Home pneumograms in normal infants

To obtain age-specific normative data, we performed home cardiorespiratory recordings (pneumograms) in 56 normal infants at 1 month of age. A repeat pneumogram was performed at 3 months in 39 infants. Total sleep time was determined and all sleep intervals were summed and analyzed for five respiratory pattern variables: frequency of all apneic episodes greater than or equal to 6 seconds in duration (A6/D%), periodic breathing, longest apneic episode, and number of episodes greater than 11 and greater than 15 seconds. The normal infants at 1 and at 3 months were compared with 66 patients with apnea of infancy. Median A6/D% was 0.1 in the normal infants at 1 and 3 months, compared with 0.64 in those with apnea of infancy (P less than 0.001). Median periodic breathing was 0.4 and 0.2 episodes per 100 minutes in the normal infants at 1 and 3 months, respectively, compared with 1.25 in infants with apnea of infancy (P less than 0.001). Median longest apneic episode was 8.0 seconds in the normal infants at 1 and 3 months, compared with 11 seconds in those with apnea of infancy (P less than 0.001). No normal infant had an apneic episode greater than 15 seconds in duration, whereas the group with apnea of infancy had 0.4 +/- 1.0 episodes of apnea of greater than 15 seconds (P less than 0.01). Despite these significant group differences, use of these respiratory patterns either alone or in combination permitted only about 80% correct classification of normal infants and those with apnea of infancy.     

Breathing pattern and ventilation during oral feeding in term newborn infants

The effect of oral feeding on breathing pattern and ventilation was studied in 19 healthy term neonates in the semiupright supine position. Ventilation was measured with a nasal flowmeter, and sucking pressure via a modified nipple that permitted milk delivery. The feeding pattern in these infants consisted of an initial period of continuous sucking followed by intermittent sucking for the remainder of the feed. A significant reduction in minute ventilation (P less than 0.01) was observed during continuous sucking, and resulted entirely from a reduction in breathing frequency (P less than 0.01). Tidal volume did not change (P greater than 0.05), but prolongation of expiration (P less than 0.01) and shortening of inspiration (P less than 0.05) were also observed. During intermittent sucking, the minute ventilation was similar to that of the control period. However, smaller but significant changes in breathing frequency and in duration of inspiration and expiration persisted during intermittent sucking. Our results document a significant reduction in ventilation during the initial part of oral feeding in term neonates, and subsequent recovery with continued feeding. Depending on the magnitude of this reduction in ventilation, cyanosis and bradycardia may develop in some infants during oral feeding.     

Vitamin D metabolites in adolescents and young adults with cystic fibrosis: effects of sun and season

To assess mineral metabolism in patients with cystic fibrosis and to study the effects of season and sunlight exposure on generation of vitamin D metabolites, we quantified serum levels of calcidiol and calcitriol, other measures of bone metabolism, and radiographic bone mass in 20 adolescents and young adults with CF and 20 age-matched normal volunteers. Levels of calcidiol were lower in patients with CF than in controls and lower in Massachusetts than in Arizona in both study groups. Controls in Arizona had higher (P less than 0.05) levels of calcitriol than in Massachusetts throughout the year. All control subjects in both states had higher levels of calcitriol than did patients with CF. Patients in Massachusetts had significantly lower levels of calcitriol in winter than in summer. Summer levels of calcitriol in CF were significantly higher in Massachusetts than in Arizona; during winter, lower levels were found in Massachusetts than in Arizona. Mean bone density in patients with CF was 88% and 89% of normal American standards in Massachusetts and Arizona, respectively. These data indicate a seasonal, sunlight-related influence on levels of vitamin D metabolites in patients with CF receiving approximately 1000 IU vitamin D per day. Older patients with CF with progressively diminishing sunlight exposure may be at increased risk for development of osteopenia. The detected radiographic abnormalities of bone mineralization may also be related to malabsorptive deficiencies of calcium and phosphorus.     

Effects of maternal alcohol intoxication on fetal circulation and myocardial function: an experimental study in the ovine fetus

To determine whether acute alcohol ingestion during pregnancy could affect fetal myocardial function, studies were carried in six chronically catheterized fetal sheep during maternal alcohol infusion. Absolute ethyl alcohol (0.8 ml/kg) was administered to the mother over 10 minutes via the jugular vein. These infusions were repeated every 30 minutes during 3 hours, and peak maternal and fetal blood concentrations close to 200 mg/dl alcohol were reached. Fetal PCO2 decreased from a baseline of 43.15 +/- 3.75 to 36.13 +/- 2.6 torr 1 hour after the start of alcohol infusion (P less than 0.05). Similarly, pH rose from 7.37 +/- 0.027 to 7.44 +/- 0.015 (P less than 0.05). Both values returned to baseline level at the end of alcohol infusion. PO2 remained within physiologic limits. The systolic time intervals of the fetal heart showed a rapid and prolonged modification. The pre-ejection period from 58 +/- 8 to 66 +/- 4 msec (P less than 0.05) during the infusion; this change was related to an increase in the isometric contraction period. The ratio of the pre-ejection period over the ejection time was also significantly increased (P less than 0.01), and remained elevated until the end of the experiment (12 hours). A rise in fetal systolic and diastolic pressures was observed at about 2 hours after the start of the alcohol infusion, and lasted 4 hours. This study suggests that an episode of maternal alcohol intoxication causes rapid depression of fetal myocardial contractility that is maintained several hours after cessation of alcohol ingestion.     

Nutritional status in children receiving home parenteral nutrition

Nutrition status was evaluated in 19 children aged 4 to 65 months who received total parenteral nutrition as their only source of nutrition (nine patients, group 1) or who ingested 30% to 70% of their total energy requirements orally and received the remainder intravenously (10 patients, group 2). All patients had received parenteral nutrition for 31.8 +/- 9.8 SD and 33.1 +/- 17.1 months, respectively. All patients in group 1 and four in group 2 had short bowel syndrome; five in group 2 had pseudo-obstruction syndrome. The children in group 1 had normal height, weight, midarm circumference (MAC), midarm muscle circumference (MAMC), and triceps skinfold thickness (TSF). In group 2 patients, height, MAC, and TSF, were significantly below normal, and their weight, MAMC, and TSF, were lower than in group 1. Hemoglobin, total lymphocyte count, and serum albumin concentration were below normal in group 1; serum total protein concentration was low in both groups. Serum bilirubin concentration was higher in group 1; serum glutamic pyruvic transaminase activity was elevated in both groups. These data indicate that children receiving long-term total parenteral nutrition can obtain and maintain normal height, weight, and other anthropometric measurements of nutritional status. Group 1 patients had better nutritional status than those in group 2, perhaps because of differences in the underlying medical disorders between the two groups, or possibly because of a propensity to underestimate the amount of parenteral nutrition needed by patients who ingest some nutrients.     

Age-related alterations in immunoreactive pancreatic lipase and cationic trypsinogen in young children with cystic fibrosis

Serum immunoreactive pancreatic lipase and cationic trypsinogen are elevated in young infants with cystic fibrosis (CF) and may be useful neonatal screening tests for CF. We compared lipase measured by a recently developed ELISA immunoassay with trypsinogen measured by radioimmunoassay in 70 children (ages 0.1 to 9.9 years) with CF who had various degrees of pancreatic dysfunction and in 79 similarly aged children without CF (controls). In the control children, lipase activity increased with advancing age, whereas trypsinogen showed no age-related trend. Lipase and trypsinogen were significantly elevated in the infants with CF who were younger than 1 year, irrespective of pancreatic function (trypsinogen, P less than 0.001; lipase, P less than 0.05). Sensitivities in detecting CF were 76% and 90% for lipase and trypsinogen, respectively. After the first year of life, lipase and trypsinogen values declined toward normal, the rate of decline of lipase being greater than that of trypsinogen; 67% of lipase values were within or below the normal range by 3 years, whereas 67% of trypsinogen values continued to be elevated. We conclude that trypsinogen is an excellent screening test for CF in young infants regardless of pancreatic function, and that the addition of a serum pancreatic lipase determination does not improve the accuracy of trypsinogen as a screening test for cystic fibrosis.     

Prednisone therapy of membranoproliferative glomerulonephritis in children

Six children with biopsy-proved type 1 membranoproliferative glomerulonephritis (MPGN) improved clinically during a 2-year course of prednisone therapy. All children had nephrotic syndrome. Creatinine clearance was less than or equal to 80 ml/min/1.73 m2 in four patients. Initial prednisone dosage ranged from 20 mg every other day to 2 mg/kg/day (maximum 60 mg), with subsequent modifications based on improvement. After completion of a 2-year course of steroid therapy, a repeat kidney biopsy was performed in each child; a decrease in glomerular disease activity was noted in five of them. After a mean follow-up of almost 5 years, all children have creatinine clearance greater than 120 ml/min/1.73 m2, and only one remains nephrotic. Although the use of prednisone in children with MPGN remains controversial, we have observed a diminution in proteinuria and normalization of creatinine clearance with therapy initiated early in the disease course.