Editor’s Note: We asked columnist Patrick Lickiss to pick a winner to this month’s challenge and he wrote: “The winner this month will be John Golden. John selected the working diagnosis of hypothermia with the complication of sepsis, possibly due to an upper respiratory infection. John also realized that a pulse oximeter may not read reliably in a patient with cold extremities. Additionally, he identified a possibility of substance abuse. Nicely done!”
You have just loaded George into the ambulance, out of the cold environment he had been in for a few hours. You know his medical history is complex and there’s probably more here than meets the eye.
Discussion
Around the northern hemisphere, EMS systems have moved toward wintertime operations. Along with effects on day-to-day staffing and logistics, the dropping temperature has clinical implications. Exposure to cold environments can increase the severity of pre-existing medical conditions and can constitute its own medical emergency.
Heat is transferred from the body to the environment through several mechanisms: conduction, convection, radiation and evaporation. Conduction occurs with direct contact to a surface that is colder than the body. A field example of conductive heat loss would be a lightly dressed patient lying on a tile floor.
Convection is heat transfer into a fluid moving around the heat source. For the purposes of physics, air is considered a fluid. A patient experiences convective heat loss when wind pushes cold air past their body.
Radiation is the loss of heat in the form of infrared energy into the surrounding environment, which occurs when there is no wind.
Evaporation is cooling during the conversion of a liquid to a gas. While this occurs during sweating in the summer, it also takes place when the clothes (or body) are wet.
Hypothermia is the terminology used for patients suffering from significant heat loss. There are three types of hypothermia: mild, moderate and severe.[1] Mild hypothermia occurs at body temperatures from 95°F (35°C) to 90°F (32.2°C), and patients present initially with signs of the body’s compensatory mechanism: shivering, tachycardia, tachypnea and hypertension (from vascular constriction).
After time a mildly hypothermic patient will become apathetic and may demonstrate difficulty walking and poor judgment. These patients have been known to undress despite cold temperatures. Treatment for mild hypothermia involves moving the patient to a warm environment, removing any wet clothes, wrapping them in blankets and protecting from exposure to the wind.
Heat packs or warm blankets may be placed in the groin, axillae and neck, and warmed humidified oxygen may be given.
Moderate hypothermia occurs between body temperatures of 90°F (32.2°C) and 82.4°F (28°C). Symptoms include bradycardia, decreasing level of consciousness, slowing respiratory rate, hypotension and cessation of shivering. Patients with moderate hypothermia should have a blood glucose check performed and should be aggressively re-warmed. If available, these patients may be given warmed IV fluids.
Severe hypothermia occurs at core temperatures of less than 82.4°F (28°C). Patients with severe hypothermia may present with apnea, coma and cardiac arrest. For patients with hypothermia and in cardiac arrest, the American Heart Association has specific guidelines that affect both BLS and ALS care.[2] In the previous version of the AHA guidelines, the recommendation was made to limit defibrillation attempts to one and administer only one round of cardiac medications if the patient’s core temperature was below 86°F (30°C).
In the current guidelines, however, the statement has been softened, with deferring subsequent defibrillation and rounds of medication being classified as “Class IIb LOE C”, which means that the likely benefit (of deferring) outweighs the risk, but that the evidence supporting that position is comprised mostly of case studies and expert opinion. EMS providers should reference their local medical direction and protocols for recommendation on the resuscitation of hypothermic cardiac arrest patients.
In addition to cardiac arrest care, there are several other special considerations regarding assessing and treating patients with hypothermia. The first is that patients who spend all their time outdoors throughout the winter are potentially suffering from mild hypothermia on a regular basis. Additionally, such patients may suffer from chronic respiratory infections and may be septic, which can predispose them to hypothermia.
When planning to treat patients in the winter months, realize that the bags of IV solution in the ambulance cabinets are likely close to the ambient temperature of the vehicle. Care should be exercised when deciding what volume of fluid to give to these patients.
Finally, consider running the heater continuously in the back of the ambulance to maintain a comfortable temperature in the patient compartment.
Treatment
George’s detailed secondary exam reveals no signs of trauma. Based on his history of upper respiratory infection and vital signs, you suspect that he is septic. Additionally, a finger stick blood glucose returns a value of 455 mg/dL. George’s core feels cold to the touch and his fingers are blue. You move him to the gurney and into the ambulance.
Your partner establishes an IV and begins to run in warm saline as the ambulance heater runs on high. You are unable to obtain a temperature on the patient’s forehead. You transport to the local emergency department, where George’s esophageal temperature is found to be 88°F. George undergoes rewarming in the ED and has his blood sugar brought back under control. He is admitted for treatment of pneumonia and sepsis and is discharged 6 days later.
References
- McCullough, Lynne, and Sanjay Arora. “Diagnosis and Treatment of Hypothermia.” American Family Physician 70.12 (2004): 2325-2332. Print.
- Vanden Hoek, Terry L., Laurie J. Morrison, Michael Shuster, Michael Donnino, Elizabeth Sinz, Eric J. Lavonas, Farida M. Jeejeebhoy, and Andrea Gabriello. “2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science - Part 12: Cardiac Arrest in Special Situations.”Circulation 122(2010): S829-S861. Print.
