Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

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Wilderness and Rescue Medicine

civilized setting where the most common cause of cardiac arrest is a heart attack and hospitals are nearby. The hope is that by circulating still- oxygenated blood through the heart and brain, the patient will be more likely to survive with early defibrillation and quick access to hospital care.

General Principles

BLS - Respiratory Failure P osition for easiest respiration: • Clear airway, position for drainage • Nasopharyngeal and oropharyngeal airway use, suction R eassurance to improve respiration O xygen via mask or nasal cannula: • Titrate to response • Heat and humidify P ositive Pressure Ventilation: • Can be effective for hours or days • Can be used to assist inadequate respiratory effort

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General Principles

CPR

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CPR 2015 Update: • Begin compressions if unresponsive and in respiratory arrest. • 30:2 ratio on adults and children (100 -120 per minute) • 15:2 ratio for two rescuer CPR on infants and children • Breaths given over 1 second, blow until chest rises • One shock followed by 2 minutes of CPR before next attempt.

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If the obstruction is caused by swelling of the airway, back blows and chest compressions will not help. The only BLS treatment is to continue PPV in an attempt to force air past the obstruction while repositioning the neck for the best air flow. These patients will need medication or a surgical airway. If the cause of airway swelling is anaphylaxis, an injection of epinephrine can be lifesaving. This is part of the Wilderness Protocol for anaphylaxis, a technique taught to basic practitioners because it is a low risk treatment for a high-risk prob- lem (see the allergy and anaphylaxis chapter). Life-threatening lower airway constriction due to asthma can be treated with epinephrine and steroids. This procedure is part of the Wilderness Protocol for asthma, also taught to basic level practitioners for the same reason (see the severe asthma chapter). Circulatory Failure Cardiac Arrest Chest compressions are used to temporarily support perfusion when the heart has stopped functioning. Unlike PPV, chest compressions are effective for only a few minutes. An early return of spontaneous circulation is necessary for the patient to have any chance of survival. Current CPR standards call for 2 minutes of chest compressions, with or without PPV depend- ing on the level of training, before checking a pulse on any patient who is unresponsive and not breathing effectively. This makes sense in the

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However, chest compressions are not the best immediate treatment for all unresponsive patients in the backcountry setting. If the primary cause is respiratory arrest, as in drowning, avalanche burial, or lightning strike, emphasis should be placed on ensuring an airway and ventilation. Chest compressions could be harmful to a patient in decompensated shock from internal bleed- ing or respiratory failure from chest wall injury. Chest compressions could cause cardiac arrest in a severely hypothermic patient. A quick but careful scene and primary survey, including a pulse check, should be used to determine if chest compressions are really indicated. The pulse can be very difficult to find under adverse field conditions where you may be work- ing with cold hands in dangerous places. The pulse can be weak or absent in the extremities of a person in shock, and very slow in severe hypo- thermia. The carotid and temporal pulses are the easiest to access, and most likely to be felt if the heart is beating. The carotid is located on either side of the Adam’s apple (larynx) in the neck. The temporal pulse is on the side of the head just in front of the ear. Confirmed cardiac arrest in the field should be treated on scene with cardiopulmonary resus- citation (CPR), which is a combination of chest