Prevalence of Invasive Bacterial Infection in Hypothermic Young Infants: A Multisite Study

Performance of Febrile Infant Decision Tools on Hypothermic Infants Evaluated for Infection

BACKGROUND

Given the lack of evidence-based guidelines for hypothermic infants, providers may be inclined to use febrile infant decision-making tools to guide management decisions. Our objective was to assess the diagnostic performance of febrile infant decision tools for identifying hypothermic infants at low risk of bacterial infection.

METHODS

We conducted a secondary analysis of a retrospective cohort study of hypothermic (≤36.0 C) infants ≤90 days of age presenting to the emergency department or inpatient unit among 9 participating sites between September 1, 2016 and May 5, 2021. Well-appearing infants evaluated for bacterial infections via laboratory testing were included. Infants with complex chronic conditions or premature birth were excluded. Performance characteristics for detecting serious bacterial infection (SBI; urinary tract infection, bacteremia, bacterial meningitis) and invasive bacterial infection (IBI; bacteremia, bacterial meningitis) were calculated for each tool.

RESULTS

Overall, 314 infants met the general inclusion criteria, including 14 cases of SBI (4.5%) and 7 cases of IBI (2.2%). The median age was 5 days, and 68.1% of the infants (214/314) underwent a full sepsis evaluation. The Philadelphia, Boston, IBI Score, and American Academy of Pediatrics Clinical Practice Guideline did not misclassify any SBI or IBI as low risk; however, they had low specificity and positive predictive value. Rochester and Pediatric Emergency Care Applied Research Network tools misclassified infants with bacterial infections.

CONCLUSIONS

Several febrile infant decision tools were highly sensitive, minimizing missed SBIs and IBIs in hypothermic infants. However, the low specificity of these decision tools may lead to unnecessary testing, antimicrobial exposure, and hospitalization.

Time to Positive Blood and Cerebrospinal Fluid Cultures in Hypothermic Young Infants

BACKGROUND AND OBJECTIVE

Hypothermia in young infants may be secondary to an invasive bacterial infection. No studies have explored culture time-to-positivity (TTP) in hypothermic infants. Our objective was to compare TTP of blood and cerebrospinal fluid (CSF) cultures between pathogenic and contaminant bacteria in hypothermic infants ≤90 days of age.

METHODS

Secondary analysis of a retrospective cohort of 9 children's hospitals. Infants ≤90 days of age presenting to the emergency department or inpatient setting with hypothermia from September 1, 2017, to May 5, 2021, with positive blood or CSF cultures were included. Differences in continuous variables between pathogenic and contaminant organism groups were tested using a 2-sample t test and 95% confidence intervals for the mean differences reported.

RESULTS

Seventy-seven infants met inclusion criteria. Seventy-one blood cultures were positive, with 20 (28.2%) treated as pathogenic organisms. Five (50%) of 10 positive CSF cultures were treated as pathogenic. The median (interquartile range [IQR]) TTP for pathogenic blood cultures was 16.8 (IQR 12.7-19.2) hours compared with 26.11 (IQR 20.5-48.1) hours for contaminant organisms (P < .001). The median TTP for pathogenic organisms on CSF cultures was 34.3 (IQR 2.0-53.7) hours, compared with 58.1 (IQR 52-72) hours for contaminant CSF organisms (P < .186).

CONCLUSIONS

Our study is the first to compare the TTP of blood and CSF cultures between pathogenic and contaminant bacteria in hypothermic infants. All pathogenic bacteria in the blood grew within 36 hours. No difference in TTP of CSF cultures between pathogenic and contaminant bacteria was detected.

Clinician Management Practices for Infants With Hypothermia in the Emergency Department

BACKGROUND

Young infants with serious bacterial infections (SBI) or herpes simplex virus (HSV) infections may present to the emergency department (ED) with hypothermia. We sought to evaluate clinician testing and treatment preferences for infants with hypothermia.

METHODS

We developed, piloted, and distributed a survey of ED clinicians from 32 US pediatric hospitals between December 2022 to March 2023. Survey questions were related to the management of infants (≤60 days of age) with hypothermia in the ED. Questions pertaining to testing and treatment preferences were stratified by age. We characterized clinician comfort with the management of infants with hypothermia.

RESULTS

Of 1935 surveys distributed, 1231 (63.6%) were completed. The most common definition of hypothermia was a temperature of ≤36.0°C. Most respondents (67.7%) could recall caring for at least 1 infant with hypothermia in the previous 6 months. Clinicians had lower confidence in caring for infants with hypothermia compared with infants with fever (P < .01). The proportion of clinicians who would obtain testing was high in infants 0 to 7 days of age (97.3% blood testing for SBI, 79.7% for any HSV testing), but declined for older infants (79.3% for blood testing for SBI and 9.5% for any HSV testing for infants 22-60 days old). A similar pattern was noted for respiratory viral testing, hospitalization, and antimicrobial administration.

CONCLUSIONS

Testing and treatment preferences for infants with hypothermia varied by age and frequently reflected observed practices for febrile infants. We identified patterns in management that may benefit from greater research and implementation efforts.