What is the step by step treatment and assessment of perinatal asphyxia?

Step-by-Step Assessment and Treatment of Perinatal Asphyxia

For newborns ≥35 weeks with perinatal asphyxia, begin resuscitation with room air (21% oxygen) rather than 100% oxygen, focus primarily on establishing effective ventilation, and use a 3:1 compression-to-ventilation ratio if chest compressions become necessary. 1

Initial Assessment (First 60 Seconds - "The Golden Minute")

Assess three vital characteristics simultaneously: 1

• Heart rate (primary indicator): Auscultate precordial pulse; umbilical pulse palpation acceptable but may underestimate rate 1
• Respirations: Determine if apneic, gasping, or breathing (labored vs unlabored) 1
• Tone: Assess muscle tone 1

Apply pulse oximetry probe to right hand/wrist BEFORE connecting to instrument for faster, more reliable readings; this provides preductal oxygen saturation values 1

Initial Stabilization Steps

Complete within the first 60 seconds: 1

1. Provide warmth immediately - hypothermia increases oxygen consumption and worsens outcomes 2
2. Position airway - clear only if necessary; routine suctioning is NOT recommended even with meconium unless infant is non-vigorous 1
3. Dry the infant 1
4. Stimulate by drying 1

Critical pitfall: Do NOT perform routine endotracheal suctioning in vigorous infants born through meconium-stained fluid; evidence does not support this practice 1

Oxygen Administration Strategy

For term infants (≥35 weeks) requiring respiratory support: 1

• Start with 21% oxygen (room air) - strong recommendation against starting with 100% oxygen 1
• Titrate oxygen concentration using pulse oximetry to match normal transition values 1
• Healthy term infants start at 60% saturation and take 10 minutes to reach 90% 1
• Only increase oxygen concentration if heart rate fails to improve or oxygenation remains unacceptable despite effective ventilation 1

Rationale: High oxygen concentrations cause free radical formation and cellular toxicity; meta-analyses show decreased mortality when resuscitation is initiated with air versus 100% oxygen 1

Ventilation (Primary Intervention)

Ventilation is the cornerstone of neonatal resuscitation since asphyxia is the predominant cause of cardiovascular collapse: 1

Indications for positive pressure ventilation (PPV): 1

• Apnea or gasping respirations
• Heart rate <100 bpm despite initial steps
• Persistent labored breathing or cyanosis

Technique: 1

• Use bag-mask ventilation initially
• Consider endotracheal intubation if bag-mask ventilation is ineffective or prolonged ventilation is anticipated
• Most critical factor for success: achieving effective lung aeration and ventilation 1

Monitor response by heart rate increase - this is the most sensitive indicator of successful intervention 1

Chest Compressions

Indications: Heart rate remains <60 bpm despite adequate ventilation for 60 seconds 1

Technique: 1

• Use 2-thumb, hands-encircling-chest method (preferred technique)
• Compression-to-ventilation ratio: 3:1 (90 compressions:30 ventilations per minute) 1
• Compress at least one-third anterior-posterior chest diameter 1
• Coordinate compressions with ventilations

Rationale for 3:1 ratio: Asphyxia requires significant focus on ventilation; fluid-filled lungs at birth must be aerated, and higher ratios may decrease minute ventilation 1

Exception: If arrest is known to be of primary cardiac etiology (not asphyxia), consider 15:2 ratio 1

When chest compressions are needed, consider increasing FiO2 toward 100%, though evidence shows no clear advantage for ROSC or survival with 100% versus 21% oxygen during CPR 1

Medications and Fluid Administration

Epinephrine indications: Heart rate remains <60 bpm despite adequate ventilation AND chest compressions 1

Epinephrine dosing: 1

• IV route (preferred): 0.01-0.03 mg/kg - administer as soon as IV access obtained 1
• Endotracheal route: 0.05-0.1 mg/kg (higher dose required, less effective) 1
• Establish umbilical venous access for IV administration 1

Volume expansion: Consider if evidence of hypovolemia or shock unresponsive to other measures 1

Post-Resuscitation Management

For infants with evolving moderate to severe hypoxic-ischemic encephalopathy: 1

• Therapeutic hypothermia is recommended - must be initiated within 6 hours of birth 1
• Transfer to neonatal intensive care facility with multidisciplinary capabilities 1
• Use standardized scoring systems (e.g., Thompson score) to assess encephalopathy severity 3

Supportive care priorities in first 48 hours: 4

• Maintain normothermia 4
• Monitor and correct blood glucose - hypoglycemia worsens brain injury 4
• Maintain normal blood pressure for age 4
• Optimize oxygenation - avoid both hypoxemia and hyperoxemia 4
• Treat seizures - phenobarbital is drug of choice 4

Critical monitoring: 4

• Continuous vital signs
• Neurologic examination using standardized grading (Levene or Sarnat classification)
• Assess for multi-organ dysfunction (kidneys, liver, lungs)

Reassessment and Decision Points

Evaluate response after each intervention: 1

• Heart rate is the primary indicator of successful resuscitation 1
• Reassess every 30-60 seconds
• Progress to next step only if current intervention is ineffective

Consider stopping resuscitation: If heart rate remains undetectable for 10 minutes despite appropriate resuscitation efforts 1

Common Pitfalls to Avoid

• Do not delay effective ventilation - this is the most critical intervention 1
• Do not start with 100% oxygen in term infants 1
• Do not use compression-only CPR for asphyxiated neonates - ventilation is essential 1
• Do not routinely suction vigorous infants born through meconium 1
• Do not miss the therapeutic window for hypothermia - must begin within 6 hours 1
• Do not assume normal color indicates adequate oxygenation - use pulse oximetry 1