PubMed Health⌕ Search

Biomedical subjects

F M Midgley

Publications and source records attributed to F M Midgley.

At least 19 recordsLinked to original sources
PubMed1992

Circulating endotoxin and tumor necrosis factor during pediatric cardiac surgery.

OBJECTIVES: To study the hypothesis that endotoxin and tumor necrosis factor-alpha (TNF) are released into the circulation during the perioperative period in children undergoing open-heart surgery, and to assess the possible role of these factors in postoperative morbidity. DESIGN: Prospective study. SETTING: Operating room and ICU of a children's hospital. PATIENTS: Twenty-four consecutive patients undergoing open-heart surgery for repair of congenital heart disease. METHODS: Endotoxin and TNF concentrations were measured in blood samples withdrawn from patients at predetermined time points in the perioperative period. These concentrations were also measured in samples from all fluids and drugs administered to patients. Clinical variables were measured throughout the perioperative period, and the Pediatric Risk of Mortality score was calculated daily. RESULTS: All of the preoperative control samples were negative for endotoxin and TNF. Endotoxin or TNF was detected in the blood of 21 (88%) of 24 patients during or after surgery. Endotoxin (ranging in concentrations from 0.32 to 438 pg/mL) was detected in the blood of 16 (67%) of the 24 patients. The majority of the samples positive for endotoxin were withdrawn during cardiopulmonary bypass and were associated with positive samples from the pump, from cardiotomy suction specimens, and from autotransfused blood. Blood cultures of all patients, except one, were negative for bacterial growth. TNF (ranging in concentrations from 3 to 132 U/mL) was detected in the blood of nine (37%) of the 24 patients. Patients positive for TNF had significantly (p less than .05) lower mean central venous pressures at 20 hrs after surgery and higher mean heart rates postoperatively compared with patients negative for TNF. No differences in other indicators of perioperative morbidity and intraoperative conditions were found, when the groups positive for endotoxin or TNF were compared with the groups negative for endotoxin or TNF, respectively. CONCLUSIONS: Endotoxin and TNF are released into the circulation during and after pediatric open-heart surgery. TNF release may be related to some of the hemodynamic changes observed after open-heart surgery.

Child↗
PubMed1991

Immune dysfunction in children after corrective surgery for congenital heart disease.

OBJECTIVE: To study the effect of open- and closed-heart surgery on the immune status of infants and children. DESIGN: Prospective study. Data collected before anesthesia and surgery and 2 and 24 hrs after surgery. SETTING: Operating room and pediatric ICU in a children's hospital. PATIENTS: Children undergoing surgery for correction of congenital heart disease (age 3 months to 12 yrs). A total of 31 patients were studied (open-heart surgery, n = 25; closed-heart surgery, n = 6). MEASUREMENTS AND MAIN RESULTS: Increased neutrophil counts and lymphopenia were observed after both open- and closed-heart surgery. Serum levels of the complement components C3 and C4 were depressed after open-heart surgery, but not after closed procedures. The percentage of T3+ and T4+ lymphocytes, proliferative responses of the lymphocytes and serum immunoglobulin (Ig)G and IgM were decreased from preoperative levels after open-heart surgery. The percentage of T8+ lymphocytes and serum IgA levels did not change. Intraoperative variables and postoperative severity of illness (Pediatric Risk of Mortality score) did not correlate with immune suppression. CONCLUSIONS: The immune system is affected after pediatric cardiac surgery, particularly after open-heart surgery.

Cardiac Surgical Procedures↗
PubMed1989

Doppler echocardiographic evaluation of tilting-disc prosthetic heart valves in children.

To determine the Doppler characteristics of tilting-disc prosthetic heart valves in children, 22 children with mitral prostheses were studied 8 +/- 2 months after surgery, and 10 children with aortic prostheses were studied 37 +/- 26 months after surgery. All valves were thought to be functioning normally by clinical examination. Valve competence was interrogated and peak and mean velocities were measured by standard pulsed wave, continuous wave and color Doppler techniques. Prosthetic valve area was calculated and compared to the known valve area. Mild prosthetic valve regurgitation was present in 8 of 22 mitral and 7 of 10 aortic prostheses. For mitral prostheses, peak velocity was 192 +/- 41 cm/s, mean velocity was 118 +/- 37 cm/s and mean gradient was 7 +/- 4 mm Hg. For aortic prostheses, peak velocity was 287 +/- 88 cm/s, mean velocity was 197 +/- 59 cm/s, peak gradient was 36 +/- 21 mm Hg and mean gradient was 19 +/- 11 mm Hg. Prosthetic mitral valve area, calculated by the pressure half-time and modified Gorlin methods, correlated well with the known valve area (r = 0.89, standard error of the estimate = 0.29 and r = 0.95, standard error of the estimate = 0.21, respectively). Prosthetic aortic valve area, calculated by the modified Gorlin method, correlated well with the known valve area (r = 0.89, standard error of the estimate = 0.18). Residual valvular abnormalities are common after prosthetic valve insertion in children. Doppler estimates of prosthetic valve area correlate well with the known valve area but have a large standard error of the estimate.

Aortic Valve↗
PubMed1989

Long-term results after surgical repair of incomplete endocardial cushion defects.

Since 1964, 56 children (mean age, 6.7 years) underwent repair of incomplete endocardial cushion defects. Forty patients had isolated ostium primum defects. Additional congenital defects were present in 17 patients (30%). All patients underwent patch closure of the ostium primum defect and 47 of 56 patients (84%) underwent mitral valvuloplasty. Hospital mortality was 1.8% (one death). Arrhythmias developed in 7 other patients in the early postoperative period, of which six were transient and resolved completely. One patient required early pacemaker placement for complete heart block. Cumulative follow-up was 378 patient-years. There were three late deaths (5.7%), and additional operations were required in 12 patients (22.6%). Seven of these 12 patients required mitral valve replacement for severe mitral regurgitation. The mean interval between initial repair and mitral valve replacement was 4.2 years, with only three valves needing replacement within 12 months. There was a significant correlation between the severity of mitral regurgitation before initial repair and subsequent need for mitral valve replacement. Late onset atrial arrhythmias have developed in 6 patients. Current functional status has been evaluated in 50 of 52 surviving patients and 88.5% are in NYHA class I, with the remainder in class II.

Adolescent↗
PubMed1986

High-frequency ventilation versus conventional ventilation in dogs with right ventricular dysfunction.

A randomized crossover protocol was used to compare conventional mechanical ventilation (CMV) and high-frequency ventilation (HFV) in mongrel dogs experiencing right ventricular dysfunction after right ventriculotomy. When inspired oxygen, pH, PCO2, core temperature, and preload were held constant, cardiac output increased significantly (p less than .05) from 1.16 +/- 0.24 to 1.38 +/- 0.25 L/min and pulmonary vascular resistance decreased significantly (p less than .05) from 734 +/- 257 to 554 +/- 169 dyne X sec/cm5 during HFV relative to CMV. We also noted a significant (p less than .05) increase in mean arterial pressure from 116 +/- 27 to 124 +/- 23 mm Hg and a significant (p less than .05) increase in left ventricular stroke work from 10.2 +/- 3.5 to 12.3 +/- 2.6 g X m during HFV. During the inspiratory phase of CMV there were increases in CVP, pulmonary artery pressure, and systemic arterial pressure, and decreases in pulmonary artery flow which did not occur during HFV. HFV may be preferable to CMV in the presence of right ventricular dysfunction.

Animals↗
PubMed1986

Costs and results of cardiac operations in infants less than 4 months old. Are they worthwhile?

From 1979 through 1983, 328 of 1,388 pediatric cardiac operations involved patients undergoing their first procedure at less than 4 months of age. Of these, 220 patients had 265 nonductal procedures, and their case histories are reviewed for results and total hospital cost. Initial operative mortality was 20% (43 patients). Infants with lower operative age and operative weight tended to have closed procedures. Mortality and cure were not related to gestational age, birth weight, age at operation, number of operations, or type of operation. Lower operative weight was associated with a greater mortality. Evaluated survivors (142 patients) were followed for a mean of 24 months. Fifteen percent (33 patients) died during follow-up. Of survivors, 80% (114 patients) had optimized general health; a subset of 29% had normal cardiac function, and 17% were cured. Lower birth weight was associated with curable lesions and normalcy (p less than 0.04). Longer preoperative hospital stay and lower weight at operation were associated with higher hospital cost (p less than 0.05). Hospital cost was not related to type of operation, gestational age, birth weight, age at operation, mortality, cure, or normalcy. Acquired neurologic dysfunction and long-term disability were uncommon. The mean hospital cost for surviving infants was +80,000 (1984 dollars). Effective hospital cost per survivor was +110,000. Mortality, cure, and normal function after cardiac operations in infants less than 4 months of age were not related to gestational age, birth weight, or age at operation. Mortality was higher in patients with a lower weight at operation. Separation into distinct fiscal cost groups is not reasonable in this series. Because most survivors are in normal or optimized cardiac health, intensive cardiovascular care in this population is justified.

Age Factors↗
PubMed1985

Anticoagulation therapy in children with mechanical prosthetic cardiac valves.

From 1980 through 1984, 28 children younger than 19 years (mean 7.9) underwent cardiac valve replacement with 30 mechanical prostheses. Patients were followed for a total of 471 months (mean 15.7) and received either warfarin (mean 0.16 mg/kg/day) or acetylsalicylic acid and dipyridamole (mean 6.1 and 1.9 mg/kg/day, respectively) as thromboembolism prophylaxis. The frequency and incidence of thromboembolism and hemorrhage were compared. Warfarin-treated patients were at increased risk of hemorrhage (5 of 20 [25%], or 22 per 100 patient-years, vs 0 of 10 [0%], or 0 per 100 patient-years, p less than 0.05). Three of the 5 hemorrhagic episodes were mild, and in no case was hemorrhage life-threatening. Patients who did not receive warfarin had a greater risk of thromboembolism (2 of 10 [20%], or 12 per 100 patient-years, vs 0 of 20 [0%], or 0 per 100 patient-years, p less than 0.05). Both episodes of thromboembolism were life-threatening and necessitated emergency valve replacement. Although warfarin is associated with greater risk of hemorrhage than is acetylsalicylic acid and dipyridamole, warfarin is better than antiplatelet drugs in thromboembolism prophylaxis and is indicated for anticoagulation therapy in children with mechanical cardiac prostheses.

Aspirin↗
PubMed1985

Small left atrium and change in contour of the ventricular septum in total anomalous pulmonary venous connection: a morphometric analysis of 22 infant hearts.

Morphometric measurements of 22 hearts with total anomalous pulmonary venous connection (TAPVC) were compared with measurements of 8 matched control specimens without heart disease. Each of the TAPVC specimens had a shorter left atrium, smaller left atrial surface area and larger diameter of the fossa ovalis. In addition to increased length of the right ventricle and larger circumferences for tricuspid and pulmonary valve anuli, the left ventricular contour of the ventricular septum was flat or convex in 18 of the 22 hearts; the septum was significantly longer than normal in these specimens and wider at its midportion. Because mitral and aortic valve anuli were normal in circumference, the data suggest that left ventricular volume is not decreased despite change in ventricular shape.

Heart Atria↗
PubMed1984

Surgical approach to corrected transposition of the great vessels and situs inversus [I, D, D] with ventricular septal defect and systemic atrioventricular valve regurgitation.

Successful surgical repair of a 4-year-old boy with situs inversus [I, D, D] and corrected transposition of the great vessels (TGV) as well as hemodynamically significant ventricular septal defect (VSD), systemic atrioventricular (tricuspid) valve regurgitation, and atrial septal defect is described. Unique technical aspects of VSD and tricuspid valve repair in association with corrected TGV and situs solitus or inversus are discussed and clarified.

Child, Preschool↗
PubMed1984

Repair of anomalous origin of the left coronary artery in the infant and small child.

Anomalous origin of the left coronary artery from the pulmonary artery is associated with myocardial infarction, left ventricular dysfunction, mitral valve dysfunction and, occasionally, intracardiac congenital abnormalities. A technique that utilizes a flap of the anterior wall of the pulmonary artery to serve as a neocoronary artery to direct aortic flow from a created aortopulmonary window to the pulmonary artery orifice of the anomalous left coronary artery was used in five patients aged 2.5 months to 4.75 years. Two patients were less than 4 months of age at operation. There was one death 2 days after operation and one late death. The two youngest patients required mitral valve replacement. Two of the three surviving patients are well at follow-up at 7 to 44 months. One patient has been lost to follow-up study. One patient had postoperative catheterization which showed an intact repair. The pulmonary artery neocoronary procedure is applicable to infants and small patients with anomalous origin of the left coronary artery from the pulmonary artery.

Child, Preschool↗
PubMed1981

Two-dimensional echocardiographic evaluation of mitral bioprosthetic function in infants and children.

Two-dimensional echocardiography (2DE) was performed on 13 bioprosthetic mitral valves in 11 pediatric patients, 1 week to 46 months following implantation. Cardiac catheterization confirmed the echocardiographic findings of seven valves. The 11 normally functional bioprosthetic mitral valves by 2DE had leaflet thickness not exceeding 2.0 mm, freely moving leaflets, and normal sewing ring motion. The left atrium (LA) was enlarged only in the presence of mitral valve obstruction, atrial fibrillation, or left ventricular (LV) dysfunction. One bovine valve was stenotic due to fibrous tissue beneath normal valve leaflets; 2DE demonstrated limited leaflet motion, tissue beneath a thin valve leaflet, increase rocking motion of the sewing ring, and LA enlargement. In another patient, a bovine valve produced subaortic LV obstruction due to growth of fibrous tissue outside the stent; 2DE showed that the valve leaflets were thin and moved normally without excessive rocking of the valve ring, and identified the abnormal fibrous tissue in the LV outflow tract.

Adolescent↗
PubMed1978

Subclavian flap aortoplasty for treatment of coarctation in early infancy.

In a 2-yr period 12 infants less than 2 mo of age underwent surgery for critical coarctation of the aorta. All had severe congestive failure with unsatisfactory response to medical therapy. In all patients the coarctation was located in the preductal or preligamentous region. Eleven patients had an associated ventricular septal defect (VSD). Early (1-mo) survival in the patients with VSD was 82%. Two early deaths occurred; there have been five late deaths on follow-up of up to 30 mo. In all patients who expired, the cause of death was unrelated to the coarctation repair. Recurrent coarctation has occurred in one patient. Early aggressive surgical intervention is indicated in the management of coarctation of the aorta both with and without VSD.

Abnormalities, Multiple↗
PubMed1977

Subclavian steal syndrome in the pediatric age group.

Four pediatric patients with subclavian steal syndrome (SSS) are described. One patient with congenital SSS had persistence of the lesion following surgical repair of coarctation of the aorta due to a gradient across a hypoplastic aortic arch. In 3 patients SSS developed on an acquired basis as a sequel to corrective operation, for coarctation in 1 patient, and interrupted aortic arch in 2 patients. Contributory factors included hypoplasia of the aortic arch, anatomical variation of the origin of the vertebral artery, and discrete recoarctation involving the ostium of the subclavian artery. Treatment was by vertebral artery ligation in 3 patients and by prosthetic patch arterioplasty in the patient with recoarctation. The 4 patients remain asymptomatic on follow-up of 16 to 25 months.

Aortic Coarctation↗