapy require surgical intervention. Choice of treatment depends upon the cumulative mortality and morbidity rates of the two-stage approach of initial pulmonary artery banding followed by debanding and VSD closure as compared to the risk of primary intracardiac repair in infancy. Sixteen infants underwent pulmonary artery banding at Columbia-Presbyterian Medical Center between 1967 and 1976, with one operative death but with a significant incidence of morbidity and late death. Forty patients underwent pulmonary artery debanding and closure of VSD with three operative deaths. This second-stage procedure was frequently complicated by repair of acquired lesions. During the same 10 year period 37 infants underwent primary closure of VSD with eight operative deaths. The morbidity related to this procedure is low. With the use of profound hypothermia and circulatory arrest, results have significantly improved and the risk of early correction now compares favorably with the cumulative mortality rate of the two-stage approach. Primary intracardiac repair is the procedure of choice.

Heart Arrest, Induced↗
PubMed1978

[Counterpulsation by means of a new device with a pulsatile blood flow in open heart operations (author's transl)].

A new counterpulsation method in operations on an open heart is described. Clinical experience in the use of the new device in 124 patients, which also makes it possible to produce a pulsatile flow of blood in the system of extracorporeal circulation, testifies to its effectiveness. The authors claim that the positive changes in cardiac output, diastolic and systolic pressure, and coronary circulation are among the factors which cause an improvement in the final result of the operation in patients with severe valvular diseases and ischemic heart disease.

Adult↗
PubMed1977

A pulsatile assist device (PAD) for use during cardiopulmonary bypass.

A pulsatile assist device (PAD) has been developed to convert roller pump flow to pulsatile flow in a simple fashion. The device can also be used as an arterial counterpulsator before and after cardiopulmonary bypass. The PAD has been used in 125 adult patients undergoing open-heart operations for coronary artery or valvular heart disease or the combination. Ninety-two patients were in New York Heart Association Functional Class III or IV or had ejection fractions of less than 0.3. The PAD functioned as a hemodynamically effective arterial counterpulsator before and after perfusion. All patients were successfully weaned from bypass with the PAD. There has been 1 intraoperative death and 2 late deaths. Only 1 patient had a perioperative myocardial infarction, and this person was successfully treated with intraaortic balloon pumping. We believe the PAD is a simple and reliable device for intraoperative counterpulsation and for the creation of pulsatile cardiopulmonary bypass. More important, use of the PAD may decrease both the incidence of perioperative myocardial infarction and the need for postoperative intraaortic balloon pumping.

Adult↗
PubMed1977

An improved method of myocardial protection with pulsation during cardiopulmonary bypass.

A new valveless pulsatile assist device (PAD) has been developed that converts roller pump flow into synchronized pulsatile flow. The PAD can also be used as an arterial counter-pulsator (ACtP) before and after cardiopulmonary bypass (CPB). The PAD was employed in 100 adult patients undergoing open heart surgery for coronary artery and/or valvular heart disease. Seventy-three of these patients were NYHA class III or IV, had ejection fractions of less than 0.3, or an LVEDP greater than or equal to 18 mm Hg. Sixty-one patients underwent coronary artery bypass alone, 17 valve replacement alone, three ventricular aneurysm alone, 12 combined coronaries and valves, and seven combined coronaries and ventricular aneurysms. The device functioned as a hemodynamically effective ACtP before and after CPB. During CPB, pulse pressures of 40-50 mm Hg were readily obtained. Urinary outputs during CPB were increased on the PAD when compared to a control group (9.18 +/- 0.68 cc/min vs 3.90 +/- 0.34 cc/min). In addition, during CPB, coronary graft blood flow (CBF) increased an average of 21.4 +/- 6.1% with the PAD, and after CPB, CBF increased an average of 25.0 +/- 5.9%. Free plasma hemoglobins after CPB were not elevated. Only one patient had a perioperative myocardial infarction, and this patient was successfully treated with intra-aortic balloon pumping. It is suggested from these data that use of the PAD may decrease both the incidence of perioperative myocardial infarction and the need for postoperative intra-aortic balloon pumping.

Assisted Circulation↗
PubMed1976

Open-heart experience in infants using normothermia and deep hypothermia.

During the 9-year period from 1967 through 1975, 124 open-heart operations were performed on infants less than 1 year of age with 35 operative deaths (28%). Ninety-seven of these procedures used continuous cardiopulmonary bypass with normothermia or mild hypothermia, and 27 were done under deep hypothermia and circulatory arrest. Mortality and morbidity were similar regardless of the operative technique, although deep hypothermia facilitated the repair of complex lesions. The highest mortality occurred in infants less than 3 months of age. Respiratory insufficiency, usually requiring prolonged ventilatory support, occurred only among infants who had pulmonary overcirculation or congestion prior to operation. Adequacy of intraoperative repair and postoperative care were the major determinants of survival.

Cardiac Surgical Procedures↗