Monthly Archives: May 2014

Simulation on a budget

When you are teaching procedures, most educators prefer for the first couple of attempts to be simulations, and not on actual patients. But if you’re going to be teaching wilderness procedures, there are other factors in question. Do you use your standard, computerized, high fidelity simulation mannequin in the hospital and play “wilderness” sounds in the background? Or do you try to truck that heavy and expensive equipment out into the woods?

Neither of those options is ideal. Thankfully, a group at the University of Michigan has come up with another option that involves a tradeoff in fidelity of the mannequin but incorporates fidelity of the environment. They took 7 common procedures and made low-cost, low fidelity simulation models that are portable, so you can take them out in the field.  The best part about their option is the budget friendly nature of it.

The seven procedures for which they made models were: cricothyrotomy, needle decompression with tube thoracostomy, lateral canthotomy, epistaxis control, pelvic binder, sucking chest wound management, and femur fracture. For the scenario, they use an actual person moulaged as the patient, then ask what procedure needed to be performed. Procedures were then performed on the models.  They made sure and used supplies that could be obtained easily at stores nearby, rather than having to call Laerdal® for replacement equipment. Because their designs are so ingenious, I’m going to go ahead and list the supplies used so it’s easier to emulate their models. I find it easier to use the ideas of people smarter than me than it is to come up with my own ideas. That being said, here are their models:

  • Cricothyrotomy: The actor had a history of facial trauma and makeup with blood in the oropharynx, was unable to speak, and had stridor. The model is nebulizer tubing (the part that is ribbed) that has a small hole already created but covered with athletic tape to mimic the cricothyroid membrane. Ketchup packets are then used on both sides to mimic vasculature, gauze as subcutaneous tisssue, and foam tape for skin.
  • Needle Decompression/Thoracostomy: The actor had a history of a fall with shortness of breath and right sided rib pain. Tracheal deviation and lack of breath sounds (hard to mimic) were given verbally. The model is an empty box with an inflated balloon inside. They used a wooden tangerine box, but a cardboard box would work fine. Pork ribs were placed over the balloon, and these were covered with thickened Jell-O for subcutaneous fat. Foam tape was used as skin.
  • Lateral Canthotomy: The actor was an elderly man who fell on his face while trail running. He has decreased vision and ecchymosis around his eye. He is on anticoagulants. On prompting, he has decreased vision, afferent pupillary defect, periorbital edema, and proptosis. The model is a ping pong ball on a base (they used a paper plate). The eyelids and skin were foam tape, and the crural ligament is athletic tape folded up to a 5mm width. The foam tape is stretched before attaching to athletic tape to allow it to come open when the crural ligament is cut.
  • Pelvic Binder: This and the sucking chest wound used the same actor. He had fallen from a tree and had chest and pelvis pain. He had diminished lower extremity pulses and was implied to have an unstable pelvis. The model was to use fabric wrapped around the pelvis and tightened with a stick used as a windlass. They specifically mention shirts or cravats for fabric, but I wouldn’t actually know where to obtain a cravat.
  • Sucking Chest Wound: The wound was created with makeup. They would dress it with whatever occlusive dressing they could mock-up, be it tape and gauze, a defibrillator pad, or an actual commercial device made for such purposes.
  • Femur Traction: The actor had fallen from a horse, and had right femur pain. The right leg is mocked up to be shorter than the left. They were to then apply a traction splint with 3 anchors, and if they didn’t have supplies, a telescoping ski rod, webbing, and a mug were used.
  • Epistaxis: The actor had experienced facial trauma and had a bloody nose. The model was a potato with a hole drilled through it. A 60cc syringe filled with red fluid was placed at one end, pushing this “blood” through the hole. They then packed it with whatever they had available. If they lacked supplies, a tampon sprayed with oxymetazoline was provided.

As you can see, these are easily reproducible, and you can even use the same supplies for multiple uses with only minimal changes (replace what is damaged). Only changes I would make are to put tape on the balloon you’re using to recreate tension pneumo, as this allows a steady rush of air without a sudden “pop” that isn’t as true to life. Honestly, I’ve never heard someone pop like a balloon when I put a needle in them, and I don’t know what I would do in a situation that they did. Also, make sure and take care going into bear country with a package or two of raw pork ribs.

Also, they used these stations in a MedWAR type race where they broke their students into groups and made them perform the tasks correctly, and also with the correct tools. This adds a bit of fun to the experience, as they have to combine orienteering, medicine, and physical activity into one event. It also adds a component of competition. The only hard part is getting enough proctors/moderators to man each station, as well as making sure students don’t actually get lost. On a final note, they did use testing and surveys before and after the scenarios to determine if students felt more comfortable with the procedures, and also if they had gained knowledge about the procedures. They found improvement in all, but statistically significant improvement in some. Small sample size certainly applies here. Still, it’s a great paper that gives easy instructions towards making an educational and enjoyable wilderness rotation for students.

How To Teach Emergency Procedural Skills in an Outdoor Environment Using Low-Fidelity Simulation

Anticoagulants bad for the woods

As I have written about before, more and more people are taking oral anticoagulants for various medical conditions. For better or for worse, they aren’t then staying at home in a padded room, but continuing on their daily activities and hobbies. Since many of these hobbies occur in the wilderness setting, there is an increased incidence of injuries to the iatrogenically coagulopathic patient.

This paper states that the reason they performed a review of the literature is due to a case report of an person attempting to take part in an outdoor course(NCOBS) while taking warfarin for previous DVT. The course instructors declined the person due to their own guidelines, but the patient and his physician appealed. This prompted the course to consult with their medical advisor. Since the course included rock climbing, there was concern that an injury in the backcountry (defined by the authors as areas requiring more than 1 hour of transport to get to definitive medical care) would add unnecessary risk in the person.

In searching the literature, they discovered that there really isn’t much out there. The guidelines are vague and have statements against activities with cuts, bruising, injury, contact sports, or bodily collisions. These are well and good, but are not based on any data. Even worse, there are conflicting guidelines out there, with some allowing sport climbing, and others recommending against rock climbing, as if there is some enormous difference. Certainly the injury most are worried about is intracranial hemorrhage, as this presents significant morbidity and mortality in the coagulopathic patient. There is nothing in the literature directly pertaining to the wilderness setting for ICH though. Other studies point towards increased risk of bleeding. Since most were designed to study need for imaging in low risk patients, the high risk patients are excluded.This makes the validity questionable. You also can’t really “watch and wait” a patient in the woods, so effectively this means you’re going to be calling for evacuation for anyone who has more than the most trivial injury.

Patients on warfarin taking trips longer than a week run the risk of either falling out of therapeutic range, or having to carry their own device to measure INR and then adjusting their dose. Seeing as how I’ve seen exactly zero people do this in a community setting, I’m not going to hold by breath that the guy hiking the AT is going to do it either. I guess they would be really motivated. The authors do note that both low molecular weight heparin as well as the newer agents have more stable pharmacokinetics, allowing less risk of coagulopathies from excess anticoagulation.

Of utmost importance is deciding whether the risks of anticoagulation outweigh the risks of not being anticoagulated. The example they give is the mechanical heart valve vs the distant thrombosis. After that decision tree, then you decide whether the activity is high or low risk for the anticoagulated patient. High risk activities should be avoided, and low risk activities only after collaboration of patient, their physician, and then any applicable staff and medical advisors. Then they give specific guidelines (listed below) for treatment and evacuation of these patients:

A. We recommend that patients anticoagulated with clopidogrel or warfarin involved in traumatic incidents not involving head injury or significant hemorrhage be treated similarly to nonanticoagulated patients, with only slightly heightened conservatism based on increased theoretical risk for bleeding sequelae. However, there does not appear to be compelling evidence that these patients need to be automatically evacuated or treated as having objectively verifiable increased risk of bleeding sequelae.

B. We recommend that every effort be made to prevent head injury in anticoagulated patients (warfarin or clopidogrel) during wilderness activities. This includes helmet use and activity modification whenever possible and reasonable.

C. We recommend any patient anticoagulated who sustains a head injury and is taking clopidogrel or warfarin be evacuated, when feasible, regardless of clinical symptoms. Note that clopidogrel patients may have an increased risk of immediate ICH versus warfarin patients, but warfarin patients have an increased risk of delayed ICH (not initially apparent radiographically, but appearing within 14 days), which does not appear to be a concern with clopidogrel. Note however that there appears to be a low rate of need for surgical intervention in these cases of delayed ICH.

Their guidelines are a reasonable attempt to clear a fairly muddy picture. Nobody wants to place patients at unnecessary risk, but preventing everyone on anticoagulants from participating in any activity is also not the answer. I feel that most will be fairly conservative with this patient population.

Participation of Iatrogenically Coagulopathic Patients in Wilderness Activities