The differentiation of
SIDS from accidental or inflicted
suffocation may be impossible without corroborating findings from the death scene or autopsy or in the absence of a confession from a perpetrator. Pulmonary intra-alveolar
hemorrhage (PH) has been proposed as a potential clue to
suffocation, but none of the previous studies on this topic have limited
SIDS cases to those who were in a safe sleep environment, in which all were found supine and alone on a firm surface with their heads uncovered. Our aims are to: (1) compare PH in
SIDS cases found in a safe sleep environment to a control group comprised of infants whose deaths were attributed to accidental or inflicted
suffocation and (2) assess the effect of age,
CPR, and postmortem interval (PMI), with regard to the severity of PH in this subset of safe-sleeping
SIDS cases. We conducted a retrospective study of all postneonatal cases accessioned by the Office of the Medical Examiner in San Diego County, California who died of
SIDS or
suffocation between 1999 and 2004. A total of 74 cases of
sudden infant death caused by
SIDS (34 cases as defined above, comprising 8% of the total
SIDS cases), accidental
suffocation (37), and inflicted
suffocation (3) from the San Diego
SIDS/SUDC Research Project database were compared using a semiquantitative measure of pulmonary intra-alveolar
hemorrhage. The most severe (grade 3 or 4) PH occurred in 35% of deaths attributed to
suffocation, but in only 9% of the
SIDS cases. Age, duration of
CPR attempts and PMI had no effect on the severity of PH in
SIDS. Our results indicate that the severity of PH cannot be used independently to differentiate
SIDS from
suffocation deaths. Each case must be evaluated on its own merits after thorough review of the medical history, circumstances of death, and postmortem findings.