Smoking and the sudden infant death syndrome.

The aims of this review are (a) to critically examine the epidemiologic evidence for a possible association between smoking and the sudden infant death syndrome (SIDS), (b) to review the pathology and postulated physiological mechanism(s) by which smoking might be causally related to SIDS, and (c) to provide recommendations for SIDS prevention in relation to tobacco smoking. Over 60 studies have examined the relation between maternal smoking during pregnancy and risk of SIDS. With regard to prone-sleep-position intervention programs, the pooled relative risk associated with maternal smoking was RR = 2.86 (95% CI = 2.77, 2.95) before and RR = 3.93 (95% CI = 3.78, 4.08) after. Epidemiologically, to distinguish the effect of active maternal smoking during pregnancy from involuntary tobacco smoking by the infants of smoking mothers is difficult. Clear evidence for environmental tobacco smoke exposure can be obtained by examining the risk of SIDS from paternal smoking when the mother is a non-smoker. Seven such studies have been carried out. The pooled unadjusted RR was 1.49 (95% CI = 1.25, 1.77). Consideration of the pathological and physiological effects of tobacco suggests that the predominant effect from maternal smoking comes from the in utero exposure of the fetus to tobacco smoke. Assuming a causal association between smoking and SIDS, about one-third of SIDS deaths might have been prevented if all fetuses had not been exposed to maternal smoking in utero.

International Child Care Practices Study: infant sleeping environment.

BACKGROUND: The International Child Care Practices Study (ICCPS) has collected descriptive data from 21 centres in 17 countries. In this report, data are presented on the infant sleeping environment with the main focus being sudden infant death syndrome (SIDS) risk factors (bedsharing and infant using a pillow) and protective factors (infant sharing a room with adult) that are not yet well established in the literature. METHODS: Using a standardised protocol, parents of infants were surveyed at birth by interview and at 3 months of age mainly by postal questionnaire. Centres were grouped according to geographic location. Also indicated was the level of SIDS awareness in the community, i.e. whether any campaigns or messages to "reduce the risks of SIDS" were available at the time of the survey. RESULTS: Birth interview data were available for 5488 individual families and 4656 (85%) returned questionnaires at 3 months. Rates of bedsharing varied considerably (2-88%) and it appeared to be more common in the samples with a lower awareness of SIDS, but not necessarily a high SIDS rate. Countries with higher rates of bedsharing appeared to have a greater proportion of infants bedsharing for a longer duration (>5 h). Rates of room sharing varied (58-100%) with some of the lowest rates noted in centres with a higher awareness of SIDS. Rates of pillow use ranged from 4% to 95%. CONCLUSIONS: It is likely that methods of bedsharing differ cross-culturally, and although further details were sought on different bedsharing practices, it was not possible to build up a composite picture of "typical" bedsharing practices in these different communities. These data highlight interesting patterns in child care in these diverse populations. Although these results should not be used to imply that any particular child care practice either increases or decreases the risk of SIDS, these findings should help to inject caution into the process of developing SIDS prevention campaigns for non-Western cultures.

Nicotine exposure and the risk of SIDS.

The effects of parental smoking and nicotine exposure link a number of seemingly independent observations in SIDS research. There is accumulating evidence that fetal development and wellbeing are closely related to the subsequent risk of SIDS in the offspring. Furthermore, it appears that this risk is related, in particular, to alterations in brain development. The risk of dying of SIDS may thus, in reality, be confined to a limited number of infants with developmental changes in CNS function. Our findings of age-specific attenuation of hypoxic defense following nicotine exposure focus the attention on brain catecholamine metabolism as a potential target for adverse fetal and neonatal influences. To clarify the mechanisms of nicotine exposure on postnatal development of the control of respiration and cardiovascular control may thus offer insights into the ultimate mechanism of SIDS.

The effect of palatoplasty on airway patency and growth in infants with clefts and failure to thrive.

We monitored respiratory patterns, transcutaneous PO2 (tcPO2) and transcutaneous PCO2 (tcPO2) in three infants with clefts and severe failure to thrive. Unexplained dysphagia, muscular weakness and cardiac enlargement were other prominent symptoms. During sleep, repeated obstructive apneas accompanied by significant hypoxemia (tcPO2 less than 6 kPa) were recorded in all infants. Relief of the respiratory obstructions by means of nasopharyngeal intubation led to rapid growth catch-up and disappearance of the cardiac and gastrointestinal symptoms. This improvement in clinical condition was paralleled by an increase in transcutaneous PO2. Palatal closure according to Veau-Wardill-Killner led to a marked decrease in the number of airway obstructions and a significant improvement in blood gas homeostasis. The clinical condition of the infants was equally improved. We suggest that a respiratory investigation should be performed in infants with clefts and poor growth in spite of adequate caloric intake. Early closure of the palate should be considered in infants with signs of a respiratory failure.

[Patent ductus arteriosus. A common clinical problem in extremely premature infants]. / Oppetstående ductus arteriosus. Ett vanligt kliniskt problem för extremt underburna barn.

An analysis was made of the incidence and treatment regimen of symptomatic patent ductus arteriosus (PDA) in 95 preterm infants treated 1997-1999 in a level three intensive care unit in Stockholm. 47 infants (49 percent) had PDA. Of these 17 infants were managed conservatively (fluid restriction and diuretics), 13 were treated with indomethacin, 10 underwent primary surgical ligation and 7 were treated with indomethacin first and surgery later on. The proportion of infants given "active" therapy (surgery and/or indomethacin) rose from 50 percent in 1997 to 85 percent in 1999. In a stepwise multiple regression analysis low birthweight, septicaemia and need for mechanical ventilation were all independently associated with PDA.

[Fiberoptic endoscopy confirms the cause of upper respiratory obstruction in small children. The most common causes to referrals are sleep apnea syndrome and inspiratory stridor]. / Fiberskopi fastställer orsak till höga andningshinder hos små barn. Vanligaste remissorsakerna sömnapnésyndrom och inspiratorisk stridor.

Guidelines for the clinical investigation of young children with stridor and sleep apnea are presented. Clinical examination and flexible videolaryngoscopy performed in local anaesthesia are the most important diagnostic tools for this group of children. If the impairment is severe or an objective evaluation is needed the child should also undergo nocturnal polygraphic recording and lung function tests. Out of 43 children examined with flexible videolaryngoscopy 21 had positive findings, laryngomalacia being the most common diagnosis. Flexible videolaryngoscopy is a good complement to laryngoscopy under general anaesthesia. It can be performed as early as in the neonatal period.

Effects of theophylline on ventilatory response to hypoxic challenge.

The respiratory and arousal responses to mild hypoxia during quiet sleep were studied using inductive plethysmography and transcutaneous gas electrodes in 11 apnoeic infants before and after the administration of oral theophylline (3 mg/kg). Theophylline changed the ventilatory response to a more biphasic pattern--that is, ventilation decreased after an initial increase. The relative ventilatory slope (defined as the decrease in transcutaneous carbon dioxide tension (PCO2) in relation to the fall in transcutaneous oxygen tension (PO2)) decreased significantly after theophylline. Four infants were roused during hypoxia before theophylline administration compared with none after treatment. Theophylline abolished the periodic breathing induced by hypoxia in one of six infants. These findings suggest that methylxanthines may not, as previously thought, enhance the respiratory drive during hypoxia.

Snoring in infancy.

Obstructive sleep apnoea (OSAS) in infants is a risk factor for sudden infant death (SIDS). Snoring in a young child should raise suspicion of OSAS, and according to recent AAP guidelines, evaluation and polysomnographic studies are recommended in selected cases as the diagnostic test of choice. However, infants under 1 y of age are excluded from the guidelines, and interventions to prevent SIDS based on respiratory monitoring remains a matter of controversy. As often happens, the evidence we need most is usually scarce.

Sudden infant death and prevalence of whooping cough in the Swedish and Norwegian communities.

UNLABELLED: Whooping cough (WC) has been suggested to be a trigger factor for sudden infant death (SID), the proposed mechanism being unrecognised hypoxaemic episodes. In contrast to Norway, Sweden ceased its immunisation programme against Bordetella pertussis (BP) in 1979. We investigated the relation between SID mortality and the prevalence of BP during 1983 to 1988, by month, in the two ethnically and socially similar, bordering countries adopting different strategies towards WC. In addition, the greater Stockholm area was analysed. For both countries the prevalence of BP was collected from monthly reports by regional health officers. SID mortality rates were provided by the Norwegian Central Bureau of Statistics and the SID registry at the Swedish National Board of Health and Welfare. The relation between SID mortality rate and prevalence of WC, by month, was analysed by linear regression. In addition, the consistency of seasonal fluctuations was investigated by analysing the covariance between average, pooled, monthly values of the two variables. SID mortality rate followed significantly the monthly prevalence of BP in Sweden (P < 0.01) and Stockholm (P < 0.0001) during the study period. In Norway there was a significant correlation only during the epidemic outbreak of WC (P < 0.05), but not for the whole study period. When controlling for seasonality a significant correlation remained in the urban area of Stockholm (P < 0.05). CONCLUSION: It is suggested that covariations between WC and SID mortality rate may be related to transmission rate and immunisation status of the investigated population.