1. Dr CY Yung ICU, PYNEH 19 June 2009
Fever in ICU
Dr CY Yung
ICU, PYNEH
19 June 2009

2. Fever in ICU Definition Methods of measuring body temperature
Commons causes
Non-infective causes
Use of antipyretics

3. Fever
New hypothalamic set point due to cytokines production in inflammatory status
Shivering and non-shivering thermogenesis
Heat conservation in the peripheries

4. Body Temperature
The traditional norm of 37°C is the mean axillary temperatures of healthy adults
Wunderlich CA, Sequine E. Medical thermometry and human temperature. New York: William Wood, 1871.
A more recent study revealed normal mean oral temperature of 36.8°C, with fever defined as >37.2 °C in the morning and >37.7°C in the afternoon by 99th percentile
A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich. Mackowiak PA; Wasserman SS; Levine MM JAMA 1992 Sep 23-30;268(12):

5. Definition of Fever
A body temperature above 38.3°C represents a fever and deserves further evaluation to search for an infection
Guidelines for evaluation of new fever in critically ill adult patients: 2008 update from the American College of Critical Care Medicine and the Infectious Diseases Society of America. O'Grady NP, Barie PSAmerican College of Critical Care Medicine; Infectious Diseases Society of America. Crit Care Med Apr;36(4):
Could be influenced by drugs, immune status, renal replacement therapy, etc.

6. Ways of Measure
Pulmonary artery and bladder temperatures closely represent core body temperature
Rectal, oral temperature are acceptable alternatives
Rectal temperature is ~ °C higher than core temperature, risks of injury, transmitting infection
Oral temperature shown to be reliable even in intubated patients
Temperature measurement in critically ill orally intubated adults: a comparison of pulmonary artery core, tympanic, and oral methods.Giuliano KK et al. Crit Care Med. (1999)

7. Ways of Measure
Infrared ear temperature is an acceptable way, but had shown poor agreement with PA temperature
Accuracy of an infrared tympanic thermometer. Amoateng-Adjepong Y et al.
Chest. (1999)
Axillary and temporal artery measurement had unacceptable vairations
Pulmonary artery > Intravesical > rectal > oral > tympanic

12. Post-operative Fever
15-40% after major surgery, but most are not associated with infection
Freischlag J, Busuttil RW. The value of postoperative fever evaluation. Surgery 1983; 94:
Usually resolved after 24-48hrs
Association with atelectasis, but no direct causal relationship
Lack of association between atelectasis and fever
Chest 107.n1 (Jan 1995): pp81(4). 

13. Bronchoscopy 5% of patients underwent FOB developed fever
Mean duration of 14 hrs
Maybe associated with underlying diagnosis and bleeding
Prospective Analysis of Clinical Characteristics and Risk Factors of Postbronchoscopy Fever
Chest - Volume 125, Issue 3 (March 2004)

14. Drug Fever Patient can be seriously ill
Common association: amphotericin, cephalosporins, penecillins, phenytoin, procainamide, quinidine
Less common: cimetidine, carbamaepine, hydralazine, rifampacin, streptokinase, vancomycin
Mackowiak PA, LeMaister CF. Drug Fever: a critical apprasal of conventional concepts. Ann Intern Med 1987;106:

15. Drug Fever Clinical features Rigors (53%) Myalgias (25%)
Leukocytosis (22%)
Eosinophillia (22%)
Rash (18%)
Hypotension (18%)
Mackowiak PA, LeMaister CF. Drug Fever: a critical apprasal of conventional concepts. Ann Intern Med 1987;106:
Mean lag time of starting drugs and manifestation is 21 days in one series
Cunha B. Drug fever: the importance of recognition. Postgrad Med 1986;80:

16. Drug Fever Differentials include drug induced hyperthemia
malignant hyperthermia, neuroleptic malignant syndrome, serotonin syndrome

17. Non-infectious Causes
Blood transfusion: febrile reactions occurs in 5% of patients
Acalculous cholecystitis: could be up to 1.5% of critically ill patients
Venous thromboembolism
Haemodialysis
Cerebral and myocardial infarction

18. Treating Fever
Mainly invitro evidence fever can increase immune response, by increasing production of antibodies and cytokines, activating T lymphocytes, enhancing phagocytosis by neutrophils
High body temperature also decrease replication of bacteria in animal models
Kluger M, Rothenburg BA. Fever and reduced iron: their interaction as a host defense response to bacterial infection. Science 1979;203:
There is still definite proof of how fever affect course of infection

19. Treating Fever Role of systemic corticosteriods
Postaglandin E2 mediates endogenous pyrogen production in pathogenesis of fever
Aspirin was widely used as antipyretics before discovery of Reye’s Syndrome in 1980’s
Acetaminophen and NSAID
Ibuprofen was shown superior in mean temperature reduction in children (1.84°C Vs 1.24°C)
Autret E. Comparative efficacy and tolerance of of ibuprufen syrup and acetaminophen syrup in children with pyrexia associated with infectious disesases and reated with antibiotics
Role of systemic corticosteriods

20. Treating Fever
Treating fever also reduced systemic symptoms of headache, myalagia and arthralgias
Some evidence suggested uncontrolled cytokines production in fever will lead to adverse outcome
Side effects of drugs

21. Stroke/Brain Injury
Shown in both animal and human studies that worsened clinical outcome
Combating hyperthermia in acute stroke: a significant clinical concern.
Ginsberg MD; Busto R Stroke 1998 Feb;29(2):529-34
Effects of poststroke pyrexia on stroke outcome : a meta-analysis of studies in patients. Hajat C; Hajat S; Sharma P Stroke 2000 Feb;31(2):410-4.
May also suggest underlying severity of brain damage
Body temperature in acute stroke: relation to stroke severity, infarct size, mortality, and outcome. Reith J; Jorgensen HS; Pedersen PM; Nakayama H; Raaschou HO; Jeppesen LL; Olsen TS Lancet 1996 Feb 17;347(8999):422-5
Suggested in AHA/ASA guideline for antipyretics