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Biomedical subjects

C S Weldon

Publications and source records attributed to C S Weldon.

At least 55 records · Page 3Linked to original sources
PubMed1976

Clinical experience with the use of a valve-bearing conduit to construct a second left ventricular outflow tract in cases of unresectable intra-ventricular obstruction.

Two patients, ages 7 and 17, with unresectable obstructions within the left ventricular cavity, have been managed by interposing a conduit bearing a porcine aortic valve between the apex of the left ventricle and the infra-renal abdominal aorta. The younger child had idiopathic hypertrophic subaortic stenosis (IHSS) recognized in infancy. At the age of three, a right ventricular myomectomy and a trans-aortic left ventricular myotomy were performed. Symptoms were progressive with congestive failure, diaphoresis, syncope , and angina pectoris. Following construction of a second left ventricular outflow tract with relief of intraventricular obstruction, the patient has become asymptomatic. The second patient has fibrous tunnel obstruction of the left ventricular outflow tracting providing a 100 mm Hg gradient. Fibrous tissue was resected in part through the transaortic route, and a second outflow tract was constructed. A postoperative cardiac catheterization revealed an obliteration of the previous intraventricular gradients and an equal distribution of left ventricular output through the two available outflow tracts. She remains asymptomatic.

Adolescent↗
PubMed1976

Infection control in cardiac surgery.

This report relates the results of a multifaceted, 4 year program directed toward reduction of infection in patients undergoing cardiac operations and extracorporeal circulation in a large teaching hospital. Retrospective analysis of all superficial and deep wound infections and prosthetic valve infections for the period of 1966 to 1970 and a prospective study of the period of 1970 to 1974 were made. The multifaceted program begun in 1970 consisted of (1) renovation of a cardiac operating room with incorporation of a high flow, vertical unidirectional ventilation system, (2) change in the gown and draping material for improvement of barriers to bacteriologic shedding, (3) frequent steam sterilization of prosthetic valves, (4) routine use of an antistaphylococcal agent in patients receiving valve replacement, and (5) an unannounced bacteriologic monitoring program of the cardiac operating room personnel. Studies of airborne particulates and bacteria and adequacy of skin preparation and hair removal also were conducted. The studies showed that (1) a high-flow HEPA filtered vertical ventilation system and altered operating room clothing reduced the concentration of airborne particles and the concentration of bacteria at the wound by a factor of 10 compared to conventional operating rooms, (2) the incidence of markedly contaminated scrubbed and unscrubbed hands decreased, (3) shedders and carriers were identified, and (4) current patient skin preparation and hair removal practices were satisfactory. The results of the program were a reduction of the deep wound infection rate from 2.9 to 0.6 percent (p less than 0.01) and a concomitant total wound infection decrease from 6.6 to 3.3 percent. Prosthetic valve infection rates decreased fourfold, from 5.6 to 1.4 percent. It is concluded that careful attention to possible endogenous sources of infection from the patient and a multifaceted program directed to exogenous sources of infection can lower infection rates in cardiac surgical patients.

Air Microbiology↗
PubMed1976

Concordance of electrocardiographic and scintigraphic criteria of myocardial injury after cardiac surgery.

The concordance of transmural electrocardiographic (ECG) changes and myocardial infarct imaging in detecting myocardial injury in the perioperative period was evaluated in 50 patients undergoing coronary artery bypass surgery and in 6 patients without coronary artery disease undergoing valve replacement. Scintigraphy with technetium-99m (Sn) labeled pyrophosphate was performed 3 to 7 days after surgery. Plasma creatine phosphokinase (CPK) levels were determined preoperatively and daily for 7 days postoperatively. Plasma MB-CPK was assayed fluorometrically in samples obtained at 12 hour intervals for 36 hours. Total CPK and MB-CPK concentrations were normal in all patients preoperatively but increased in every patient postoperatively. A total of 8 patients (16%) had evidence of perioperative infarction. Six of these patients (12%) with coronary artery disease exhibited abnormal images after bypass surgery, associated with transmural ECG changes in each case. The other 2 patients (4%) with coronary artery disease who had abnormal images were among 4 patients who developed bundle branch block after the operation. Abnormal images did not occur in any patient undergoing valve replacement despite total CPK and MB-CPK elevations. These results indicate that total CPK and MB-CPK elevations occur consistently after cardiac surgery and cannot be relied upon for detection of transmural infarction. Furthermore, new conduction defects may not necessarily be a sign of perioperative infarction, and infarct imaging may be a useful means of establishing myocardial infarction in this group of patients.

Acute Disease↗
PubMed1975

Considerations in the surgical management of infantile coarctation of aorta.

The results of a recent 5 year experience with resection of coarctation of the aorta in infants less than 1 year of age are compared with those of an earlier series from the same institution. The significant improvement in mortality and morbidity statistics is attributed to modifications in operative and postoperative care. Operative mortality has decreased from 38 to 17 percent and the incidence rate of significant restenosis has diminished from 60 to 33 percent. It is suggested that in patients with large associated intracardiac shunt banding of the main pulmonary artery should be performed before resection of the coarctation. Three of five patients have survived procedures performed in this sequence. Microsurgical techniques and careful approximation of the aortic lumen with interrupted sutures are the major factors responsible for the reduced incidence of recoarctation. Prolonged ventilatory support postoperatively with the occasional addition of controlled positive airway pressure and continued aggressive medical therapy for heart failure are recommended.

Aortic Coarctation↗
PubMed1975

Experimentally reversed pulmonary blood flow. Implications for the surgical management of complex forms of congenital heart disease.

Blood flow to the right lung was reversed in 28 dogs, 14 of which survived more than 1 month. Four successful long-term survivors (1 years to 4 years 7 months) were repeatedly studied by cardiac catheterization, angiography, and ventilation/perfusion scans as well as hemodynamically when they were killed. Hemodynamics and gas transfer were normal up to 4 1/2 years after the procedure, and the histology of the right lung was essentially normal. The application of reversed pulmonary blood flow is proposed in the surgical management of forms of congenital heart disease in which the right ventricle is diminutive. The procedure consists of repartitioning of the atria to allow venous blood to flow into the lung through the pulmonary veins and exit to the left atrium through the pulmonary artery.

Animals↗
PubMed1975

The use of the TDMAC-heparin shunt in replacement of the descending thoracic aorta.

The use of a flexible polyvinyl tube bonded with tridodecylmethylammonium-heparin (Gott) as a temporary shunt during the resection of lesions of the descending thoracic aorta has proven a safe and simple means of providing adequate circulation to the abdominal viscera and spinal cord. This technique avoids the metabolic consequences of ischemia to the lower body, diminishes left ventricular afterload during aortic clamping, and obviates the requirement for systemic anticoagulation associated with pump bypass. Between September 1970 and October 1974, 24 patients have been operated using the TDMAC shunt. There were two deaths (9%) among the 22 patients undergoing elective resections. Two patients with acutely dissecting and ruptured aneurysms expired. Followup data has been obtained on all patients from one to 46 months postoperative. The ease with which the shunt is inserted and its adaptability to varied clinical and anatomic situations is stressed. We feel that TDMAC-Heparin shunt provides the best method of circulatory support for elective operative procedures on the descending thoracic aorta.

Adult↗