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Biomedical subjects

R A Mathews

Publications and source records attributed to R A Mathews.

48 records · Page 3Linked to original sources
PubMed1978

Clinical implications of postoperative unilateral phrenic nerve paralysis.

Unilateral phrenic nerve paralysis (PNP) folowed 32 (1.7 percent) of 1,891 consecutive cardiac surgical procedures during an 8 year peroid. Diagnosis was based on radiographic criteria with comparison of preoperative and postoperative chest radiographs and was confirmed in all 21 evaluated by fluoroscopy. Six had persistent radiographic abnormality more than 12 months postoperatively. PNP occurred most frequently in association with Blalock-Taussig shunts. These operations represented 22 percent of this series, and PNP complicated 7 percent of all Blalock-Taussig shunts. PNP was less well tolerated in the 14 infants than in the 18 older children. Eleven infants had serious difficulties during weaning from mechanical ventilatory support. Five infants required tracheostomy, one underwent diaphragmatic plication, and three died. Infants had a mean duration of mechanical ventilation of 24 days and required prolonged intensive care and long-term hospitalization. In comparison, older children had a more benign postoperative course. Diaphragmatic plication should be considered in infants with paradoxical motion of the hemidiaphragm who remain dependent on mechanical ventilatory support for more than 2 weeks postoperatively.

Adolescent↗
PubMed1977

Down syndrome with congenital heart malformation.

Two hundred fifty-one patients with Down syndrome and congenital heart disease was based on clinical (41%), catheterization (38%), surgical (11%), or autopsy data (10%). The most common lesions were endocardial cushion defect (43%), ventricular septal defect (32%), secundum atrial septal defect (10%), tetralogy of Fallot (6%), and isolated patent ductus arteriosus (4%). Thirty percent had multiple cardiac defects. The most common associated lesions were patent ductus arteriosus (16%) and pulmonic stenosis (9%). Twenty-five percent of the patients uncerwent cardiac surgery. Motality in the 68 patients undergoing surgery was 26% for open heart procedures and 11% for closed heart surgery. In 32% of nonsurgically treated patients with large left-to-right shunts, irreversible pulmonary vascular disease developed. Improved medical and surgical care have decreased morbidity and mortality in these patients in recent years.

Abnormalities, Multiple↗
PubMed1977

Tetralogy of Fallot: postoperative electrophysiologic studies.

Electrophysiologic studies performed during postoperative cardiac catheterization in 51 patients following repair of tetralogy of Fallot (TF) were compared with studies performed in a control group of 30 patients. These studies include His bundle electrograms, measurement of atrioventricular (A-V) conduction at progressively increasing atrial pacing rates, and evaluation of sinus node recovery time. More postoperative TF patients (20%) had prolonged H-V intervals compared to the controls (7%). With atrial pacing, no patient in the control group developed second degree A-V block below 160 beats/min, while 23% of the postoperative TF patients developed block below this level. Half of these patients had normal His bundle studies. Stress of the A-V conduction system by atrial pacing may unmask conduction abnormalities not present on the surface electrocardiogram or on His bundle electrogram. Two-thirds of the patients had some form of conduction abnormality on the basis of evaluation of one or more parameters but about half of the patients with a given abnormality had normal findings in other areas. The high incidence of electrophysiologic abnormalities following TF repair may have future prognostic significance. Systematic evaluation of atrioventricular conduction during preoperative and postoperative cardiac catheterization may be of value.

Adolescent↗
PubMed1977

Discrete subvalvular aortic stenosis. An evaluation of operative therapy.

Angiocardiographic and operative observations support the validity of classifying the spectrum of congenital subvalvular aortic stenosis into a membrane, fibromuscular collar, and tunnel. Our current operative method is to excise a thin membrane or thick fibrous ridge, and, if a fibromuscular collar or tunnel is identified, to effect a left ventricular myomectomy as described by Morrow for hypertrophic subaortic stenosis. Data from experience with 35 children indicate that this approach is effective and safe. Gradients are substantially reduced and residual obstruction acceptable. Successive clinical evaluations (100 percent of 33 survivors) over an interval of 1 to 13 years (mean of 6) affirm that amelioration of the obstruction endures.

Angiocardiography↗
PubMed1977

Valve replacement in children and adolescents.

Replacement of diseased heart valves has become the treatment of choice in many adults. Valve replacement in older children and adolescents has been done in our institution only when other procedures are ineffective. Over the past 10 years, 24 patients have received 28 artificial valves. Thirteen (54 per cent) had rheumatic heart disease; the remainder had congenital or acquired valvular abnormalities. The Björk-Shiley valve was most commonly used in the aortic position and the Beall prosthesis in the mitral position. Sixteen patients (67 per cent) survived operation and have been followed from 3 to 79 months, averaging 27 months. All are free of cardiac symptoms. Hemarthrosis occurred once in 2 survivors (13 per cent). Eight patients died (33 per cent), 5 immediately postoperatively and 3 within a year after the operation. The mortality rate has declined to 21 percent during the past 3 years. Our experience in the pediatric age group suggests that valve replacement is a serious undertaking with higher mortality rate than in adults. The operation should be reserved for those patients in whom valvuloplasty or valvulotomy is expected to be ineffective.

Adolescent↗
PubMed1977

Management of bilateral ductus arteriosus in complex cyanotic heart disease.

Bilateral ductus arteriosus (BDA) usually is associated with complex cyanotic heart disease. Since pulmonary valve atresia often is part of the complex, hypoxia may necessitate emergency cardiac catheterization and surgery for these critically ill newborn infants. Optimum management depends on accurate delineation of the intracardiac and great vessel anatomy. Since the ductus arteriosus has a tendency to close spontaneously, the true anatomy of the fourth to sixth aortic arch connections should be determined on the first catheterization. An over-all plan for future care by the medical-surgical team should have been made at the time of the initial surgical procedure. The case histories of four newborn infants with BDA associated with cyanotic heart diseases are reported. The anatomy and basic embryology of the fourth to sixth arch system is reviewed and recommendations for long-term management are given.

Aorta, Thoracic↗
PubMed1976

Synthesis and turnover of plasma-membrane proteins and glycoproteins in a neuroblastoma cell line.

A kinetic analysis of the appearance of 14C-labelled proteins in the surface membranes isolated from exponentially growing neuroblastoma cells (N2a) showed that the total membrane proteins reached a steady-state specific radioactivity in 18-20 h. However, examination of individual protein bands resolved by sodium dodecyl sulphate-urea-polyacrylamide-gel electrophoresis illustrated that differences in the kinetics of specific surface-membrane proteins could be detected. Although most of the protein bands reached a steady-state specific radioactivity at a time similar to that for total membrane proteins, at least two bands (mol. wt. 180000 and 130000) attained the steady-state within 8-10 h. It was shown by the use of dual-labelling techniques that these two protein bands turned over in the surface membranes of neuroblastoma N2a cells at least 180 and 150% faster than the total membrane protein. These two proteins were glycosylated and located on the outer surface of the cells, since they were labelled with radioactive carbohydrates and readily removed by treatment of the intact neuroblastoma cell with proteinases.

Cell Line↗
PubMedDate not supplied

Unilateral pulmonary vein atresia: clinical and radiographic spectrum.

Three cases of unilateral pulmonary vein atresia are presented to illustrate part of the clinical and radiographic spectrum of this anomaly. One patient had major associated cardiovascular abnormalities and pulmonary hypertension, one had recurrent hemoptysis, and the other patient was asymptomatic with normal pulmonary artery pressure and no associated abnormalities. In one case, serial catheterizations indicated that the pulmonary vein atresia was acquired. This report stresses the radiographic, hemodynamic, and angiographic findings in patients with unilateral severe pulmonary venous obstruction. The embryology, pathology, and surgical approach are also discussed. The diagnosis should be strongly suspected before cardiac catheterization when typical features are present on the chest radiograph and isotopic ventilation perfusion scan.

Abnormalities, Multiple↗
PubMedDate not supplied

Use of haloperidol infusions to control delirium in critically ill adults.

OBJECTIVE: To describe and discuss the use of continuous intravenous infusions of haloperidol to treat severe delirium and agitation in 3 intensive care unit (ICU) patients. CASE SUMMARIES: Three severely agitated patients in ICU did not respond to conventional therapy with opiates, benzodiazepines, and intermittent intravenous doses of haloperidol. In each case, control was achieved rapidly after initiation and titration of a continuous haloperidol infusion. Two patients had a history of schizophrenia. No adverse effects attributable to therapy were identified. DISCUSSION: Haloperidol is often used in the ICU for control of severe agitation, even in patients without a psychiatric history. It usually is given by bolus intravenous injection, sometimes in high doses (> 5 mg), even though that is not approved by the Food and Drug Administration. Intravenous haloperidol is generally well tolerated, but multiform ventricular tachycardia has been reported. Experience with continuous haloperidol infusions is growing, and it appears to be an effective method for control of severe agitation or delirium. In our experience and in other limited published data, adverse effects are rare, but prolongation of the QT interval has occurred and multiform ventricular tachycardia is likely a risk. CONCLUSIONS: In selected patients, a continuous infusion of haloperidol may be a useful alternative for control of agitation and delirium. Close monitoring for QT prolongation or rhythm disturbances is mandatory.

Adult↗