Marc F. Collin
EPIDEMIOLOGY
Children have very poor survival rates from cardiac arrest.
PATHOPHYSIOLOGY
Children primarily develop cardiac arrest secondary to hypoxia from respiratory arrest or shock syndromes.
Almost all newborn resuscitations are secondary to respiratory causes.
Drug dosages, chest compression and respiratory rates, and equipment sizes vary according to the age and size of children.
SECURING THE AIRWAY
The airways of infants and children are much smaller than those of adults and have pronounced anatomic and functional differences.
The prominent occiput and relatively large tongue may lead to obstruction that may be relieved with mild extension of the head (sniffing position) and a chin lift or jaw thrust maneuver.
In the unconscious child who requires continuous jaw thrust or chin lift, an oral airway may be useful. Oral airways are inserted by direct visualization using a tongue blade.
Ventilation may be administered using a bag-valve-mask system. The minimum volume for ventilation bags for infants and children is 450 mL. Observe chest rise and auscultate breath sounds to ensure adequate ventilation.
The large and flaccid epiglottis is best displaced using a straight (Miller) laryngoscope blade. Use Miller 0 blade in preterm newborns and Miller 1 blade in term newborns.
Endotracheal tube (ET) size can be reasonably estimated using the formula: (16 + age in years)/4. In newborns <1 kg, use 2.5-mm ET; 1–2 kg, use 3.0-mm ET; 2–3 kg, use 3.5-mm ET; and >3 kg, use 3.5- to 4.0-mm ET.
The position of the tube at the lip is approximately 3 times the size of the tube (eg, 5.0x3 = 15 cm at the lip).
Tidal volume for children is 8–12 mL/kg.
If the child does not require hyperventilation, then the respiratory rate should be started at 40–60 breaths/min in newborns, 20 breaths/min for infants, 15 breaths/min for young children, and 10 breaths/min for adolescents.
Confirmation of endotracheal intubation is similar to that in adults: adequate chest rise, symmetric breath sounds, CO2 readings, vapor steam noted in ET, improved oxygenation, and clinical improvement.
The laryngeal mask airway (LMA) may be used if endotracheal intubation is not possible.
RAPID SEQUENCE INDUCTION
Rapid sequence induction is the intravenous administration of an anesthetic and a neuromuscular blocking agent to facilitate endotracheal intubation.
Preoxygenate the patient with 100% oxygen.
Atropine (0.02 milligram/kg; minimum dose = 0.1 milligram; maximum dose = 1 milligram) should be given to prevent reflex bradycardia in children less than 5 years old or in the older child or adolescent who requires a second dose of succinylcholine.
Cricoid pressure should be applied before paralysis and continued until successful intubation is confirmed. As cricoid pressure may occlude the pliable infant trachea, release pressure if intubation is difficult.
VASCULAR ACCESS
Vascular access is performed in the quickest, least invasive manner possible; peripheral vein (antecubital, hand, foot, or scalp) cannulation should be attempted first.
Intraosseous cannulation is a rapid, safe, and reliable method and may be used for administration of fluids, resuscitation medications, colloids, and blood.
Percutaneous central lines or saphenous vein cutdowns may also be used, but are more time consuming.
FLUIDS
In patients with hypovolemia/shock, intravenous iso-tonic fluid (ie, normal saline) boluses of 20 mL/kg should be given as rapidly as possible and should be repeated, depending on the clinical response.
If hypovolemia has been corrected and shock or hypotension persists, a pressor agent should be considered.
DRUGS
Proper drug dosages in children require knowledge of the patient’s weight. The use of a length-based system for estimating the weight of a child in an emergency situation may reduce dosage errors.
The rule of 6s may be used to quickly calculate continuous infusions of drugs such as dopamine and dobutamine. The amount of drug needed is 6 milligrams times the weight in kilograms added to a total volume of 100 mL D5W. This produces an infusion rate in milliliters per hour that is equal to the micrograms per kilogram per minute rate (ie, an infusion of 1 mL/h = 1 microgram/kg/min or 5 mL/h = 5 micrograms/kg/min).
Epinephrine is the only drug proven effective in cardiac arrest. It is indicated in pulseless arrest and in hypoxia-induced slow pulse rates that are unresponsive to oxygenation and ventilation.
The initial dose of epinephrine is 0.01 milligram/kg (0.1 mL/kg of 1:10,000 solution) IV/intraosseous or 0.05–05.0 milligram/kg (0.5–1 mL/kg of 1:10,000 solution) by the endotracheal route. Repeat dosing of epinephrine is recommended every 3–5 minutes for persistent arrest. Intratracheal route of epinephrine is inferior to intravascular route and should be used only if immediate vascular access is unavailable.
Glucose, 10%, given at 2 mL/kg generally corrects hypoglycemia. Repeat dose if hypoglycemia persists.
Sodium bicarbonate is no longer considered as a first-line resuscitation drug. It is recommended, if needed, only after effective ventilation is established, epinephrine is administered, and chest compressions to ensure circulation are provided.
Calcium is also not recommended in routine resuscitation, but may be useful in hyperkalemia, hypocal-cemia, and calcium channel blocker overdose.
DYSRHYTHMIAS
Dysrhythmias in infants and children are most often secondary to respiratory insufficiency and hypoxia, not primary cardiac causes as in adults. Specific attention to oxygenation and ventilation is paramount to dysrhythmia management in pediatrics.
The most common rhythm seen in a pediatric arrest is bradycardia progressing to asystole. Often, oxygenation and ventilation are sufficient to correct the situation. Epinephrine followed by atropine may be useful in bradycardia unresponsive to ventilation.
The most common dysrhythmia outside of the arrest situation is supraventricular tachycardia (SVT). It presents as a narrow complex tachycardia with rates typically between 250 and 350 beats/min. The recommended treatment for stable SVT in children is adenosine (0.1 milligram/kg) given simultaneously with a saline flush as rapidly as possible through a well-functioning IV Treatment for the unstable SVT patient is synchronized cardioversion (0.5–1 J/kg).
It is often difficult to differentiate between sinus tachycardia (ST) and SVT. Small infants may have ST with rates above 200 beats/min. Patients with ST may have a history of fever, dehydration, or shock. In ST, the heart rate typically varies with activity or stimulation.
DEFIBRILLATIONAND CARDIOVERSION
Ventricular fibrillation is rare in children. It is initially treated with defibrillation at 2 J/kg. If unsuccessful, repeat defibrillation energy is doubled to 4 J/kg.
If two attempts at defibrillation at 4 J/kg are unsuccessful, epinephrine should be given. Reassessment for treatable causes such as hypoxemia, hypovolemia, and metabolic acidosis should be performed.
Unstable tachyarrhythmias are treated with cardioversion at a dose of 0.5–1 J/kg.
The largest paddles that still allow contact of the entire paddle with the chest wall should be used. Electrode cream or paste is used to prevent burns. One paddle is placed on the right of the sternum at the second intercostal space, and the other is placed at the left midclavicular line at the level of the xiphoid.
NEONATAL RESUSCITATION
The initial decision to resuscitate an infant should be made within the first 30 seconds of delivery.
The first step is to maintain body temperature. The infant should be immediately dried and placed under a preheated radiant warmer.
Reserve immediate suctioning for babies who have obvious obstruction to spontaneous breathing or who require positive-pressure ventilation. If needed, the mouth followed by the nose should be gently suctioned with either a bulb syringe or a mechanical suction device.
The examiner should then rapidly assess heart rate, respiratory effort, color, and activity.
Infants who are apneic, or who are centrally cyan-otic, or whose heart rate is less than 100 beats/min should have positive pressure ventilation initiated with room air ventilation. If the heart rate is below 60 beats/min despite 30 seconds of effective positive-pressure ventilation, increase the oxygen concentration to 100% and begin chest compressions.
For infants who have not taken an initial breath, pressures over 30 cm H2O may be required to initially expand the lungs. However, infants, especially if preterm, may be more susceptible to developing pneumothoraces with higher pressures.
If no improvement is noted or if prolonged bagging is anticipated, endotracheal intubation should be performed.
If the heart rate is still below 60 beats/min after intubation and assisted ventilation, cardiac massage should be started at 90 compressions/min and coordinated with assisted ventilation in a 3:1 ratio.
If still unsuccessful in restoring heart rate >60 beats/min after at least another 45–60 seconds, epinephrine therapy should be initiated.
Drugs may be administered via ET, umbilical vein, or peripheral vein. However, the endotracheal route is not the preferred route and should only be utilized if vascular access cannot be readily achieved.
Umbilical vein catheterization is a fast, reliable method of obtaining vascular access. The umbilical catheter is placed in the umbilical vein and advanced to 10 to 12 cm or until blood return is noted.
IV epinephrine (0.01 milligram/kg of 1:10,000 solution) may be used for heart rates less than 60 beats/min despite adequate ventilation and oxygenation.
Sodium bicarbonate during neonatal resuscitation remains controversial. Adequate ventilation and circulation must be established prior to administration. Sodium bicarbonate (1 mEq/kg of a 4.2% solution = 0.5 mEq/L) should be given intravenously only.
PREVENTION OF MECONIUM ASPIRATION
Aspiration of meconium-stained amniotic fluid is associated with both morbidity and mortality.
Ten percent to 20% of all births will have meconium staining of the amniotic fluid.
If meconium is present, suctioning after delivery of the head and before delivery of the shoulders is no longer recommended.
If the infant is vigorous after delivery, the mouth and nose may be gently suctioned with no further intervention necessary.
If the infant is depressed after delivery, direct suctioning of the trachea should be performed by visualizing the trachea with a laryngoscope and suctioning via an endotracheal tube.
If at any time during this procedure the heart rate drops below 100 beats/min, positive pressure ventilation should be initiated.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 14, “Resuscitation of Neonates,” by Marc F. Collin; Chapter 15, “Resuscitation of Children,” by William E. Hauda II; and Chapter 29, “Pediatric Airway Management,” by Robert J. Vissers.