Medication
National Neonatal Resuscitation Guidelines
Drugs are rarely indicated in neonatal resuscitation (see Inverted Pyramid).
Adequate ventilation is the most important step in correcting bradycardia. If a baby’s heart rate remains below 60 bpm with adequate ventilation and chest compressions, then medication may be needed.
The medications used in neonatal resuscitation include adrenaline (epinephrine), sodium bicarbonate, naloxone and volume expanders.
Naloxone
Naloxone is discussed in the section on basic neonatal life support.
Adrenaline (Epinephrine)
Adrenaline is the most important medication used in neonatal resuscitation. Adrenaline is given if the baby’s heart rate remains below 60 bpm despite adequate ventilation and chest compressions. Adrenaline is especially important if there is no detectable heartbeat. Adrenaline causes vasoconstriction, which improves circulation and oxygen delivery to the heart and brain. Adrenaline also improves the contractility of the heart (inotropic effect) and increases the heart rate (chronotropic effect).
The recommended dose of adrenaline is 0.1 to 0.3ml/kg of a 1:10 000 solution (0.01 to 0.03mg/kg). It is necessary to dilute the 1:1 000 ampoule of adrenaline with 9mls of normal saline. The adrenaline can be given intravenously through an umbilical venous line. The volume of adrenaline administered is small, so you can dilute the adrenaline further with 2mls of normal saline, or follow the injection of the adrenaline solution with 2mls of normal saline.
Repeat the dose every 3 to 5 minutes as needed. There is no good evidence for the routine use of higher doses of adrenaline in neonatal resuscitation. Higher doses intravenously are not recommended and may be associated with an increased risk of hypertension, myocardial damage and a worsened neurological outcome.
Recent studies have suggested that adrenaline at the above doses, given via the ET tube, is ineffective. Administration of a single higher dose via the ET tube (up to 0.1mg/kg) 1ml/kg of a 1:10 000 dilution, can be considered while IV access is being established, but is of unproven benefit and may be potentially harmful. The IV route should then be used.
Bicarbonate
Bicarbonate should not be used routinely in neonatal resuscitation. It causes hyperosmolarity and increases the amount of CO2 in the blood, which may be harmful to the function of the heart and brain. In preterm infants the rapid infusion of sodium bicarbonate may cause intraventricular haemorrhage. Bicarbonate may be used in a prolonged arrest unresponsive to other resuscitation.
It should only be given after establishing good ventilation and circulation. If possible, a blood gas should be done to confirm the presence of a severe metabolic acidosis. A dose of 2mls of 4.25% solution/kg can be given by slow intravenous push, over about 2 minutes. (Dilute the 8.5% sodium bicarbonate solution with an equal volume of sterile water.) Do not give bicarbonate via the ET tube, as it is caustic.
Volume expansion
Volume expanders may be needed to resuscitate a baby who is hypovolaemic. Think of hypovolaemia if there is a history of blood loss, the baby is shocked and pale, with poor perfusion and weak pulses, and has not responded to other resuscitation. This is uncommon in neonatal resuscitations and volume expansion is, therefore, seldom required. Normal saline 10ml/kg is given intravenously via the umbilical venous line over several minutes.
Avoid rapid infusions of bigger volumes of volume expanders as these may cause fluid overload and intraventricular haemorrhage in asphyxiated newborns, especially preterm infants.