The editors would like to acknowledge that this chapter is abridged from a chapter originally written by Dr. George W. Williams.
Before CPR is initiated, the rescuer should determine that the victim is unresponsive and activate the emergency response system. During low blood flow states such as cardiac arrest, oxygen delivery to the heart and brain is limited by blood flow rather than by arterial oxygen content; thus, current guidelines place greater emphasis on immediate initiation of chest compressions than on rescuer breaths.
The patient is positioned supine on a firm surface. After initiation of chest compressions, the airway is evaluated. The airway is most commonly obstructed by posterior displacement of the tongue or epiglottis. If there is no evidence of cervical spine instability, a head-tilt chin-lift should be tried first.
Any vomitus or foreign body visible in the mouth of an unconscious patient must be removed. If the patient is conscious or if the foreign body cannot be removed by a finger sweep, the Heimlich maneuver is recommended. This subdiaphragmatic abdominal thrust elevates the diaphragm, expelling a blast of air from the lungs that displaces the foreign body. A combination of back blows and chest thrusts is recommended to clear foreign body obstruction in infants (Table 19–1).
Table 19–1.Summary of Recommended Basic Life Support Techniques ||Download (.pdf) Table 19–1. Summary of Recommended Basic Life Support Techniques
| ||Infant (1–12 mo) ||Child (>12 mo) ||Adult |
|Breathing rate ||20–30 breaths/min ||20–30 breaths/min ||6 breaths/min1 |
|Pulse check ||Brachial ||Carotid ||Carotid |
|Compression rate ||>100/min ||100/min ||100–120/min |
|Compression method ||Two or three fingers or thumb-encircling hands technique ||Heel of one hand ||Hands interlaced |
|Compression/ventilation ratio ||30:2 ||30:2 ||30:2 |
|Foreign body obstruction ||Back blows followed by chest thrusts ||Heimlich maneuver ||Heimlich maneuver |
If after opening the airway breathing remains inadequate, the rescuer must initiate assisted ventilation by inflating the victim’s lungs with each breath using a bag-mask device. Breaths are delivered slowly (inspiratory time of ½–1 s) at a rate of about 10 breaths/min, with smaller tidal volumes [VT] so as to minimize the adverse effect on cardiac preload. Chest compressions (100–120/min) should not be suspended during two-person CPR to permit ventilation unless ventilation is not possible during compressions.
Gastric inflation with subsequent regurgitation and aspiration is possible with positive-pressure mask ventilation, even with a small VT. Therefore, the airway should be secured with an ETT as soon as feasible, or, if that is not possible, an alternative airway should be inserted. Chest compressions should not be interrupted for more than 10 s to place ...