Tania Gunn

Efficacy of caffeine in treatment of apnea in the low-birth-weight infant

The efficacy of caffeine citrate in the management of apnea in the newborn infant was evaluated. Caffeine citrate was given to 18 preterm neonates with recurrent apneic spells. Mean (+/- SE) birth weight and gestational age were 1,065.0 +/- 71.9 gm and 27.5 +/- 0.6 weeks, respectively. Mean age at onset of apnea and at initiation of caffeine treatment was 6.5 +/- 3.7 days and 18.2 +/- 4.9 days, respectively. Caffeine citrate was administered with a loading dose of 20 mg/kg intravenously followed within two to three days by 5 to 10 mg/kg once or twice daily. All infants except one showed a significant decrease in the frequency of apneic episodes associated with caffeine therapy. Mean frequencies of apneic spells were 13.6 +/- 2.5 and 2.1 +/- 0.6 apnea per day before and after initiation of caffeine treatment, respectively. Respiratory rate was increased, and blood [h]+ion concentration and Pco2 were decreased. The data suggest that caffeine is an effective pharmacologic respirogenic agent in the preterm infant with apnea.

Juvenile diabetes mellitus, optic atrophy, sensory nerve deafness, and diabetes insipidus—a syndrome

Four patients with diabetes mellitus, optic atrophy, and high-frequency neurosensory hearing loss, two of whom also had diabetes insipidus, are described. The frequency of this syndrome among patients with juvenile diabetes appears to be between 1/148 and 1/175. Because of the progressive nature of the disabilities and the autosomal recessive mode of inheritance, careful monitoring of all juvenile diabetic patients for other signs of the syndrome is warranted.

Sequelae of caffeine treatment in preterm infants with apnea.

Growth, neurologic, and ophthalmologic assessments were done in 21 low-birth-weight infants given caffeine for neonatal apnea and in 21 matched control infants. Caffeine significantly decreased the need for and the duration of mechanical ventilation. No difference in growth and development was noted between the control and caffeine-treated infants. A high incidence of cicatricial retrolental fibroplasia was observed in both control (10/21) and caffeine-treated infants (7/18).

Peripheral total parenteral nutrition for premature infants with the respiratory distress syndrome: A controlled study

In 40 premature infants, in whom severe respiratory distress precluded oral feeding, peripheral total parenteral nutrition consisting of casein hydrosylate, dextrose, and soybean emulsion was compared to nutrition with dextrose and electrolytes. The TPN group received more calories, and the total serum protein in them increased significantly. Metabolic complications did not occur. Transient thrombocytosis occurred in six infants who received TPN and eosinophilia occurred in nine. The case fatality rate in the TPN group (three of 20) was not significantly less than in the glucose group (six of 20). The differences suggested that infants who weigh less than 1,500 gm may receive the greater benefit from TPN.

Circulating thyrotropin in the ovine fetus: evidence for pulsatile release and the effect of hypothermia in utero.

ABSTRACT: The secretion of thyrotropin (TSH) has been investigated in the chronically catheterized ovine fetus (term 145–150 days). Forty-two random plasma samples from 25 fetuses (86–149 days of gestation) were measured for TSH concentrations by radioimmunoassay. Plasma TSH concentrations were highest in the youngest fetuses [86–110 days, 3.9 ± (SD) 5.5 μU/ml, n = 13]. Thereafter TSH concentrations declined to 0.4 ± 0.6 μU/ml (n = 13, p < 0.05) at 130–150 days of gestation. However, serial sampling at 15–20 min intervals for 180 min from 14 individual fetuses (91–139 days) showed that TSH was secreted in a markedly exaggerated pulsatile manner compared to that observed after birth. The mean amplitude of TSH pulses fell (p < 0.005) from 5.9 ± 8.1 μU/ml in the fetuses to 2.1 ± 1.1 μU/ml in five neonatal lambs (6–22 days) and to 1.5 ± 0.4 μU/ml in three adult nonpregnant ewes. The mean pulse frequency for the 14 fetuses was 0.7 ± 0.3 pulses/h and was reduced (p < 0.001) to 0.3 ± 0.1 pulses/h in lambs and to 0.3 ± 0.1 pulses/h in the ewes. In the neonate, hypothermia is a potent stimulus to TSH release. To examine the ontogeny of this response, the temperature of the fetus in utero (106–127 days of gestation) was lowered by circulating water (14–18°C) at either a fast or slow rate through a coil placed either externally around the fetus or internally in the fetal esophagus and stomach. The fetuses were cooled for a period of 1 h during which fetal samples were obtained. In eight fetuses (106–127 days), the mean plasma TSH concentration rose (p < 0.001) from 1.5 ± 1.6 μU/ml to 6.7 ± 2.1 μU/ml during 1 h of fast external cooling (maximum fetal temperature fall 3.5°C). Plasma TSH values also rose (p < 0.02) during fast internal cooling (maximum temperature fall 1.9°C) from 1.4 ± 1.9 to 5.9 ± 8.2 μU/ml (n = 5, 116–132 days). A slower rate of cooling either externally (temperature fall 1.1°C) or internally (temperature fall 0.9°C) induced a variable response. The marked pulsatility of fetal TSH secretion which decreases after birth is postulated to be a consequence of immature negative feedback by thyroid hormones on fetal TSH release. The presence of a TSH response to hypothermia from 0.7 gestation is evidence that neuroendocrine mechanisms mediating TSH release and hypothalamic thermoregulatory responses have differentiated by this age.

Surface Cooling Rapidly Induces Coordinated Activity in the Upper and Lower Airway Muscles of the Fetal Lamb in Utero

ABSTRACT: Stimulation of cutaneous thermoreceptors may be an important factor in the initiation of continuous breathing at birth. Maintenance of a patent airway is also important in the continuation of effective ventilation after birth, but whereas in the adult the principal pharyngeal dilator is the genioglossus muscle, in the fetus genioglossus phasic activity is not synchronous with that of the fetal diaphragm. To ascertain whether a cold stimulus that initiates continuous breathing would also induce synchronized inspiratory activity in the upper airway muscles of the fetus, we have cooled fetal lambs in utero and examined the response of the genioglossus and alae nasi muscles in relation to diaphragm activity. Deep regular breathing as recorded by diaphragmatic activity and tracheal pressure started within 1–102 s after cooling commenced and coordinated inspiratory activity was seen in the alae nasi within 2–356 s. Genioglossus activity became synchronized with that of the diaphragm within 11–356 s. Cooling was continued for 4 h but although in one fetus continuous breathing with associated inspiratory activity in the genioglossus and alae nasi muscles lasted throughout the 4-h period, in the others continuous breathing was not sustained and adaptation to the cold stimulus occurred after periods ranging from 27–218 min. The relationship between breathing, upper airway muscle activity, and sleep state passed through one or more different phases, including breathing through high voltage electrocortical activity, before the normal fetal pattern of episodic breathing restricted to the low voltage electrocortical state resumed. As breathing reverted to the normal fetal pattern, inspiratory activity was lost in the genioglossus. These observations suggest that afferent input arising from cutaneous thermoreceptors may be an important factor in initiating respiration at birth and in ensuring coordinated activity of the upper and lower airway and reducing the possibility of airway obstruction in the neonate.

The Problem of “Cheating” in the Diabetic Child and Adolescent

The frequency, causes, and consequences of “cheating” in diabetic children and adolescents were studied during summer camp. A philosophical approach is proposed for its understanding and management.

931 FACTORS RELATED TO THE OCCURRENCE OF RETROLENTAL FIBROPLASIA (FLF)

RLF relates inversely to maturity and directly to duration of O2 therapy. Other factors which may influence the occurrence of RLF were studied in all 84 infants <1500 g birth weight in 1975 and 1976. 77 children had indirect ophthalmoscopy, while 7 had refused examination or had been lost to follow-up. Infants with cicatricial RLF were compared to those without.Other factors shown to increase (p<0.05) RLF occurrence were: durations of CDAP, NPO and parenteral nutrition, as well as episodes of capillary PO2>40 mmHg, maximum weight loss, days to regain birth weight and blood transfused/kg. Analysis of infants who required bag and mask resuscitation for apnea revealed significant increase of RLF only with the factors listed in the table. High myopia requiring corrective lenses increased with cicatricial RLF. Data suggest that apnea and bagging, septicemia and severity of illness are important determinants in occurrence of RLF

730 DIMINISHED T CELLS FOLLOWING NEONATAL STEROID THERAPY

Patients treated at birth with hydrocortisone for the respiratory distress syndrome(RDS) were reassessed at 5 yrs of age for growth & development,neurologic status,immunologic status & incidence of infection. The pts include 10 who received neonatal steroids,6 placebo plus 4 non-placebo RDS controls. Studies included intelligence & developmental tests,EEGs,Immunoglobulin & complement levels,diphtheria & tetanus titers,T & B cell enumeration,thymosin induction in 3 pts and delayed skin tests. The percentages of T & B cell subclasses are shown in the table.The steroid group had a marked reduction in T cells associated in some with increased cells with C3 receptors. No significant differences were observed in numbers of cells with Fc receptors or surface immunoglobulin(SmIG) or in other immunologic parameters. There was an increased incidence of bronchopneumonia & otitis in the steroid group. Thymosin incubation led to an 11% increase in T cells in one steroid pt while no increase was seen in 2 RDS controls or adult controls. No significant differences were seen in hgt,wgt or head circumference(25-50%ile) or IQs which were 108 ± 11 for controls and 102 ± 11 for steroid pts.The data suggests that followup of infants who receive perinatal steroids should include evaluation of the immune system.

IS CAFFEINE FAFE FOR THE TREATMENT OF APNEA IN PREMATURE INFANTS

The long term effects of drugs given in the neonatal period must be evaluated before their use can be recommended. Infants have been followed for from 6 to 24 months, to determine the outcome of treatment with caffeine for recurrent apnea (cessation of breathing > 20 sec and requiring assisted ventilation by bag and mask). 18 infants treated with caffeine citrate, available for follow-up, were compared to a group of infants with apneic spells of similar severity, individually matched as to birth weight, gestational age, birth date and sex.In both groups a high incidence of R.L.F. (gr 1 to 5) 27% occurred. A significant reduction in the need for mechanical ventilation was noted for the infants treated with caffeine. Thus, the use of caffeine may reduce the need for mechanical ventilation for apnea, without apparent later complications.