Editing Hypothermia (section)

==Diagnosis==
[[Image:HypothermiaECG.jpg|thumb|upright=1.4|[[Atrial fibrillation]] and [[Osborn wave|Osborn J wave]]s in a person with hypothermia. Note what could be mistaken for [[ST elevation]].]]

Accurate determination of core temperature often requires a special low temperature thermometer, as most clinical thermometers do not measure accurately below {{convert|34.4|C|F}}.<ref name="McCullough L, Arora S 2004 2325–32"/> A low temperature thermometer can be placed in the rectum, esophagus or bladder. Esophageal measurements are the most accurate and are recommended once a person is [[intubated]].<ref name="NEJM 2012" /> Other methods of measurement such as in the mouth, under the arm, or using an [[infrared]] ear thermometer are often not accurate.<ref name="NEJM 2012" />

As a hypothermic person's heart rate may be very slow, prolonged feeling for a pulse could be required before detecting. In 2005, the [[American Heart Association]] recommended at least 30–45 seconds to verify the absence of a pulse before initiating CPR.<ref name="ACLS 2005">{{cite journal | author=ECC Committee, Subcommittees and Task Forces of the American Heart Association | title=2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care | journal=Circulation | volume=112 | issue=24 Suppl | pages=IV–136 | date=December 2005 | pmid=16314375 | doi=10.1161/CIRCULATIONAHA.105.166550 | url=http://circ.ahajournals.org/cgi/content/full/112/24_suppl/IV-136 | url-status=live | archive-url=https://web.archive.org/web/20110324012223/http://circ.ahajournals.org/cgi/content/full/112/24_suppl/IV-136 | archive-date=2011-03-24 | doi-access= }}</ref> Others recommend a 60-second check.<ref name="NEJM 2012" />

The classical ECG finding of hypothermia is the Osborn J wave. Also, [[ventricular fibrillation]] frequently occurs below {{convert|28|C|F}} and [[asystole]] below {{convert|20|C|F}}.<ref name="Care 1999">{{cite journal |vauthors=Hanania NA, Zimmerman JL | title=Accidental hypothermia | journal=Critical Care Clinics | volume=15 | issue=2 | pages=235–49 | year=1999 | pmid=10331126 | doi=10.1016/s0749-0704(05)70052-x}}</ref> The Osborn J may look very similar to those of an acute ST elevation [[myocardial infarction]].<ref name="Marx 2010 p.1869"/> [[Thrombolysis]] as a reaction to the presence of Osborn J waves is not indicated, as it would only worsen the underlying [[coagulopathy]] caused by hypothermia.