“To Die, To Sleep ...”A Discussion on SIDS

COL H. Joel SchmidtPediatric Pulmonology

SIDS - outline

ALTE not “near-miss SIDS”

SIDS background definition etiology control of breathing epidemiology avoidable risk factors

ALTE definition

frightening to the observer characterized by some combination of

apnea color change marked change in muscle tone choking gagging

(involves vigorous stimulation or resuscitation)

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

Causes

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

Work-Up

History History History History History History History

Home Monitor?

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

– severe ALTE– tracheostomy <18 months old– ISAM’s– twin of SIDS victim

not indicated– normal infant– asymptomatic premature infant

Questionable Risk Group

Sib of SIDS moderate ALTE

decision based risks, benefits, liabilities, and

limitations parent - provider decision

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

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

causes of infant death

Unknown

other

maternal complications RDS

prematurity

birth defects

<1 year old, 1992

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

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 sib

death– simultaneous death of twins

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

etiology - focused

developing nervous system developing immune system inherited metabolic disease changes in cardiac conduction

system changes in respiratory control non-accidental trauma

Baruch’s Observation

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

nail.”

CNS autopsy findings

increased gliosis increased brainstem dendritic

spine density delayed myelin maturation

epidemiologic studies

NICHD Cooperative Epidemiologic Study of SIDS Risk Factors

New Zealand Cot Death Study Avon Infant Mortality Study King County Washington SIDS

Study

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

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.”

NICHD SIDS Study - results

maternal factors inadequate prenatal care smoking anemia ISAM VD UTI

NICHD SIDS Study - results

other factors low birth weight inadequate post-natal care lack of breast feeding GI infections

NICHD SIDS Study - results

non-factors URI’s apnea of prematurity

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

New Zealand Study - results

significant avoidable risks prone sleeping position co-sleeping not breast fed maternal smoking

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

Avon Study - results

significant avoidable risks prone sleeping position thermal environment role of infection parental smoking

avoidable SIDS risk factors

prone sleeping position thermal environment parental smoking co-sleeping?

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

Infant Sleeping Position and SIDS Rate- 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

Infant Sleeping Position and SIDS Rate- Avon England

1987 1988 1989 1990 1991 19920

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

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

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.”

US 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

US 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

adverse effects of supine sleep

airway obstruction Pierre Robin syndrome

RDS 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)

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

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

thermal environment - studies

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

tog > controls mean ambient temp was 1.5

oC >

controls SIDS more likely to have home

heating

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

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

“And this woman’s son died in the night because she lay on it.”

1 Kings 3:19

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

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

co sleeping & SIDS

Questions breastfeeding and co-sleeping

relation infant safety (fall) adult sleeping surfaces (waterbed,

soft mattress)

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.

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.

AAP Recommendations:revised 12/96

The recommendations are for sleeping babies. Some “tummy time” while the baby is awake and observed is recommended.