Biomedical subjects
F M Moylan
Publications and source records attributed to F M Moylan.
Aluminum hydroxide in the symptomatic treatment of infants with chronic diarrhea.
Two neonates with milk intolerance and two older infants, one with acute gastroenteritis and the other with prolonged malnutrition, developed chronic diarrhea. Despite bowel rest, total parenteral nutrition, and alterations in the protein and carbohydrate content of the milk preparations used, every attempt to feed them resulted in diarrhea. All four patients were given aluminum hydroxide because of its bile salt-binding activity and its tendency to cause constipation. Coincident with its administration the diarrhea stopped and the enteral feedings were successfully reinstituted. The only complication seen was the development of constipation in two of the infants; this responded to lowering of the dose of the aluminum hydroxide.
Fulminant neonatal meningococcemia.
Neisseria meningitidis is a rare cause of infection in infants younger than 2 months of age, presumably because of transplacental passage of protective maternal antibodies. In most reported cases of meningococcal disease in neonates, a relatively mild clinical course has been observed. A 25-day-old infant survived acute, severe meningococcemia due to group B N meningitidis. This organism should be considered when neonates have signs of septicemia, especially in the presence of cutaneous petechiae and purpura.
Defective primary dentition in survivors of neonatal mechanical ventilation.
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Preferential distribution of lobar emphysema and atelectasis in bronchopulmonary dysplasia.
The chest roentgenograms of 142 neonates who survived mechanical ventilation for respiratory distress syndrome (N = 99) and prolonged apnea (N = 43) were reviewed. Thirty-seven infants had bronchopulmonary dysplasia (BPD) and 17 of these developed lobar hyperinflation of the right lower lobe and collapse of the right upper lobe. Regional lung function was measured with a xenon 133 technique in three of these infants and in five other patients who either died or were lost to follow-up. All had BPD with right lower lobe overinflation. Ventilation was less in the lower regions than the upper regions bilaterally (P less than .001), indicating that the hyperinflation of the lower lobes was not compensatory for upper lobe collapse but was due to emphysema. Mean regional perfusion was equal in the upper and lower regions of the chest. This preferential distribution of lobaremphysema and ipsilateral atelectasis in BPD tended to present and regress simultaneously, but in many infants it lasted as long as eight weeks. Only one infant with persistent atelectasis developed pneumonia. The best mode of therapy appears to be supportive.
Inappropriate antidiuretic hormone secretion in premature infants with cerebral injury.
We describe 11 premature infants with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The syndrome is far more common than the single case report in the literature would indicate. All the infants had either asphyxiation at birth, intracranial hemorrhage, or meningitis. Of the nine children available for follow-up observation, seven demonstrated serious neurological sequelae. The diagnosis of SIADH in the premature neonate may be difficult to establish due to the complexity of precipitating factors.
Ventilation-perfusion scans in neonatal regional pulmonary emphysema complicating ventilatory assistance.
Two cases of ventilator-related neonatal lobar overexpansion with similar radiographic appearance, but probably different pathogenesis, are presented. In one infant, persistent interstitial lobar emphysema was confirmed by markedly decreased perfusion shown on scintigraphy; this information was of great value in predicting the beneficial effect of lobectomy. In the other case, ventilation and perfusion scans indicated functional value of the emphysematous lobe and correctly suggested conservative management. Radioisotope lung scans may provide valuable information regarding lung function in regional pulmonary emphysema associated with assisted ventilation in neonatal respiratory distress syndrome, and thus determine patient management.
Evaluation of neonatal intracranial hemorrhage by computerized tomography.
Computerized tomographic (CT) brain scan was performed on 28 infants with unexplained cardiorespiratory and neurologic deterioration and bloody lumbar cerebrospinal spinal fluid. Fourteen of 20 with intraventricular hemorrhage (IVH) died; the six infants with lesser degrees of IVH survived. Significant subarachnoid hemorrhage (SAH) was demonstrable in three infants and three had negative scans despite bloody CSF. We have found that CT scans provide useful information about the size and extent of neonatal IVH and distinguished it from SAH. It also confirms the diagnosis of post-hemorrhagic hydrocephalus in these infants. Continued use of the CT scan will help us to understand the natural history and the effects of neonatal intracranial hemorrhage among the survivors of intensive care.
Infantile lobar hyperinflation: expectant treatment.
Arterial blood gases and regional lung function, measured with a 133xenon technique, were used to evalute the physiological defects and follow the natural history of 16 infants with lobar hyperinflation ("emphysema"). Hypoxemia was due to V/Q inequality at rest. Worsening of hypoxemia (mean Pao2 delta--26 mm Hg) with crying was due to shunting as a consequence of cessation of ventilation in the involved lobe. Surgery was necessary in three patients. Two deaths were caused by bronchopulmonary dysplasia after respiratory distress syndrome (RDS). In 12 of 14 infants, lung function was normal between the ages of 5 days and 1 year. Pediatrics, 59:1012-1018, 1977, LOBAR EMPHYSEMA, BLOOD GASES, REGIONAL LUNG FUNCTION.
Endotracheal tube displacement in the newborn infant.
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Percutaneous catheterization of the radial artery in the critically ill neonate.
Percutaneous catheterization of the radial artery appears to be a simple and safe alternative to catheterization of the umbilical artery for monitoring critically ill neonates. This avoids the serious and potentially fatal complications associated with use of the umbilical arterial catheter, and it is also applicable to monitoring of neonates in whom the umbilical artery is no longer patent. We observed no serious sequelae in cannulation of the radial artery and think that the technique should be used more widely.
Studies on the pathophysiology of encephalopathy in Reye's syndrome; Hyperammonemia in Reye's syndrome.
The initial acid-base status of eight survivors of Reye's syndrome was characterized by acute respiratory alkalosis (Pco2=32 mm Hg; Hco3-=22.0 mEq/liter) while that of eight children who died was associated with metabolic acidosis as well (HCO3-=10.0 mEg/liter). Arterial-internal jugular venous ammonia concentration differences on day 1 (299 mg/100 ml) and day 2 (90 mg/100 ml) reflected cerebral uptake of ammonia while those on days 3 and 4 (-43 and -55 mg/100 ml) demonstrated cerebral release. Arterial blood hyperammonemia can be detoxified safely in the brain as long as the levels do not exceed approximately 300mug/100 ml. Beyond that level lactic acidosis is observed, particularly in cerebral venous drainage. Arterial blood hyperammonemia was also related to the extent of alveolar hyperventilation. These findings are very similar to those seen in experimental hyperammonemia and support the concept that neurotoxicity in children with Reye's syndrome is at least partly due to impaired oxidative metabolism secondary to hyperammonemia.
Prevention of apnea and bradycardia in low-birthweight infants.
The efficacy of theophylline in preventing severe apnea was evaluated in 17 low-birthweight infants (mean weight, 1,400 gm). Apnea was detected and accurately quantified by 13-hour pneumogram recordings and correlated with serum theophylline levels. Nursing observations coupled with on-line alarm systems detected only 39% of severe apneic episodes as compared to the pneumogram recording technique. Theophylline in six hourly oral doses(1.5 to 4.0 mg/kg) yielded two-hour serum concentrations of 6.6 to 11.0 mug/ml which completely controlled apneic spells exceeding 20 seconds in duration and markedly reduced 10- 19-second apneic episodes and any resultant bradycardia. At these serum levels, toxicity was not observed. Therapy with theophylline should be instituted at a dose of 2 to 3 mg/kg every six hours and the optimum therapeutic dose should be individualized as determined by objective quantitation of apnea and serum theophylline concentration.
Edema of the pulmonary interstitium in infants and children.
Ten infants and children with respiratory failure, receiving standard maintenance water requirements, were treated on 13 occasions with intravenously given furosemide (1 to 2 mg/kg) because of continued impairment of oxygenation despite conventional therapy. Pulmonary auscultation and radiographs were normal or typical of the primary diagnosis. After a five-fold increase in urine output the mean Po2 rose from 61 mm Hg at a mean FiO2 of 0.7 to 140 mm Hg at an FiO2 of 0.65. The Pco2 decreased from 46 to 38 mm Hg. Interstitial pulmonary edema in these patients can be related to both their lung disease and impaired water tolerance during ventilatory therapy.
Regional lung function in infants.
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Alveolar rupture as an independent predictor of bronchopulmonary dysplasia.
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The relationship of bronchopulmonary dysplasia to the occurrence of alveolar rupture during positive pressure ventilation.
The effect of altered mechanical ventilation on the incidence of alveolar rupture and bronchopulmonary dysplasia (BPD) was reviewed in infants who had neonatal respiratory distress syndrome (RDS) (N = 99). From 1971 to 1974 we attempted to minimize pulmonary oxygen exposure. Accordingly, during the resolution of respiratory distress syndrome, the ventilator pressures were not reduced until the FIO2 had been lowered to 0.4 (n = 61). In 1974 to 1975 earlier reduction of pressure was instituted as the FIO2 was lowered to 0.6 or less (N = 38). Birth weight and gestational age were comparable in the two groups. With earlier reduction of ventilator pressures, there was a significant decrease in the duration of exposure to peak inspiratory pressures greater than or equal to 40 cm H2O (p is less than 0.004) and greater than or equal to 50 cm H2O (p is less than 0.002). The incidence of alveolar rupture during postive pressure ventilation fell from 51 to 24% (p is less than 0.015) and bronchopulmonary dysplasia from 41 to 13% (p is less than 0.003). In addition, there was a decrease in the duration of mechanical ventilation (p is less than 0.02) and exposure to an FIO2 is greater than or equal to 0.6 (p = 0.07). The results confirm the intimate relationship of pulmonary barotrauma, as reflected by the occurrence of alveolar rupture during positive pressure inflation of the lungs, to the subsequent development of bronchopulmonary dysplasia and that prevention of the former is associated with a concomitant fall in incidence of the latter.