Birth asphyxia and neonatal hypoxic-ischaemic injury
Birth asphyxia describes failure to initiate and sustain breathing at birth. Hypoxic-ischaemic encephalopathy (HIE) is the neurological syndrome that may follow reduced oxygen and blood flow around birth. It is an emergency: effective ventilation, circulation, glucose, temperature and seizure management must begin immediately while the cause and severity are clarified.
Do not wait for an Apgar score or cord-gas result before ventilating a newborn who is apnoeic, gasping or persistently bradycardic.
Causes and risk factors
- Placental abruption, uterine rupture, cord prolapse/compression and severe maternal hypotension.
- Obstructed or prolonged labour, malpresentation, shoulder dystocia and difficult operative delivery.
- Maternal hypoxia, seizures, severe anaemia, infection, diabetes or sedative/opioid exposure.
- Prematurity, congenital anomaly, fetal growth restriction and severe meconium aspiration.
Immediate assessment and resuscitation
- Warm, dry, position airway, stimulate and assess breathing and heart rate.
- If apnoeic/gasping or heart rate below 100/min, provide effective positive-pressure ventilation with a correctly fitted mask and observe chest movement.
- Reassess heart rate; correct mask seal, airway position and ventilation technique before escalating.
- If heart rate remains below 60/min despite effective ventilation, begin coordinated chest compressions with ventilation and follow the neonatal algorithm for oxygen, vascular access and adrenaline.
- After stabilisation, monitor oxygen saturation, temperature, glucose, perfusion, urine output and neurological status.
Assessing HIE
Look for altered consciousness, abnormal tone, weak or absent suck, poor feeding, abnormal posture, seizures, apnoea, unequal pupils and abnormal reflexes. Stage severity using a validated neurological examination (for example, Sarnat-based assessment) and repeat because signs evolve. Record cord pH/base deficit when available, but do not use one value alone to label injury.
Investigations
- Blood glucose immediately and repeatedly; correct hypoglycaemia.
- Blood gas, lactate, electrolytes, calcium, magnesium, renal/liver function, full blood count and coagulation studies.
- Blood culture and sepsis evaluation when infection is possible; start antibiotics if clinically indicated.
- Amplitude-integrated EEG or conventional EEG for seizures and subclinical status.
- Neuroimaging: cranial ultrasound initially where available; MRI with diffusion when stable and timing is appropriate.
- Chest radiograph only when respiratory disease, aspiration or tube position needs evaluation.
Supportive care
Airway and breathing
Maintain airway, oxygenate using monitored targets, use CPAP or ventilation for respiratory failure and avoid both hypoxia and hyperoxia. Confirm tube position clinically and radiographically when intubated.
Circulation
Assess perfusion, pulses, blood pressure, lactate and urine output. Treat hypovolaemia cautiously with appropriate fluids/blood; use inotropes for myocardial dysfunction or persistent shock under specialist guidance.
Glucose, electrolytes and fluids
Prevent hypoglycaemia, correct calcium/electrolyte abnormalities, avoid fluid overload and monitor renal function. Restrict or adjust fluids when renal injury or cerebral oedema is suspected.
Seizures
Check glucose, calcium, magnesium and infection. Treat clinically significant seizures promptly with the current neonatal protocol; use EEG to detect electrographic seizures and reassess treatment response.
Therapeutic hypothermia
For selected term or near-term infants with evidence of significant perinatal hypoxia and moderate/severe HIE, controlled therapeutic hypothermia started within the recommended early window may reduce disability and death. It must be delivered in an equipped unit with strict temperature, cardiorespiratory, glucose, coagulation and neurological monitoring. Do not improvise uncontrolled cooling; refer urgently to a centre with a protocol.
Nutrition and developmental care
Withhold oral feeds during instability or severe encephalopathy; provide safe expressed breast milk when ready, using tube/cup feeding if coordination is poor. Protect sleep, minimise painful stimulation, support skin-to-skin when stable and involve parents. Arrange hearing, vision, motor, feeding, seizure and developmental follow-up before discharge.
Complications and prognosis
- Seizures, cerebral oedema, respiratory failure, pulmonary hypertension and myocardial dysfunction.
- Acute kidney injury, hepatic injury, coagulopathy, necrotising enterocolitis and hypoglycaemia.
- Long-term cerebral palsy, epilepsy, developmental delay, feeding/swallowing difficulty, hearing/vision impairment and behavioural problems.
- Prognosis depends on severity, duration, neurological course, EEG/MRI and multisystem injury; avoid deterministic counselling from Apgar alone.
References
- SlideShare: Birth asphyxia.
- WHO: Perinatal asphyxia.
- Current neonatal resuscitation and HIE cooling protocols.
