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(For neonatal resuscitation, see Perinatal Problems: Neonatal Resuscitation.)
Cardiopulmonary resuscitation (CPR) is an organized, sequential response to cardiac arrest, including
Prompt initiation of chest compression and early defibrillation (when indicated) are the keys to success. Speed, efficiency, and proper application of CPR determine successful outcome; the rare exception is profound hypothermia caused by cold water immersion, when successful resuscitation may be accomplished even after prolonged arrest (up to 60 min).
Overview
Guidelines for health care professionals from the American Heart Association are followed (see Fig. 1: Cardiac Arrest: Adult comprehensive emergency cardiac care. ). If a person has collapsed with possible cardiac arrest, a rescuer first establishes unresponsiveness and confirms absence of breathing or the presence of only gasping respirations. Then, the rescuer calls for help. Anyone answering is directed to activate the emergency response system (or appropriate in-hospital resuscitation personnel) and, if possible, obtain a defibrillator. If no one responds, the rescuer first activates the emergency response system and then begins basic life support by giving 30 chest compressions at a rate of 100/min and then opening the airway (lifting the chin and tilting back the forehead) and giving 2 rescue breaths. The cycle of compressions and breaths is continued (see Cardiac Arrest: CPR Techniques for Health Care Practitioners ) without interruption; preferably each rescuer is relieved every 2 min. When a defibrillator (manual or automated) becomes available, a person in ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) is given an unsynchronized shock. If the cardiac arrest is witnessed and a defibrillator is on the scene, a person in VF or VT is immediately defibrillated; early defibrillation may promptly convert VF or pulseless VT to a perfusing rhythm. Defibrillation is further discussed on discussed in Cardiac Arrest: Airway and Breathing.
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Table 1
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 | | |
| CPR Techniques for Health Care Practitioners |
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Age Group
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One-Rescuer CPR*
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Two-Rescuer CPR
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Breath Size
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Adults and children > 8 yr
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2 breaths (1 sec each) after every 30 chest compressions at 100/min
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2 breaths (1 sec each) after every 30 chest compressions at 100/min†
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Each breath about 500 mL (caution against hyperventilation)
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Children 1–8 yr
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2 breaths (1 sec each) after every 30 chest compressions at 100/min
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2 breaths (1 sec each) after every 15 chest compressions at 100/min†
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Smaller breaths than for adults (enough to make chest rise)
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Infants (< 1 yr)
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2 breaths (1 sec each) after every 30 chest compressions at 100/min
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2 breaths (1 sec each) after every 15 chest compressions at 100/min†
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Only small puffs from the rescuer's cheeks
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*For a single lay rescuer, compression-only CPR is now recommended.
†Breaths are given without stopping chest compressions.
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For children, unless collapse is sudden and witnessed, the first step if no one answers the call for help is to do 5 cycles of CPR before activating the emergency response system.
Airway and Breathing
In a change from previous recommendations, opening the airway is given 2nd priority (see Respiratory Arrest: Clearing and Opening the Upper Airway) after beginning chest compressions.
Mouth-to-mouth (adults and children) or combined mouth-to-mouth-and-nose (infants) rescue breathing or bag-valve-mask ventilation is begun for asphyxial cardiac arrest. If available, an oropharyngeal airway may be inserted. Cricoid pressure is no longer recommended.
If abdominal distention develops, the airway is rechecked for patency and the amount of air delivered during rescue breathing is reduced. Nasogastric intubation to relieve gastric distention is delayed until suction equipment is available because regurgitation with aspiration of gastric contents may occur during insertion. If marked gastric distention interferes with ventilation and cannot be corrected by the above methods, patients are positioned on their side, the epigastrium is compressed, and the airway is cleared.
When qualified providers are present, an advanced airway (endotracheal tube or supraglottic device) is placed without interruption of chest compression as described under Airway Establishment and Control (see Respiratory Arrest: Airway Establishment and Control). A breath is given every 6 to 8 sec (8 to 10 breaths/min) without interrupting chest compression. However, chest compression and defibrillation take precedence over endotracheal intubation. Unless highly experienced providers are available, endotracheal intubation may be delayed in favor of ventilation with bag-valve-mask, laryngeal mask airway, or similar device.
Circulation
Chest compression
In witnessed cardiac arrest, defibrillation, if available immediately, precedes chest compression. In an unresponsive patient whose collapse was unwitnessed, the trained rescuer should immediately begin external (closed chest) cardiac compression, followed by rescue breathing. Chest compressions must be interrupted as little as possible (eg, for intubation, central IV catheter placement, or transport). A compression cycle should consist of 50% compression and 50% release. Mechanical chest compression devices are available; these devices are no more effective than properly executed manual compressions but can minimize effects of performance error and fatigue and can be helpful during patient transport.
Ideally, external cardiac compression produces a palpable pulse with each compression, although cardiac output is only 20 to 30% of normal. However, palpation of pulses during chest compression is difficult, even for experienced clinicians, and often unreliable. End-tidal CO2 monitoring provides a better estimate of cardiac output during chest compression; patients with inadequate perfusion have little venous return to the lungs and hence a low end-tidal CO2. Normal-sized, light-responsive pupils signal adequate brain circulation and oxygenation. Light-responsive but dilated pupils may indicate inadequate cerebral oxygenation, although brain injury may not have occurred. However, persistently dilated, nonreactive pupils do not prove brain injury or death because adrenergic drugs, especially epinephrine and atropine, or cataracts may modify pupil size and reaction. Restoration of spontaneous breathing or eye opening indicates restoration of spontaneous circulation (ROSC).
Open-chest cardiac compression may be effective, but its use is restricted to patients after penetrating chest injuries, shortly after cardiac surgery (ie, within 48 h), in cases of cardiac tamponade, and most especially after cardiac arrest in the operating room when the patient's chest is already open. However, thoracotomy requires training and experience and is best done only within these limited indications.
Complications of chest compression
Laceration of the liver is a rare but potentially serious (sometimes fatal) complication and is usually caused by compressing the abdomen below the sternum. Rupture of the stomach (particularly if the stomach is distended with air) is also a rare complication. Delayed rupture of the spleen is very rare. An occasional complication, however, is regurgitation followed by aspiration of gastric contents, causing life-threatening aspiration pneumonia in resuscitated patients.
Costochondral separation and fractured ribs often cannot be avoided because it is important to compress the chest deeply enough to produce sufficient blood flow. Fractures are quite rare in children because of the flexibility of the chest wall. Bone marrow emboli to the lungs have rarely been reported after external cardiac compression, but there is no clear evidence that they contribute to mortality. Lung injury is rare, but pneumothorax after a penetrating rib fracture may occur. Serious myocardial injury caused by compression is very unlikely, with the possible exception of injury to a preexisting ventricular aneurysm. Concern for these injuries should not deter the rescuer from doing CPR.
Monitor and IV
ECG monitoring is established to identify the underlying cardiac rhythm. An IV line is started; 2 lines minimize the risk of losing IV access during CPR. Large-bore peripheral lines in the antecubital veins are preferred. In adults, if a peripheral line cannot be established, a subclavian or internal jugular central line can be placed provided it can be done without stopping chest compression (often difficult). Intraosseous and femoral lines (see Approach to the Critically Ill Patient: Intraosseous Infusion) are the preferred alternatives, especially in children. Femoral vein catheters (preferably long catheters advanced centrally) are practical because CPR does not need to be stopped and they have less potential for lethal complications; however, they may have a lower rate of successful placement because no discrete femoral arterial pulsations are available to guide insertion.
The type and volume of fluids or drugs given depend on the clinical circumstances. Usually, IV 0.9% saline is given slowly (sufficient only to keep an IV line open); vigorous volume replacement (crystalloid and colloid solutions, blood) is required only when arrest results from hypovolemia (see Shock and Fluid Resuscitation: Intravenous Fluid Resuscitation).
Defibrillation
The most common rhythm in witnessed adult cardiac arrest is VF; rapid conversion to a perfusing rhythm is essential. Pulseless VT is treated the same as VF.
A precordial thump is advised only when a defibrillator is not available. A forceful precordial thump can rarely convert VF or VT to a functional cardiac rhythm, and there is no evidence of deleterious effect (eg, converting VT to VF) in the cardiac arrest setting. However, it is not recommended for children. One or 2 blows can be delivered to the junction of the middle and lower third of the sternum with a clenched fist held 20 to 25 cm above the chest.
Prompt direct current cardioversion is more effective than antiarrhythmic drugs; however, the success of defibrillation is time dependent, with about a 10% decline in success after each minute of VF (or pulseless VT). Automated external defibrillators (AEDs) allow minimally trained rescuers to treat VT or VF. Their use by first responders (police and fire services) and their prominent availability in public locations has increased the likelihood of resuscitation.
Defibrillating paddles or AED pads are placed between the clavicle and the 2nd intercostal space along the right sternal border and over the 5th or 6th intercostal space at the apex of the heart. Conventional defibrillator paddles are used with conducting paste; pads have conductive gel incorporated into them. Only 1 initial countershock is now advised (the previous recommendation was 3 stacked shocks), after which chest compression is resumed. Energy level for biphasic defibrillators is between 120 and 200 joules (2 joules/kg in children); monophasic defibrillators are set at 360 joules. Postshock rhythm is not checked until after 2 min of chest compression. Subsequent shocks are delivered at the same or higher energy level (maximum 360 joules, 2 to 4 joules/kg in children). Patients remaining in VF or VT receive continued chest compression and ventilation and optional drug therapy as discussed in Cardiac Arrest: Drugs for ACLS.
Special Circumstances
In accidental electrical shock, rescuers must be certain that the patient is no longer in contact with the electrical source to avoid shocking themselves. Use of nonmetallic grapples or rods and grounding of the rescuer allows for safe removal of the patient before starting CPR.
In near drowning, rescue breathing may be started in shallow water, although chest compression is not likely to be effectively done until the patient is placed horizontally on a firm surface, such as a surfboard or float.
If cardiac arrest follows traumatic injury, airway opening maneuvers and a brief period of external ventilation after clearing the airway have the highest priority because airway obstruction is the most likely treatable cause of arrest. To minimize cervical spine injury, jaw thrust, but not head tilt and chin lift, is advised. Other survivable causes of traumatic cardiac arrest include cardiac tamponade and tension pneumothorax, for which immediate needle decompression is lifesaving. However, most patients with traumatic cardiac arrest have severe hypovolemia due to blood loss (for which chest compressions may be ineffective) or nonsurvivable brain injuries.
Drugs for ACLS
Despite widespread and long-standing use, no drug or drug combination has been definitively shown to increase survival to hospital discharge in patients with cardiac arrest. Some drugs do seem to improve the likelihood of ROSC and thus may reasonably be given (for dosing, including pediatric, see Table 2: Cardiac Arrest: Drugs for Resuscitation*). Drug therapy for shock and cardiac arrest continues to be researched.
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Table 2
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| Drugs for Resuscitation* |
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Drug†
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Adult Dose
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Pediatric Dose
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Comments
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Adenosine
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6 mg initially, then 12 mg × 2
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0.1 mg/kg initially, then 0.2 mg/kg × 2
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Rapid IV push is followed by flush (maximum single dose 12 mg).
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Amiodarone
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|
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For VF/pulseless VT
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300 mg
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5 mg/kg
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Give as IV push over 2 min.
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For perfusing VT
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Loading dose: 150 mg
Infusion (drip): 1 mg/min × 6 h, then 0.5 mg/min × 24 h
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5 mg/kg over 20–60 min, repeated to a maximum of 15 mg/kg/day
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Give initial dose as IV push over 10 min.
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Amrinone
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Loading dose: 0.75 mg/kg over 2–3 min
Infusion (drip): 5–10 μg/kg/min
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Loading dose: 0.75–1 mg/kg over 5 min (may be repeated up to 3 mg/kg)
Infusion: 5–10 μg/kg/min
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500 mg in 250 mL 0.9% saline gives 2 mg/mL.
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Atropine
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0.5–1 mg
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0.02 mg/kg
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Repeat q 3–5 min to effect or total dose of 0.04 mg/kg (minimum dose 0.1 mg).
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Ca chloride
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1 g
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20 mg/kg
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10% solution contains 100 mg/mL.
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Ca gluceptate
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0.66 g
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N/A
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22% solution contains 220 mg/mL.
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Ca gluconate
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0.6 g
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60–100 mg/kg
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10% solution contains 100 mg/mL.
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Dobutamine
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2–20 μg/kg/min (starting at 2–5 μg/kg/min)
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Same as adult dose
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500 mg in 250 mL 5% D/W gives 2000 μg/mL.
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Dopamine
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2–20 μg/kg/min (starting at 2–5 μg/kg/min)
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Same as adult dose
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400 mg in 250 mL 5% D/W gives 1600 μg/mL.
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Epinephrine
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Bolus: 1 mg
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0.01 mg/kg
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Repeat q 3 to 5 min as needed.
8 mg in 250 mL 5% D/W gives 32 μg/mL.
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Infusion: 2–10 μg/min
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0.1–1.0 μg/kg/min
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Glucose
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Infusion: 2–10 μg/min
25 g 50% D/W
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0.1–1.0 μg/kg/min
0.5–1 g/kg
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Avoid high concentrations in infants and young children.
5% D/W: Give 10–20 mL/kg.
10% D/W: Give 5–10 mL/kg.
25% D/W: Give 2–4 mL/kg.
For older children, use a large vein.
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Mg sulfate
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1–2 g
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25–50 mg/kg to a maximum of 2 g
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Give over 2–5 min.
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Milrinone
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Loading dose: 50 μg/kg over 10 min
Infusion: 0.5 μg/kg/min
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Loading dose: 50–75 μg/kg over 10 min
Infusion: 0.5–0.75 μg/kg/min
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50 mg in 250 mL 5% D/W gives 200 μg/mL.
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Naloxone
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2 mg
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0.1 mg/kg if patients are < 20 kg or < 5 yr
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Repeat as needed.
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Norepinephrine
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Infusion: 2–16 μg/min
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Infusion: Starting with 0.05–0.1 μg/kg/min (maximum dose 2 μg/kg/min)
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8 mg in 250 mL 5% D/W gives 32 μg/mL.
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Phenylephrine
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Infusion: 0.1–1.5 μg/kg/min
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Infusion: 0.1–0.5 μg/kg/min
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10 mg in 250 mL 5% D/W gives 40 μg/mL.
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Procainamide
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30 mg/min to effect or a maximum of 17 mg/kg
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Same as adult dose
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Procainamide is not recommended for pulseless arrest in children.
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Sodium bicarbonate (NaHCO3)
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50 mEq
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1 mEq/kg
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Infuse slowly and only when ventilation is adequate.
4.2% contains 0.5 mEq/mL; 8.4% contains 1 mEq/mL.
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Vasopressin
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40 units × 1
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Not recommended
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Vasopressin is given as a single dose.
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*For indications and use, see text.
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†IV or intraosseous.
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VF = ventricular fibrillation; VT = ventricular tachycardia.
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In a patient with a peripheral IV line, drug administration is followed by a fluid bolus (“wide open” IV in adults; 3 to 5 mL in young children) to flush the drug into the central circulation. In a patient without IV or intraosseous access, atropine and epinephrine, when indicated, may be given via the endotracheal tube at 2 to 2.5 times the IV dose. During administration of a drug via endotracheal tube, compressions should be briefly stopped.
First-line drugs
First-line drugs include
Epinephrine has been the main drug used in cardiac arrest, although, as noted previously, its benefit is increasingly challenged. It may be given q 3 to 5 min. Epinephrine has combined α-adrenergic and β-adrenergic effects. The α-adrenergic effects may augment coronary diastolic pressure, thereby increasing subendocardial perfusion during chest compressions. Epinephrine also increases the likelihood of successful defibrillation. However, β-adrenergic effects may be detrimental because they increase O2 requirements (especially of the heart) and cause vasodilation. Intracardiac injection of epinephrine is not recommended because, in addition to interrupting precordial compression, pneumothorax, coronary artery laceration, and cardiac tamponade may occur.
A single dose of vasopressin 40 units, which has a duration of activity of 40 min, is an alternative to epinephrine (adults only); it has not been proved more effective than epinephrine.
Amiodarone 300 mg can be given once if defibrillation is unsuccessful after epinephrine or vasopressin, followed by 1 dose of 150 mg. It is also of potential value if VT or VF recurs after successful defibrillation; a lower dose is given over 10 min followed by a continuous infusion. There is no persuasive proof that it increases survival to hospital discharge.
Other drugs
A range of additional drugs may be useful in specific settings.
Atropine sulfate is a vagolytic drug that increases heart rate and conduction through the atrioventricular node. It is given for symptomatic bradyarrhythmias and high-degree atrioventricular nodal block. It is no longer recommended for asystole or pulseless electrical activity.
Ca chloride is recommended for patients with hyperkalemia, hypermagnesemia, hypocalcemia, or Ca channel blocker toxicity. In others, because intracellular Ca is already higher than normal, additional Ca is likely to be detrimental. Because cardiac arrest in patients on renal dialysis is often a result of or accompanied by hyperkalemia, these patients may benefit from a trial of Ca if bedside K determination is unavailable. Caution is necessary because Ca exacerbates digitalis toxicity and can cause cardiac arrest.
Mg sulfate has not been shown to improve outcome in randomized clinical studies. However, it may be helpful in patients with torsades de pointes or known or suspected Mg deficiency (ie, alcoholics, patients with protracted diarrhea).
Procainamide is a 2nd-line drug for treatment of refractory VF or VT. However, procainamide is not recommended for pulseless arrest in children.
Phenytoin may rarely be used to treat VF or VT, but only when VF or VT is due to digitalis toxicity and is refractory to other drugs. A dose of 50 mg/min is given until rhythm improves or the total dose reaches 18 mg/kg.
NaHCO3 (sodium bicarbonate) is no longer recommended unless cardiac arrest is caused by hyperkalemia, hypermagnesemia, or tricyclic antidepressant overdose with complex ventricular arrhythmias. In children, NaHCO3 may be considered when cardiac arrest is prolonged (> 10 min); it is given only if there is good ventilation. When NaHCO3 is used, arterial pH should be monitored before infusion and after each 50-mEq dose (1 to 2 mEq/kg in children).
Lidocaine and bretylium are no longer recommended for management of cardiac arrest.
Dysrhythmia Treatment
VF or pulseless VT is treated with one direct current shock, preferably with biphasic waveform, immediately after witnessed arrest and after 2 min of chest compression in patients with unwitnessed arrest; chest compression is interrupted as little as possible. Recommended energy levels vary: 120 to 200 joules for biphasic waveform and 360 joules for monophasic. If this treatment is unsuccessful, epinephrine 1 mg IV is administered and repeated q 3 to 5 min. Alternatively, vasopressin 40 U IV may be given only once (not in children) although its value is questioned. Cardioversion at the same energy level is attempted 1 min after each drug administration. If VF persists, amiodarone 300 mg IV is given. Then, if VF/VT recurs, 150 mg is given followed by infusion of 1 mg/min q 6 h, then 0.5 mg/min. Current versions of AEDs provide a pediatric cable that effectively reduces the energy delivered to children. (For pediatric energy levels, see Table 3: Cardiac Arrest: Guide to Pediatric Resuscitation—Mechanical Measures; for drug doses, see Table 2: Cardiac Arrest: Drugs for Resuscitation*.)
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Table 3
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| PrintOpen table in new window |
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| Guide to Pediatric Resuscitation—Mechanical Measures |
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Age (yr)
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Term neonate
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< 12 mo
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1
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2
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3
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4
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5
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6
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7
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8
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9
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10
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11
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12
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13
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14
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15
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16
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Weight (kg)
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3.5
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< 10
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10
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12
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14
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16
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18
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20
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22
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25
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28
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30
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35
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40
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45
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50
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55
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60
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Ventilation rate/min (advanced airway)
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Perfusing rhythm
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30–60
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20
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20
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12
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Nonperfusing rhythm
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8–10
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Compression rate/min
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120*
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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100
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Compression/ventilation ratio (unprotected airway)
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30:2 (1 rescuer)
15:2 (2 rescuers)
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30:2
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Compression techniques
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Thumb compression, hands around chest (preferred) or 2 fingers
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1 hand
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2 hands
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Airway size (Portex) in cm
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000
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00
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00
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0
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0
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7
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7
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7
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7
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7
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7
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7
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7
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7
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8
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8
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8
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8
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3.5
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5
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5
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6
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6
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|
|
|
|
|
|
|
|
|
|
|
|
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Masks in Laerdal sizes or equivalent
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Circular 0/1
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Rendell- Baker type # 1
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Rendell-Baker type # 2
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Dome cuff mask # 3
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Dome cuff mask # 4
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Ventilation bag with reservoir for 100% O2 delivery
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Infant 240 mL
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Child 400–500 mL
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Adult 1600 mL
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Laryngoscope blade size
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Miller 0
Straight blade
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1
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1
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1
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2
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2
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2
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2
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2
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2
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2
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3
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3
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3
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3
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3
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3
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3
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Straight blade (preferred) or curved blade
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Curved or straight blade
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ETT size (Portex) in mm
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3
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3.5
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4
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4.5
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4.5
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5
|
5
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5.5
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5.5
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6
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6
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6
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6
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6.5
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6.5
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6.5
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6.5
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7
|
|
Uncuffed
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Uncuffed
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Cuffed
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|
Suction catheter
|
Direct oro-pharyngeal
Through ETT
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10 F
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Pediatric tonsil suction
8 Fr
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Adult tonsil suction
10 Fr
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|
Defibrillation (joules)
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Dose (2 joules/kg)
Frequency
Maximum dose (4 joules/kg)
|
7 10
Pediatric paddles
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20 20 3030 30 50 50 50 50 70 70 70 100 100 200 200
Adult paddles
|
|
20
|
30
|
If no response, give maximum dose × 2
50 50 50 70 70 100 100 100 100 100 150 150 200 200 300 300
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|
Cardioversion (joules)
|
Synchronized shock (0.5 joules/kg)
|
2
|
3
|
5
|
5
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7
|
7
|
10
|
10
|
10
|
10
|
10
|
20
|
20
|
20
|
20
|
30
|
30
|
30
|
|
Frequency
Maximum dose (1 joule/kg)
|
5
|
5
|
10
|
10
|
Increase dose slowly at subsequent attempt to maximum
10 20 20 20 20 20 30 30 30 50 50 50 5070
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|
*Pause for ventilation
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ETT = endotracheal tube; Fr = French.
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Courtesy of Dr. B. Paes and Dr. M. Sullivan, the Departments of Pediatrics and Medicine, St. Joseph's Hospital, The Children's Hospital, Hamilton Health Sciences Corporation, McMaster University, Hamilton, Ontario, Canada.
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Asystole can be mimicked by a loose or disconnected monitor lead; thus, monitor connections should be checked and rhythm viewed in an alternative lead. If asystole is confirmed and heart block is suspected, transcutaneous pacing is done and the patient is given epinephrine 1 mg IV repeated q 3 to 5 min and atropine 1 mg IV repeated q 3 to 5 min to a total dose of 0.04 mg/kg. Electrical pacing is not successful in other settings. Pacing and atropine, however, are contraindicated in children with asystole. Defibrillation of apparent asystole (because it “might be fine VF”) is discouraged because electrical shocks injure the nonperfused heart.
Pulseless electrical activity is circulatory collapse that occurs despite satisfactory electrical complexes on the ECG. Patients with pulseless electrical activity receive 500- to 1000-mL (20 mL/kg) infusion of 0.9% saline. Epinephrine may be given in amounts of 0.5 to 1.0 mg IV repeated q 3 to 5 min. If the heart rate is < 60/min, atropine 0.5 to 1 mg IV is given. Cardiac tamponade can cause pulseless electrical activity, but this disorder usually occurs in patients after thoracotomy and in patients with known pericardial effusion or major chest trauma. In such settings, immediate pericardiocentesis or thoracotomy is done (see Fig. 2: Pericarditis: Pericardiocentesis.). Tamponade is rarely an occult cause of cardiac arrest but, if suspected, can be confirmed by ultrasonography or, if ultrasonography is unavailable, pericardiocentesis.
Termination of Resuscitation
CPR must be continued until the cardiopulmonary system is stabilized, the patient is pronounced dead, or a lone rescuer is physically unable to continue. If cardiac arrest occurs in hypothermic patients, CPR should be continued until the body is rewarmed to 34° C.
The decision to pronounce death is somewhat subjective, taking into account duration of arrest before treatment, age, prior medical conditions, and other factors but typically is made after failure to establish spontaneous circulation after 30 to 45 min of CPR and ACLS measures.
Postresuscitative Care
Restoration of spontaneous circulation (ROSC) is only an intermediate goal in resuscitation. Only 3 to 8% of patients with ROSC survive to hospital discharge. To maximize the likelihood of a good outcome, clinicians must manage underlying conditions. In adults, it is particularly important to recognize MI (see Coronary Artery Disease: Acute Coronary Syndromes (ACS)) and institute reperfusion therapy (preferably percutaneous transluminal coronary angioplasty) promptly. (Caution: Thrombolysis after aggressive CPR sometimes causes cardiac tamponade, and therefore angioplasty is preferred.)
Postresuscitation laboratory studies include ABG, CBC, and blood chemistries, including electrolytes, glucose, BUN, creatinine, and cardiac markers. (Creatine kinase is usually elevated because of skeletal muscle damage caused by CPR.) Arterial Pao2 should be kept near normal values (80 to 100 mm Hg). Hct should be maintained at ≥ 30, and glucose at < 200 mg/dL; electrolytes, especially K, should be within the normal range.
BP support
Current recommendations are to maintain a mean arterial pressure (MAP) of > 80 mm Hg in older adults or > 60 mm Hg in younger and previously healthy patients. In patients known to be hypertensive, a reasonable target is systolic BP 30 mm Hg below prearrest level. MAP is best measured with an intra-arterial catheter. Use of a flow-directed pulmonary artery catheter for hemodynamic monitoring has been largely discarded.
BP support includes
Patients with low MAP and low central venous pressure should have IV fluid challenge with 0.9% saline infused in 250-mL increments.
 Clinical Calculator
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Although use of inotropic and vasopressor drugs is not proved to enhance long-term survival, older adults with moderately low MAP (70 to 80 mm Hg) and normal or high central venous pressure may receive an infusion of an inotrope (eg, dobutamine started at 2 to 5 μg/kg/min). Alternatively, amrinone or milrinone is used (see Table 2: Cardiac Arrest: Drugs for Resuscitation*). If this therapy is ineffective, the inotrope and vasoconstrictor dopamine may be considered. Alternatives are epinephrine and the peripheral vasoconstrictors norepinephrine and phenylephrine (see Table 2: Cardiac Arrest: Drugs for Resuscitation*). However, vasoactive drugs should be used at the minimal dose necessary to achieve low-normal MAP because they may increase vascular resistance and decrease organ perfusion, especially in the mesenteric bed. They also increase the workload of the heart at a time when its capability is decreased because of postresuscitation myocardial dysfunction. If MAP remains < 70 mm Hg in patients who may have sustained an MI, intra-aortic balloon counterpulsation should be considered. Patients with normal MAP and high central venous pressure may improve with either inotropic therapy or afterload reduction with nitroprusside or nitroglycerin.
Intra-aortic balloon counterpulsation can assist low-output circulatory states due to left ventricular pump failure that is refractory to drugs. A balloon catheter is introduced via the femoral artery, percutaneously or by arteriotomy, retrograde into the thoracic aorta just distal to the left subclavian artery. The balloon inflates during each diastole, augmenting coronary artery perfusion, and deflates during systole, decreasing afterload. Its primary value is as a temporizing measure when the cause of shock is potentially correctable by surgery or percutaneous intervention (eg, acute MI with major coronary obstruction, acute mitral insufficiency, ventricular septal defect).
Dysrhythmia treatment
Although VF or VT may recur after resuscitation, prophylactic antiarrhythmic drugs do not improve survival and are no longer routinely used. However, patients manifesting such rhythms may be treated with procainamide or amiodarone (see Cardiac Arrest: First-line drugs).
Postresuscitation rapid supraventricular tachycardias occur frequently because of high levels of β-adrenergic catecholamines (both endogenous and exogenous) during cardiac arrest and resuscitation. These rhythms should be treated if extreme, prolonged, or associated with hypotension or signs of coronary ischemia. An esmolol IV infusion is given, beginning at 50 μg/kg/min.
Patients who had arrest caused by VF or VT not associated with acute MI are candidates for an implantable cardioverter-defibrillator (ICD). Current ICDs are implanted similarly to pacemakers and have intracardiac leads and sometimes subcutaneous electrodes. They can sense arrhythmias and deliver either cardioversion or cardiac pacing as indicated.
Neurologic support
Between 8% and 30% of adults have CNS dysfunction after resuscitation from cardiac arrest. Hypoxic brain injury is a result of ischemic damage and cerebral edema (see Cardiac Arrest: Pathophysiology). Both damage and recovery may evolve over 48 to 72 h after resuscitation.
Maintenance of oxygenation and cerebral perfusion pressure (avoiding hypotension) may reduce cerebral complications. Both hypoglycemia and hyperglycemia may damage the postischemic brain and should be treated.
Additionally, there is now persuasive evidence of the benefits of inducing mild hypothermia. Surface cooling with ice packs can reduce core body temperature to between 30° and 34° C. Alternative methods of cooling include cardiopulmonary bypass or intravascular cooling devices.
Numerous pharmacologic treatments, including free radical scavengers, antioxidants, glutamate inhibitors, and Ca channel blockers, are of theoretic benefit; many have been successful in animal models, but none have proved effective in human trials.
CPR in Infants and Children
Despite the use of CPR, mortality rates for cardiac arrest are 80 to 97% for infants and children. The mortality rate is almost 25% for respiratory arrest alone. Neurologic outcome is often severely compromised.
About 50 to 65% of children requiring CPR are < 1 yr; of these, most are < 6 mo. About 6% of neonates require resuscitation at delivery (see Perinatal Problems: Neonatal Resuscitation); the incidence increases significantly if birth weight is < 1500 g.
Standardized outcome guidelines should be followed in reporting outcomes of CPR in children; eg, the modified Pittsburgh Outcome Categories Scale reflects cerebral and overall performance (see Table 4: Cardiac Arrest: Pediatric Cerebral Performance Category Scale*).
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Table 4
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| Pediatric Cerebral Performance Category Scale* |
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Score
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Category
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Description
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1
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Normal
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Age-appropriate level of functioning
In preschool-aged children, appropriate development
In school-aged children, attendance in regular classes
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2
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Mild disability
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Can interact at an age-appropriate level
Minor neurologic disease that is controlled and does not interfere with daily functioning (eg, seizure disorder)
In preschool-aged children, possibly minor developmental delays, but with > 75% of all daily living developmental milestones above the 10th percentile
In school-aged children, attendance in regular school but in a grade that is not appropriate for age or in the appropriate grade but failing because of cognitive difficulties
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3
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Moderate disability
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Below age-appropriate functioning
Neurologic disease that is not controlled and severely limits activities
In preschool-aged children, most daily living developmental milestones below the 10th percentile
In school-aged children, can do activities of daily living but attend special classes because of cognitive difficulties or a learning deficit
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4
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Severe disability
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In preschool-aged children, activities of daily living milestones below the 10th percentile and excessive dependence on others for activities of daily living
In school-aged children, possibly severe impairment that prevents school attendance and dependence on others for activities of daily living
In preschool-aged and school-aged children, possibly abnormal motor movements, including nonpurposeful, decorticate, or decerebrate responses to pain
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5
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Coma or vegetative state
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Unawareness
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6
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Death
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*Worst level of performance for any single criterion is used for categorizing. Deficits are scored only if they result from a neurologic disorder. Assessments are based on medical records or an interview with the caretaker.
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From Recommended guidelines for uniform reporting of pediatric advanced life support: The pediatric Utstein style; statement for health care professionals from the Task Force of the American Academy of Pediatrics, the American Heart Association, and the European Resuscitation Council; Pediatrics 96(4):765–779, 1995.
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Major Differences Between Pediatric and Adult CPR
Prearrest
Bradycardia in a distressed child is a sign of impending cardiac arrest. Neonates, infants, and young children are more likely to develop bradycardia caused by hypoxemia, whereas older children initially tend to have tachycardia. An infant or child with a heart rate < 60/min and signs of poor perfusion that do not rise with ventilatory support should have cardiac compressions (see Fig. 2: Cardiac Arrest: Chest compression.). Bradycardia secondary to heart block is unusual.
After adequate oxygenation and ventilation, epinephrine is the drug of choice.
BP should be measured with an appropriate-sized cuff, but direct invasive arterial BP monitoring is mandatory in severely compromised children.
Because BP varies with age, an easy guideline to remember the lower limits of normal for systolic BP (< 5th percentile) by age is as follows: < 1 mo, 60 mm Hg; 1 mo to 1 yr, 70 mm Hg; > 1 yr, 70 + (2 × age in yr). Thus, in a 5-yr-old child, hypotension would be defined by a BP of < 80 mm Hg (70 + [2 × 5]). Of significant importance is that children maintain BP longer because of stronger compensatory mechanisms (increased heart rate, increased systemic vascular resistance). Once hypotension occurs, cardiorespiratory arrest may rapidly follow. All effort should be made to start treatment when compensatory signs of shock (eg, increased heart rate, cool extremities, capillary refill > 2 sec, poor peripheral pulses) are present but before hypotension develops.
Equipment and environment
Equipment size, drug dosage, and CPR parameters vary with patient age and weight (see Table 1: Cardiac Arrest: CPR Techniques for Health Care Practitioners, Table 2: Cardiac Arrest: Drugs for Resuscitation*, and Table 3: Cardiac Arrest: Guide to Pediatric Resuscitation—Mechanical Measures). Size-variable equipment includes defibrillator paddles or electrode pads, masks, ventilation bags, airways, laryngoscope blades, endotracheal tubes, and suction catheters. Weight should be measured rather than guessed; alternatively, commercially available measuring tapes that are calibrated to read standard patient weight based on body length can be used. Some tapes are printed with the recommended drug dose and equipment size for each weight. Dosages should be rounded down; eg, a 2 ½-yr-old child should receive the dose for a 2-yr-old child.
Clinical Calculator
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Susceptibility to heat loss is greater in infants and children because of a large surface area relative to body mass and less subcutaneous tissue. A neutral external thermal environment is crucial during CPR and postresuscitation and may range from 36.5° C in a neonate to 35° C in a child. Hypothermia with core temperature < 35° C makes resuscitation more difficult (distinct from the beneficial effects of postresuscitation hypothermia discussed in Cardiac Arrest: Neurologic support).
Airway
Upper airway anatomy is different in children. The head is large with a small face, mandible, and external nares, and the neck is relatively short. The tongue is large relative to the mouth, and the larynx lies higher in the neck and is angled more anteriorly. The epiglottis is long, and the narrowest portion of the trachea is inferior to the vocal cords at the cricoid ring, allowing the use of uncuffed endotracheal tubes. In younger children, a straight laryngoscope blade generally allows better visualization of the vocal cords than a curved blade because the larynx is more anterior and the epiglottis is more floppy and redundant.
Rhythm disturbances
In asystole, atropine and pacing are not used.
VF and pulseless VT occur in only about 15 to 20% of cardiac arrests. Vasopressin is not indicated. When cardioversion is used, the absolute energy dose is less than that for adults; waveform can be biphasic (preferred) or monophasic (see Table 3: Cardiac Arrest: Guide to Pediatric Resuscitation—Mechanical Measures). For either waveform, the recommended energy dose is 2 joules/kg for the first shock, increasing to 4 joules/kg for subsequent attempts (if necessary—see Cardiac Arrest: Defibrillation).
AEDs with adult cables may be used for children as young as 1 yr, but an AED with pediatric cables (maximum biphasic shock of 50 joules) is preferred for children between 1 yr and 8 yr. There is insufficient evidence to recommend for or against the use of AEDs in children < 1 yr.
Last full review/revision December 2009 by Max Harry Weil, MD, PhD, ScD (Hon)
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