Cardiopulmonary Resuscitation

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What is cardiac arrest and sudden cardiac death?

Cardiac arrest is the sudden cessation of effective cardiac pumping function. Sudden cardiac death is the unexpected natural death from a cardiac cause within 1 hour of onset of symptoms, in a person without a previous condition that would appear fatal.

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What is the most common dysrhythmia encountered during sudden cardiac death and what is its treatment?

Ventricular fibrillation (VF) is the predominant rhythm encountered in the first 3–5 minutes after sudden cardiac arrest. Immediate therapy with defibrillation is the only effective treatment for VF and is most effective if performed within 5 minutes of collapse. Initiation of cardiopulmonary resuscitation (CPR) with chest compressions provides a small but critical amount of blood to the heart and brain while waiting for a defibrillator to arrive.

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What is the C-A-B approach to the pulseless patient for basic life support (BLS), and why was this changed from A-B-C?

The 2010 AHA guidelines for CPR changed the sequence in steps in BLS from A-B-C (airway, breathing, circulation) to C-A-B (circulation, airway, breathing). This change was made because the highest survival is seen among patients with cardiac arrest from pulseless ventricular tachycardia (VT) or VF. The critical initial elements in resuscitation of these patients are chest compressions and early defibrillation. Assessing the airway and delivering mouth-to-mouth breaths delays the critical time to performing defibrillation.

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What is the proper method of chest compressions in children and adults?

Rescuers should push hard and fast (rate 100–120 compressions per minute). The proper position for the hands during chest compressions in children and adults (about 1 year of age and older) is in the center of the chest at the nipple line. Using the heel of both hands, the rescuer should compress the chest approximately 2–2.5 inches for adults. The same method is used for children; however, one hand is often adequate to compress the chest, and the depth of compression should be one-third to one-half of the depth of the chest. Rescuers should allow complete chest recoil between compressions and minimize interruptions in compressions. Use 30:2 compression to ventilation ratio without an advanced airway or continuous chest compressions with advanced airway.

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Is endotracheal intubation mandatory during cardiopulmonary resuscitation?

No. Adequate ventilation may be achieved with proper airway positioning, an oropharyngeal or nasopharyngeal airway, and a bag-valve mask attached to an oxygen source. Insertion of an endotracheal tube may be deferred until the patient fails to respond to initial CPR and defibrillation. If an advanced airway is placed (endotracheal intubation or supraglottic airway), this should be performed by an experienced provider and should not interrupt adequate delivery of chest compressions.

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How is the airway positioned during a resuscitation attempt?

In an unconscious patient, the most common airway obstruction is the patient’s tongue, which falls back into the throat when the muscles of the throat and tongue relax. Opening the airway to relieve the tongue from obstruction can be done using the head tilt-chin lift maneuver, or in the patient with suspected cervical spine injury, the jaw-thrust maneuver. If available, an oral airway or nasal trumpet should be inserted. Oral airway is preferred if there is suspicion for basal skull fracture or severe coagulopathy.

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What is the rate of ventilation after placement of an advanced airway?

Delivery of one breath every 6 seconds (or 10 breaths per minute) is recommended while continuous chest compressions are being performed after an advanced airway is in place. It is important not to hyperventilate as this can increase intrathoracic pressure and lead to decreased preload and reduced cardiac output, especially in the setting of hypovolemia or obstructive lung disease. Hyperventilation may also lead to intracranial vasoconstriction, further impeding cerebral blood flow.

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What are the two major categories of cardiac arrest?

Cardiac arrest can be divided into asystole/pulseless electrical activity (PEA) and pulseless VT/VF. PEA arrest was previously called electromechanical dissociation because, while the electrical system of the heart is functioning, there is mechanical dysfunction (which can be caused by a variety of conditions) resulting in inadequate cardiac output to maintain a pulse. In cardiac arrest purely due to VT/VF, inadequate cardiac output is mediated primarily by the rhythm disturbance: In VT, the heart is beating too rapidly to allow adequate filling during diastole, and in VF, there is chaotic rapid depolarization in the ventricle causing the heart to quiver rather than beat effectively.

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