Sleep position,autonomic function,and arousal

AIMS—To investigate and compare heart rate variability (HRV) and responses of heart rate and arousal to head-up tilting in infants sleeping prone and supine.
METHODS—Thirty seven healthy infants aged 2-4 months were studied. HRV was measured for 500 beats while they were in a horizontal position. Subjects were then tilted 60° head-up, and heart rate recorded over 1 minute and arousal responses observed. Data were collected during both quiet and active sleep for both prone and supine sleep positions.
RESULTS—HRV, as assessed by the point dispersion of Poincaré plots, was significantly reduced in the prone position for both sleep states. Sleep position did not influence the changes in heart rate seen during a head-up tilt. Full awakening to the tilt was common in active sleep but significantly less so in the prone position (15% of prone tests vs 54% supine). Full awakening to the tilt rarely occurred during quiet sleep in either sleep position.
CONCLUSION—This study provides some evidence that blunted arousal responses and/or altered autonomic function are a feature of the prone sleeping position. Decreased HRV may be a sign of autonomic impairment. It is seen in many disease states and in infants who later die of sudden infant death syndrome (SIDS).

     

Behaviour and physiological responses during prone and supine sleep in early infancy

AIMS: To study the effect of prone and supine sleep on infant behaviour, peripheral skin temperature, and cardiorespiratory parameters to aid understanding of why prone sleeping is associated with an increased risk of sudden infant death syndrome. METHODS: Of 33 enrolled infants, 32 were studied at 2.5 and 28 at 5 months of age. A computer aided multichannel system was used for polysomnographic recordings. Behaviour was charted separately. RESULTS: Prone REM (active) sleep was associated with lower frequencies of short arousals, body movements and sighs, and a shorter duration of apnoeas than supine REM sleep at both ages. At 2.5 months there were less frequent episodes of periodic breathing during prone sleep in non-REM (quiet) and REM sleep. Heart rate and peripheral skin temperature were higher in the prone position during both sleep states at both ages. CONCLUSIONS: The observation of decreased variation in behaviour and respiratory pattern, increased heart rate, and increased peripheral skin temperature during prone compared with supine sleep may indicate that young infants are less able to maintain adequate respiratory and metabolic homoeostasis during prone sleep.     

Posture and gastro-oesophageal reflux: a case for left lateral positioning

Accepted 4 November 1996
AIM—Prone posture is often recommended for symptomatic gastro-oesophageal reflux in young infants, but prone positioning has been associated with sudden infant death. The aim of this study was thus to establish the optimal alternative posture for reducing reflux.
METHODS—24 infants (< 5 months) with symptomatic gastro-oesophageal reflux were studied prospectively with 48 h pH monitoring. They were randomly assigned to one of the 24 permutations of the four positions (supine, prone, right, left). During the first 24 hours the infant was held horizontally, and then the permutation was repeated at 30 degrees head elevation, giving a total of eight study segments for each infant. Data were edited to remove all time when the infants were not in the prescribed positions. Results were evaluated using analysis of covariance.
RESULTS—Gastro-oesophageal reflux expressed as reflux index (mean % (SEM)) was significantly less in the prone and left lateral positions (6.72 (1.06) and 7.69 (1.03) respectively) than in the supine and right lateral positions (15.33 (2.33) and 12.02 (1.38); p < 0.001). Head elevation did not affect any variables significantly.
CONCLUSIONS—Head elevation may not always be of clinical value. The left lateral position is a suitable alternative to prone for the postural management of infants with symptomatic gastro-oesophageal reflux.

     

Pacifier use and sudden infant death syndrome: results from the CESDI/SUDI case control study

OBJECTIVES—To investigate the relation between pacifier use and sudden infant death syndrome (SIDS).
DESIGN—Three year population based, case control study with parental interviews for each death and four age matched controls.
SETTING—Five regions in England (population > 17 million).
SUBJECTS—325 infants who had died from SIDS and 1300 control infants.
RESULTS—Significantly fewer SIDS infants (40%) than controls (51%) used a pacifier for the last/reference sleep (univariate odds ratio (OR), 0.62; 95% confidence interval (CI), 0.46 to 0.83) and the difference increased when controlled for other factors (multivariate OR, 0.41; 95% CI, 0.22 to 0.77). However, the proportion of infants who had ever used a pacifier for day (66% SIDS v 66% controls) or night sleeps (61% SIDS v 61% controls) was identical. The association of a risk for SIDS infants who routinely used a pacifier but did not do so for the last sleep became non-significant when controlled for socioeconomic status (bivariate OR, 1.39 (0.93 to 2.07)).
CONCLUSIONS—Further epidemiological evidence and physiological studies are needed before pacifier use can be recommended as a measure to reduce the risk of SIDS.
     

Randomised controlled trial of sucrose by mouth for the relief of infant crying after immunisation

OBJECTIVES—To evaluate the effect of sucrose solution given by mouth on infant crying times and measures of distress in the immunisation clinic.
DESIGN—Randomised, double blind, placebo controlled trial of sucrose solution 75% wt/vol v sterile water as a control.
SETTING—The immunisation clinic of the Women''s and Children''s Hospital, Adelaide.
PATIENTS—A total of 107 healthy infants attending for 2, 4, or 6 month immunisations with polio by mouth (Sabin), intramuscular diphtheria, tetanus, and pertussis (DTP), and intramuscular Haemophilus influenzae type b were randomised to receive 2 ml 75% sucrose solution or sterile water by mouth before the two injections.
METHODS—The duration of infant crying was recorded during and immediately after two intramuscular immunisations and infant distress was assessed by a visual analogue scale (Oucher scores) independently by a nurse and a parent.
RESULTS—The administration of 2 ml 75% sucrose solution by mouth reduced the infant crying time and Oucher distress scores after immunisation with DTP/H influenzae type b.
CONCLUSIONS—Infant immunisation by intramuscular injection is a distressing procedure for infants and parents. Sucrose solution at a high concentration reduces infant distress and is safe and clinically useful in this setting.

     

Heavy caffeine intake in pregnancy and sudden infant death syndrome

AIMS—To examine the association between maternal caffeine consumption during pregnancy and the risk of sudden infant death syndrome (SIDS).
METHODS—A nationwide case-control study surveying parents of 393 SIDS victims and parents of 1592 control infants. Caffeine consumption in each of the first and third trimesters was estimated by questionnaire. Heavy caffeine intake was defined as 400 mg/day or more (equivalent to four or more cups of coffee per day).
RESULTS—Infants whose mothers had heavy caffeine consumption throughout their pregnancy had a significantly increased risk for SIDS (odds ratio 1.65; 95% confidence interval 1.15 to 2.35) after adjusting for likely confounding factors.
CONCLUSION—Caffeine intake has been associated with fetal harm and now SIDS. Reducing heavy caffeine intake during pregnancy could be another way to lessen the risk of SIDS. This needs confirmation by others.

     

Maternal hypertension and neurodevelopmental outcome in very preterm infants

AIM—To determine the outcome of preterm infants born to mothers with hypertension during pregnancy, and preterm controls.
METHODS—107 infants of 24-32 weeks gestation, born to hypertensive mothers, and 107 controls matched for gestational age, sex, and multiple pregnancy, born to normotensive mothers, were prospectively enrolled over 2 years. Information on maternal complications and medication was obtained and neonatal mortality and morbidities recorded. Survivors were followed up to at least 2 years, corrected for prematurity.
RESULTS—One third of the hypertensive mothers were treated with antihypertensive drugs, while 18% received convulsion prophylaxis with phenytoin. Magnesium sulphate was not prescribed. Both groups had a mean gestational age of 29.9 weeks, with the study infants having a significantly lower birthweight than the controls. Four study and three control infants died in the neonatal period. Cerebral palsy was not diagnosed in any infant of a hypertensive mother compared with five of the controls. The mean general quotient for the two groups was very similar and no difference in the incidence of minor neuromotor developmental problems was shown.
CONCLUSIONS—Maternal hypertension seems to protect against cerebral palsy in preterm infants without increasing the risk of cognitive impairment. This was independent of the use of maternally administered magnesium sulphate.

     

Urinary antimony in infancy

Accepted 6 January 1997
OBJECTIVE—To determine whether antimony may be detected in the urine during infancy and early childhood and its association with passive exposure to tobacco smoke, as assessed by urinary cotinine.
DESIGN—Analysis of spare aliquots of urine collected from infants participating in studies of respiratory function and passive smoking. Urinary antimony was assayed using inductively coupled plasma mass spectroscopy in 201 urine specimens collected at different ages throughout the first two years of life from 122 term and 26 preterm infants. Urinary cotinine was measured using gas liquid chromatography.
MAIN OUTCOME MEASURE—Urinary antimony concentrations.
RESULTS—Absolute antimony concentrations varied widely between infants, being below the laboratory detection limit of 0.02 µg/l in 7% of samples, below 0.5 µg/l in 90.5%, and above the reference value of 1 µg/l reported for non-occupationally exposed UK populations in 4%. Creatinine standardised antimony values were unrelated to postnatal age or urinary cotinine concentrations and were highest in urine collected from preterm infants within 24 hours of birth (geometric mean (95% confidence interval): 2.3 ng/mg (1.5 to 3.4)).
CONCLUSION—Although antimony is present at very low concentrations in urine during infancy and early childhood, the relevance to health is uncertain. The higher levels found in preterm infants may reflect prematurity or fetal assimilation of antimony. Tobacco is unlikely to be an important source of environmental exposure to antimony during infancy and early childhood.

     

Health and behaviour problems at 8 weeks as predictors of behaviour problems at 8 months

OBJECTIVE—To assess the value of health and behavioural problems at 8 weeks as predictors of behavioural problems at 8 months in a whole year birth cohort.
STUDY DESIGN—Prospective birth cohort study.
SETTING—The socially and ethnically diverse city of Coventry.
MAIN OUTCOME—Parent reported behavioural problems at 8months.
METHOD—Parent reported infant health and behaviour data were collected, using a validated questionnaire administered by the family health visitor at 8 weeks and 8 months, on 1541 infants participating in the Coventry cohort study. Sociodemographic data were collected at the health visitor''s initial visit. Unadjusted relative risks (with 95% confidence intervals (CI)) of behaviour problems at 8 months by sociodemographic variables and health and behavioural problems at 8 weeks were estimated. Adjustment for confounding was made by logistic regression.
RESULTS—Infants reported to have behavioural problems at 8 weeks had a significant risk of parent reported behavioural problems at 8 months (adjusted relative risk, 3.44; 95% CI, 1.95 to 6.09) after adjustment for other health outcomes and sociodemographic factors. Of infants with behavioural problems by 8 weeks of age, 19.1% were reported to have behavioural problems at 8months.
CONCLUSIONS—Infants whose parents report behaviour problems by 8 weeks of age are at higher risk of behavioural problems at 8 months. However, despite the higher risk, the proportions of infants identified by behaviour at 8 weeks were too small for the early outcomes to be useful as predictors of behaviour at 8 months in the whole infant population.

     

Subglottic haemangioma

Accepted 15 January 1997
OBJECTIVES—To describe experience with subglottic haemangioma in a unit where conservative treatment has been favoured.
METHODS—Retrospective case note review of infants presenting with subglottic haemangioma over a 25 year period.
RESULTS—Thirty one infants were identified. Diagnosis was difficult where skin haemangiomas were absent and where the lesion was circumferential rather than asymmetrical. Tracheostomy was safe, well tolerated, and managed by the patients'' family at home. Major complications were seen only when laser treatment was used.
CONCLUSIONS—Aggressive treatment with substantial risks of long term complications may not be necessary in this spontaneously resolving disorder.

     

Total serum IgE and outcome in infants with recurrent wheezing

OBJECTIVE—To investigate the relation between total serum IgE at 0.5-3 and 3-6 years, and the risk of allergic sensitisation and persistent wheezing up to 8 years of age.
METHODS—Prospective follow up study of 45 infants with highly recurrent wheezing, no allergic symptoms, and negative skin tests.
RESULTS—In the last follow up year, 15 children still suffered from wheezing. Five wheeze-free and four episodically wheezing children had become sensitised. No association was found between early (0.5-3 years) IgE z scores and the recurrence of wheezing during follow up, or atopic sensitisation. IgE z scores at 3-6 years were significantly higher in children with positive skin tests (p = 0.013), but were still not associated with recurrence of wheezing.
CONCLUSIONS—In subjects with frequent early wheezing and no signs of atopy, early total serum IgE measurements are not predictive of outcome.

     

Iodine and hypothyroidism in neonates with congenital heart disease

AIM—To evaluate the influence of the intravenous injection of iodine during cardiac catheterisation, and of topical iodine antiseptics during surgical procedures, on thyroid function in full term neonates.
METHODS—Twenty one full term infants with major cardiac anomalies who survived for more than a month were studied. Thyroxine and thyrotropin concentrations were measured (by radioimmunoassay) before each procedure, 24 hours after the procedure, and every week thereafter until the age of 1 month or until normal. Thyroxine values less than 64.4 nmol/l were considered low, while thyrotropin values greater than 30 mU/l were considered high.
RESULTS—Thyroid function tests before iodine exposure were within normal limits in all infants. Following catheterisation or surgery six infants had raised thyrotropin concentrations; three had low thyroxine concentrations. Two of those infants were treated with L-thyroxine.
CONCLUSION—Iodine exposure during cardiac catheterisation or surgery may induce transient hypothyroidism in term infants.

     

Influence of socioeconomic conditions on growth in infancy: the 1921 Aberdeen birth cohort

OBJECTIVES—To identify environmental influences on infant growth using data from a birth cohort established in 1921.
DESIGN—A longitudinal cohort study.
SETTING—Aberdeen 1921-22.
SUBJECTS—Five hundred and sixteen individuals (263 boys and 253 girls) born in Aberdeen during 1921. Health visitor assessments ranged from two to 40 (47% received at least 10 visits). No records were available for infants who died. Individuals were grouped as those who did not breast feed, those who breast fed initially but not at 6 months, and those who were continuing to breast feed at 6months.
MAIN OUTCOME MEASURE—Rate of weight gain over the 1st year of life. A random effects model was used to identify environmental factors and conditions contributing to rate of weight gain in the 1st year of life.
RESULTS—Breast feeding rates were about 80% and 50% at 10 days and 6 months, respectively. Breast fed infants were significantly heavier than bottle fed infants at 28 days but this difference disappeared by 12 months. Significant negative effects on rate of weight gain, independent of initial body weight, were found for overcrowding in family homes and maternal parity, whereas social class had no effect.
CONCLUSION—Studies based on historical cohorts that have controlled socioeconomic variables only in terms of social class (derived from parental occupation) may have been subject to residual confounding. Growth in the 1st year of life is likely to reflect a number of environmental influences, some of which may continue to have effects throughout early life and beyond.

     

Randomised controlled trial of cisapride in feed intolerance in preterm infants

AIM—To assess the efficacy of cisapride in reducing the time required to establish enteral feeds in preterm infants.
METHODS—A randomised, double blind, placebo controlled trial was conducted of 34 infants of ⩽ 32 weeks of gestation, assigned to receive either cisapride 0.2 mg/kg/dose four times daily (n=18) or placebo (n=16).
RESULTS—The time taken by the babies to tolerate full enteral feeds was not significantly different between the groups (median 9.5days vs 10 days). There was a significantly lower incidence of large gastric residuals and regurgitation in the treated group compared with the placebo group. The number of episodes of large gastric residuals per infant was also significantly less. No adverse effects were noted.
CONCLUSION—The routine use of cisapride in preterm infants cannot be recommended to decrease the time to establish enteral feeds. Its use may be justified for clincally significant gastric stasis or regurgitation.

     

Infant rolling abilities – the same or different 20 years after the back to sleep campaign?

Aim

To compare the order and age of emergence of rolling prone to supine and supine to prone before the introduction of back to sleep guidelines and 20 years after their introduction.

Methods

The original normative data for the Alberta Infant Motor Scale (AIMS) were collected just prior to the introduction of back to sleep guidelines in 1992. Currently these norms are being re-evaluated. Data of rolling patterns of infants 36 weeks of age or younger from the original sample (n = 1114) and the contemporary sample (n = 351) were evaluated to compare the sequence of appearance of prone to supine and supine to prone rolls (proportion of infants passing each roll) and the ages of emergence (estimated age when 50% of infants passed each roll).

Results

The sequence of emergence and estimated age of appearance of both rolling directions were similar between the two time periods.

Conclusion

The introduction of the supine sleep position to reduce the prevalence of Sudden Infant Death Syndrome (SIDS) has not altered the timing or sequence of infant rolling abilities. This information is valuable to health care providers involved in the surveillance of infants’ development. Original normative age estimates for these two motor abilities are still appropriate.     

Basal ganglia damage and impaired visual function in the newborn infant

AIM—To examine the effects of early lesions in the visual pathway on visual function; and to identify early prognostic indicators of visual abnormalities.
METHODS—The visual function of 37 infants with perinatal brain lesions on magnetic resonance imaging was assessed using behavioural and electrophysiological variables.
RESULTS—Normal visual behaviour was observed in most infants with large bilateral occipital lesions, but all the infants with associated basal ganglia involvement had abnormal visual function. Visual abnormalities were also present in six infants with isolated basal ganglia lesions.
CONCLUSIONS—These observations suggest that basal ganglia may have an integral role in human visual development and that their presence on neonatal MRI could be an early marker of abnormal visual function.

     

Immunological responses to respiratory syncytial virus infection in infancy

Accepted 4 November 1996
OBJECTIVES—To determine whether there is evidence of immunological responses in infants with respiratory syncytial virus (RSV) bronchiolitis by measuring inflammatory mediators in peripheral blood and, if found, whether these related to the severity of illness.
PATIENTS AND METHODS—Blood was taken from 94 children with RSV infection during the acute episode and 10 or more days later when the child was well. Control serum samples were obtained from well children of similar ages. Serum samples were assayed for mediators of lymphocyte activity (interleukin-4 (IL-4), soluble interleukin-2 receptor (sCD25), soluble intercellular adhesion molecule-1 (sICAM-1), eosinophil activity (eosinophil cationic protein) and neutrophil activity (myeloperoxidase). Symptoms were assessed as very mild (coryza only), mild (symptoms of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation).
RESULTS—IL-4 concentrations were at the lower limits of detection of the assay. The concentrations of sCD-25 were greater in samples from patients with acute illness than from convalescent patients and both were greater than in control samples. sICAM-1 concentrations were similar in samples from patients with acute illness and convalescent patients, but both were greater than in samples from controls. Eosinophil cationic protein concentrations were lower in samples from patients with acute illness than in those from convalescent patients; there was no difference between samples from convalescent and control patients. Myeloperoxidase concentrations were similar in all samples. There was no correlation between the severity of infection and the concentrations of any inflammatory mediators.
CONCLUSIONS—There is evidence of an inflammatory response in the peripheral blood of infants with acute bronchiolitis which may affect lymphocytes and eosinophils, but an association between this response and the severity of illness was not shown here.

     

Volume delivery during high frequency oscillation

AIM—To examine the delivered volume during "high volume strategy" high frequency oscillation, used as rescue treatment in preterm infants; and to identify factors, other than frequency and oscillatory amplitude, influencing the magnitude of volume delivery.
METHOD—Twenty infants (median gestational age 29 weeks) were studied on 45 occasions. Two oscillator types were used (SensorMedics and SLE). Delivered volume was measured under clinical conditions with the arterial blood gases within a predetermined range. A specially calibrated pneumotachograph system was used.
RESULTS—Overall, the median delivered volume was 2.4 ml/kg (range 1.0 to 3.6 ml/kg); on 32 occasions the delivered volume was greater than 2.0 ml/kg and on seven greater than 3.0 ml/kg. The delivered volume related significantly to disease severity; there was an inverse correlation between delivered volume and both the oxygenation index (OI) (r=−0.51) and AaDO₂ (r=−0.54).
CONCLUSION—Delivered volume during HFO may, in certain infants, exceed the anatomical dead space, permitting some direct alveolar ventilation.

     

Unnatural sudden infant death

AIM—To identify features to help paediatriciansdifferentiate between natural and unnatural infant deaths.
METHOD—Clinical features of 81 children judged bycriminal and family courts to have been killed by their parents werestudied. Health and social service records, court documents, andrecords from meetings with parents, relatives, and social workers were studied.
RESULTS—Initially, 42 children had been certifiedas dying from sudden infant death syndrome (SIDS), and 29 were givenanother cause of natural death. In 24 families, more than one childdied; 58died before the age of 6 months and most died in the afternoon or evening. Seventy per cent had experienced unexplained illnesses; over half were admitted to hospital within the previous month, and 15 had been discharged within 24 hours of death. The mother, father, orboth were responsible for death in 43, five, and two families,respectively. Most homes were disadvantaged—no regular income,receiving income support—and mothers smoked. Half the perpetrators hada history of somatising or factitious disorder. Death was usually bysmothering and 43% of children had bruises, petechiae, or blood on the face.
CONCLUSIONS—Although certain features areindicative of unnatural infant death, some are also associated withSIDS. Despite the recent reduction in numbers of infants dyingsuddenly, inadequacies in the assessment of their deaths exist. Until athorough postmortem examination is combined with evaluation of thehistory and circumstances of death by an experienced paediatrician,most cases of covert fatal abuse will go undetected. The term SIDSrequires revision or abandonment.

     

Causes of preterm delivery and intrauterine growth retardation in a malaria endemic region of Papua New Guinea

AIM—To identify causes of preterm delivery and intrauterine growth retardation (IUGR) in a malaria endemic region of Papua New Guinea.
METHODS—Independent predictors of preterm delivery and birthweight in term infants were identified using multiple regression analysis in a prospective study of 987 singleton live births delivered in Madang Hospital.
RESULTS—Overall, Plasmodium falciparum infection of the placenta was associated with a reduction in birthweight of 130 g. Malaria was significantly more common in primigravidae than multigravidae and probably contributed to both preterm delivery and IUGR. Maternal haemoglobin concentrations were significantly lower in malaria infected than non-infected women and reduced haemoglobin was the main determinant of preterm delivery. Poorer maternal nutritional status and smoking were associated with both prematurity and IUGR. Greater antenatal clinic attendance predicted increased birthweight in term infants.
CONCLUSIONS—Protection against malaria during pregnancy, especially in primigravidae, improved nutrition in women and discouragement of smoking would probably reduce both preterm delivery and IUGR. Greater use of existing antenatal clinics might increase birthweight in term infants.