Wilderness and Rescue Medicine 8th Edition

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Section III: Critical System Problems and Treatment

specific treatment may be necessary. This will be easier if you are able to identify what part of the respiratory system seems to be affected. If the heart is still beating, PPV can help maintain oxy- genation for many hours as assessment continues, and the patient is evacuated to definitive care. You can apply PPV directly using mouth-to- mouth, as is still taught in some CPR courses, but a mask or other barrier device should be used whenever possible. This is part of standard pre- cautions and serves to protect both you and your patient. A barrier device with a filter and one-way valve is an essential part of any emergency medi- cal kit. These now come in two forms: the tradi- tional face mask that covers the mouth and nose, and the newer intraoral mask that is placed inside the patient’s lips and over the teeth like a snorkel mouthpiece. The latter has the advantage of being a much smaller unit unaffected by facial hair but has the disadvantage of requiring the rescuer to seal the nose or apply a nose clip.

Timing your PPV to the patient’s efforts is not critical; a patient in trouble will quickly adjust. You may be able to apply more specific treat- ment for respiratory failure if you are able to iden- tify which part of the system is affected. If you are unable to get air into the lungs, for example, the problem may be upper airway obstruction. You may have already found clues to the mecha- nism in your scene size-up, such as an unfinished meal. Other causes of obstruction include swell- ing, spasm, position, and deformity from trauma. Airway obstruction may be complete or partial. Complete obstructions will be rapidly fatal if not corrected. Clearing a complete airway obstruction is a progression of actions from simple to desper- ate. Try to open the airway using a jaw thrust, chin lift, or direct pull on the tongue. Attempt to maintain in-line position of the head and neck to protect the spinal cord in trauma patients. If this type of positioning does not clear the airway, look inside the mouth. You may see a foreign body that can be pulled out with your fingers or a clamp. If there is nothing to see, try using residual air to help clear the obstruction with chest compres- sions and abdominal thrusts. This can be done with the patient supine or sitting. Whether you are squeezing the abdomen or the chest, the effect is the same. The sudden thrust can force out the air left in the patient’s lungs under pressure, blowing out any obstruction with it. Current CPR training calls for the rescuer to begin chest compressions on any unresponsive patient, which will produce the same result. If chest compressions fail, try firm back blows between the shoulder blades. This also applies intrathoracic pressure and can help dislodge an obstruction. Partial upper airway obstructions are indicated by choking, gasping, or coarse noise on inspira- tion (stridor). The patient may be unable to swal- low their own saliva. These obstructions tend to become worse over time, especially if aggravated by treatment. Do not attempt to clear a partial obstruction in the field unless it is causing respira- tory failure. Early access to ALS airway manage- ment skills and tools would be a priority in calling for assistance and evacuation.

Respiratory Failure

Ventilation: • Pocket mask • Suction device • Oxygen • Bag-valve-mask • Airway adjuncts

The rate of ventilation should be about 10 to 12 breaths per minute. If you are unable to keep count, just start the next breath as soon as the patient has finished exhaling. Blow in enough air to cause the chest to rise slightly. Each breath is done slowly over two to three seconds. Faster flow rates tend to blow air into the stomach, causing distension and vomiting. Patients who are breathing on their own, but not deeply or frequently enough, can still be assisted with PPV. This is especially useful in treating inad- equate respiration due to chest wall injury, fluid in the alveoli, or decreased nervous system drive.