7.12: Pediatric Cardiac Arrest

Paediatric arrest usually originates from a primary respiratory event causing hypoxia, hypercarbia and acidosis that result in bradyarrhythmias and eventually asystole. (The majority of adult arrests are due to a primary cardiac event). Primary cardiac arrest in children is rare.

The difference in the cause of the arrest is very important. As most pediatric arrests are due to a respiratory event, there is a longer pre arrest phase allowing time for recognition and treatment of the primary event before death. In pediatric life support, recognition and aggressive treatment of primary pulmonary events will improve survival.

Management

The immediate response to a pediatric arrest must be to clear the airway and ventilate the patient.

Causes of pediatric arrest include sudden infant death syndrome, trauma, near-drowning, upper airway obstruction, respiratory infections, congenital diseases and severe sepsis.

Airway

A clear airway is essential. The first action of the anesthetist must be to clear the airway. A simple head tilt and lifting the jaw forward will prevent obstruction by the tongue. The anesthetist must check for a foreign body obstructing the airway. Foreign bodies should be removed carefully under direct vision.

Breathing

A clear airway and adequate ventilation are the first priorities of pediatric resuscitation. If the child is not breathing the anesthetist must ventilate the child before performing any other procedure.

Breathing can be assessed by looking for chest movement, feeling for air movement and listening for breath sounds. If there is no chest movement then there is no ventilation. Always check that the airway is clear.

The tidal volume should be enough to raise the child’s chest. Excessive tidal volumes can cause gastric distension and regurgitation of gastric content.Expired air resuscitation will deliver 16% oxygen. Ventilation with high-inspired oxygen concentrations should be established as soon as possible. A self-inflating resuscitation bag with an oxygen reservoir can provide up to 90% oxygen concentration. (Self-inflating resuscitation bags can function without an oxygen source unlike an anaesthetic breathing system). Endotracheal intubation should be considered as an “elective” procedure. (Endotracheal size equals age/4 plus 4) The anesthetist should only have a couple of attempts of less than 30 seconds. Self-inflating bag and mask ventilation is usually adequate.

Circulation

Drugs can be given via intravenous, intraosseous routes or via the endotracheal tube.Drugs given by a peripheral route should be followed by a fluid flush to speed the onset of action. Several drugs can be given by the tracheal method, if no other method is available, including lignocaine, atropine, naloxone and adrenaline. There is little research as to their efficiency.

The speed of onset is the same for peripheral intravenous and intraosseous administered drugs. All drugs, including blood, can be given by the intraosseous route.The anesthetist can use a special short bevel needle, 18 gauge intravenous needle or spinal needle. The needle is inserted 1 to 2 cm below and medial to the tibial tuberosity on the medial surface of the tibia. It should be inserted at 75 degrees,directed towards the feet to avoid the epiphyseal plate. The anesthetist feels for a loss of resistance as the needle enters the medullary cavity. When the needle is in the marrow cavity it should remain upright without support, bone marrow can be aspirated and there is free flow of drugs and fluids.

Paediatric Cardiorespiratory arrest

Commence basic CPR with a compression to ventilation ratio of 30:2. Attach defibrillator/ECG monitor and assess the rhythm. Shockable VT/ pulseless VT should receive on DC shock of 2 J/kg followed by immediate CPR for 2 minutes and reassess Further single shocks should be delivered at 4 J/kg. During CPR, check electrodes,attempt intravenous access, correct reversible causes, consider intubation, vasopressor (adrenaline 10 µg/kg every 3 minutes), antiarrhythmics (amiodarone 5 mg/kg,lignocaine 1 mg/kg, magnesium 0.1-0.2 mmol/kg for torsades de pointes) and atropine 20µg/kg for bradycardia.For a witnessed arrest, give up to 3 stacked shocks (2,4,4 j/kg) at the first defibrillation attempt. Non shockable PEA/asystole requires adrenaline 10 µg/kg and CPR plus the same assessment and management during CPR as for shockable rhythms.