- Author: James Li, MD; Chief Editor: Joe Alcock, MD, MS more...
Arterial blood gas determination includes the following:
Blood gas analyzers warm blood to 37°C.
Because gasses are less soluble in hypothermic plasma, arterial blood gas (ABG) level may show higher oxygen and carbon dioxide levels and a lower pH than a patient's actual values as the blood is warmed in the ABG machinery.
The best approach is to expect uncorrected ABG values compared with the normal values at 37°C.
An uncorrected pH at 7.4 and pCO 2 at 40 mm Hg reflect acid-base balance.
Many hypothermic patients are volume contracted because of cold diuresis. As a result, hematocrit level may be deceptively high. Hematocrit levels may increase 2% for each 1°C drop in core temperature.
Hypothermia may present with wide fluctuations in electrolytes, and no clear trend or predictability exists as to when a patient's electrolytes will be abnormal or how large swings may be. Plasma potassium levels can be useful in evaluating prognosis. A level of 10 mmol/L or greater is associated with a very low likelihood of recovery. Classic ECG changes of hyperkalemia may be absent or diminished. Chronic hypothermia occasionally can lead to hypokalemia.
Acute hypothermia can result in hyperglycemia, while chronic hypothermia or secondary hypothermia may present with low blood glucose level.
The body's coagulation mechanism is often disrupted in moderate or severe hypothermia, and a disseminated intervascular coagulation–type syndrome can be present.
Coagulopathy has several causes. The primary issue is disruption of enzymatic reactions of the clotting cascade caused by protein denaturization at decreased temperature.
Because the kinetic tests of coagulation are performed at 37°C in the laboratory, a clinically evident coagulopathy may not be reflected by deceptively normal laboratory values.
A chest radiograph is indicated in patients with hypoxia. Aspiration pneumonia and pulmonary edema are common findings.
Patients with trauma or altered mental status of indeterminate cause may need a noncontrast head CT scan and further imaging for a standard trauma evaluation.
The ECG may show prolonged PR, QRS, and QT intervals, and atrial or ventricular arrhythmias. The length and height of the respective QT-interval prolongation and characteristic J (Osborne) waves are often proportional to the degree of hypothermia.
Polderman KH. Mechanisms of action, physiological effects, and complications of hypothermia. Crit Care Med. 2009 Jul. 37(7 Suppl):S186-202. [Medline].
Long WB 3rd, Edlich RF, Winters KL, Britt LD. Cold injuries. J Long Term Eff Med Implants. 2005. 15(1):67-78. [Medline].
Sessler DI. Thermoregulatory defense mechanisms. Crit Care Med. 2009 Jul. 37(7 Suppl):S203-10. [Medline].
Centers for Disease Control and Prevention. Number of Hypothermia-Related Deaths, by Sex - National Vital Statistics System, United States, 1999–2011. Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6151a6.htm. Accessed: August 22, 2014.
McCullough L, Arora S. Diagnosis and treatment of hypothermia. Am Fam Physician. 2004 Dec 15. 70(12):2325-32. [Medline].
Buckley JJ, Bosch OK, Bacaner MB. Prevention of ventricular fibrillation during hypothermia with bretylium tosylate. Anesth Analg. 1971 Jul-Aug. 50(4):587-93. [Medline].
Murphy K, Nowak RM, Tomlanovich MC. Use of bretylium tosylate as prophylaxis and treatment in hypothermic ventricular fibrillation in the canine model. Ann Emerg Med. 1986 Oct. 15(10):1160-6. [Medline].
[Guideline] Zafren K, Giesbrecht GG, Danzl DF, Brugger H, Sagalyn EB, Walpoth B, et al. Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2014 update. Wilderness Environ Med. 2014 Dec. 25 (4 Suppl):S66-85. [Medline].
[Guideline] ECC Committee, Subcommittees and Task Forces of the American Heart Association. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010 Nov. 122(18):Suppl 3.
Brown DJ, Brugger H, Boyd J, Paal P. Accidental hypothermia. N Engl J Med. 2012 Nov 15. 367(20):1930-8. [Medline].
Boué Y, Payen JF, Brun J, Thomas S, Levrat A, Blancher M, et al. Survival after avalanche-induced cardiac arrest. Resuscitation. 2014 Sep. 85(9):1192-6. [Medline].
Darocha T, Kosiński S, Jarosz A, Drwila R. Extracorporeal Rewarming From Accidental Hypothermia of Patient With Suspected Trauma. Medicine (Baltimore). 2015 Jul. 94 (27):e1086. [Medline].
Laniewicz M, Lyn-Kew K, Silbergleit R. Rapid endovascular warming for profound hypothermia. Ann Emerg Med. 2008 Feb. 51(2):160-3. [Medline].
Romlin BS, Winberg H, Janson M, Nilsson B, Björk K, Jeppsson A, et al. Excellent Outcome With Extracorporeal Membrane Oxygenation After Accidental Profound Hypothermia (13.8°C) and Drowning. Crit Care Med. 2015 Nov. 43 (11):e521-5. [Medline].