Therapeutic hypothermia is associated with a decrease in urine output in acute stroke patients.
OBJECTIVE
It is unclear what effect therapeutic hypothermia may have on renal function, because its effect has so far been primarily evaluated in settings in which there may be possible confounding perturbations in cardiovascular and renal physiology, such deep intraoperative hypothermia, general anesthesia, and post-cardiac arrest. We sought to determine if therapeutic hypothermia affects renal function in awake patients with normal renal function who were enrolled into a clinical trial of hypothermia plus intravenous thrombolysis for acute ischemic stroke.


METHODS
Eleven patients with normal renal function were cooled to 33°C for 24 h using an endovascular catheter, and then re-warmed over 12 h to 36.5°C, while hourly temperature, blood pressure, and fluid status data was recorded. Blood samples for blood urea nitrogen (BUN), creatinine, and hematocrit were drawn prior to treatment (baseline), immediately after hypothermia and re-warming (day 2), and again at day 7 or discharge, and values compared.


RESULTS
On initiation of cooling, temperatures dropped from a median pre-treatment value of 36.1°C (IQR: 35.8-36.4°C) to 33.1°C (IQR: 33.1-33.4°C). Urine output decreased 5.1 ml/h for every 1°C decrease in body temperature (p-value=0.001), with no associated serious adverse events. There were no statistically significant changes in BUN, creatinine, or hematocrit in the hypothermia patients.


CONCLUSIONS
Inducing hypothermia in patients with relatively unperturbed renal physiology results in a decrease in urine output that is linearly correlated with the decrease in core temperature. This has important implications for fluid management in patients undergoing therapeutic hypothermia.
Guluma
Kama Z
KZ
Department of Emergency Medicine, University of California San Diego Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8676, United States.
Liu
Lin
L
Hemmen
Thomas M
TM
Acharya
Aninda B
AB
Rapp
Karen S
KS
Raman
Rema
R
Lyden
Patrick D
PD
D000368:Aged; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D005260:Female; D006400:Hematocrit; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects*; D007668:Kidney / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000503:physiopathology* / Q000628:therapy*; D014556:Urine
D003404:Creatinine
Acta Anaesthesiol Scand. 1988 Nov;32(8):698-701
3213396
N Engl J Med. 2002 Feb 21;346(8):557-63
11856794
Resuscitation. 2010 Apr;81(4):393-7
20122776
Anaesthesia. 2006 Sep;61(9):873-7
16922754
Ann Thorac Surg. 2009 Feb;87(2):489-95
19161766
Acta Anaesthesiol Scand. 2007 Aug;51(7):866-71
17635393
Cerebrovasc Dis. 2002;13(2):127-31
11867887
Br J Anaesth. 1970 Jun;42(6):557
5423849
Arctic Med Res. 1991;50 Suppl 6:23-7
1811574
Arch Intern Med. 1993 Jan 25;153(2):235-9
8422211
Physiol Rev. 1978 Jul;58(3):529-81
356067
Ann Surg. 1957 Apr;145(4):488-99
13412025
Respir Care. 2004 Feb;49(2):192-205
14744270
Acad Emerg Med. 2006 Aug;13(8):820-7
16766740
Acta Neurol Scand. 1994 Jun;89(6):439-45
7976232
Crit Care Med. 2006 Jul;34(7):1865-73
16715035
Circulation. 2005 Dec 13;112(24 Suppl):IV1-203
16314375
Int Anesthesiol Clin. 1984 Spring;22(1):157-68
6392108
Crit Care Med. 2006 Jul;34(7):1935-40
16691134
J Neurosurg Anesthesiol. 1998 Jan;10(1):37-41
9438618
QJM. 2002 Dec;95(12):775-85
12454320
Eur J Appl Physiol. 2000 Mar;81(5):436-42
10751106
Stroke. 1990 Jul;21(7):1000-7
2368099
N Engl J Med. 2002 Feb 21;346(8):549-56
11856793
Resuscitation. 2004 Mar;60(3):253-61
15050756
J Appl Physiol. 1976 Apr;40(4):605-10
931882
Am J Physiol. 1985 May;248(5 Pt 2):R560-6
3993814
Crit Care Clin. 1987 Apr;3(2):373-93
3332204
Acta Anaesthesiol Scand. 2007 Feb;51(2):137-42
17181536
Intensive Care Med. 2001 Jul;27(7):1194-9
11534568
Resuscitation. 2003 Jun;57(3):231-5
12858857