Sudden Infant Death Syndrome (SIDS)

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 for death.

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 unaccustomed.

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.

Aminophylline and caffeine citrate have been used in some centers to decrease the incidence of apneas in near-SIDS infants postoperatively.