Cardiopulmonary resuscitation (CPR) is concerned with the restoration of pulmonary and cardiovascular function, and the prevention of neurologic damage. Initially, it consists of artificial ventilation and artificial circulation by whatever means are immediately available. This is termed basic life support . Its object is to prevent clinical death from progressing to biologic death before other remedial measures (i.e., advanced life support ) can be instituted.
As in adults, heroic resuscitative efforts may not be indicated in children with lethal terminal disease. This is a decision that should be made in advance and clearly documented and communicated.
The overall success rate for pediatric CPR is possibly worse than for adults, especially if success is defined as long-term survival without neurologic deficit. A possible reason is that the majority of cardiac arrests in children result from hypoxemia. In such children, it must be assumed that by the time the heart has suffered hypoxia enough to stop it, the brain has also suffered hypoxia enough to severely damage it. This being so, every effort must be directed at detecting and treating any respiratory compromise before it leads to serious hypoxemia.
PREVENTION OF CARDIAC ARREST
Awareness of precipitating factors is essential in preventing cardiac arrest in children.
Common causes include:
Failure of ventilation:
Due to central depression, airway obstruction, or primary pulmonary disorders
Secondary to regurgitation and pulmonary aspiration. As a result of neurologic and neuromuscular disorders (i.e., residual neuromuscular block)
Toxicity (drugs, poisons, toxins).
Primary cardiac disorders. (These account for only a small percentage of cardiac arrests on the general wards of a pediatric hospital.)
Recognition of potential causes
Early recognition of respiratory failure
Special Hazards for Children
Anesthesiologists should constantly be aware of factors that may be insignificant in the adult but may rapidly be life-threatening in infants and children.
The upper airway may become obstructed by:
Laryngospasm (common); due to small amounts of mucus or blood or inadequate or unwisely planned anesthesia (see Chapter 4, page 92 ).
Hypertrophied adenoidal tissue and/or enlarged tonsils, which may completely block the airway.
The relatively large tongue, associated with:
Muscle flaccidity in the anesthetized patient
Inadvertent displacement or compression of submental soft tissue and tongue by the anesthesiologist’s fingers
Inadequate neck extension
Inadequate elevation of the mandible
Premature removal of an artificial airway
Regurgitated stomach contents—a common occurrence because of the frequency of feedings
Remember: Infants have large tongues and may be primarily nose-breathers. If the nasal airway is inadequate, an oral airway should be inserted without delay.
Ventilation may be compromised if the stomach becomes inflated, usually a result of
Excessive inflation pressures
Partial airway obstruction
After protecting the airway with an endotracheal tube, pass a No. 10 or 12 suction catheter and aspirate stomach contents to reduce the possibility of aspiration.
Blood volumes are relatively small—significant hypovolemia may develop rapidly.
Be prepared to give atropine to all young children who are scheduled for laryngoscopy/tracheal intubation or to receive cholinergic drugs (i.e., halothane, succinylcholine), or have surgery that may elicit dangerous reflexes. Vagal reflexes are brisk and may lead to cardiac arrest. The longer you delay giving atropine, the longer it will take to have effect. ( N.B. atropine does not correct hypoxemia.)
Always give 100% O 2 before intubating the trachea in children. (Desaturation occurs much more rapidly in children, particularly infants, than in adolescents.) Intubate the trachea as quickly and smoothly as possible.
Select the endotracheal tube size carefully, secure it firmly, and check its position; confirm EtCO 2 and listen to both sides of the chest. Position and support the tracheal tube so that it cannot kink. (These procedures are critical in children.)
Carefully maintain a patent airway and adequate ventilation.
Monitor the following constantly:
Heart and lung functions by stethoscope, ECG and NIBP.
SaO 2 and EtCO 2 (Do not disable alarms.)
Measure carefully all gases, vapors, and drugs; always read the drug label.
Measure fluid losses accurately and replace as indicated. (Even a small loss is significant in a small child). Ensure that you have a reliable, generous sized, IV route before you allow surgery to start.
Remember that rapid infusion of blood products may cause hyperkalemia or hypocalcemia (especially into a central vein in small infants).
Prevent unintentional pressure on the chest and abdominal wall from dressings, hands, surgical assistants leaning on drapes, and so on.
If problems arise, advise other members of the team (especially the surgeon) immediately.
Note: Cardiac arrest in the postanesthesia care unit (PACU) is as likely as in the operating room.
For all infants and all seriously ill children: do not extubate the trachea unless and until the child is reacting vigorously.
If possible, all children should be transported to the PACU in the lateral position, with the upper leg flexed at the hip and knee and the neck moderately extended (the tonsil or recovery position).
In the PACU:
Immediately monitor SaO 2 , NIBP and ECG.
Provide a full report to the PACU nursing staff regarding underlying medical problems, surgical problems, medication doses and time of administration, and anticipated possible PACU problems.
Ensure that the child remains safely positioned with a clear airway.
Order humidified O 2 by mask until the child is responding well.
Ensure that vital signs are recorded and reported to you.
Do not leave until you are assured vital signs are stable and have handed over care of your child to a nurse.
Before discharge from the PACU, ensure that the danger of drug-induced respiratory depression has passed and that the child is fully conscious.
Some neonates and infants need to be disturbed frequently to stimulate respiration.
All former preterm infants of less than 60 weeks conceptual age and those with a history of chronic respiratory disease should be monitored on an apnea alarm for at least 12 hours apnea-free or 24 hours ( Chapter 2, page 19 ).
Children with obstructive sleep apnea (OSA) require extended observation and monitoring and may be sensitive to the respiratory depressant effects of opioids (see Chapter 10, page 283 ).
Treatment of Arrhythmias
Arrhythmias that cause hemodynamic compromise or those that might progress to cardiac arrest must be promptly treated. The advice of a pediatric cardiologist should be obtained whenever this is possible.
Supraventricular Tachycardia (SVT)
SVT may be difficult to differentiate from sinus tachycardia, but the history and the heart rate (SVT rates greater than 220 bpm in infants or greater than 180 bpm in children) usually clarify this.
Early consultation with a pediatric cardiologist is recommended for hemodynamically stable VT. Vagal maneuvers (Valsalva maneuver or ice applied to face) are recommended as initial therapy. Adenosine may be administered and if this is unsuccessful amiodarone may be indicated (page 560 for dosing). If circulatory instability is present, immediate synchronized electrical cardioversion (0.5 to 1 joule/kg) is recommended.
Ventricular Tachycardia (VT) and Fibrillation (VF)
For VT with hypotension but with a palpable pulse immediate synchronized cardioversion is recommended. Children with less hemodynamic compromise should be assessed for the cause of the VT and may be sedated before cardioversion.
For pulseless VT and VF, very prompt defibrillation is recommended. If this is unsuccessful or VT recurs, amiodarone 5 mg/kg may be considered.
Non-shockable Rhythm (asystole & PEA (pulseless electrical activity))
Asystole and PEA are the most common ECG findings in cardiac arrest in infants and children. PEA is a cluster of slow, wide QRS complexes in the absence of palpable pulses. CPR should be continued, defibrillation is not indicated. Underlying causes should be sought.