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Biomedical subjects

J Heaton

Publications and source records attributed to J Heaton.

18 recordsLinked to original sources

Extracorporeal membrane oxygenation for nonneonatal respiratory failure.

Extracorporeal membrane oxygenation (ECMO) has been used for 20 years in neonates and children with cardiac and respiratory failure. The number of neonates treated with ECMO has increased exponentially, but the number of older children treated is small. The selection and exclusion criteria for pediatric ECMO are poorly defined, and the results vary because of variable selection criteria and institutional experience with the technique. In order to help define the role of pediatric ECMO, we reviewed our experience in noneonatal pediatric respiratory failure. We have treated 22 patients ranging in age from 1 to 105 months and ranging in weight from 3 to 35 kg. Eighteen patients met the criteria for adult respiratory distress syndrome, two had respiratory syncytial virus pneumonia, and one had severe barotrauma complicating the management of reactive airway disease. All patients were considered by the referring institutions and by us to be failing conventional management as evidenced by hypoxia, hypercarbia, excessive ventilatory pressures, or progressive barotrauma. All were considered likely to die with continued conventional management. Sixteen of the 22 patients had complications (73%), but half of the last 10 patients had no complications. Hemorrhagic complications occurred in 12 patients. Mechanical complications included membrane failure, raceway rupture, pump malfunction, and improper cannula positioning. Other complications included culture-proven infection and renal failure. Eleven of the 22 patients survived (50%); nine of the last 12 survived (75%). These results suggest that ECMO may be a useful technique in selected pediatric patients with respiratory failure. Survival and complication rates improve as experience with the technique increases.

Child

Value of urologic investigation in a targeted group of women with recurrent urinary tract infections.

According to the conclusions of clinical studies, excretory urography and cystoscopy are of no value in managing the majority of women who have a history of recurrent urinary tract infection (UTI). Of 475 women with recurrent UTIs, 186 were prospectively targeted for evaluation by cystoscopy and ultrasonography or excretory urography from selection criteria based on the degree of complicating factors, to determine the value of urologic investigation. Thirty-nine patients had significant detectable abnormalities, and 20 of them required surgical intervention. Definite indications for urologic evaluation include hematuria (gross hematuria and persistent microscopic hematuria between infections), pyelonephritis and a presentation that is not typical for simple uncomplicated UTIs (obstructive symptoms, infection with urea-splitting bacteria, clinical impression of persistent infection or urinary calculi). Diabetes itself does not warrant urologic evaluation. The findings from this study suggest that cystoscopy and upper urinary tract evaluation do play a role in the management of a selected group of women with UTIs.

Adult

A correlation of pulmonary hypoplasia, mean airway pressure, and survival in congenital diaphragmatic hernia treated with extracorporeal membrane oxygenation.

Thirty infants with congenital diaphragmatic hernia (CDH) who required therapy within the first day of life were treated in our institution over the past 3 years. Eighteen of these infants were not treated with extracorporeal membrane oxygenation (ECMO). Survival in this group was 83%. Twelve infants were treated with ECMO. Seven (58%) were weaned from ECMO and ventilator support with six (50%) long-term survivors. Minimum preoperative alveolar-arterial oxygen gradient (AaDO2), maximum postoperative mean airway pressure (MAP), and pulmonary hypoplasia were evaluated. Bohn et al have prospectively shown that the relationship of PaCO2 to mechanical ventilatory requirements accurately predicted survival in a group of 58 infants with CDH in whom ECMO was not a therapeutic option. This criteria would predict nonsurvival in all 12 of our patients treated with ECMO, including the seven survivors. Differences between our ECMO and non-ECMO groups were statistically significant for all three criteria. All P values less than .05. Morphometric analysis of the lungs of all ECMO nonsurvivors revealed hypoplastic ipsilateral lungs by lung weight to body weight ratios and radial alveolar counts when compared with experimental and historical controls (P less than .05). The contralateral lung was hypoplastic in 80% of the nonsurvivors. There is a strong correlation between the maximum postoperative MAP and the degree of contralateral pulmonary hypoplasia (r = .03, P = .02). We conclude that the maximum postoperative MAP is an accurate predictor of survival in the treatment of CDH and can be correlated with the degree of pulmonary hypoplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Prostaglandins and the control of muscle tone in the ductus arteriosus.

Several lines of evidence implicate E-type PGs in the maintenance of patency of the foetal ductus arteriosus. The PGE mechanism is functional in man, sheep, rat and rabbit, but it is seemingly absent in guinea pig. The role of the PGs in the closure of the vessel at birth is uncertain. Work with different species suggests that as PO2 rises at birth the relaxant effect of PGEs on the ductal muscle decreases. This decreased sensitivity may facilitate the oxygen triggered contraction. The calf ductus is an exception and its closure may be mediated by PGF2alpha. An important fact emerging from this review is that species may differ with regard to the occurrence and possible function of the PGs in the ductus arteriosus. The significance of these differences to the function of the oxygen-sensing mechanism remains a major question for future research.

5,8,11,14-Eicosatetraynoic Acid

A quantitative study of cholinesterase in myoneural junctions from rat and guinea-pig extraocular muscles.

1. Cholinesterase staining of rat and guinea-pig extraocular muscle shows focally and multiply innervated fibres.2. The distribution of cholinesterase activities in the populations of focal endings (from singly innervated fibres) and fine motor endings (from multiply innervated fibres) was determined by a sensitive radiochemical method.3. Focal endings had a greater cholinesterase activity than fine motor endings.4. It is suggested that this difference in enzyme activities is related to the functional difference between twitch and slow fibres in extraocular muscle.

Animals