Increased susceptibility to infection in hypothermic children: possible role of acquired neutrophil dysfunction.

The addition of hypothermia to regimens to control cerebral edema in children at our institution has been associated with a substantial incidence of infectious complications. Of the 13 children maintained at 30 degrees C to prevent cerebral edema, 3 developed Haemophilus influenzae pneumonia and 2 developed Streptococcus pneumoniae sepsis (one with pneumonia). The importance of neutrophil (PMN) function for elimination of bacterial pathogens prompted in vitro studies of PMN function at clinically attainable hypothermic temperatures. Neutrophils at 30 degrees C had significantly less ability to migrate towards a chemotactic stimulus (45 +/- 10% inhibition; P less than 0.02), to ingest staphylococci (22 +/- 5% inhibition; P less than 0.01) and to be metabolically activated as measured by superoxide production (35 +/- 10% inhibition; P less than 0.01) or by chemiluminescence (18 +/- 8% inhibition; P less than 0.05). These in vitro findings support the clinical observation that persons with decreased body temperature may be at an increased risk for bacterial infections secondary to PMN dysfunction.