Sudden Infant Sudden Infant Death SyndromeDeath Syndrome

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ObjectivesObjectives Describe possible etiologic Describe possible etiologic

mechanisms for mechanisms for suddensudden infantinfant deathdeath syndromesyndrome (SIDS). (SIDS).

Identify the risk factors for SIDS. Identify the risk factors for SIDS.

Understand the relationship Understand the relationship between apnea and SIDS. between apnea and SIDS.

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ALTE definitionALTE definition

frightening to the observerfrightening to the observer characterized by some combination of characterized by some combination of

apneaapnea color changecolor change marked change in muscle tonemarked change in muscle tone chokingchoking gagginggagging

Often elicits vigorous stimulation or Often elicits vigorous stimulation or resuscitationresuscitation

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FactoidsFactoids

prevalence from 0.05% to 6.0%prevalence from 0.05% to 6.0% most with ALTE do not die of SIDSmost with ALTE do not die of SIDS

combined prevalence of SIDS among other combined prevalence of SIDS among other family members of infants w/ ALTE = 11%family members of infants w/ ALTE = 11%

most with SIDS have never had ALTEmost with SIDS have never had ALTE 73 - 96% w/o ALTE73 - 96% w/o ALTE

median age at presentation = 2 monthsmedian age at presentation = 2 months slight male predominanceslight male predominance

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CausesCauses

GE RefluxGE Reflux 28%28% Neurologic problemsNeurologic problems 12%12% InfectionInfection 6% 6% Upper Airway ObstructionUpper Airway Obstruction 2% 2% Metabolic problemsMetabolic problems 2% 2% Cardiac problemsCardiac problems 1% 1% IdiopathicIdiopathic 47%47%

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Work-UpWork-UpHISTORYHISTORYHISTORYHISTORYHISTORY

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Home Monitor?Home Monitor?

1986 NIH Consensus Conference on 1986 NIH Consensus Conference on Infantile Apnea and Home MonitoringInfantile Apnea and Home Monitoring definitely indicated for:definitely indicated for:

severe ALTEsevere ALTE tracheostomy <18 months oldtracheostomy <18 months old ISAM’s (infants of substance abusing mothers)ISAM’s (infants of substance abusing mothers) twin of SIDS victimtwin of SIDS victim

not indicatednot indicated normal infantnormal infant asymptomatic premature infantasymptomatic premature infant

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Questionable Risk GroupQuestionable Risk Group

Sibling of SIDSSibling of SIDS Moderate ALTE – what are the Moderate ALTE – what are the

criteria for this…….not clearcriteria for this…….not clear

decision baseddecision based risks, benefits, liabilities, and risks, benefits, liabilities, and

limitationslimitations parent - provider decisionparent - provider decision

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Monitor RequirementsMonitor Requirements

home telephonehome telephone basic infant CPR instruction for all basic infant CPR instruction for all

caregiverscaregivers use and trouble shooting of monitor use and trouble shooting of monitor

for all caregiversfor all caregivers 24’ medical and technical back-up24’ medical and technical back-up

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SIDS backgroundSIDS background decreasing infant mortality this decreasing infant mortality this

centurycentury one category of infant death not one category of infant death not

decreasingdecreasing 1969 - “SIDS” title given1969 - “SIDS” title given Steinschneider A: Prolonged apnea Steinschneider A: Prolonged apnea

and the sudden infant death syndrome. and the sudden infant death syndrome. PediatricsPediatrics 1972; 50 (4): 646. 1972; 50 (4): 646.

1991 - definition expanded by NICHD1991 - definition expanded by NICHD

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causes of infant deathcauses of infant death

Unknown

other

maternal complications RDS

prematurity

birth defects

<1 year old, 1992

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Definition of SIDSDefinition of SIDSSudden death of an infant under 1 year Sudden death of an infant under 1 year

old that can not be explained despite:old that can not be explained despite: autopsy within 24’ incl. skeletal survey, autopsy within 24’ incl. skeletal survey,

tox and metabolic screenstox and metabolic screens prompt examination of the death scene prompt examination of the death scene

including interviews of household including interviews of household members by knowledgeable indevidualmembers by knowledgeable indevidual

review of the clinical history from review of the clinical history from caretaker, key medical providers and caretaker, key medical providers and medical recordsmedical records

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AAP Addition to AAP Addition to EvaluationEvaluation

Exam of the dead infant at a hospital Exam of the dead infant at a hospital ED by a child maltreatment ED by a child maltreatment specialistspecialist 1-5% of SIDS may be infanticide1-5% of SIDS may be infanticide clues to infanticideclues to infanticide

> 6 months old> 6 months old previous unexpected or unexplained sibling previous unexpected or unexplained sibling

deathdeath simultaneous death of twinssimultaneous death of twins

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Etiology - broadEtiology - broad no common etiology- multifactorialno common etiology- multifactorial final common pathway may be:final common pathway may be:

failure to arouse to cope w/ homeostatic failure to arouse to cope w/ homeostatic challengechallenge

abnormal development of the control of abnormal development of the control of cardiorespiratory systemscardiorespiratory systems

maldevelopment of fetal to newborn maldevelopment of fetal to newborn transition mechanismtransition mechanism

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Etiology - focusedEtiology - focused developing nervous systemdeveloping nervous system developing immune systemdeveloping immune system inherited metabolic diseaseinherited metabolic disease changes in cardiac conduction changes in cardiac conduction

systemsystem changes in respiratory controlchanges in respiratory control non-accidental traumanon-accidental trauma

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Baruch’s ObservationBaruch’s Observation

““If all you have is a hammer, If all you have is a hammer, everything looks like a nail.”everything looks like a nail.”

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Epidemiologic studiesEpidemiologic studies NICHD Cooperative Epidemiologic NICHD Cooperative Epidemiologic

Study of SIDS Risk FactorsStudy of SIDS Risk Factors New Zealand Cot Death StudyNew Zealand Cot Death Study Avon Infant Mortality StudyAvon Infant Mortality Study King County Washington SIDS StudyKing County Washington SIDS Study

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NICHD SIDS StudyNICHD SIDS Study Oct ‘78 - Dec '79Oct ‘78 - Dec '79 multicenter, population based, case multicenter, population based, case

controlledcontrolled 838 SIDS838 SIDS 1676 controls1676 controls

age-matched living - randomly selectedage-matched living - randomly selected age-matched living - matched for race age-matched living - matched for race

and low birth weightand low birth weight

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NICHD Study - NICHD Study - conclusionconclusion

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

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NICHD SIDS Study - NICHD SIDS Study - resultsresults

maternal factorsmaternal factors inadequate prenatal careinadequate prenatal care smokingsmoking anemiaanemia ISAMISAM VDVD UTIUTI

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NICHD SIDS Study - NICHD SIDS Study - resultsresults

other factorsother factors low birth weightlow birth weight inadequate post-natal careinadequate post-natal care lack of breast feedinglack of breast feeding GI infectionsGI infections

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NICHD SIDS Study - NICHD SIDS Study - resultsresults

non-factorsnon-factors URI’sURI’s apnea of prematurityapnea of prematurity

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New Zealand Cot Death New Zealand Cot Death StudyStudy

1987 - 19901987 - 1990 multicenter, prospective, case-multicenter, prospective, case-

controlledcontrolled covered 78% of all birthscovered 78% of all births

485 cot deaths485 cot deaths 1800 random controls - matched for 1800 random controls - matched for

post-natal agepost-natal age

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New Zealand Study - New Zealand Study - resultsresults

significant avoidable riskssignificant avoidable risks prone sleeping positionprone sleeping position co-sleepingco-sleeping not breast fednot breast fed maternal smokingmaternal smoking

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Avon Infant Mortality Avon Infant Mortality StudyStudy

1984 - 19921984 - 1992 Avon County in SW EnglandAvon County in SW England

pop. 940,000 with 13,000 births/yearpop. 940,000 with 13,000 births/year 1 coroner, 1 Peds Path, 3 OB units1 coroner, 1 Peds Path, 3 OB units

all unexpected deathsall unexpected deaths detailed history and conditionsdetailed history and conditions collection of bact, and virology specimenscollection of bact, and virology specimens 2 controls/death matched for age, Hx, 2 controls/death matched for age, Hx,

exam, and home exam, and home

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Avon Study - resultsAvon Study - resultssignificant avoidable riskssignificant avoidable risks prone sleeping positionprone sleeping position thermal environmentthermal environment role of infectionrole of infection parental smokingparental smoking

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Avoidable SIDS risk Avoidable SIDS risk factors factors

prone sleeping positionprone sleeping position thermal environmentthermal environment parental smokingparental smoking co-sleeping?co-sleeping?

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studies of infant sleep studies of infant sleep positionposition

> 20 retrospective studies> 20 retrospective studies odds ratio 1.9 - 12.7odds ratio 1.9 - 12.7 ? recall bias? recall bias

1 prospective study in high risk 1 prospective study in high risk infantsinfants 15 SIDS, 116 controls15 SIDS, 116 controls odds ratio 3.92 x’s higherodds ratio 3.92 x’s higher

2 intervention studies2 intervention studies 1 U.S. study 1 U.S. study

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Infant Sleeping Position and SIDS Infant Sleeping Position and SIDS RateRate

- Netherlands- Netherlands

0

10

20

30

40

50

60

70

% in

fan

ts

1965 1970 1975 1980 1985 1988 1990

prone sleep

SIDS rate

0

0.25

0.5

0.75

1.0

1.25

1.5

1.75

SID

S r

ate

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Infant Sleeping Position and SIDS Infant Sleeping Position and SIDS RateRate

- Avon England- Avon England

0

10

20

30

40

50

60

70

% in

fan

ts

1987 1988 1989 1990 1991 1992

prone sleep

SIDS rate

0

0.6

1.1

1.7

2.3

2.9

3.4

4.0

SID

S r

ate

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Infant Sleeping Position and SIDS Infant Sleeping Position and SIDS RateRate

- King County Washington- King County Washington

population based, case-controlled population based, case-controlled studystudy

Nov. 1992 - Oct. 1994Nov. 1992 - Oct. 1994 47 SIDS, 142 matched controls47 SIDS, 142 matched controls 57.4% of SIDS cases usually slept 57.4% of SIDS cases usually slept

prone vs./ 24.6% of controlsprone vs./ 24.6% of controls adjusted odds ratio = 3.12adjusted odds ratio = 3.12

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Infant Sleeping Position and SIDS Infant Sleeping Position and SIDS RateRate

- King County Washington- King County Washington

Conclusion:Conclusion:

“ “Prone sleep position was Prone sleep position was significantly associated with an significantly associated with an increased risk of SIDS among a increased risk of SIDS among a group of American infants.”group of American infants.”

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US SIDS Rate 1991 - ‘99US SIDS Rate 1991 - ‘99

year % prone rate deaths

‘91 1.30 5349

‘92 70 1.20 4891

‘93 59 1.17 4669

‘94 43 1.03 4073

‘95 29 0.87 3396

‘99 0.68 2648

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US SIDS Rate 1980 - ‘99US SIDS Rate 1980 - ‘99

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

'80 '82 '84 '86 '88 '90 '92 '94 '96 '98

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Adverse effects of supine Adverse effects of supine sleepsleep

airway obstructionairway obstruction Pierre Robin syndromePierre Robin syndrome

choking/aspiration choking/aspiration notnot a problem a problem Czech & Hong Kong dataCzech & Hong Kong data Netherlands interventional study dataNetherlands interventional study data 750 newborn deaths reviewed750 newborn deaths reviewed

only lethal episodes of aspiration occurred only lethal episodes of aspiration occurred in neurologically impaired (all were prone) in neurologically impaired (all were prone)

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Thermal environmentThermal environment well known association of SIDS & well known association of SIDS &

coldcold suggests hypothermiasuggests hypothermia no data showing low temp or less no data showing low temp or less

insulation are risk factorsinsulation are risk factors 2 controlled studies investigating tog2 controlled studies investigating tog

AvonAvon TasmaniaTasmania

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Thermal environment - Thermal environment - studiesstudies

Avon (risk increases 1.14/tog if > 8 tog)Avon (risk increases 1.14/tog if > 8 tog) SIDS slightly more heavily wrappedSIDS slightly more heavily wrapped SIDS more likely have heating left onSIDS more likely have heating left on 25% SIDS found with head covered 25% SIDS found with head covered

(no controls)(no controls) >10 tog + URI increased odds ratio to >10 tog + URI increased odds ratio to

51.551.5

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Thermal environment - Thermal environment - studiesstudies

Tasmania (28 SIDS c/w 54 controls)Tasmania (28 SIDS c/w 54 controls) mean insulation for SIDS was 1.3 tog mean insulation for SIDS was 1.3 tog

> controls> controls mean ambient temp was 1.5mean ambient temp was 1.5oo

C > C > controlscontrols

SIDS more likely to have home SIDS more likely to have home heatingheating

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Thermal environmentThermal environment- pathophysiologic - pathophysiologic

mechanismsmechanisms birth to 3 monthsbirth to 3 months

metabolic rate increases by 50%metabolic rate increases by 50% SQ fat increasesSQ fat increases peripheral vasomotor control becomes more peripheral vasomotor control becomes more

effectiveeffective >> 3 mo. metabolic rate markedly 3 mo. metabolic rate markedly

increases with virusincreases with virus < 3 mo. metabolic rate decreases or < 3 mo. metabolic rate decreases or

remains the same with virusremains the same with virus increased temp causes hypoventilationincreased temp causes hypoventilation

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Smoking & SIDSSmoking & SIDS prospective cohort studiesprospective cohort studies

highly significant + correlation between highly significant + correlation between parental smoking and SIDS (odds ratio parental smoking and SIDS (odds ratio >>2)2)

dose effectdose effect retrospective case controlsretrospective case controls

odds ratio for maternal smoking = 1.68odds ratio for maternal smoking = 1.68 odds ratio for paternal smoking = 1.39odds ratio for paternal smoking = 1.39 odds ratio if both smoke = 3.46odds ratio if both smoke = 3.46

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Co-sleepingCo-sleeping infants and children sleeping in contact or close infants and children sleeping in contact or close

proximity to their parentsproximity to their parents same bedsame bed rocked or held while sleepingrocked or held while sleeping parent & child close enough to hear feel or smell one parent & child close enough to hear feel or smell one

anotheranother common in:common in:

pre-industrial societiespre-industrial societies Far, Near, & Middle EastFar, Near, & Middle East La Leche LeagueLa Leche League

discouraged in Euro./Western societydiscouraged in Euro./Western society

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Co-sleeping & SIDSCo-sleeping & SIDS sleep data demonstrate overlapping, sleep data demonstrate overlapping,

partner induced arousalspartner induced arousals ? fosters development of optimal sleep pattern? fosters development of optimal sleep pattern ? gives infants practice arousing? gives infants practice arousing

New Zealand cot death studyNew Zealand cot death study increased in Maori Indiansincreased in Maori Indians

also highest poverty, drug use, smokingalso highest poverty, drug use, smoking

?evolved with & to offset neurologic ?evolved with & to offset neurologic immaturityimmaturity

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Co-sleeping & SIDSCo-sleeping & SIDS QuestionsQuestions

breastfeeding and co-sleeping relationbreastfeeding and co-sleeping relation infant safety (fall)infant safety (fall) adult sleeping surfaces (waterbed, soft adult sleeping surfaces (waterbed, soft

mattress)mattress)

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AAP Recommendations:AAP Recommendations:revised 12/96revised 12/96

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

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AAP Recommendations:AAP Recommendations:revised 12/96revised 12/96

Soft surfaces and gas trapping Soft surfaces and gas trapping objects should be avoided in the crib objects should be avoided in the crib or other sleeping surfaces. In or other sleeping surfaces. In particular, pillows or quilts should not particular, pillows or quilts should not be placed beneath a sleeping infant.be placed beneath a sleeping infant.

The recommendations are for healthy The recommendations are for healthy infants only. Some medical problems infants only. Some medical problems may prompt a pediatrician to may prompt a pediatrician to recommend prone sleep.recommend prone sleep.

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