My first exposure to hypothermia occurred at a very early age when a pediatrician told my mother that kids remained healthier if they slept in a cold room because it lowered the body's heart rate and other functions, placing it in a somewhat suspended state, much like that of a hibernating bear. So my mother had all the radiators on the second floor of our house removed.
Later, while taking scuba classes, I learned about the mammalian diving reflex. I was told that frigid water could trigger bradycardia and peripheral vasoconstriction, and that the reflex could send the body into a suspended state and allow an unconscious diver to survive for a significant period of time without actually breathing. It took only one dive below the cold-to-frigid thermocline level of a flooded quarry for me to appreciate how freezing water could slow my pulse and respiratory rates. I began to feel relaxed and lethargic, and I recognized the need to surface to a warmer level.
The rapidly growing practice of placing cardiac arrest patients into a hypothermic state in the field and continuing for 48 hours after ED admission is producing results that will knock you off your seat when they_re published. Some EMS systems are reporting up to a 300% increase in the number of resuscitated patients waking up and eventually being discharged from the hospital with no neurological deficit after receiving prehospital hypothermic resuscitation (HTR) as compared with the room temperature resuscitation we_ve done for decades.
If you really think about it, proof of the clinical impact of hypothermia has been around us all along. We_ve known that cooling injured skin, brain, bones and joints reduces swelling, hemorrhage, pain and associated complications after blunt subcutaneous injuries, sprains and the common hangover. And many of us have been drilled that, when confronted with a hypothermic cardiac arrest patient, we "can_t shock a cold heart," and the patient is to be resuscitated and not declared dead until they_re "warm and dead."
Remember how the Apollo 11 astronauts conserved precious oxygen (and battery life) after ship was crippled in space? They did so by lowering their body temperature and reducing electrical draw on their equipment. Making more sense?
We are finally realizing that the body_s organs are like Apollo 11. Some organs occasionally need to be cooled down to conserve vital oxygen and reduce demands on them until such time as we can repair them (through drugs, electricity or other interventions) and then power them back up slowly and carefully.
Hospitals have successfully re-warmed and resuscitated adults and children recovered from frigid outdoor settings or under water for more than an hour. So it shouldn_t be hard for you, and your medical director, to accept the fact that a few liters of cooled saline, cold packs and cooling devices can produce the same results if performed in the field.
When a thrombus slams into a narrowed artery, what you have to realize is that it doesn_t just clog it. The impact causes minute trauma and associated swelling, which can benefit from chilling to reduce that swelling and allow time for the heart and vessels to begin to heal at the site of the ˙injury.Ó In an unconscious stroke or cardiac arrest patient, the application of cold therapy is equally, if not more, important as its application to soft tissue injuries we can see, or the conscious patient is able to complain about.
Such visionaries as the late Dr. Peter Safar studied and postulated on brain and body resuscitation via HTR decades ago but weren_t able to live to see their research put into widespread practice. It_s encouraging to see many disciples of Safar moving ahead with the practice of hypothermic resuscitation.
HTR isn_t limited to patients resuscitated to the return of spontaneous circulation (ROSC). Many systems are moving toward HTR of all cardiac arrests, and others are adding it to their stroke and spinal-cord injury protocols, particularly after the dramatic case of Buffalo Bills tight end Kevin Everett, who suffered a severe spinal cord injury last year and wasn_t expected to ever walk again. On Jan. 31, Everett walked across the stage of The Oprah Winfrey Show and credited the prehospital HTR treatment for his miraculous recovery.
JEMS will help lead the charge for HTR by presenting continuous updates on HTR programs and results in JEMS, on JEMS.com, in our bi-weekly e-newsletters and at EMS Today. I encourage you to continue to watch for the impressive results from the early adopters of HTR and pass them along to the naysayers and traditionalists in your medical community who have a ˙coldÓ attitude toward this revolutionary new procedure.