HYPOXIC ISCHEMIC ENCEPHALOPATHY CARE

Medical Care (hypoxic ischemic encephalopathy):
Treatment of seizures is an essential component of management. Seizures are generally self-limited to the first days of life but may significantly compromise other body functions, such as maintenance of ventilation, oxygenation, and blood pressure. Additionally, seizures should be treated early and be well controlled, since even asymptomatic seizures (ie, seen only on EEG) may continue to injure the brain. Seizures should be treated with phenobarbital or lorazepam; phenytoin may be added if either of these medications fails to control the seizures.

No specific therapy for HIE exists; after seizure control, supportive care remains the cornerstone of management. The elements of supportive care are as follows:
• Maintain adequate ventilation, perfusion, and metabolic status; most infants with HIE need ventilatory support during the first week.
• Prevent hypoxia, hypercapnia, and hypocapnia; the latter is due to inadvertent hyperventilation, which may lead to severe hypoperfusion of the brain.
• Maintain the blood gases and acid-base status in the physiological ranges including partial pressure of arterial oxygen (PaO2), 80-100 mm Hg; partial pressure of arterial carbon dioxide (PaCO2), 35-40 mm Hg; and pH, 7.35-7.45.
• Maintain the mean BP above 35 mm Hg (for term infants). Dopamine or dobutamine can be used to maintain adequate cardiac output.
• Fluid, electrolyte, and nutritional status should be monitored and corrected and adequate calories and proteins provided.
o Avoid hypoglycemia or hyperglycemia, as both are known to cause brain injury.
o In the first 2 days of life, restrict intravenous fluids to two thirds of the daily requirement for gestational age and nursing environment in light of the high frequency of acute tubular necrosis and IADH.
o Individualize fluid and electrolyte therapy on the basis of clinical course, changes in weight, urine output, and results of serum electrolyte and renal function studies. When infants begin to improve, urinary output increases, and fluid administration must be adjusted. Similarly, in high-output renal tubular failure, the fluid volume and electrolyte composition need to be adjusted. For infants on high-frequency ventilators, the administered fluid volumes must be increased since in those infants, venous return may be impaired, affecting cardiac preload.

Surgical Care (hypoxic ischemic encephalopathy):
In cases of posterior cranial fossa hematoma, surgical drainage may be lifesaving if no additional pathologies are present.

Consultations (hypoxic ischemic encephalopathy):
• A pediatric neurologist should help assist in the management of seizures, interpretation of EEG, and overall care of the infant with HIE. The neurologist should also work with the primary care physician to address long-term disabilities.
• A developmental specialist also can help plan for long-term assessments and care.

Diet (hypoxic ischemic encephalopathy):
In most cases (particularly in moderately severe and severe HIE), the infant is restricted to nothing by mouth (NPO) during the first 3 days of life or until the general level of alertness and consciousness improves. Begin trophic feeding with dilute formula or expressed breast milk, about 5 mL every 3-4 hours. Monitor abdominal girth and the composition of stools and for signs of gastric retention; any of these may be an early indicator of necrotizing enterocolitis, for which infants with perinatal asphyxia are at high risk. Individualize increments in feeding volume and composition.

Providing standard intensive care support, correcting metabolic acidosis, limiting fluid intake to two-thirds the maintenance volume for the first 3-4 days, and seizure control are the main elements of treatment. Anticonvulsants are the only specific drugs used often in this condition. Treat seizures early and control them as fully as possible. Even asymptomatic seizures (ie, seen only on EEG) may continue to injure the brain.

Drug Category: Anticonvulsants -- Used to control seizures.

Drug Category: Cardiovascular (inotropic) agents -- Increase BP and combat shock. Drugs in this category act primarily by increasing systemic vascular resistance, cardiac contractility, and stroke volume, thus increasing cardiac output. Most inotropic agents also have dose and gestational age-dependent effects on vessels, particularly those of the renal and GI systems. For the most part, these effects are beneficial but, at higher doses, the systemic side effects may be unpredictable. No clear information is available on the effects of these drugs on CBF in neonates.