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Increased susceptibility to infection in hypothermic children: possible role of acquired neutrophil dysfunction
Insights
Therapeutic hypothermia in children, while controlling cerebral edema, increases infection risk. Lower body temperatures impair neutrophil (PMN) function, hindering bacterial elimination and raising infection susceptibility.
Area of Science:
- Immunology
- Pediatric Critical Care
Background:
- Therapeutic hypothermia is used to manage cerebral edema in children.
- Infectious complications have been noted in children treated with hypothermia.
Observation:
- Children treated with hypothermia (30°C) experienced infections like Haemophilus influenzae pneumonia and Streptococcus pneumoniae sepsis.
- Neutrophil (PMN) function is critical for combating bacterial infections.
Findings:
- In vitro studies demonstrated impaired neutrophil migration, phagocytosis, and metabolic activation at 30°C.
- Neutrophil dysfunction was significant, with reduced chemotaxis, staphylococcal ingestion, and superoxide production.
Implications:
- Clinical observations of increased infection risk during hypothermia are supported by in vitro findings.
- Hypothermia-induced neutrophil dysfunction may predispose patients to secondary bacterial infections.
- Further research into mitigating infection risk during therapeutic hypothermia is warranted.
Abstract:
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.