Hypothermia In Young Infants

Predicting Serious Bacterial Infections Among Hypothermic Infants in the Emergency Department

BACKGROUND

There is insufficient evidence to guide the initial evaluation of hypothermic infants. We aimed to evaluate risk factors for serious bacterial infections (SBI) among hypothermic infants presenting to the emergency department (ED).

METHODS

We conducted a multicenter case-control study among hypothermic (rectal temperature <36.5°C) infants ≤90 days presenting to the ED who had a blood culture collected. Our outcome was SBI (bacteremia, bacterial meningitis, and/or urinary tract infection). We performed 1:2 matching. Historical, physical examination and laboratory covariables were determined based on the literature review from febrile and hypothermic infants and used logistic regression to identify candidate risk factors.

RESULTS

Among 934 included infants, 57 (6.1%) had an SBI. In univariable analyses, the following were associated with SBI: age > 21 days, fever at home or in the ED, leukocytosis, elevated absolute neutrophil count, thrombocytosis, and abnormal urinalysis. Prematurity, respiratory distress, and hypothermia at home were negatively associated with SBI. The full multivariable model exhibited a c-index of 0.91 (95% confidence interval: 0.88-0.94). One variable (abnormal urinalysis) was selected for a reduced model, which had a c-index of 0.82 (95% confidence interval: 0.75-0.89). In a sensitivity analysis among hypothermic infants without fever (n = 22 with SBI among 116 infants), leukocytosis, absolute neutrophil count, and abnormal urinalysis were associated with SBI.

CONCLUSIONS

Historical, examination, and laboratory data show potential as variables for risk stratification of hypothermic infants with concern for SBI. Larger studies are needed to definitively risk stratify this cohort, particularly for invasive bacterial infections.

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.