CURRICULUM Emergency Medicine Curriculum Utilizing the Flipped Classroom Method: Environmental Emergencies

: Audience: This curriculum created and implemented at The Ohio State University Emergency Medicine Residency was designed to educate our emergency medicine (EM) residents, PGY-1 to PGY-3, as well as medical students and attending physicians.

c. Describe the risk factors for classic heat stroke. d. Describe the various methods of cooling for the hyperthermic patient. 3. Barotrauma, Hyperbaric Oxygen, and Altitude.
a. Compare/contrast the different types of diving-related illness including: decompression sickness, barotrauma, and gas toxicity. b. Describe the treatment options for divingrelated illness. c. Discuss the spectrum of altitude illness and list the preventative and acute treatment approaches. 4. Electrical/Radiation/Submersion Injuries a. Review the key pathophysiology related to drowning and the major organ systems involved. b. Discuss management of drowning. c. List risk factors for drowning d. Discuss the characteristics of different electrical injuries: high voltage versus low voltage. e. Explore the initial management of electrical injuries and how triage of a mass casualty lightning strike differs from standard mass casualty triage. f. Define the difference between radiation exposure and radiologic contamination. g. Discuss the concept of time/distance/shielding related to radiation exposure. h. List the expected manifestations of acute radiation sickness based on the dose absorbed. 5. Bites, Stings and Envenomation a. Identify and characterize common bite/envenomation patterns of poisonous fauna found in the United States (US). b. Describe the management and treatment for common reptile and arthropod envenomation. c. Understand and perform initial management of these injuries including venom specific antidotes. d. Describe the presenting symptoms of rabies. e. Compare the difference in the natural reservoirs for rabies in the US and internationally. f. Review the post-exposure prophylaxis for rabies exposure.

Brief introduction:
In 2015, injuries from natural and environmental factors represented about two million ED visits in the United States, representing 4.9% of all ED visits. 1 While this topic represents a relatively minor percent of questions on the ABEM qualifying exam, 13 this content is not well covered in undergraduate medical education or other specialties post-graduate education. Thus, many emergency medicine physicians are the de facto experts for these somewhat infrequent presentations. Also, there are many recognized environmental medicine-related fellowships that emergency medicine residency graduates can pursue. Because of these, when we developed our 18-month flipped classroom residency curriculum, we decided to include a block on environmental emergencies. The flipped classroom learning approach is becoming more commonly recognized as a preferred curricular model for mature learners, specifically those in medical education. This particular model is a natural fit for the hands-on, experiential emergency medicine learner. 7 The active learning fostered by this curriculum increases faculty and learner engagement and interaction time, which is typically absent in traditional lecturebased formats. 8,12 Education literature shows that resident learners prefer learning activities that involve small group discussion, are case/skill based, and emphasize the application of newly obtained knowledge. 3,4 This educational model also provides a clear channel for the incorporation of evidencebased medicine and increases opportunities for educatorlearner conversations. A successful flipped classroom curriculum fosters learner accountability and provides robust opportunities for formal assessment in various emergency medicine milestones. 7,11,13 For these reasons, we developed a flipped classroom curriculum at The Ohio State University Emergency Medicine Residency. This environmental emergencies curriculum is one of several topics in our overall 18-month didactic curriculum.

Problem identification, general and targeted needs assessment:
Traditional lecture-based didactics may not be the most effective or preferred method for emergency medicine resident education. 9 Previously, we used a traditional lecture format in our residency curriculum despite overwhelming evidence favoring a more hands-on, "flipped classroom" approach. 11,12 From the perspective of resident learners, the chance to remain fully engaged through the asking of questions developed from personal experiences, in addition to learning from the experiences of others, provides a technique of learning that makes a topic more difficult to forget. 8 The ABEM model curriculum lists environmental disorders as an important core content area for training emergency medicine residents. 14 We used this model curriculum to guide creation of the block content. Environmental emergencies are not emphasized in undergraduate medical education, and many times emergency medicine providers are the most likely to encounter environmental-related disorders. Also, wilderness medicine, hyperbaric and undersea medicine are recognized fellowships that emergency medicine residency graduates can pursue.
As current literature reveals, both educators and learners benefit from an interactive and collaborative classroom, leading to the creation and implementation of this proposed curricular model at our emergency medicine residency program. Learners divide into small groups of at most 20 participants, but the curriculum could be effectively run with much smaller groups. A faculty facilitator leads the discussion through the cases and question prompts. Since implementation, residents and educators are engaging in new, valuable flipped classroom learning communities at The Ohio State University Emergency Medicine Residency. Through the curriculum, we continually seek to foster self-directed learning and increased collaboration between resident learners and education faculty members. This ensures that resident time will be maximized and learning will be more efficient and effective, therefore providing a potential positive impact on patient care and physician wellness. Currently, minimal flipped classroom curricular materials dedicated to the core content of emergency medicine exist.

Goals of the curriculum:
We aim to teach the presentation and management of environmental emergencies in an emergency department through the creation of a flipped classroom design. The topics specifically include cold-related illness, heat-related illness, undersea medicine, high altitude medicine, submersion, electrocution, radiation injury, and envenomation. Resident learners will learn the core content of emergency medicine in an 18-month curriculum utilizing self-directed learning and small group discussions based on the flipped classroom model.
This unique, innovative curriculum utilizes resources chosen by education faculty and resident learners, study questions, reallife experiences, and small group discussions in place of traditional lectures. In doing so, a goal of the curriculum is to encourage self-directed learning, improve understanding and knowledge retention, and improve the educational experience of our residents. Of note, this curriculum does not include specific pre-hospital management of environmental emergencies.

Objectives of the curriculum:
Each chapter within our curriculum has individual objectives; however, educational objectives for the curriculum and more specifically, the environmental emergencies module include:

Evaluation and Feedback:
This innovative curriculum was literature-based and specifically designed to maximize active learning using the flipped classroom learning model. We overcame initial challenges and skepticism from both educators and learners to execute a successful, novel curricular model. Both resident learners and faculty educators have provided positive feedback. Additionally, a survey was administered to each resident prior to initiation of the curricular innovation and repeated at the conclusion of the first 18-month cycle. Learners and educators were enthusiastic about the conference structure and expressed a preference for it rather than the previous, lecture-based didactics.
More recently during the second 18-month cycle of the flipped classroom curriculum, students were surveyed on their perceived quality of instruction of the various program components. A majority of residents (60.9%) reported that the small group discussions were good or excellent, compared to only 26% of residents that felt that our grand rounds sessions during the same time were good or excellent. This curriculum has been delivered to two cohorts of learners, who have received the content twice in three years, with about 50 residents per cycle. On the most recent iteration, residents evaluated the teaching methods as effective, with an average rating of more than 4.5 out of 5 (4 being agree, 5 being strongly agree). The curriculum is critically evaluated and updated by education faculty members in order to ensure educational material remains current and consistent with the emergency -Encourage participants to share clinical experiences to enhance discussion.

References/Further
-30-45 minutes for case and content discussion.
-Indications for and rates of rewarming in different stages of hypothermia.
-Resuscitation in hypothermia and concept of core temperature afterdrop.
-Characteristic findings and management for soft tissue injuries including chilblains, trench foot and frostbite.
By the end of this session, learners will: -List and define stages of hypothermia; -Review indications and methods of rewarming for hypothermic patients.
-Discuss pathophysiology of core temperature afterdrop.
-Review management of a hypothermic patient in cardiac arrest. Heat-Related Illness -"Flipped" classroom discussion of prereading material, case discussions, and discussion questions.
-Encourage participants to share clinical experiences to enhance discussion.
-30-45 minutes for case and content discussion.
-Pathophysiology and methods of temperature regulation.
-Risk factors, clinical differences, and complications of heat exhaustion and heat stroke.
-Methods and considerations of rapid cooling.
By the end of this session, learners will: -Discuss the body's methods of heat loss that allow temperature regulation.
-Differentiate between patients presenting with heat exhaustion versus heat stroke.
-Describe the risk factors for classic heat stroke. -"Flipped" classroom discussion of prereading material, case discussions, and discussion questions.
-Encourage participants to share clinical experiences to enhance discussion.
-30-45 minutes for case and content discussion.
-Pathophysiology, diagnosis, and management of common divingrelated illnesses including decompression sickness, barotrauma, and gas toxicity.
By the end of this session, learners will: -Encourage participants to share clinical experiences to enhance discussion.
-30-45 minutes for case and content discussion.
-Pathophysiology, diagnosis, and management of drowning.
-Diagnostic evaluation, complications of high-and lowvoltage electrical injuries.
-Decontamination procedures for a radiologically contaminated patient.
-Definition and management of Acute Radiation Syndrome (ARS).
By the end of this session, learners will: -Review the key pathophysiology related to drowning and the major organ systems involved.
-Discuss management of drowning.
-List risk factors for drowning.
-Discuss the characteristics of different electrical injuries: high voltage versus low voltage.
-Explore the initial management of electrical injuries and how triage of a mass casualty lightning strike differs from standard mass casualty triage.
-Define the difference between radiation exposure and radiologic contamination.
-Discuss the concept of time/distance/shi elding related to radiation exposure.
-List the expected manifestations of acute radiation sickness based on the dose absorbed.

PGY-1 PGY-2 PGY-3 Medical Students
Equipment: projector and screen preferable (instructor can pull up web images during session). Tables and space promoting small group discussion.
Instructors: 1-2 faculty members or content experts. Recommended senior resident discussion leader.
Timing: small group discussions involve no more than 20 learners and last 45-60 minutes. -Describe the management and treatment for common reptile and arthropod envenomation.
-Understand and perform initial management of these injuries including venom specific antidotes.
-Describe the presenting symptoms of rabies.
-Compare the difference in the natural reservoirs for rabies in the US and internationally.
-Review the postexposure prophylaxis for rabies exposure.

Objectives
By the end of this small group session, learners will: 1. List and define stages of hypothermia; 2. Review indications and methods of re-warming for hypothermic patients; 3. Discuss pathophysiology of core temperature afterdrop; 4. Review management of a hypothermic patient in cardiac arrest; 5. Discuss differences between cold injuries of the soft tissue (trench foot, chilblains, frostbite) and their management.

Case Studies
Case 1: An approximately 30-year-old female is brought into the emergency department (ED) at 4 AM by a man who found her lying at the side of the road. It is 2°F outside and she has no coat or shoes. The man does not know her and is unable to provide any additional history except that she was blue and having trouble breathing when he found her. She is noted to have a decreased level of consciousness and labored breathing though no obvious signs of trauma are present.
Question Prompts: 1. Define the different stages of hypothermia (temperature and symptoms). a. Characterization of hypothermia depends on an accurate core temperature. The best core temperature measurement is made with an esophageal probe. Rectal and bladder temperatures are not as accurate because they tend to lag behind true core temperature. Oral temperatures are typically colder than core temperature and less reliable. b. The stage of hypothermia is determined by the patient's symptoms, with typical temperature ranges listed below. The Swiss staging system includes I-IV (with V being death), and is based on symptoms of the patient. The patient who is shivering and completely normal from a mental status standpoint is considered to NOT be hypothermic but simply cold-stressed (>35°C). The patient who is shivering and not quite completely normal is MILDLY hypothermic (32-35°C). The patient who is altered and may or may not be shivering is MODERATELY hypothermic (28-32°C). The patient who is unconscious is SEVERELY hypothermic (<28°C). The shivering response usually ceases below 30-31°C. These temperature ranges are generally accepted ranges where symptoms develop, however this relies on an accurate core temperature which may be difficult to obtain especially in the field. c. Hypothermia stages: . What are the rates of re-warming based on method? a. Passive rewarming takes advantage of the heat that is already being produced by the body. This is useful for the mildly hypothermic patient who is shivering. The shivering response can increase temperature by 1-3°C/hour. Passive rewarming techniques include removing wet clothes and replacing with dry clothes, seeking shelter, wrapping with a barrier layer to hold in the heat produced by radiation, and providing caloric intake to support metabolism. b. Active external rewarming is indicated for the patient who is moderately hypothermic.
Depending on the environment, this may include chemical heating pads, warm water bottles, or warmed air (Bair Hugger). Once the patient loses consciousness (severely hypothermic), active internal rewarming is indicated; these techniques include: use of warmed humidified air on the ventilation circuit, use of warmed intravenous (IV) fluids (when fluids are needed for resuscitation; warmed IV fluid will not actively rewarm but prevents cooling from room temperature saline), body cavity lavage (thorax, peritoneal cavity, bladder), and intravascular devices ( Case 2: You are hiking in Denali National Park with friends when you come upon a man in his twenties who seems distraught and anxious. He states that he was hiking by himself and is lost. Yesterday he fell near a crevasse. He was able to self-arrest before going over the edge, but he lost his pack, trekking poles and ones of his gloves into the crevasse. Without his map, GPS, or any means of communication, he was stranded overnight outside and without shelter. He is ambulatory, not shivering, and able to answer questions appropriately. His left hand is exposed and cold to the touch. The skin is white with blue mottling and his distal fingers are insensate. You are at approximately 13,500 ft elevation with an ambient air temperature 30-35°F (wind chill temperature is 20-25°F). Overnight temperatures were 10-15°F.
Question Prompts: 1. Describe the difference between different cold injuries of the soft tissue (trench foot, chilblains, frostbite). What are the characteristic findings for each degree of frostbite (first to fourth)? Discuss the management of soft tissue cold injuries. a. "Trench foot" is a non-freezing, immersion injury with initial vasoconstriction followed by an hyperemic vasodilated phase. This can be seen in environments with ambient temperatures above freezing. This is almost always associated with wet skin. This is treated with analgesic medications, keeping the foot dry, and elevation of the foot to avoid excessive edema. Chilblains (pernio) is an acrally located cutaneous eruption resulting from exposure to cold. This is self-limited and also requires only supportive care. b. Frostbite is soft tissue injury occurring through freeze-warming cycles, which is more complex than just freezing of tissue itself. This injury is classified similar to burns. The characteristic findings include: 4 First degree white-yellowish, edema Second degree erythema with clear blisters Third degree deep blisters with hemorrhagic fluid Fourth degree injury thru dermis into the deep tissue (muscle and bone) c. For deep frostbite (third and fourth degree), bone scanning or magnetic resonance imaging (MRI) is often needed to define the extent of injury. Time is also needed for the distribution of injury to fully demarcate. 2. What are the pre-hospital and initial hospital management principles for treatment of frostbite?
a. The most important principle of frostbite treatment is to avoid any further freeze-thaw cycles because this is the most destructive pattern of the injury. This could possibly mean intentionally NOT rewarming tissue in the field until sustained resources are available. Dressings that will accommodate for swelling may be loosely applied but care should be taken not to rub or compress the skin. Once rewarming is available, the tissue can be placed in a 37-39°C water bath for 20-30 minutes. Analgesic medication is a must; a non-steroidal anti-inflammatory drug (NSAID) may be sufficient for mild cases, though opiate analgesia may also be considered. b. In the hospital setting, severe frostbite is often managed by burn specialists. Novel approaches to treatment are focused on the microvascular thrombosis that occurs with reperfusion. Current protocols include use of iloprost (a prostacyclin vasodilator) for third degree frostbite and also with tissue plasminogen activator (tPA) for fourth degree injuries. Long-term care may include amputation for more severe cases; however, this is not something that can be predicted at initial injury.

Case Studies
Case 1: A 55-year-old female is brought to the medical aid tent during an outdoor concert. The patient is complaining of dizziness and nausea. She started tailgating around 9am and has been outside for the past seven hours. The ambient air temperature is 92°F with 90% relative humidity and there is no cloud-cover or shade where she has been standing. She reports some alcohol consumption but can't quantify how much or whether she had any non-alcoholic hydration. She felt like she might pass out at one point but did not actually do so. Vital signs show a heart rate of 100/minute, blood pressure of 118/84 mmHg, pulse oximetry of 98%, and oral temperature of 100.5°F. Examination is notable for clammy skin and diaphoresis.
Question Prompts: 1. What are the body's methods of heat loss that allow temperature regulation? a. There are four methods of transferring heat out of the body: i. Radiation -direct heat loss 1. Minimal heat loss in a hot environment. ii. Conduction -heat loss due to contact with colder surface 1. Minimal heat loss in a hot environment, though can be significant in a cold environment when the body is trying to retain heat. iii. Convection -heat loss due to air movement 1. An effective mechanism but it requires active circulation of the air or fluid surrounding the body. iv. Evaporation -heat loss due to warmed fluid loss, like sweat 1. The body's primary mechanism for heat dissipation, but the efficacy of this is reduced as ambient humidity increases. b. Higher mechanisms of cooling also contribute to temperature regulation. This includes the behavioral actions of humans in hot environments. Examples include: decreasing physical activity, increasing hydration, seeking shade or rest, and limiting heat exposure. a. Heat edema is lower extremity swelling that occurs secondary to compensatory vasodilation resulting in elevated hydrostatic pressures and vascular leak. b. Heat cramps are involuntary skeletal muscle contractions usually occurring in the calves and associated with electrolyte-poor hydration. c. Heat syncope typically occurs due to peripheral vasodilation, orthostatic blood pooling, and low blood volume secondary to dehydration. Healthcare providers should be vigilant and comprehensive in their approach to these patients to address other causes of syncope. 3. Compare and contrast the symptoms and findings related to heat exhaustion versus heat stroke.

DIDACTICS AND HANDS-ON CURRICULUM
a. This patient has a presentation consistent with heat exhaustion. Heat exhaustion shares many similar features with heat stroke including: elevated temperature, tachycardia, and diaphoresis (though not universally present in heat stroke). The temperature is usually higher with heat stroke (>40C), though this can be inconsistent. The main differentiating factor for heat stroke is the presence of end-organ dysfunction. The central nervous system (CNS) is the most sensitive organ system to hyperthermia. The liver is also sensitive to elevated temperatures. Thus, altered mental status, neurological deficits, or hepatic dysfunction are keystones of the diagnosis of heat stroke. CNS dysfunction is most commonly considered with heat stroke because it is manifest without need for labs and because the hepatic dysfunction may lag up to 12 hours after heat exposure. b. Here is a a. The primary treatment for heat stroke (classic or exertional) starts with considerations of airway, breathing and circulation (ABCs) and basic resuscitation. These patients may present with a spectrum of manifestations which could be relatively mild or include cardiac arrest. Airway should be secured if warranted and intravenous (IV) access established. All of these patients need comprehensive care and should be transported to an ED as soon as possible. b. Once hemodynamic stability is achieved, the focus should turn to rapid cooling of the patient. Rapid cooling is the most effective method to prevent heat-related mortality. The recommended target temp range is 38-39°C to prevent overshooting normothermia. Cold water immersion is the most rapid form of cooling and is especially successful with exertional heat stroke. Shivering does not counteract this method of cooling. The potential drawbacks of ice water immersion include limited ability for monitoring and lack of adequate vessel large enough for an ice bath in an ED. Innovative attempts have been performed using a large plastic sealable bag (i.e. a "body bag") filled with ice and water and partially closed around the patient to maintain the fluid contact. Evaporative cooling with mist and fan is also effective. This method is much easier to perform in most EDs. Other cooling methods include ice pack cooling to groin and axilla. Cooling blankets are generally not effective. Body cavity lavage with cold fluid is not well studied and should be avoided except in severe cases. 6 In these cases, cardio-pulmonary bypass may be more effective and more practical than body cavity lavage. 3. What are other considerations in the acute treatment of heat stroke? a. Medications have little role in the treatment of hyperthermia, and antipyretics and dantrolene should be avoided. Complications such as seizures and severe shivering can be managed with short acting benzodiazepines. These patients are often hypovolemic, and empiric IV isotonic fluid hydration is warranted. b. Consideration of end-organ failure aside from neurologic effects is important.
Rhabdomyolysis is common and monitoring of creatine kinase (CK) levels is advised. Other screening labs should include: compete blood count (CBC), electrolytes, arterial or venous blood gas, glucose, blood urea nitrogen (BUN)/creatinine, liver enzymes, coagulation studies, urinalysis, urine myoglobin, and electrocardiogram (ECG). 4. List some of the common complications of heat related illness.
a. The complications of heat stroke are generally the direct or indirect manifestations of various end-organ dysfunction. These may include: pulmonary edema, hemorrhage and acute respiratory distress syndrome (ARDS), cardiac failure and arrhythmias (relatively unusual in heatstroke, and resolve as the temperature comes down), 4 hypotension (due to hypovolemia, vasodilatation and cardiac dysfunction), seizures, rhabdomyolysis, renal failure, hepatic injury, and coagulopathy such as DIC.

Objectives
By the end of this small group session, learners will: 1. Compare/contrast the different types of diving-related illness including: decompression sickness, barotrauma, and gas toxicity. 2. Describe the treatment options for diving-related illness. 3. Discuss the spectrum of altitude illness and list the preventive and acute treatment approaches.

Case Studies
Case 1: A 20-year-old male diver presents to emergency department (ED) with right elbow pain. He completed a scuba dive at a maximum depth of 100 feet sea water for 40 minutes. He was in cold water, spearfishing, and the pain began approximately two hours after the dive. He describes the pain as throbbing, 6/10 severity. Review of systems are otherwise negative. He has no past medical history and no pertinent social history. Physical exam shows right elbow with normal range of motion but pain with movement. There is no edema or ecchymosis, and sensory and motor functions are intact.

Question Prompts:
1. What is the differential diagnosis for this patient? What diving related illnesses are not likely in this patient and why? a. The differential includes decompression sickness (DCS) or musculoskeletal injury. Specifically, the patient appears to have DCS type 1 because there are only pain symptoms associated with his complaint. DCS type 1 could also include skin findings with a characteristic rash called cutis marmorata.
Cutis marmorata in DCS1: b. DCS type 2 requires the additional findings of neurologic deficits (usually sensory or motor changes but can also include extreme fatigue). c. DCS type 3 is rare but more profound including pulmonary symptoms (cough, dyspnea), cardiovascular collapse, or cerebellar symptoms related to inner ear bubble formation (vertigo, nystagmus, and vomiting). Decompression sickness type 1

DIDACTICS AND HANDS-ON CURRICULUM
Only pain symptoms, may include rash (cutis marmorata) Decompression sickness type 2 Neurologic deficits -including extreme fatigue Decompression sickness type 3 Pulmonary symptoms (cough, shortness of breath), cardiovascular collapse, cerebellar symptoms (vertigo, nystagmus, vomiting) d. The features of the dive itself that favor DCS are greater depth and more prolonged duration. Both of these factors increase the nitrogen that dissolves in the blood at depth and then eventually returns to bubble form (think of opening a can of Guinness with nitrogen in it; bubbles that form are due to the nitrogen going from solute to gas as the can is rapidly depressurized). These bubbles get trapped in the joints and vascular system (primarily the venous side) when decompression back to the surface is not slow enough to allow the bubbles to be flushed and filtered in the lungs. Bubbles at the air-blood & airendothelial interfaces are highly reactive, initiating thrombotic and inflammatory processes. e. Barotrauma is unlikely to be at play here. Barotrauma occurs due to rapid changes in pressure that result in corresponding changes in the volume of air in a fixed space (recall Boyle's Law: P1V1 = P2V2; or the volume of a gas will vary inversely with pressure). Barotrauma can affect any air-filled part of the body, though the most common site is the middle ear due to inability of the eustachian tube to equilibrate the pressure changes in that small cavity. Other sites of non-pulmonary barotrauma include: the sinuses, teeth, the face (covered by the dive mask), and rarely the gastrointestinal (GI) tract. Pulmonary barotrauma is less common but can be more severe. This occurs when a diver ascends rapidly while breath holding. The manifestations include: pneumomediastinum, pneumothorax, and arterial gas embolism (AGE). The damaged lung parenchyma from over inflation allows large air bubbles to escape into the pulmonary circulation. These bubbles can traverse the left heart and embolize to the cerebral circulation. Thus, AGE presents with stroke-like symptoms rapidly after surfacing (usually within 10 minutes of surfacing). This type of diving related illness does not require prolonged duration or deep depth, only rapid ascent to the surface. f. Gas toxicity primarily relates to a phenomenon called nitrogen narcosis. This refers to the intoxicating effect of breathing inert gas (nitrogen) at high partial pressures. It affects individuals differently, but usually is not seen at depths less than 100 feet of sea water. Symptoms include: loss of judgment, skill, or concern, euphoria (similar to alcohol intoxication), and inappropriate laughter. Oxygen can also cause side effects at high partial pressures, but this is only noted with prolonged exposures. This patient's symptoms are not consistent with gas toxicity. g. While musculoskeletal injury is always a possible etiology for acute joint pain, the context of this dive requires serious consideration for DCS and empiric treatment for it. 2. What is the best treatment modality for each diving related diagnosis?

DIDACTICS AND HANDS-ON CURRICULUM
a. The treatment for any DCS is compression in a hyperbaric oxygen (HBO) chamber. The basis for this treatment is recompression followed by slow decompression to allow the nitrogen to be washed out without trapping bubbles in the joints and microvasculature. Additionally, 100% oxygen is breathed during the treatment to avoid additional nitrogen loading. A qualified hyperbaric physician should be consulted for specific HBO protocols. The Divers Alert Network (DAN) is a good resource for community physicians in the United States (DAN Hotline: 919-684-9111). b. Emergent hyperbaric oxygen treatment is also the answer for AGE, though the mechanism is somewhat different. In this case, the rapid recompression eliminates the bubble in the cerebral circulation that is causing ischemia. c. Treatment for the other types of barotrauma is primarily supportive, though close observation for worsening is often warranted. Gas toxicity is self-limited and resolves with return to normal partial pressures of nitrogen or oxygen.
Case 2: A 38-year-old female from Miami, Florida is mountain climbing in Colorado. She is just starting her second day of climbing and is at 13,800 feet. She starts to get short of breath and develops a dry cough. She is now experiencing fatigue with minimal effort. The previous day she noted some mild headache and nausea but dismissed the symptoms. Her pulse is fast but other vital signs are unknown because she is not currently in a healthcare location. She reports compliance with recommended prophylactic medications. 1. What is the differential diagnosis for this patient? What other conditions should be considered and monitored for? a. The differential includes the spectrum of altitude-related illness. These conditions are all related to rapid ascent to high altitudes and the body's response to the resultant hypobaric, hypoxic environment. b. The most common and benign type of altitude illness is called acute mountain sickness (AMS). This is a syndrome of nonspecific symptoms usually seen above 10,000 feet. c. Simple diagnostic criteria for AMS include headache plus one of the following:

DIDACTICS AND HANDS-ON CURRICULUM
1. Gastrointestinal upset, such as anorexia, nausea, vomiting 2. General weakness or fatigue 3. Dizziness or lightheadedness 4. Difficulty sleeping. d. The risk factors for AMS include: Prior altitude illness, residence less than 2500 feet, exertion, and rapid ascent. e. The most likely etiology on the differential is a more severe form of altitude illness called high altitude pulmonary edema (HAPE). This is the most common fatal manifestation of altitude illness. The pathophysiology relates to hypoxia causing pulmonary vasoconstriction and subsequently edema. f. Clinical presentation of HAPE includes: 1. Dyspnea on exertion or resting dyspnea 2. Fatigue with minimal effort 3. Dry cough 4. Progressive tachypnea and tachycardia 5. Fever (common) 6. Pink or bloody sputum (late sign) 7. Rales in bilateral lung fields. 8. Acute mountain sickness is seen concomitantly with HAPE in 50% of patients afflicted by HAPE. g. Also on the differential, but less concerning for this patient is high altitude cerebral edema (HACE). This can also be severe and is thought to represent progression from mild AMS. The symptoms include those of AMS plus neurologic deficits (ataxia, seizures, speech changes, or altered mental status). Ataxia is the most common symptom. All patients with AMS must be monitored closely for progression to HACE because mortality exceeds 60% once coma is present. 2. What is the best treatment modality for each possible diagnosis? a. Acute mountain sickness usually peaks at 24-48 hours of altitude and resolves by 96 hours as acclimatization is achieved. Slow ascent with sleep at lower altitudes is the best prevention. Medications can be used prophylactically with acetazolamide 125mg twice daily being used most commonly. Acute treatment of AMS includes no further ascent until 5. Explore the initial management of electrical injuries and how triage of a mass casualty lightning strike differs from standard mass casualty triage. 6. Define the difference between radiation exposure and radiologic contamination. 7. Discuss the concept of time/distance/shielding related to radiation exposure. 8. List the expected manifestations of acute radiation sickness based on the dose absorbed.

Case Studies
Case 1: A 10-month-old male presents to the emergency department (ED) via ambulance. The patient was placed in a bathtub by his parent who subsequently left to get her cell phone for one minute. When she returned the infant was face down in the water, apneic and cyanotic. She called 911 and proceeded to give rescue breaths. When paramedics arrived, the patient was awake and coughing.

Question Prompts:
1. What is the pathophysiology of drowning and how does it lead to mortality? a. Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid. Drowning can be due to: submersion (the airway goes below the level of the surface of the liquid) or immersion (a liquid is splashed across a person's face, eg waterboarding). Respiratory impairment must be present for drowning to have occurred. b. Terms such as "near drowning," "dry or wet drowning," "secondary drowning," "active and passive drowning," and "delayed onset of respiratory distress" are no longer used. 4 c. Preferred terminology is non-fatal or fatal. Non-fatal drowning is where the drowning process is interrupted and the person survives. Fatal drowning is an event when the person dies during the drowning process at any stage. 4 d. The primary cause of mortality is related to pulmonary dysfunction. Aspirated water causes surfactant dysfunction and washout. An osmotic gradient is formed which damages the a. The major risk factor for pediatric drowning is inadequate supervision of small children. This includes lack of mitigating measures for residential areas such as a fence with locking gate around a pool, a pool cover, or buckets and tubs that are not emptied when not in use. Inground swimming pools without complete 4-sided isolation fencing are 60% more likely to be involved in drownings than those with 4-sided isolation fencing. b. Other more generalized risk factors include: neurological events (eg, epilepsy, stroke), cardiac events (eg, myocardial infarction, hypertrophic cardiomyopathy, dysrhythmia, long QT, and short QT), impaired judgement due to intoxication, trauma, or overdose. c. Mitigation measures can significantly decrease many of these risk factors. d. Hypothermia associated with drowning can provide a protective mechanism that allows persons to survive prolonged submersion episodes. Rate of cerebral oxygen consumption is reduced by ~ 5% for each reduction of 1°C in temperature within the range of 37°C to 20°C. For hypothermia to be protective, the body temperature must drop rapidly to prevent significant cerebral hypoxia before the metabolism slows. 3. What would be the appropriate diagnostic evaluation and management for this patient? What should the disposition be for this patient? a. The diagnostic tests to consider include: arterial blood gas (ABG), chemistry panel, electrocardiogram (ECG), chest X-ray and pulse oximetry monitoring. Secondary trauma should also be considered and may require more comprehensive imaging. b. Treatment begins with addressing airway, breathing and circulation (ABCs basic metabolic panel (BMP), creatine kinase (CK), coagulation studies, and urine myoglobin. ECG should be obtained in lightning injuries, though in lower voltage injuries ECG is unlikely to affect management. 5 The clinical importance of elevated troponin levels after electrical injury is unclear. 2. What delayed complication can occur due to an oral commissure burn from biting into an electrical cord? a. Burns to the oral commissure can be seen in toddlers who chew an electrical cord. Close follow-up is warranted due to risk of severe hemorrhage as the eschar comes off allowing bleeding from the labial artery. Fortunately, this is a rare complication (only 2 out of 48 in one case series) and generally will occur in a delayed fashion seven to ten days after initial injury. Other complications include contraction of the mouth leading to facial deformities. 3. Consider a different scenario: How is mass causality triage different in lightning strikes? a. Typical triage protocol would label an adult patient who is not breathing as deceased (black tag). However, in lightning strikes it is recommended to "reverse triage," where those in cardiopulmonary arrest are managed first. b. Despite these patients lacking vital signs and appearing deceased with fixed and dilated pupils, many have the potential for full recovery. c. Management of these patients follows standard Advanced Cardiac Life Support (ACLS) with high quality chest compressions, manual respirations, and defibrillation if in a shockable rhythm.
Case 3: A 12-year-old male and his 38-year-old mother are brought in by paramedics after an explosion at a nearby park. The explosive consisted of shrapnel and some sort of "radioactive material." The male patient is awake and alert with some open wounds noted to both lower extremities. The female has no obvious traumatic injuries, but she is very distressed and agitated. She has been following Twitter and is very concerned about their exposure to this "dirty bomb." Question Prompts: 1. What decontamination procedures should be done prior to medical evaluation? What is the priority for care of a contaminated patient? a. The most effective decontamination method is simply removing the clothing of a patient. This may reduce contamination by 90-95%. The next step is simply washing with copious soap and water. Decontaminate wounds first and then intact skin. Start with areas of the body with the highest measured levels. If open wounds are involved, scrubbing the wound with gauze and soap/water is advised. If there is significant contamination of hair, shaving can be performed. b. The medical triage and treatment of the radiologically contaminated patient is always the priority. If a patient is in extremis, then decontamination efforts can be delayed until medical stability is achieved. 1 This does not mean that screening for level of contamination cannot be done while medical resuscitation is being provided. It also does not mean that healthcare providers should not do as much as they can to protect themselves from formation can also develop, with necrosis seen in severe envenomation only. The action on the nervous system is not significant. There can occasionally be systemic manifestations with more severe bites. These may include nausea, vomiting, diaphoresis, hypotension, respiratory distress, and cardiovascular collapse. Fortunately, these severe presentations are rare, representing approximately 1% of envenomations. 1 d. The other type of venomous snake in North America is the Coral snake. Its bites result in little to no local damage. Instead, venom causes neuromuscular blockade that manifests as weakness, ptosis, cranial nerve palsies, dysarthria, and dysphagia. This can progress to full respiratory paralysis and death without treatment. e. Since the development of anti-venom, bites are rarely fatal. No deaths were reported from 1983 through 2006, and published case reports are in those that did not seek treatment. 4 2. What is the initial management for reptilian envenomation in the emergency department (ED) setting and what definitive care options exist? a. Envenomation care includes: Rapid transport to an ED, stabilization of airway, breathing and circulation (ABCs), antivenom therapy, and intensive care unit admission for those with severe systemic symptoms. Attempts to kill the snake are NOT recommended because this could result in additional bites. Sites of progressing erythema should be marked every fifteen minutes. b. Keep in mind that 25% of bites are dry bites, so patients with no symptoms or signs of actual envenomation after 6-8 hours of observation can safely be discharged home. Note this observation period is longer for coral snakes due to delayed manifestations; patients should be observed 24 hours before safe discharge after coral snake exposure. c. Local wound care should be provided in similar fashion to other traumatic wounds with cleansing of the area, update of tetanus immunization as indicated, and consideration of antibiotics (but only if there is concern for active infection and not recommended prophylactically). d. Lab workup includes: complete blood count (CBC) with manual differential and peripheral blood smear, prothrombin time (PT), activated partial thromboplastin time (PTT), international normalized ratio (INR), fibrinogen and split products, blood type and crossmatch, basic metabolic panel (BMP) and a urinalysis for myoglobinuria, arterial blood gas (ABG) and lactate level for patients with systemic symptoms. e. Antivenom is a polyvalent immune Fab product called CroFab. Pediatric CroFab dosages are the same as adult dosages because dosage of antivenin reflects the venom load, not a patient's size. Treatment is indicated in any patient with progressive local tissue effects, hematologic venom effects, and systemic signs attributable to venom. 5 It is suggested that administration of CroFab occur within 6 hours of envenomation. The usual initial dose is between 4 and 6 vials. After initial control of the envenomation is established, additional 2 or 4 or 6-vial doses may be administered every 6 hours for up to 18 hours (3 doses) until swelling halts or labs stabilize. 5 f. Treatments that are generally NOT recommended include: Use of tourniquets, excision of the bite site or fasciotomy, and use of a venom extractor.

Small Group Evaluation
The moderator demonstrated adequate knowledge of subject.

5) Strongly
Agree 4) Agree 3) Slightly Agree 2) Disagree 1) Strongly Disagree The moderator's facilitation of the conference facilitated my learning.

5) Strongly Agree 4) Agree 3) Slightly Agree 2) Disagree 1) Strongly Disagree
The overall discussion was relevant to the stated topic(s).

Preparation -was faculty well prepared?
Needs Improvement Effective Exemplary

Engaged residents -Encouraged discussion and actively participated, demonstrated enthusiasm?
Needs Improvement Effective Exemplary Strengths: Areas for Improvement: Reviewer Recommendations:

Preparation -was the resident facilitator well prepared?
Needs Improvement Effective Exemplary