Question about Hypothermia

I think it's 32 C that causes v-fib. Other arrhythmias may be caused in hypothermia that is not as severe, but I recall from class that in cardiac surgery patients, that 32 C is the critical temp when almost all patients go into v-vib. ANyone else?

Here are some approximate numbers from Duke's Anesthesia Secrets:

~32 - J waves, although these aren't necessarily specific for hypothermia

~30 - nodal rhythms

Here are some approximate numbers from Duke's Anesthesia Secrets:

~32 - J waves, although these aren't necessarily specific for hypothermia

~30 - nodal rhythms

You'll see problems way before you get down to 28degC.

most i work with have taught us that if the temp

In some cases, we induce hypothermia in patients that have suffered out of hospital cardiac arrest with prolonged resuscitation time and our protocol targets a cooling temp between 32-34 degrees and we rarely see any arrhythmias. Although I will say, some of these patients are on antiarrhytmics secondary to the cardiac arrest, but not all of 'em. I know situation is different from patients in the OR, but thought it was interesting enough to share.

Blake

most i work with have taught us that if the temp

most i work with have taught us that if the temp

Is this for all cases of hypothermia, or just for surgery and cases where hypothermia is the primary symptom? When I was admitted to the ED for a GI bleed (I lost about 4 units of blood), my temperature was about 34 degrees oral. They kept me naked the entire time I was in the ED, but I was completely awake, alert and oriented, and not feeling cold. It was not until I was transferred to the Critical Care Unit and uncovered again while I changed beds that I felt cold and begain to shiver. Once I was covered again, I was ok. I am not criticizing the ED, as they did a fine job, I am just curious.

those numbers were for patients in the OR where hypothermia was not induced.

Cardiac arrhythmias during rewarming of patients with accidental hypothermia.

Rankin AC, Rae AP.

Accidental hypothermia has a high mortality and is associated with cardiac arrhythmias. To determine the incidence of arrhythmias and their importance 22 patients with accidental hypothermia (core temperature less than 35 degrees C) were studied by 12 lead electrocardiography and continuous recording of cardiac rhythm. Although 14 of the patients died (64%), only six died while hypothermic. Prolongation of the Q-T interval and the presence of J waves were related to the severity of the hypothermia. Supraventricular arrhythmias, including atrial fibrillation, were common (nine cases) and benign. Ventricular extrasystoles were also common (10 cases), but ventricular tachycardia or fibrillation did not occur during rewarming. In eight patients who died while being monitored the terminal rhythm was asystole. There was no correlation between the severity of hypothermia or the rate of rewarming and the clinical outcome. In the absence of malignant arrhythmias there is no indication for using prophylactic antiarrhythmic treatment in patients with accidental hypothermia. The presence or absence of severe underlying disease is the main determinant of prognosis.

I work in an ER and this week I had an interesting case dealing with severe hypothermia. An elderly person spent two days and nights outside after falling. (night time temp dipping to 40-41 degrees F.) When patient came in our digital thermometer would only read

Patient was bradycardic with a HR of 38 BPM. EKG had Osborn waves. Needless to say, we were aggressive in our efforts to rewarm the patient. I had the patient in the ER for about 3 hours before I was able to admit to ICU. Attempted 3 times to get a temperature, never was able to. The patients HR did come up to about 58 by the time of admission to the unit. Prognosis was poor for this patient.

Two days later, the patient is moved to the med/surg floor, is A/O X3 with little or no neurological effects. Kidneys were in pretty bad shape with increased BUN/CREAT but are getting better. Looks like patient will be OK.

Except for having severe bradycardia this patient had no arrythmias with a core temperature that appeared to be less than 75 degrees.

Jetman

With manipulation of the heart, v-fib/asystole occurs @ ~32 degrees. Without manipulation of the heart, v-fib/asystole occurs @ ~28-30 degrees.

We were talking about hypothermia in class the other day and was asked about hypothermia's role in causing arrythmias. Does anyone know the temperature at which arrythmias DO occur in humans? Thanks!

most i work with have taught us that if the temp At 35 deg the bodys shivering and ability to produce heat is at its maximum. Below that the ability to produce heat decreases gradually and at a temp of 28 there is virtually no ability to produce heat and at 26 the body is poikilotherm, will eventually reach the temperature of its surroundings.

Theoretically passive warming could work from a temp of >28. In the hospital setting we use active measures, like a warm air blanket, Bair Hug, if the pat shivers or is very cold even if the temp is over 35 deg. For lower temperatures there are many different methods of active warming.

There is records of a patient surviving from accidental hypothermia with a temp of 13.7 degrees