Active internal rewarming Rewarming Rewarming can be achieved using a number of different methods including passive external rewarming, active external rewarming, and active internal rewarming. Passive external rewarming
This involves the use of a person's own heat generating ability through the provision of properly insulated dry clothing and moving to a warm environment. Active external rewarming
This involves applying warming devices externally such as hot water bottles or warmed forced air (Bair Hugger). In austere environments this is often done by placing a hot water bottle in both armpits. Another method is to place the person in a tub with hot water (of 44°C), and place their arms and legs outside of the tub/hot water. Active core rewarming
This involves the use of intravenous warmed fluids, irrigation of body cavities with warmed fluids (the thorax, peritoneal, stomach, or bladder), use of warm humidified inhaled air, or use of extracorporeal rewarming such as via a heart lung machine. Intravenous fluids As most people are moderately dehydrated due to hypothermia induced cold diuresis intravenous access and intravenous fluids are often helpful ( 250 - 500 cc 5 percent dextrose and normal saline is often recommended at a temperature of 40 -45 C ) . Rewarming collapse Rewarming collapse ( or rewarming shock ) is a sudden drop in blood pressure in combination with a low cardiac output which may occur during active treatment of a severely hypothermic person. There is theoretical concerns that external rewarming rather than internal rewarming may increase the risk. However recent studies have not supported these concerns. |