What is the workup for a hypothermic neonate?

From the Guidelines

For a hypothermic neonate, immediate attention is required to gradually rewarm the baby. The initial steps include:

Assessment and Stabilization

1. Assessment: Evaluate the neonate's overall condition, including vital signs, and determine the severity of hypothermia. Mild hypothermia is defined as a body temperature between 36°C and 36.4°C, moderate between 32°C and 35.9°C, and severe below 32°C.
2. Stabilization: Ensure the airway, breathing, and circulation (ABCs) are stable. Provide oxygen if necessary and maintain a patent airway.

Rewarming and Monitoring

1. Rewarming:
   • Mild Hypothermia: Use passive rewarming by placing the neonate in a warm room, removing wet clothing, and using blankets or a warm hat to prevent further heat loss.
   • Moderate to Severe Hypothermia: Active rewarming may be necessary. This can include the use of a radiant warmer or an incubator set at a higher temperature than the baby's body temperature, but not exceeding 37°C. Warm water baths or heated mattresses can also be used, but with extreme caution to avoid burns. According to 1, rewarming should be started, but there is insufficient evidence to recommend either rapid (≥0.5˚C/h) or slow (<0.5˚C/h) rates of rewarming.
2. Monitoring: Continuously monitor the neonate's temperature, aiming for a gradual increase. Also, monitor for signs of infection, as hypothermia can be a sign of sepsis in neonates. As stated in 1, frequent or continuous monitoring of temperature should be undertaken, particularly if using a supraphysiological set temperature point to accelerate the rewarming rate, because of the risk of causing hyperthermia.

Supportive Care and Laboratory Tests

1. Medications: There are no specific medications for hypothermia itself, but if the neonate shows signs of infection or other complications, appropriate antibiotics or other treatments should be initiated based on clinical judgment.
2. Laboratory Tests: Consider obtaining a complete blood count (CBC), blood culture, and other tests as indicated by the clinical presentation to rule out underlying infections or other conditions. Additionally, monitor blood glucose because there is a risk of hypoglycemia, as mentioned in 1.
3. Supportive Care: Ensure adequate hydration and nutrition. In cases of severe hypothermia or if the neonate shows signs of distress, consider consultation with a neonatologist for further management, which may include transfer to a neonatal intensive care unit (NICU) for closer monitoring and care. The association between hypothermia and neonatal mortality and morbidity, as discussed in 1, highlights the importance of prompt and careful management.

From the Research

Workup for Hypothermic Neonate

The workup for a hypothermic neonate involves several key steps, including:

• Assessment of the severity of hypothermia, with categorization into mild, moderate, or severe 2
• Evaluation for underlying causes of hypothermia, such as infection or respiratory distress 3, 2
• Monitoring of vital signs, including temperature, heart rate, and blood glucose levels 2, 4
• Implementation of rewarming strategies, which may include slow or rapid rewarming, depending on the severity of hypothermia and the individual patient's needs 5, 4

Rewarming Strategies

Rewarming strategies for hypothermic neonates are crucial, with different approaches recommended depending on the severity of hypothermia:

• Slow rewarming has been advocated as a safe and effective method for rewarming severely hypothermic newborns, as it replicates the normal physiological process and minimizes negative therapy impact 5
• Rapid rewarming may be as effective and safe as slow rewarming in the management of moderate to severe hypothermia in low-birth-weight pre-term neonates, with similar short-term neonatal outcomes 4

Clinical Outcomes

The clinical outcomes for hypothermic neonates depend on various factors, including the severity of hypothermia, the underlying cause, and the effectiveness of rewarming strategies:

• Hypothermic neonates are at increased risk of NICU transfer, sepsis evaluation, and antibiotic use, as well as blood glucose measurement and hypoglycemia 2
• The length of stay in the hospital may be longer for hypothermic neonates, highlighting the need for evidence-based and value-driven approaches to hypothermia management in this population 2