The purpose of this study was to measure serum T4, free T4, TSH, T3, rT3, T4 sulfate, and thyroxine binding globulin at four time points within the first 24 h of life (cord and 1, 7, and 24 h) in infants between 24 and 34 wk gestation. The infants were subdivided into gestational age groups: 24-27 wk (n = 22); 28-30 wk (n = 26); and 31-34 wk (n = 24). The TSH surge in the first hour of postnatal life was markedly attenuated in infants of 24-27 wk gestation [8 compared with 20 (28-30 wk) and 23 mU/liter (31-34 wk)]. T4 levels in the most immature group declined over the first 24 h, whereas levels increased in the more mature groups [mean cord and 24-h levels: 65 and 59 (NS) vs. 70 and 84 (P < 0.002) vs. 98 and 125 (NS) nmol/liter]. Free T4 and T3 showed only small, transient increases in the most immature group and progressively larger and sustained increases in the other gestational groups. rT3 and T4 sulfate levels in cord serum were higher in the most immature infants, and in all groups levels decreased initially and then variably increased. The features of a severely attenuated or failed hypothalamic-pituitary-thyroid response to delivery critically define this 24- to 27-wk group as distinct from more mature preterm infants.

Infant mortality rates in developed countries have shown significant decreases in recent years. Two-thirds of infant mortality still occurs in the neonatal period and our aim in this study was to review the causes of these neonatal deaths and see where further improvements may be possible. A 6-yr review of all neonatal deaths of live-born infants over 500g birthweight from 1991 to 1996 was made. The 1989 amended Wigglesworth classification was used to categorise cause of death and other perinatal variables were also recorded.

A retrospective study of all premature neonates who received artificial surfactant (Curosurf) at the Rotunda Hospital was performed. The period from October 1990 to June 1992 (n = 48) was compared with the initial experience from June 1987 to January 1988 (n = 15). In the initial period mortality rate was 67% in surfactant treated infants, and use of surfactant was not associated with an improvement in outcome compared with the previous six years. In the more recent period overall mortality was 21%. Overall survival in normally formed very low birthweight infants improved from 59% in 1986 to 86% in 1991-1992. Improvement in survival rates was most noticeable in infants with birthweight 750-999 grams, with survival increasing from 44% (before introduction of surfactant treatment) to 91% (in 1991-1992). It is probable that a certain level of experience with use of surfactant is required before optimal effects can be obtained.

A review of the duration of antibiotic courses in our Neonatal Intensive Care Unit (N.I.C.U.) has shown that in a significant number of cases there was non compliance with the antibiotic policy. An audit of neonatal sepsis and antibiotic usage over a six month period was performed in the N.I.C.U. at the Rotunda Hospital. Three hundred and forty-nine of the 3,163 infants born during this time were admitted to the N.I.C.U. One hundred and fifty-two infants had one or more episodes of suspected sepsis. In 168 instances this preceded a course of antibiotic therapy lasting longer than 48 hours. In 56 (33%) the infant was clinically septic and in 16 (9.5%) of those there was bacteriological proven sepsis. There were 112 episodes (60%) where there was no strong clinical evidence of sepsis and a negative investigation for sepsis where antibiotics were continued for more than 48 hours. The possible reasons why antibiotics were not stopped include the non specific nature of signs of sepsis in neonates, physicians' reluctance to discontinue antibiotics once started, and the logistic difficulty of obtaining routine culture results at weekends. The study emphasizes the need for regular surveillance of antibiotic usage in a N.I.C.U.

This case-controlled study examines some recently implicated risk factors for Sudden Infant Death Syndrome (S.I.D.S.) in Irish infants. Irish S.I.D.S. infants are lighter at birth than controls (3463g) compared to (3542g) and boys out-number girls by a ratio of 1.3:1. S.I.D.S. infants are more frequently: breast-fed (42% vs 25%) and sleep in a location other than the parent's bedroom (54% vs 21%), but start solids at a similar age and appear not to be sicker prior to death than the control group. This study highlights the frequency of symptoms of possible ill-health (i.e. snuffles and being "chesty") in well infants during the first months of life with 32% of the control group having snuffles and 35% described as "chesty". In addition these symptoms are frequently treated with antibiotics with 31% of the control group having already received antibiotics by 2 months of age. A majority of S.I.D.S. infants were described as cold when found (52%) with 39% described as warm and 15% as sweaty. Obviously the recently implicated role of overheating may be relevant in the latter 15% of S.I.D.S. cases. In this series, 88% of infants had died by 6 months of age. Of the 97 parents of S.I.D.S. infants questioned, 78 had subsequently become pregnant by the time the study was conducted at an average time of 5 months post the S.I.D.S. event.

The presence of excess nasal mucus causing noisy nasal breathing with an obvious mucus discharge (snuffles) is a common problem in infants in the first three months of life. The presence of "snuffles" has traditionally been ascribed, unproven, to an upper respiratory tract infection despite there being no other signs of an acute infection in the majority of infants with "snuffles". To assess the possible role of impaired vasomotor control (autonomic function) in the pathogenesis of snuffles we measured the effect of a change from the supine to the upright position on resting blood pressure in 50 infants with "snuffles" and 50 healthy control infants. The mean age in both groups was 7 weeks post delivery, all infants were attending a well baby clinic for a routine examination, had no signs of an acute infection and none were on any medication (including nasal drops). A fall of greater than 10% of resting blood pressure was taken to indicate postural hypotension. Four of fifty infants in the control group compared to 22 of 50 in the snuffles group demonstrated postural hypotension (Chi square 16.84, p<0.001). The results suggest that in some infants "snuffles" may be associated with impaired vasomotor control.

Hypercarbic and hypoxic arousal responses during sleep were measured in healthy term infants, infants where a previous sibling died from sudden infant death syndrome (SIDS) and infants suffering a clearly defined apparent life threatening event (ALTE) requiring vigorous or mouth to mouth resuscitation. Groups of infants were tested at approximately one, six and 13 weeks postnatally. Arousal was defined as gross body movement with eves opening and moving or crying. Hypercarbic arousal was by step increases in F1 Co2 until arousal occurred or until endtidal (PETCO2) reached 8.7 KpA (65 mm Hg) Hypoxic arousal was by step decreases in FIO2 until arousal occurred or until an FIO2 of 0.15 had been maintained for 20 minutes. There was no difference in hypercaribic arousal threshold with age in any group. Hypercarbic arousal threshold was significantly higher in siblings (mean 53.4, 53.6, 54.7 mmHg. [7.12, 7.14, 7.29 KPA] at 0, 6, 13 postnatal weeks) compared to controls (mean 50.9, 52.3, 53.0mm Hg. [6.78, 6.97, 7.29 KPS respectively). ALTE infants differed only at 12 weeks having a significantly lower threshold (51.0mmHg. [6.80 KPA] V 53.Omm Hg. {7.06 KPA]) compared to controls. There was no difference in hypoxic arousal response with age in any group. An arousal response to hypoxia occurred in only 22% of ALTE infants and 40% of siblings compared to 67% of normal infants.Deficient sleep arousal, especially to hypoxia, is common in infants and especially those considered at increased risk from SIDS. This deficiency is present in the first postnatal week and did not vary overy the first three months of postnatal life.

Bronchopulmonary dysplasia (B.P.D.) is a condition reflecting the reaction of the immature lung to the intensive support (barotrauma from mechanical ventilation and oxygen toxicity) required for survival in critically ill newborn infants. This study examines all infants who developed B.P.D. over a 2 year period in the Rotunda Hospital. Between 1st January 1986-31st December 1987 there were 1,360 N.I.C.U. admissions, 198 with respiratory problems and 76 requiring assisted ventilation (I.P.P.V.); 23 infants developed B.P.D. with a mean gestational age of 28.7 weeks (SD 2.5), mean birth weight 1,243 g. (SD 523 g.). One infant died at 4 months from S.I.D.S. and one was lost to follow-up (both had been clinically normal). At one year post term the weight was 7,843 g. (SD 1,134) (normal population mean 9.75 Kg. third percentile 8 Kg.) and head circumference 46 cm. (SD 2.5) (normal population mean 47 cm., third percentile 45 cm). During the 1st year of life 11 infants required re-hospitalisation (5 bronchiolitis, 2 urinary tract infections, 2 failure to thrive, 2 myrinogotomies/grommets) and a further 8 attended hospital with respiratory infections. Only 6/21 received 3 in 1 vaccine (all in hospital O.P.D.) and 14/21 received 2 in 1 vaccine. At one year 15 infants were normal, 2 had cerebral palsy, 2 mild motor delay (one with arrested hydrocephalus), 1 sensorineural deafness and 1 arrested hydrocephalus with mild motor delay. Five infants developed retinopathy of prematurity but none required treatment.

In this study the ambient temperature in which thirty-three Irish infants, within six weeks of birth, were nursed was documented. The study was conducted from October to March and a total of 1,250 individual room temperatures were recorded with a mean of 19.3 degrees C and a range of 8 degrees C, to 28 degrees C. The highest ambient temperature occurred from 1800 to 2100 hours and the lowest from midnight to 0300 hours. There was no central heating in 60% of the homes in this study. Comparing the various methods of home heating we found that houses with a coal fire and back boiler had the greatest range of temperatures recorded (from 10 degrees C to 23.5 degrees C) and also the lowest mean temperature recorded (17.14 degrees C). There was little relationship found between the ambient temperature and the amount of clothing and bedding used and some infants were heavily clothed despite a high ambient temperature. The purpose of this paper is to provide background data on which to base future studies examining the effects of varying ambient temperatures and amounts of clothing on an infant's physiological homeostasis.

Fifty-four infants underwent recording of heart rate, respiratory rate, long term and short term heart rate variability and end tidal carbon dioxide measurements at three different ambient temperatures (20 degrees C, 25-26 degrees C, 30 degrees C) under standardized conditions. The infants' skin and rectal temperature remained normal throughout the study. The ambient temperature of the room where the study was conducted significantly influenced the infants' heart rate, respiratory rate and long and short term heart rate variability but not end tidal carbon dioxide values. The thermal environment in which an infant resides has a significant influence on some physiological variables and should be standardized in future physiological studies.

In 93 of 100 infants there was a marked difference in the measured end-tidal carbon dioxide (CO2) level between nasal airways during quiet sleep (4.88 Kpa V 3.3 Kpa P less than 0.001). It is suggested that partial nasal obstruction is common in infants. Nasal airway resistance is increased by mucosal swelling, is assymetric, regularly alternates between sides (the nasal cycle), and is under autonomic control. End tidal carbon dioxide values are widely measured as part of an assessment of respiratory control and risk of sudden infant death syndrome. The preferential use of one nasal airway must be taken into account in assessing such results.

Mortality and morbidity in the neonatal period are inversely proportional to birth weight and gestational age.Pneumothorax and pulmonary interstitial emphysema (P.I.E.) are major adverse factors affecting outcome of V.L.B.W. infants

The benefit of an organized neonatal transport system is well established. Over a 30 month period, January 1987 to June 1989, 172 babies were transported to the Dublin maternity hospitals. Birth weights ranged from 640 to 5,180g 106 (62%) were less than 37 weeks gestation. Indications for transport included respiratory distress syndrome (54), prematurity only (43), convulsions and/or neurologic dysfunction (23), jaundice (11) and apnoea (11). One hundred and sixty-eight were transferred by ambulance and four by helicopter. Twenty travelled more than 100 miles. Forty (23%) received assisted ventilation during transport. On arrival 37 (21%) had temperature less than 36 degrees C; 22 (13%) had blood sugar less than 2.2 m mol/l and 34 (20%) had arterial ph less than 7.25. Fifty per cent of referral letters had incomplete information. Treatment and care given en route was recorded in only 28 babies. Twenty-four babies (14%) died. Infants who died were more likely to have been of low birth weight, travelled a long distance, been hypothermic, had poor arterial gases, had blood sugars less than 2.2 m mol/l, and had poor referral letters. This review indicates that death and morbidity continue to be associated with the present system of postnatal transfer of newborn infants. The urgent need for an organized neonatal transport service remains unmet.

Autonomic function was assessed by measuring the heart rate and blood pressure responses to a change from the horizontal to upright posture at various ambient temperatures in four groups of infants aged 8-12 weeks: 30 infants who had suffered a well-defined unexplained apparent lifethreatening event (ALTE); 8 infants who had suffered a cyanotic attack; 24 healthy infants with a sibling who had died from sudden infant death syndrome (SIDS); and 17 healthy infants. Autonomic dysfunction was uncommon in the control group; no infant showed an abnormal heart rate response to postural change (R to R interval maximum/ minimum ratio less than 1·0) and a postural fall in blood pressure of greater than 10% occurred in only 1 infant. In contrast, in the ALTE group 9 of 26, 9 of 30, and 4 of 22 infants showed an abnormal heart rate response and 20 of 26, 14 of 30, and 10 of 22 a greater than 10% fall in blood pressure on postural change at 20°C, 25°C, and 30°C, respectively. 1 ALTE infant died of SIDS 14 h after showing an RR max/min ratio of 0·8 and a postural fall in blood pressure of 11% and 14% at 20°C and 30°C. Autonomic function testing should become part of the clinical evaluation of infants at high risk of a sudden unexpected death.