7. Resuscitation and Emergency Drugs
KeywordsNeonatal resuscitationIntraosseous needleAnesthetic anaphylaxisManagement of cardiac arrest in childrenPediatric advanced life support
Any resuscitation is stressful for the staff involved, but even more so if the patient is a child. There are many differences when a child is involved— the causes of arrest may be different, staff are usually less familiar with CPR in children than in adults, doses of drugs need to be calculated, and parents are often present at the resuscitation.
7.1 Cardiac Arrest in Children
The causes of cardiorespiratory arrest in children are different from those in adults because most pediatric arrests are secondary to decompensated respiratory or circulatory failure. Causes of respiratory failure include birth asphyxia, bronchiolitis, asthma and airway obstruction either from inhalation of a foreign body or other causes. Respiratory arrest may also occur secondary to neurological dysfunction caused by events such as convulsion or poisoning. A smaller proportion of cardiac arrests in children are the end result of circulatory failure, either due to fluid or blood loss, or maldistribution of fluid within the circulatory system. Fluid loss may be due to gastroenteritis, burns or trauma. Fluid maldistribution may be due to sepsis or anaphylaxis.
Although most arrests in children are asystolic arrests secondary to underlying cardiorespiratory failure, 5–15% of cardiac arrests in children are due to a primary cardiac event. Ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) may be the primary event in a significant number of arrests on wards in hospitals with a cardiology or cardiac surgery unit. VF in children may also be caused by electrolyte disturbances, drug toxicity and hypothermia.
Whatever the cause, by the time of cardiac arrest there will usually be significant hypoxia and acidosis leading to cell damage and death. The initial cardiac rhythm is often severe bradycardia or asystole. Management of a child needing resuscitation follows guidelines published by the relevant resuscitation council, including those from Australia, New Zealand, Europe and the UK, and the American Heart Association.
The outcome for out-of-hospital cardiac arrest is better in children than in adults. The outcome in infants however, is worse than adults because of the poor outcome from sudden infant death syndrome (SIDS). Children also have a better outcome for in-hospital arrest, reflecting the underlying causes of arrest.
Most cardiac arrests in children are the end result of decompensated respiratory or circulatory failure. Children with cardiac disease may also arrest from these causes, but are also more likely to have a primary cardiac arrest in VF or pulseless VT.
7.1.1 Perioperative Cardiac Arrest in Children
Etiology of pediatric cardiac arrest during anesthesia and surgery
Etiology of anesthesia-related arrest
Arrhythmia (16%), hemorrhage (9%), primary cardiac failure (9%), pulmonary hypertension (6%)
Airway obstruction (15%) including laryngospasm, Inability to intubate or ventilate, premature extubation
Medication related (7%)
Opioid, inhaled anesthetic, muscle relaxant
Central line related (3%)
Arrhythmia, cardiac tamponade
Blood products (1%)
Could not be determined (14%)
7.1.2 Basic Life Support
Cardiopulmonary resuscitation (CPR) should be started when cardiac arrest is suspected on the basis of lack of signs of circulation, which include lack of responsiveness (unconsciousness), lack of breathing, lack of movement, pallor or cyanosis. It is not necessary to attempt to feel a pulse before starting CPR as pulse detection by palpation is unreliable in children, even when performed by healthcare personnel. If an attempt is made to palpate a pulse, CPR should be started if a pulse has not been felt within 10 s or if there is uncertainty about its presence. Chest compressions should be commenced if the pulse is less than 60 per minute in an infant or less than 40 per minute in a child.
Palpating for a pulse is unreliable in children, even when performed by healthcare personnel. However, the most accurate sites for palpation in a child are the brachial and femoral arteries.
High quality CPR includes minimal interruption to chest compressions and ventilation. The compression rate during CPR for all ages is between 100 and 120 per minute. The ratio of compressions to ventilations is 15:2 for health-care rescuers.
Compression-only CPR from bystanders produces no survival benefit in out of hospital cardiac arrest in children, whereas standard ventilation-compression CPR does result in a survival benefit. Compression rates of less than 100 per minute or greater than 140 per minute, and inadequate compression depth are associated with lower rates of survival. Apart from an interruption to summon help, BLS must not be interrupted unless the child moves or takes a breath.
7.1.3 Advanced Life Support
Advanced life support is the management of an arrested or peri-arrest patient by a team of health care providers. It builds on BLS by adding monitoring of cardiac rhythm and treatment with defibrillation or drugs, and the use of an advanced airway such as the LMA or tracheal tube for ventilation.
An advanced airway (LMA or ETT) improves ventilation compared with mask ventilation, and reduces interruptions to chest compressions, which in turn improves cardiac output. Endotracheal intubation provides better protection of the airway and control of ventilation, however insertion of an LMA is quicker and may be performed by those with less experience in airway management.
During CPR with an advanced airway in place, chest compressions should be continuous at a rate of 100–120 per minute, and ventilation at a rate of 10–12 per minute. If spontaneous cardiac output returns, a ventilation rate of 12–20 per minute is used. Capnography can be used to confirm ventilation and optimize the quality of CPR. If exhaled CO2 (ETCO2) is not detected, the position of the ETT should be checked by direct laryngoscopy. Although the absence of CO2 may reflect tube misplacement, it may also be caused by very low pulmonary blood flow (such as immediately following adrenaline administration). If the ETCO2 is consistently less than 10–15 mmHg (2 kPA), efforts should be made to improve chest compressions. Hyperventilation should be avoided due to the risk of reducing cerebral blood flow. An abrupt, sustained increase in ETCO2 may occur just before the return of spontaneous circulation.
A capnogram and detectable ETCO2 are present during effective CPR in cardiac arrest in children. Absence of ETCO2 usually suggests the ETT is not in the trachea. Avoid hyperventilation and optimize the quality of chest compressions, aiming to keep ETCO2 above 15 mmHg (2 kPA).
Hundred percent oxygen is still recommended for the arrested patient. There is no evidence to support the use of lower oxygen concentrations during resuscitation, but the inspired oxygen concentration is titrated to limit hyperoxia once spontaneous circulation has returned.
For both shockable and non-shockable rhythms, chest compressions are briefly paused to assess the cardiac rhythm at intervals of 2 min. If there is an organized rhythm, a pulse or signs of circulation are checked for at the end of that 2 min cycle. If there is a return of spontaneous circulation, post resuscitation care is continued.
188.8.131.52 Non-shockable Rhythms
These are severe bradycardia, asystole, and pulseless electrical activity (PEA). Effective basic life support and treatment of the underlying cause of the arrest affect the outcome of the arrest. Drug treatment includes adrenaline (epinephrine) 10 μg/kg (0.1 mL/kg of 1:10,000 solution) via intravenous or intra-osseous route every 4 min (every second cycle) until the return of spontaneous circulation. Higher doses of intravascular adrenaline in children may worsen outcome. Adrenaline (epinephrine) may be given through a peripheral line in the emergency situation, followed by a normal saline flush. If the child has no existing IV access, the intraosseous route is recommended as it is rapid and effective (see below). A central venous catheter is recommended if the child has ongoing inotrope requirements. Drug delivery via a tracheal tube is no longer recommended.
Adequate ventilation and chest compression are the best way to reverse acidosis during arrest. Alkalizing agents are not used routinely in resuscitation care. However, in prolonged arrest, severe metabolic acidosis may be treated with sodium bicarbonate 1 mmol/kg. Sodium bicarbonate inactivates adrenaline, therefore the line must be flushed with saline if adrenaline is going to be given. Atropine has no role in the routine management of cardiac arrest.
184.108.40.206 Shockable Rhythms
These include VF and pulseless VT. They are treated with a single asynchronous DC shock of 4 J/kg (either monophasic or biphasic). External chest compression is then immediately restarted and continued for 2 min before re-analyzing the cardiac rhythm. All subsequent shocks should be 4 J/kg and interruptions to chest compression minimized. Chest compression is only paused to check the child’s pulse if there has been a change in cardiac rhythm, or if the child shows signs of life such as spontaneous movement or resumption of normal breathing. The risk of harm from unnecessary chest compressions is minimal, whereas interruption of chest compressions reduces the chance of a successful outcome.
Three ‘stacked’ shocks of 4 J/kg may be used in special circumstances such as witnessed arrests in the cardiac catheter lab, and ICU or theatre after cardiac surgery. Synchronized shocks of 0.5–2 J/kg are used for VT when there is hypotension but a pulse is present.
Paddles and defibrillation pads are equally effective. There are two sizes of defibrillation pad or paddle:
Adult-size (8–12 cm diameter) for adults and children >10 kg (approximately 1 year); and infant-size (4.5 cm diameter) for infants less <10 kg. Their placement should follow their manufacturer’s recommendations—usually antero-apical with one electrode placed below the clavicle just to the right of the sternum, and the other over the apex in the mid-axillary line. In infants, anterior-posterior placement should be used if the pads cannot be adequately separated in the standard position. If infant pads are not available then standard adult pads can be used in the anterior-posterior position. Defibrillator pads must not touch, and a gap of least 3 cm between electrodes is preferable.
220.127.116.11 Automated External Defibrillators (AEDs)
Recommendations for the use of automated external defibrillators (AEDs) in children
8 years and older
Use unmodified adult AED
Younger than 8 years
AED can be used, preferably with energy attenuation (if not available use standard AED)
Shockable rhythms are unusual in infants (particularly in out-of-hospital arrest), and the focus of resuscitation is on high quality CPR. However, there are rare case reports of successful use of AEDs in this age group. If an infant is arrested and in a shockable rhythm, current recommendations are to use an AED (preferably attenuated) if a manual defibrillator is not available.
Defibrillation of infants:
Manual defibrillator preferable, 4 J/kg
Infant pads, anterior-apical or antero-posterior—left side of lower sternum and below left scapula
Defibrillation of children 1–8 years:
Manual defibrillator, 4 J/kg
Adult pads, apical (mid axillary line) and to right of sternum below clavicle
Gap of more than 3 cm between edge of the two pads
18.104.22.168 Anti-arrhythmic Drugs
Defibrillation is the definitive treatment of VF and pulseless VT. Anti-arrhythmic drugs are given to stabilize the converted rhythm. Amiodarone 5 mg/kg IV/IO bolus, is the first-line agent and is given once, only after the third shock. Lidocaine 1 mg/kg may be used if amiodarone is not available. Magnesium (0.1–0.2 mmol/kg) is indicated in arrest due to polymorphic VT (torsades de pointes), or in the presence of hypomagnesaemia.
7.1.4 Estimation of Children’s Weight
In emergencies, it may not be practical to weigh children before starting treatment. Several methods have been devised to estimate children’s weight.
Formulae for weight of children based on age
Best Guess formula
UK Resuscitation Council
(2 × age) + 8
(2 × age) + 10
2 × (age + 4)
(3 × age) + 7
4 × age
2 × (age + 4)
Age × 3.3
Digital methods such as the Helix Weight Estimation Tool improve accuracy over other age-based estimates, as they allow calculations based on age in months, incorporate gender and body habitus, and reduce the risk of calculation errors. With these tools, the child’s data is entered and a page of values printed and included with the hospital notes. The page of values can be referred to in an emergency, and includes information about drug doses, ETT size, DC shock energy and fluid volumes. These are useful for children being cared for in non-pediatric hospitals if prepared at admission, before any emergency situation has begun.
Length- based methods such as the Broselow tape, are more accurate in estimation of weight and do not require the child’s age to be known. The tape is laid alongside the child and the length is used to estimate weight. Appropriate drug doses, ETT size and energy for DC shock are also indicated.
7.2 Reversible Causes of Cardiac Arrest in Children
During resuscitation, consider and correct precipitating causes that are reversible. These causes may be remembered as the 4H’s and 4T’s, as for adults:
Hypoxia is a prime cause of cardiac arrest in children and reversing it is essential to achieve a successful resuscitation.
Hypovolemia may be significant in trauma (due to hemorrhage), gastroenteritis, burns or surgical conditions such as intussusception and volvulus. Distributive shock may occur with septicemia or anaphylaxis. Initial resuscitation is with crystalloid 20 mL/kg boluses as required, followed by colloid or blood products as indicated. Most children are able to compensate very well for hypovolemia. Hypotension is usually a late and pre-terminal sign. By contrast, infants have a relatively fixed stroke volume and are less able to compensate for hypovolemia.
Hyperkalemia, hypokalemia, hypocalcemia and other metabolic abnormalities may be suggested by the child’s underlying condition, such as renal failure, or by ECG and blood tests taken during the arrest.
Hypothermia may be associated with drowning or environmental exposure. A low reading thermometer must be used to detect it, and active rewarming begun. VF may be resistant to defibrillation until the core temperature is increased to above 32 °C.
Tension pneumothorax and cardiac tamponade causing pulseless electrical activity may occur after trauma or surgery.
Toxic substances may be the result of accidental or deliberate overdose or iatrogenic error. Specific antidotes may be required and expert advice should be sought.
Local anesthetic toxicity may cause VT and VF. Resuscitation can be difficult and VF may be resistant to defibrillation, although outcome may be favorable if good quality CPR is quickly initiated. A bolus of lipid emulsion 2 mL/kg 20% lipid (such as Intralipid) followed by an infusion of 0.2 mL/kg/h may assist resuscitation.
Thromboembolic phenomena such as pulmonary embolism are less common in children than adults, but should still be considered. Children with Fontan circulation and cardiac conduits are at high risk of clot formation Spontaneous coronary thrombosis is very rare in children.
Successful resuscitation requires identification and treatment of the underlying cause.