 Welcome back to emergency medicine video series. In this segment, we will discuss the various rewarming techniques and the potential complications in the hypothermic patient. These rewarming techniques range from the least to the most invasive. As you can imagine, they also range from the slowest to the fastest way to rewarm the patient. For a patient who is in mild hypothermia, so 32 to 35 degrees Celsius, we will use passive external rewarming technique. That means dry, warm blankets, that is after the wet clothing has been removed in your primary survey, and p.o. hydration with dextrose containing drinks. This is a slow technique, and the patient needs to be able to produce heat to rewarm themselves. For moderate hypothermia, we will add active external rewarming technique. We will use forced air blankets that has warm air coming out from the little holes in the blanket themselves. We will give warmed IV fluids. We also would give warmed humidified oxygen. Since, as we discussed from part two, that 30% of the heat lost in the body comes from the lungs. Warm humidified oxygen decreases that amount of heat loss. For severe hypothermia, we will use all the above mentioned methods and then active internal rewarming. This method warms the different body cavities. There are four main body cavities that rewarm actively. First, the pleural space. Two chest tubes are inserted in each lung. Like so. Warm saline is pushed through two of the chest tubes and drain out through the remaining two. This is called pleural lavage. Next, the bladder. A three-way catheter is put in and warm fluid is used to do a continuous bladder irrigation. Third space is the peritoneal space. Two catheters are put in the peritoneal space. Similar to pleural lavage, warm fluid is put in through the first tube and drain through the second catheter. This is known as peritoneal lavage. The last system that will be warmed is the vascular system. We shove the blood into a warming device and then give it back to the patient. It can be done by dialysis or we can do this through bypass. It can be done by traditional cardiopulmonary bypass or through ECMO, which stands for extra corporeal membrane oxygenation. These are done in conjunction with specialists. The basic premise is that the blood is shunted through something that warms them and returned back to the patient warmed. What complications can occur with rewarming? When we start to warm up the central core of the patient, heat can still conduct from the relatively warmer core to the peripheral tissues. That will cause the core temperature to drop. This is called afterdrop. When we apply heat, we will cause peripheral vasodilation. That can cause hypotension, not so known as rewarming shock. Lastly, lactic acid from peripheral tissue can decrease the pH of the blood once it goes back into central circulation. Once the peripheral tissues start to rewarm, it can cause increased metabolic demand on the hypothermic heart. That might also cause more acidosis. In terms of disposition, patients with moderate to severe hypothermia, especially those who have had active internal rewarming, need to stay in the hospital. To summarize, we've discussed the causes and effects of hypothermia, the approach and the rewarming techniques you might want to use in the emergency department for these patients. Thank you for watching.