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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Introduction
The pelvis is an integral part of the human skeletal system and contains some of the largest bones in the body. Structurally, it connects the lumbar spine to the lower extremities and carries and supports the abdominal organs. Its right and left sides (coaxe) are formed by the fused bones of the ilium, ischium, and pubis; an outside socket on each coxa (the acetabulum) holds the femoral head. Internal ligaments connect the sacrum to both sides in the back at the sacroiliac joint and to one another in the front at the symphysis pubis to form a circle. When intact, the combination of bones and ligaments create an amazingly strong structure capable of withstanding a significant amount of pressure.

That said, fractures and ligament damage can occur. While most pelvic injuries are minor, a few can cause severe internal hemorrhage and death. Fractures of the two rings (rami) at the bottom of the pelvis and fractures of the iliac wing, although painful, are rarely serious. On the other hand, fractures of the sacrum or ilium, separation of the symphysis pubis, or tears to major pelvic ligaments that cause the pelvis to open like a book, shear vertically, or compress inward may cause massive internal bleeding and are usually life-threatening.

Most serious pelvic injuries are caused by high energy events: falls from a height, motor vehicle accidents, and crush injuries. While torn ligaments can bleed profusely, the majority of bleeding associated with pelvic injuries is typically venous bleeding directly from the fracture site. Arterial bleeding is rare and usually leads rapidly to death from volume shock. Blood accumulates in the retroperitoneal space (which is capable of holding up to four liters) and if the pressure is great enough, may also track into the abdomen; genitourinary and gastrointestinal damage often accompany seriour pelvic injuries. Internal volume and bleeding increase with open-book injuries as the coxae splay backward. Click on an image to enlarge.

For over four decades and with little or no data to back it up, EMS fully immobilized all patients involved in major traumatic incidents in order to prevent neurological damage from a potential spine injury. The premise underlying this practice was that a major traumatic event could injure the patient's spine and subsequent spinal movement would result in a cord injury, and full external spinal immobilization would prevent said movement. This precept is seen as false and spine management in both urban and wilderness environments has changed—or is in the process of changing—accordingly. Read on to see how and why this transformation has taken place...and what the current spine management guidelines are for wilderness and remote locations.

Ankle injuries are, unfortunately, all to common on outdoor trips. Even though both stable and unstable ankle injuries cause soft tissue damage and swelling, field assessment is simple and based primarily on the patient's range of motion (ROM) and whether or not they are able to stand and bear weight shortly after the event. If their ROM is intact and they are able to bear weight, the injury is stable; if not, the injury is unstable.

The vast majority of stable ankle injuries in the outdoors result from rolling the ankle laterally (to the outside) while hiking or running on an uneven surface. If the patient has no obvious deformity, tenderness slightly in front of and below the lateral malleolus (ankle bone on the ouside of the patient's leg), and can bear weight shortly after the event they probably have an uncomplicated lateral ankle sprain (sprain = ligament damage).

If the ankle rolls inward (rare) the medial ligament complex may be damaged. Again, if the patient has no obvious deformity, presents with tenderness slightly below the medial malleolus (ankle bone on the inside of the patient's leg), and can bear weight shortly after the event, in all likelihood they have an uncomplicated medial ankle sprain.

In uncomplicated ankle sprains, swelling can be prevented with compression around both malleoli (ankle bones), elevation of the injured ankle higher than the heart, cold water baths, and pain-free ROM and light strengthening exercises 2-3 times a day. Commercial compression donuts are super lightweight and come coated with a waterproof skin adhesive; simply peel off the backing and attach. Ideally, the patient should avoid extended walking on the injured ankle for 2-5 days. If the patient must walk during this time, you will need to support their ankle and significantly reduce their pack weight. Whether a patient requires an evacuation for an ankle sprain depends of the severity of the injury, the type of activity (backpacking, cycling, canoeing, etc.), and the difficulty of the terrain they can be expected to traverse.

The first set of photos below show how to improvise a walking splint using a padded aluminum splint and foam donuts to deliver focal compression to the soft tissue surrounding the malleoli in order to prevent excessive swelling and promote rapid recovery in uncomplicated ankle medial or lateral ankle sprains. The second set show how to improvise a splint for an unstable ankle injury and adapt an expedition backpack to safely evacuate the patient.