Cardiopulmonary resuscitation (CPR) and cardiocerebrial resuscitation (CCR) are valuable first aid skills and we should all master them. That said, their effectiveness is severely limited in a wilderness environment. Cardiopulmonary resuscitation uses a combination of chest compressions and rescue breathing to delay brain death and extend the resuscitation window while cardiocerebral resuscitation utilizes chest compressions only; both are potentially life-saving techniques. It takes approximately 10-12 chest compressions to build enough intrathoracic pressure to start circulating blood. The same intrathoracic pressure that circulates the patient’s blood also brings in a small amount of fresh air and oxygen. If there is residual air and oxygen in the lungs—as occurs in cardiac arrest caused by a heart attack—chest compressions alone are more effective in delaying the onset of brain death than when combined with rescue breathing because they maintain a consistent intrathoracic pressure. Conversely, a combination of chest compressions and rescue breathing (CPR) is more effective than CCR for patients whose arrest stems from a primary respiratory problem and lack of available oxygen as occurs in near drowning, lightning, complete snow burial, etc. The effect of both techniques decreases rapidly over time and cannot save or prolong the life of a pulseless patient for greater than 20 minutes and neither CPR or CCR work with major trauma patients whose arrest stems from increased ICP, significant lung damage, or volume shock.
For CPR or CCR to be effective the patient’s circulatory system must be intact and their core temperature above 90º F (32º C); your chest compressions must be hard and fast (ideally at least 100 per minute) and delivered in the lower third of the patient’s sternum; your weight must be directly over the patient and the patient’s chest must be allowed to fully recoil between compressions; the recoil is as important as the compression. If rescue breathing is indicated, ventilate until the patient’s chest begins to rise; do not over-inflate—over-inflation forces air into the patient’s stomach and increases the chance or frequency of vomiting.
In settings where rapid defibrillation, advanced cardiac life support, and rapid transport to a major hospital are not possible, the overwhelming majority of patients in cardiac arrest will die. It is important that all rescuers understand the limits of CPR and CCR and when it is appropriate to start and stop.
When teaching chest compressions in our wilderness medicine courses we often tell students to compress at the rate of the beat in the Bee Gee's disco tune "Staying Alive" or Queen's "Another One Bites the Dust" depending on whether a student views the glass as half full or half empty.... (Yes, humor is important in the medical field.)
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