The sudden death of an apparently healthy infant, who
is younger than 1 year of age, which is unexpected by history and which
remains unexplained after a thorough postmortem investigation (autopsy), and
where examination of the death scene failed to demonstrate an adequate cause
SIDS; Crib Death Syndrome.
In most countries, it is <1 per 1000 live births in the
last few years following the “Back to Sleep” programs. In the United
States alone, the incidence has been reduced (1998) to 0.53 per 1000 live
births. Previously, it was nearly 2 per 1000 live births.
Uncertain; probably multifactorial, involving
subtle cardiac, respiratory, and neurological abnormalities and
precipitating environmental factors. Current theories include prolonged
apnea secondary to immature neurorespiratory control, combined with fatigue secondary to
relative lack of type 1 fibers in the respiratory muscle, and sudden
arrhythmia secondary to prolonged QT interval on ECG. A higher risk has been
demonstrated in infants placed in a sleeping position to which they were
Diagnosed by exclusion only where cause of death remains
unexplained and should be considered after an adequate postmortem
examination that includes (a) an autopsy, (b) investigation of the scene and
circumstance of the death, and (c) exploration of the medical history of the
infant and the family.
A common scenario is that of a previously well
infant being put into a crib for a nap and then found dead some time later
by the parents. Cause of death remains unexplained after investigation. From
epidemiological studies, risk of SIDS is found to be increased with a
variety of factors. Demographic factors include the age of the infant (2 to 4 months),
male predominance, high birth order, lower socioeconomic status, and younger maternal age.
Antenatal factors include low birth weight, low gestational age, multiple pregnancies,
maternal smoking, and substance-abusing mother. Postnatal factors include parental
smoking, prone sleeping position, overheating of bedroom, soft mattress with excessive
wrappings, and recent respiratory tract infections. Beast-feeding appears to
have a protective effect from SIDS. By far, the most significant factor in
the last few years has been the avoidance of a prone sleeping position,
which has led to the reduction in the incidence of SIDS in many countries.
Obtain full perinatal medical history of
“apneic spells” in near-SIDS or SIDS siblings.
In case of near-SIDS or SIDS siblings
(particularly a SIDS twin), the risk of SIDS is unknown but presumed to be
increased after anesthesia. Therefore, the patient should have
cardiorespiratory monitoring for a 24-hour postoperative period or longer,
particularly if an opioid-based analgesia regimen is further utilized. It is
uncertain whether regional anesthesia techniques may lessen the risk of SIDS
postoperatively. There is the potential for an increased risk of apnea
during spontaneously breathing techniques, but this increase has not been
documented. The patient should be nursed in back position as much as possible
postoperatively. There are also recent suggestions that the use of the BIS monitor may
help to monitor these patients postoperatively. As an indicator of the level of
consciousness in these babies, it may help to prevent sudden infant death syndrome.