Biomedical subjects
Publications and source records attributed to R M Sade.
We injected antibacterial solutions into rabbit pericardium to investigate tissue injury. Povidone-iodine was the only irrigant found to cause substantial damage. These data lend experimental support to recent clinical observations that suggest a causal relation between pericardial irrigation with povidone-iodine and the later development of constrictive pericarditis.
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Twenty-nine patients have had valvotomy with inflow occlusion since 1975 at our institution: 7 for aortic stenosis and 22 for pulmonary stenosis. All patients with aortic stenosis and 11 with pulmonary stenosis were neonates. Six patients died, 3 with aortic stenosis and 3 with pulmonary stenosis. All of them were less than 2 days old. Two newborns with critical pulmonary stenosis required reoperation with an outflow patch at age 22 and 25 months. To determine morbidity and expense of inflow occlusion versus cardiopulmonary bypass for patients with pulmonary stenosis, we compared the 11 patients who were not infants and who had inflow occlusion (age range, 3.5 to 26.8 years) with 10 patients who were operated on concurrently and who required bypass to correct associated minor intracardiac lesions (age range, 2.6 to 26.4 years). Significant differences (p less than 0.01) were as follows (inflow occlusion versus bypass): operating room time, 2.0 +/- 0.4 versus 3.6 +/- 0.8 hours (mean +/- standard deviation); blood utilized, 0.3 +/- 0.5 versus 1.7 +/- 1.7 units; and total expense, $4,600 +/- 800 versus $7,000 +/- 1,600. Thus, inflow occlusion is safe in patients more than 2 days old, with early and late results similar to bypass, and is an attractive alternative for patients with isolated pulmonary valvular stenosis and for newborns with aortic stenosis.
In a prospective, randomized study, the effectiveness of chest physiotherapy (CPT) was evaluated in preventing postoperative atelectasis in children after heart surgery. Postoperative clinical variables and chest x-ray findings of atelectasis were compared in two groups: 19 patients receiving CPT and 25 patients not receiving CPT (NCPT). Chest physiotherapy was associated with significantly more frequent (p less than 0.01) and more severe (p less than 0.01) atelectasis than NCPT. Atelectasis was not significantly associated with temperature elevation, age, or presence of preoperative left-to-right shunt.
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The physiochemical characteristics of hydroxyethyl starch make it suitable for use as a colloidal blood plasma substitute. In high doses, this drug may interfere with blood coagulation. Because of its effectiveness and low cost, we have used hydroxyethyl starch rather than albumin in the priming fluid for cardiopulmonary bypass: 500 ml of 6% hydroxyethyl starch and 2,000 ml of lactated Ringer's solution. To determine if excessive bleeding has been associated with the use of hydroxyethyl starch, we reviewed 760 cardiac operations. The patients were 49.9 +/- 0.5 years old (mean +/- SEM) and weighed 73 +/- 1 kg. Blood loss during the first postoperative day was 578 +/- 25 ml, and 4.0 +/- 0.2 units of bank blood were utilized in the perioperative period. We have used an improved method of administering heparin and protamine for the past 3 years. In the 461 patients operated upon since then, blood loss was 437 +/- 21 ml, 2.9 +/- 0.1 units of bank blood were used, and excessive postoperative bleeding necessitated re-exploration in nine patients (2.0%). These results compare favorably with other recently published series in which hydroxyethyl starch was not used in the pump prime. Thus the dose of hydroxyethyl starch in our priming fluid does not appear to be associated with excessive bleeding. In view of its safety and low cost, hydroxyethyl starch is a suitable colloidal blood plasma substitute for use during cardiopulmonary bypass.
We have used the superior approach through the dome of the left atrium to repair cardiac lesions in the left atrium in 15 children ranging from 3 months to 17 years old. The single hospital death occurred in a 16-month-old infant with levo (L) transposition of the great arteries, Ebstein's malformation of the left atrioventricular valve, and ventricular septal defect. Exposure of the intraatrial structures was excellent, injury to adjacent cardiac structures did not occur, and hemorrhage from the left atrial suture line was not a problem. Though a few transient arrhythmias were seen, all survivors are in sinus rhythm without evidence of sick sinus syndrome, except 1 patient in whom atrial flutter associated with cardiomyopathy developed 1 year after operation. The excellent surgical exposure obtained of the interior of the left atrium and the absence of important complications related to the incision cause us to recommend this approach in children.
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A ten-year-old girl with severe subaortic stenosis was found to have relatively mature valvular endocardial cushion tissue (fibromyxomatous sheets with a chorda tendinea attached to a left ventricular papillary muscle) immediately beneath the aortic valve. This structure behaved like a valve mechanism, obstructing the left ventricular outflow tract during ventricular systole. This anomaly is an extreme on the spectrum of obstructive endocardial cushion malformations.
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We have studied pulmonary hemodynamics after right ventricular bypass in dogs. Manipulations of pulmonary vascular resistance and transpulmonary blood pressure difference (delta Pp) made it possible to increase pulmonary blood flow. Decreasing resistance by raising arterial pH from 7.25 to 7.38 increased flow by 24.9%. Infusion of homologous blood to increase right atrial pressure from 10 to 30 mm Hg lowered resistance 41.5% and raised flow 183%. Left ventricular bypass (left atrium to aorta) lowered left atrial pressure, increased arteriovenous pressure gradient by 41.4%, and raised flow 32.8%. These experiments support earlier clinical observations of the importance of low pulmonary vascular resistance and of good left ventricular function both in selection of patients and in postoperative management after right ventricular bypass. Attention to the principles we discuss may permit right ventricular bypass operation in some patients who would not be operable by current criteria.
During a recent 6 years period, we managed chronic empyema by decortication, either alone or in combination with thoracoplasty, in 58 patients: In 16 patients, the empyema was a complication of Paragonimus westermani infestation (PWI), in 20, tuberculosis (TB), and in 22, of varied origins. There were no operative deaths, and satisfactory or good results were obtained in 55 patients (94.8%). We believe that the result in a patient in whom thoracoplasty is required should be called satisfactory, not good. Only 55% of the TB group achieved a good result, compared with 89% of the other patients. Of the 10 patients who required a thoracoplasty, seven were in the TB group. Empyema complicating TB is associated with a higher incidence of fistula formation and is more difficult to treat than other empyemas. The empyema associated with PWI develops more slowly, tends to form fewer fistulas, and eventuates in a good result more often than empyema associated with TB. Two of our three poor results stemmed from failure to do a thoracoplasty when the lung did not expand. We recommend thoracoplasty when the lung does not expand well at operation; it should be done at the time of decortication to avoid the necessity for a second major procedure. Chronic empyema is a common complication of paragonimiasis in Korea and by inference in other parts of the world where PWI is endemic. As international travel increases, some patients with PWI and complicating empyema may be seen in the United States. American thoracic surgeons should be aware of this disease, its treatment and its chest complications.
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To evaluate the efficacy of pulmonary artery construction with a prosthetic conduit we have reviewed 25 operations in 22 of our patients. Early mortality was 12.0%, late mortality 5.3%. Up to 13 years postoperatively, 93.8% of the survivors are asymptomatic. Of 12 patients surviving more than 1 year, 11 have been catheterized after 1-11 years. Five had prior aortopulmonary shunts (mean duration 7.3 years); highest postrepair pulmonary artery pressure was 40 mmHg. Of seven recatheterized xenograft conduits, none had severe and four had mild obstruction. Reconstruction of pulmonary artery with xenograft conduit produced good clinical results. Long duration of aortopulmonary shunt prior to repair did not result in severe pulmonary artery hypertension. Obstruction of xenograft conduit has not been a major problem in our patients, but when necessary, reoperation for obstruction can be carried out safely as late as 11 years after the operation.
A 6-year-old girl had the clinical appearance of tetralogy of Fallot but was found at cardiac catheterization to have tetralogy of Fallot associated with complete atrioventricular canal. She underwent repair, and at recatherterization two years later, the hemodynamic result was excellent. Proper angiography is necessary to diagnose this combination, and correct preoperative diagnosis is necessary to plan a rational operative approach.
We studied 60 children, 2 weeks to 10 years old, prospectively by randomly assigning them to a SciMed membrane oxygenator or Harvey bubble oxygenator. Variables of cardiopulmonary bypass (CPB) were closely controlled: prime, circuit configuration, flow rate, and blood gases. Blood variables measured at eight intervals before, during, and after operation were as follows: seven plasma proteins, free hemoglobin, formed elements, and clotting functions. Preoperatively and postoperatively, we evaluated brain function (psychological testing), renal function (creatinine clearance), and pulmonary function (compliance changes and postoperative shunt function). Postoperative blood loss, fever, and length of hospitalization were also evaluated. We compared 302 variables by computer program. No difference (p greater than 0.05) between the two groups was found in any variable related to CPB or organ function (pulmonary, renal, or cerebral) or in hematological variables except free hemoglobin. After 5 and 60 minutes of CPB and the next day, it was significantly lower (p less than 0.05) in the group with a membrane oxygenator. Safety, cost, and convenience, not physiology, should be the major factors in considering membrane versus bubble oxygenators for cardiac operations in children.
We have used two methods to maintain ductal ppatency in 13 newborns during surgery for congenital cardiac malformations: prostaglandin E1 (PGE1) infusion for the short-term and formaldehyde infiltration of the ductus arteriosuos (FID) for the longer term. PGE1 increased the arterial oxygen saturation, leading to stable intraoperative hemodynamics in the six infants in whom it was used. FID was used in all 13 patients. Four of these patients died in the hospital, all with the ductus open. Of the nine early survivors, all required an additional shunt procedure. The five long-term survivors had the second palliative operation immediately, three hours, three days, two and one-half months, and four and one-half months after FID. We continue to use PGE1 to maintain ductal atency through operation, but use aortopulmonary anastomosis in the newborn period rather than FID.