CPT® Code 99184

1. Indications

The initiation of selective head or total body hypothermia is indicated for critically ill neonates who meet specific clinical criteria. The following conditions warrant the procedure:

• Birth-related oxygen deprivation - This includes conditions such as hypoxic ischemic encephalopathy (HIE) and perinatal asphyxia, which result in brain injury due to insufficient oxygen supply during or around the time of birth.
• Signs of brain injury - The neonate must exhibit clinical signs that suggest neurological impairment, necessitating intervention to mitigate further damage.
• Documented metabolic acidosis - A cord blood pH of 7.0 or less indicates significant metabolic acidosis, which is a critical factor in determining the need for hypothermia.
• Base deficit - A base deficit of at least 12 mmol/L is required, indicating severe metabolic derangement that may benefit from hypothermic therapy.
• Multisystem organ dysfunction - The presence of dysfunction in multiple organ systems must be established, while excluding other potential causes of the clinical presentation.

2. Procedure

The procedure for initiating selective head or total body hypothermia involves several critical steps to ensure the safety and effectiveness of the treatment:

• Patient selection - A thorough review of clinical, imaging, and laboratory data is conducted to confirm that the neonate meets the criteria for hypothermia initiation.
• Confirmation of esophageal temperature probe location - An esophageal temperature probe is inserted to monitor the core body temperature accurately. The placement of this probe is verified through x-ray imaging to ensure it is correctly positioned.
• Evaluation of amplitude EEG - Amplitude integrated electroencephalography (aEEG) is performed to assess the brain's electrical activity, providing insights into the infant's neurological status during the cooling process.
• Supervision of controlled hypothermia - The healthcare team closely supervises the hypothermia process, ensuring that the infant is tolerating the cooling effectively and monitoring for any adverse reactions.
• Baseline laboratory values - Prior to initiating hypothermia, baseline laboratory tests are conducted, including serum electrolytes, blood gases, clotting time, and complete blood count (CBC) with hemoglobin levels.
• Induction of hypothermia - Hypothermia is induced by placing the infant on a cooling blanket or applying a cooling cap to the head. The target core body temperature is lowered to between 33.5 and 35 degrees Centigrade.
• Monitoring during therapy - The infant is closely monitored throughout the duration of the hypothermia therapy, which typically lasts around 72 hours, as well as during the re-warming phase to ensure safety and effectiveness.

3. Post-Procedure

After the initiation of hypothermia, the neonate requires careful monitoring and supportive care. The healthcare team must observe the infant for any signs of complications or adverse effects related to the cooling process. Continuous assessment of neurological status through aEEG and clinical evaluation is essential to determine the effectiveness of the therapy. Additionally, the infant's vital signs, temperature, and overall physiological parameters must be closely monitored during the re-warming phase to prevent any sudden changes that could impact recovery. The management of fluid balance and renal function is also critical, necessitating the use of urinary catheters to monitor urine output. Overall, the post-procedure care is aimed at ensuring the neonate's stability and optimizing outcomes following hypothermic therapy.