Sudden Infant Death Syndrome

1. Sudden Infant Death Syndrome

2. Objectives • Describe possible etiologic mechanisms for suddeninfantdeathsyndrome (SIDS). • Identify the risk factors for SIDS. • Understand the relationship between apnea and SIDS.

3. ALTE definition • frightening to the observer • characterized by some combination of • apnea • color change • marked change in muscle tone • choking • gagging • Often elicits vigorous stimulation or resuscitation

4. Factoids • prevalence from 0.05% to 6.0% • most with ALTE do not die of SIDS • combined prevalence of SIDS among other family members of infants w/ ALTE = 11% • most with SIDS have never had ALTE • 73 - 96% w/o ALTE • median age at presentation = 2 months • slight male predominance

5. Causes • GE Reflux 28% • Neurologic problems 12% • Infection 6% • Upper Airway Obstruction 2% • Metabolic problems 2% • Cardiac problems 1% • Idiopathic 47%

6. Work-Up HISTORY HISTORY HISTORY HISTORY HISTORY

7. Home Monitor? • 1986 NIH Consensus Conference on Infantile Apnea and Home Monitoring • definitely indicated for: • severe ALTE • tracheostomy <18 months old • ISAM’s (infants of substance abusing mothers) • twin of SIDS victim • not indicated • normal infant • asymptomatic premature infant

8. Questionable Risk Group • Sibling of SIDS • Moderate ALTE – what are the criteria for this…….not clear • decision based • risks, benefits, liabilities, and limitations • parent - provider decision

9. Monitor Requirements • home telephone • basic infant CPR instruction for all caregivers • use and trouble shooting of monitor for all caregivers • 24’ medical and technical back-up

10. SIDS background • decreasing infant mortality this century • one category of infant death not decreasing • 1969 - “SIDS” title given • Steinschneider A: Prolonged apnea and the sudden infant death syndrome. Pediatrics 1972; 50 (4): 646. • 1991 - definition expanded by NICHD

11. causes of infant death <1 year old, 1992

12. Definition of SIDS Sudden death of an infant under 1 year old that can not be explained despite: • autopsy within 24’ incl. skeletal survey, tox and metabolic screens • prompt examination of the death scene including interviews of household members by knowledgeable indevidual • review of the clinical history from caretaker, key medical providers and medical records

13. AAP Addition to Evaluation • Exam of the dead infant at a hospital ED by a child maltreatment specialist • 1-5% of SIDS may be infanticide • clues to infanticide • > 6 months old • previous unexpected or unexplained sibling death • simultaneous death of twins

14. Etiology - broad • no common etiology- multifactorial • final common pathway may be: • failure to arouse to cope w/ homeostatic challenge • abnormal development of the control of cardiorespiratory systems • maldevelopment of fetal to newborn transition mechanism

15. Etiology - focused • developing nervous system • developing immune system • inherited metabolic disease • changes in cardiac conduction system • changes in respiratory control • non-accidental trauma

16. Baruch’s Observation “If all you have is a hammer, everything looks like a nail.”

17. Epidemiologic studies • NICHD Cooperative Epidemiologic Study of SIDS Risk Factors • New Zealand Cot Death Study • Avon Infant Mortality Study • King County Washington SIDS Study

18. NICHD SIDS Study • Oct ‘78 - Dec '79 • multicenter, population based, case controlled • 838 SIDS • 1676 controls • age-matched living - randomly selected • age-matched living - matched for race and low birth weight

19. NICHD Study - conclusion • “None of the risk factors documented are of sufficient strength to enable identification of SIDS infants prior to their death. Instead a descriptive profile has emerged that associates several maternal, neonatal, and postnatal factors with increased SIDS risk.”

20. NICHD SIDS Study - results maternal factors • inadequate prenatal care • smoking • anemia • ISAM • VD • UTI

21. NICHD SIDS Study - results other factors • low birth weight • inadequate post-natal care • lack of breast feeding • GI infections

22. NICHD SIDS Study - results non-factors • URI’s • apnea of prematurity

23. New Zealand Cot Death Study • 1987 - 1990 • multicenter, prospective, case-controlled • covered 78% of all births • 485 cot deaths • 1800 random controls - matched for post-natal age

24. New Zealand Study - results significant avoidable risks • prone sleeping position • co-sleeping • not breast fed • maternal smoking

25. Avon Infant Mortality Study • 1984 - 1992 • Avon County in SW England • pop. 940,000 with 13,000 births/year • 1 coroner, 1 Peds Path, 3 OB units • all unexpected deaths • detailed history and conditions • collection of bact, and virology specimens • 2 controls/death matched for age, Hx, exam, and home

26. Avon Study - results significant avoidable risks • prone sleeping position • thermal environment • role of infection • parental smoking

27. Avoidable SIDS risk factors • prone sleeping position • thermal environment • parental smoking • co-sleeping?

28. studies of infant sleep position • > 20 retrospective studies • odds ratio 1.9 - 12.7 • ? recall bias • 1 prospective study in high risk infants • 15 SIDS, 116 controls • odds ratio 3.92 x’s higher • 2 intervention studies • 1 U.S. study

29. Infant Sleeping Position and SIDS Rate- Netherlands 1.75 SIDS rate 1.5 1.25 1.0 0.75 0.5 0.25 0

30. Infant Sleeping Position and SIDS Rate- Avon England 4.0 SIDS rate 3.4 2.9 2.3 1.7 1.1 0.6 0

31. Infant Sleeping Position and SIDS Rate- King County Washington • population based, case-controlled study • Nov. 1992 - Oct. 1994 • 47 SIDS, 142 matched controls • 57.4% of SIDS cases usually slept prone vs./ 24.6% of controls • adjusted odds ratio = 3.12

32. Infant Sleeping Position and SIDS Rate- King County Washington Conclusion: “Prone sleep position was significantly associated with an increased risk of SIDS among a group of American infants.”

33. US SIDS Rate 1991 - ‘99

34. US SIDS Rate 1980 - ‘99

35. Adverse effects of supine sleep • airway obstruction • Pierre Robin syndrome • choking/aspiration not a problem • Czech & Hong Kong data • Netherlands interventional study data • 750 newborn deaths reviewed • only lethal episodes of aspiration occurred in neurologically impaired (all were prone)

36. Thermal environment • well known association of SIDS & cold • suggests hypothermia • no data showing low temp or less insulation are risk factors • 2 controlled studies investigating tog • Avon • Tasmania

37. Thermal environment - studies Avon (risk increases 1.14/tog if > 8 tog) • SIDS slightly more heavily wrapped • SIDS more likely have heating left on • 25% SIDS found with head covered (no controls) • >10 tog + URI increased odds ratio to 51.5

38. Thermal environment - studies Tasmania (28 SIDS c/w 54 controls) • mean insulation for SIDS was 1.3 tog > controls • mean ambient temp was 1.5oC > controls • SIDS more likely to have home heating

39. Thermal environment- pathophysiologic mechanisms • birth to 3 months • metabolic rate increases by 50% • SQ fat increases • peripheral vasomotor control becomes more effective • > 3 mo. metabolic rate markedly increases with virus • < 3 mo. metabolic rate decreases or remains the same with virus • increased temp causes hypoventilation

40. Smoking & SIDS • prospective cohort studies • highly significant + correlation between parental smoking and SIDS (odds ratio >2) • dose effect • retrospective case controls • odds ratio for maternal smoking = 1.68 • odds ratio for paternal smoking = 1.39 • odds ratio if both smoke = 3.46

41. Co-sleeping • infants and children sleeping in contact or close proximity to their parents • same bed • rocked or held while sleeping • parent & child close enough to hear feel or smell one another • common in: • pre-industrial societies • Far, Near, & Middle East • La Leche League • discouraged in Euro./Western society

42. Co-sleeping & SIDS • sleep data demonstrate overlapping, partner induced arousals • ? fosters development of optimal sleep pattern • ? gives infants practice arousing • New Zealand cot death study • increased in Maori Indians • also highest poverty, drug use, smoking • ?evolved with & to offset neurologic immaturity

43. Co-sleeping & SIDS • Questions • breastfeeding and co-sleeping relation • infant safety (fall) • adult sleeping surfaces (waterbed, soft mattress)

44. AAP Recommendations:revised 12/96 • Placing infants to sleep supine carries the lowest risk of SIDS and is preferred. However, a side position carries a significantly lower risk than a prone position. If a side position is used, place the lower arm forward to reduce the risk of the infant rolling onto his or her stomach.

45. AAP Recommendations:revised 12/96 • Soft surfaces and gas trapping objects should be avoided in the crib or other sleeping surfaces. In particular, pillows or quilts should not be placed beneath a sleeping infant. • The recommendations are for healthy infants only. Some medical problems may prompt a pediatrician to recommend prone sleep.