Cardiac Arrest and Arrhythmias

1

What is the most common cause of cardiac arrest in children?

Respiratory failure. In sharp contrast to adults, cardiopulmonary arrest in infants and children is most often associated with hypoxia, respiratory failure, and respiratory arrest. While arrest in adults is often triggered by myocardial ischemia and dysrhythmias, children typically have no primary cardiac dysfunction. A child in cardiac arrest must be supported with immediate bag-mask ventilation with high concentrations of oxygen and high-quality cardiopulmonary resuscitation (CPR). Reversible causes of cardiopulmonary arrest in children can be seen in Table 33.1 .

2

What are the most common initial arrhythmias seen in children in cardiac arrest?

Most episodes of cardiac arrest in infants and children are associated with a terminal rhythm of bradycardia or pulseless electrical activity (PEA), which, if untreated, progresses to asystole. As a child becomes more and more hypoxic, the heart slows down and becomes bradycardic until no pulse is felt and the child is in cardiac arrest.

3

What is the exception to the arrhythmia progression outlined in the previous question?

Apparent sudden cardiac collapse.

4

How does the initial action for a solo responder for an unresponsive child differ from that for an adult?

If you are alone and find an unresponsive child under 8 years old, provide 1 minute of CPR first before calling for additional emergency services.

5

How do you define high-quality CPR?

Push hard (≥1/3 of anteroposterior diameter of the chest) and fast (100–120 compressions/minute), allowing complete chest recoil. Minimize interruptions in compressions. Avoid excessive ventilation. Rotate compressor every 2 minutes, or sooner if fatigued. If no advanced airway, 15:2 compression-ventilation ratio.

6

What factors are important to consider when assessing a pediatric patient’s heart rate?

• Patient age

• History of congenital heart disease or cardiac surgery. These patients may have underlying conduction abnormalities and heart rate should be evaluated with regard to their baseline heart rate and rhythm.

• Level of activity

• Body temperature

Normal heart rates in children can be found in Table 33.2 .

7

Where do you check for pulses in infants and children?

Brachial artery in infants to 12 months of age, which is located inside the upper arm midway between the elbow and shoulder. Carotid or femoral artery in children over 1 year of age.

8

What rhythm “abnormalities” can be normal in children?

15%–25% of children can have sinus arrhythmia, ectopic atrial rhythm, wandering pacemaker, and junctional rhythm.

9

How is bradycardia defined in neonatal and pediatric patients?

Pediatric Advanced Life Support defines bradycardia as a heart rate less than 60 beats per minute.

10

What is symptomatic bradycardia?

Bradycardia with one or more of the following: poor pulses, inadequate perfusion, hypotension, or abnormal respirations.

11

What are some reversible causes of bradycardia in children?

• Hypoxia

• Hydrogen excess (acidosis)

• Hyperkalemia

• Hypothermia

• Heart block. May be seen in children with a history of cardiac surgery

• Toxic exposures. Includes organophosphates (nerve agents, pesticides), calcium channel blockers, beta-blockers, clonidine, opioids

• Trauma, particularly with significant head injury and increased intracranial pressure