Temperature measurement for critically ill adults

Abnormal temperature can pose risks for or herald the onset of serious complications for critically ill adults. For this reason, accurate measurement of temperature is important to ensure patients receive appropriate and timely interventions to prevent significant morbidity and mortality. The clinical question underpinning this guideline is:

“What method(s) of measuring body temperature ensure(s) the timely identification of abnormal temperatures in critically ill adults?”

Temperature measurement for critically ill adults: A clinical practice guideline is provided to guide the development of local practices to support the accurate and timely measurement of temperature in critically ill adults. Specific guidance is required because surface temperature methods (1, 2) are still used despite long-standing evidence regarding their inaccuracy (3-6).

Decisions regarding temperature measurement and interventions should be guided by how important a patient’s temperature is within the full scope of diagnosis, treatment and potential complications. More invasive and continuous methods should be utilised where identification of an accurate temperature is time-critical and significant to patient outcomes.

Read more of the background to temperature measurement.

Temperature measurement for critically ill adults


How to measure temperature

Pathophysiology of fever

Pathophysiology of hypothermia

Recommendations for practice




Assessment and clinical practice


Critically ill unstable patients (see Definitions for patient groups) require continuous invasive temperature (using brain, intra-vascular or urinary bladder) monitoring that is recorded at least hourly.




Complex patients (see Definitions for patient groups) require invasive temperature (using brain, intra-vascular or urinary bladder) measurement that is recorded at least second hourly.




For routine monitoring of stable patients (see Definitions for patient groups) measurement of temperature, using either oral or axillary methods, is required at least four-hourly.


(3, 13, 14)


Tympanic or temporal artery temperature measurement methods should not be used, as these methods do not accurately reflect core body temperature.


(4-6, 10, 15, 16)

Infection prevention and Work Health and Safety


Clinicians should undertake a risk assessment to identity the risk of contamination and mucosal or conjunctival splash injuries when taking a patient’s temperature; and personal protective equipment (including goggles/face shield/gloves and gown/apron) as per NSW 2007 Infection control policy should be worn accordingly.

National and NSW Policy


Clinicians must adhere to the five moments of hand hygiene.

Hand hygiene policy


To reduce the risk of microbial transmission, ICUs should consider having either

an electronic thermometer at each bed area, or disposable single-use thermometers.



To reduce the risk of microbial transmission where patients are considered stable but are isolated, ICUs might consider the use of disposable single-use thermometers.



Electronic thermometers must be cleaned between patients. This includes where equipment is shared between bed areas and when a patient is discharged.



Clinicians should refer to state or local indwelling urinary catheter management guidelines to minimise CAUTI.




To facilitate rapid detection and treatment of abnormal temperatures, ICUs should consider developing standard definitions and interventions for hyperthermia and hypothermia.



Fever control including administration of anti-pyretics should not be commenced without consultation with senior Medical Officers.


(17, 18)


Staff should receive education on:

  • correct use and calibration of equipment
  • local definitions and standard treatments for abnormal temperatures.



Education related to temperature measurement should be included in patient assessment practices.



Evaluation of adherence to this guideline should be incorporated into the audit of clinical practices related to patient assessment.


The evidence review for these recommendations was current to May 2012. Clinicians are advised to check the literature as research may have been published that change these recommendations

Guideline development information

For more details on guideline development please refer to full document.

Health question/s at focus of clinical practice

Temperatures outside normal homeostatic ranges may pose risks for or herald the onset of significant complications in critically ill patients. Accurate measurement of temperature is important to ensure patients receive appropriate and timely interventions. The clinical question underpinning this guideline is “What method(s) of measuring body temperature ensure(s) the timely identification of abnormal temperatures in critically ill adults?”.


This guideline is provided so that acute care facilities can develop local practices to support the accurate measurement of temperature in critically ill adults (individuals aged older than 14). It does not include recommendations regarding when to undertake a blood cultures or a septic work up. It does not include practices concerning therapeutic thermoregulation, except advice regarding temperature measurement.

Target clinicians

This guideline is aimed at clinicians who care for critically ill adults across acute care hospitals in NSW. Specifically it refers to nursing staff as this clinical practice falls within their scope of practice. Medical Officers were consulted and included during consensus development.

How the guideline was developed

Guideline development methods were based on Rolls and Elliott (19) which was revised to reflect updates from NHMRC (20) and the AGREE tool (21). A guideline development network (GDN) was formed. This network developed the guideline template that outlined the clinical question and specific areas to be addressed within the guideline. Following this, a systematic review was undertaken (for more details see below). The practice review was restricted to a review of local practices from the experience of GDN members. No ICUs had specific practices related to temperature measurement. A technical report was developed from the systematic review and this document was used to inform discussions and recommendation development at the consensus meeting (November 27, 2012). NHMRC evidence statement forms were created and formed our evidence audit trail. Following the meeting, the guideline document was written and circulated among group members. Consensus development and organisational consultation was undertaken over three stages:

  1. Guideline group consensus – two intensive care doctors were recruited. This larger guideline group received the guideline and technical report. Agreement on recommendations was undertaken using an online survey (Survey Monkey) and a 1-9 Likert scale. Consensus was set as a median of ≥ 7 (see Consensus results).
  2. External validation consensus – another clinician group was recruited from NSW and their agreement with the recommendation statements was sought using the processes outlined above (see Table 5).
  3. Organisational consultation was undertaken by distribution via ACI critical care networks. No additional feedback was forwarded The guideline was revised to reflect feedback received at each stage of the process.

Consensus results

 Median (interquartile range)
Recommendation numberInternal consensusExternal consensus
19 (8.5-9)8 (7-9)
29 (6.5-9)8 (8-9)
39 (7-9)8 (7-8)
49 (9)8 (8-9)
59 (9)8 (8-9)
69 (9)8 (7-9)
79 (9)7 (7-9)
89 (7.5-9)9 (8-9)
99 (9-9)8 (8-9)
109 (8.75-9)8 (8-9)
119 (8.75-9)8 (7-9)
129 (7.75-9)8 (8-9)
139 (9)8 (7-9)
149 (9)8 (7-9)
159 (8.5-9)8 (7-8)

Guideline group

The GDN was comprised of senior nurses working in NSW ICUs as well as a nursing academic. This group undertook the bulk of work for the guideline. The GDN members were:

  • Kay Rolls, Critical Care Specialist, ICCMU, Agency for Clinical Innovation
  • Dr Sandra Walker, Nurse academic, Central Queensland University
  • Lawrence Keating, Critical Care Specialist Nurse, St George Hospital, South Eastern Sydney LHD
  • Deidre Wrightson, Critical Care Specialist Nurse, Wollongong Hospital, South Eastern Sydney LHD
  • Karyn Armstrong, Critical Care Specialist Nurse, Bankstown Hospital, South Western Sydney LHD
  • Sally Irwin, Critical Care Specialist Nurse, North Coast LHD

Evidence review

A systematic literature review was undertaken using the following clinical question: “What method(s) of temperature measurement accurately identifies body temperature in critically ill adults?” An electronic search of the main health databases was undertaken using the MeSH terms or keywords that mapped to temperature and critical illness. Limits included: 1) 2000-May 2012; 2) English language; 3) older than 14; 4) human studies; 5) peer-reviewed; and 6) abstract available. Thirty-one papers were reviewed by two guideline group members using a standardised data extraction tool with quality assessment.

The systematic review revealed that the evidence base for temperature measurement in critically ill adults is limited by the research methods used and comparison between thermometry methods. Twenty four papers, including 17 Level III-2 studies (observational with repeated measures), four systematic reviews and three guidelines, were used in the final review. Only nine studies had a low risk of bias (see Appendix 1 and Appendix 2 in guideline).  The most common problems with the quality of the studies were failure to ensure high inter-rater reliability, adequate sample size, appropriate procedures and application of Bland-Altman analysis.

Grading of recommendation taxonomy

Grade of recommendation



Body of evidence can be trusted to guide evidence


Body of evidence can be trusted to guide practice in most situations


Body of evidence provides some support for recommendation/s but care should be taken in its application


Body of evidence is weak and recommendation must be applied with caution


Consensus was set as a median of ≥ 7

Grades A–D are based on NHMRC grades (22)

Definitions for patient groups

Critically ill and unstable




Patients with significant haemodynamic, respiratory, thermoregulatory or neurological instability.

Patients whose condition is stable, however have potential for complication or deterioration.

Patients who do not require intense or invasive physiological monitoring.

Patient groups – examples only

  • Multiple organ dysfunction
  • Multi trauma
  • Traumatic brain injury (23)
  • Severe sepsis
  • Burns
  • Post-op cardiothoracic surgery
  • Major surgery (25)
  • Ventilated patients
  • Acute stroke (26)
  • Sepsis
  • Routine post op
  • DKA
  • Cleared for discharge

Treatment –examples only

  • Therapeutic thermoregulation (12)
  • Massive blood transfusion (24)
  • Rapid fluid resuscitation
  • Blood product transfusion
  • Invasively ventilated
  • NiPPV

Please note this table is provided as a GUIDE only. Units should decide how these definitions relate to their patient population.



Body mass index


Body surface area


Catheter associated urinary tract infection


Data collector




Guideline development network


Intensive care units


Indwelling urinary catheter


Inter-rater reliability


Non-invasive continuous cerebral temperature


Non-invasive positive pressure ventilation


Pulmonary artery catheter


Pulse contour cardiac output




Axillary temperature


Direct bBrain temperature


Forehead temperature


Inguinal temperature


Oral temperature


Oesophageal temperature


Pulmonary artery temperature


Rectal temperature


Tympanic Temperature


Temporal artery temperature


Urinary bladder temperature


Thromboembolic device


The branch of physics concerned with the measurement of temperature and the design and use of thermometers.


  1. Hammond NE, Saxena M, Young P, Taylor. C., Seppelt I, Glass P, et al. Temperature management for patients without brain injury in Australia and New Zealand ICUs: a point prevalence study. Critical Care. 2012;16(supplement 1):p58.
  2. Johnston NJ, King AT, Proteroe R, Child C. Body temperature measurement after severe traumatic brain injury: methods and protocols used in the United Kingdom and Ireland. Resuscitation. 2006;70:254-62.
  3. Hooper VD, Andrews JO. Accuracy of noninvasive core temperature measurement in acutely ill adults: the state of the science. Biological Research for Nursing. 2006;8(1):24-34.
  4. Khan T, Vohra H, Paul S, Rosin M, Patel R. Axillary and tympanic membrane temperature measurements are unreliable early after cardiopulmonary bypass. European Journal of Anaesthesiology (EJA). 2006;23(7):551&hyhen.
  5. Giuliano KK, Giuliano AJ, Scott SS, Maclachlan E, Pysznik E, Elliot S, et al. Temperature measurement in critically ill adults: a comparison of typmpanic and oral methods. American Journal of Critical Care. 2000;9:254-61.
  6. Farnell S, Maxwell L, Tan S, Rhodes A, Philips B. Temperature measurement: comparison of non-invasive methods used in adult critical care. Journal of clinical nursing. 2005;14(5):632-9.
  7. Lefrant J-Y, Muller L, de La Coussaye JE, Benbabaali M, Lebris C, Zeitoun N, et al. Temperature measurement in intensive care patients: comparison of urinary bladder, oesophageal, rectal, axillary, and inguinal methods versus pulmonary artery core method. Intensive care medicine. 2003;29(3):414-8.
  8. Fallis WM. Monitoring urinary bladder temperature in the intensive care unit: state of the science. American Journal of Critical Care. 2002;11(1):38-45.
  9. Fallis WM. The effect of urine flow rate on urinary bladder temperature in critically ill adults. Heart & Lung: The Journal of Acute and Critical Care. 2005;34(3):209-16.
  10. Moran JL, Peter JV, Solomon PJ, Grealy B, Smith T, Ashforth W, et al. Tympanic temperature measurements: Are they reliable in the critically ill? A clinical study of measures of agreement*. Critical care medicine. 2007;35(1):155-64.
  11. O’Grady NP, Barie PS, Bartlett JG, Bleck T, Carroll K, Kalil AC, et al. 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. Critical care medicine. 2008;36(4):1330.
  12. Olson D, Grissom JL, Dombrowski K. The Evidence Base for Nursing Care and Monitoring of Patients During Therapeutic Temperature Management. Therapeutic Hypothermia and Temperature Management. 2011;1(4):209-17.
  13. Jefferies S, Weatherall M, Young P, Beasley R. A systematic review of the accuracy of peripheral thermometry in estimating core temperatures among febrile critically ill patients. Critical care and resuscitation: journal of the Australasian Academy of Critical Care Medicine. 2011;13(3):194.
  14. Rubia-Rubia. Measurement of body temperature in adult patients: Comparative study of accuracy, reliability and validity of different devices. Measurement of obdy temperature in adult patients: comparative study of accuracy, reliability and validity of different devices. 2011;48(7):872-80.
  15. Kimberger O, Cohen D, Illievich U, Lenhardt R. Temporal artery versus bladder thermometry during perioperative and intensive care unit monitoring. Anesthesia & Analgesia. 2007;105(4):1042-7.
  16. Lawson L, Bridges EJ, Ballou I, Eraker R, Greco S, Shively J, et al. Accuracy and precision of noninvasive temperature measurement in adult intensive care patients. American Journal of Critical Care. 2007;16(5):485-96.
  17. Young PJ, Saxena M, Beasely R, Bellomo R, Bailey M, Pilcher D, et al. Early peak temperature and mortality in critically ill patients with or without infection. Intensive Care Medicine. 2012;38:437-344. Epub 31 January 2012.
  18. Niven DJ, Stelfox HT, Laupland KB. Antipyretic therapy in febrile critically ill adults: A systematic review and meta-analysis. Journal of Critical Care. in press. Epub 14 November 2012.
  19. Rolls K, Elliott D. Using consensus methods to develop clinical practice guidelines for intensive care: the Intensive Care Collaborative project. Australian Critical Care. 2008;21(4):200-15.
  20. NHMRC. Information for Guideline Developers Canberra2012 [5 July 2012]. Available from: http://www.nhmrc.gov.au/guidelines/information-guideline-developers.
  21. AGREE. AGREE Advancing the science of practice guidelines AGREE Trust [15 July 2012]. Available from: http://www.agreetrust.org/.
  22. NHMRC. NHMRC additional levels of evidence and grades for recommendations for developers of guidelines:PILOT PROGRAM 2005 - 2007. Australian Government; 2005.
  23. Childs C, Wieloch T, Lecky F, Machin G, Harris B, Stocchetti N. Report of a consensus meeting on human brain temperature after severe traumatic brain injury: its measurement and management during pyrexia. Frontiers in neurology. 2010;1.
  24. Lier H, Bottiger BW, Hinkelbein J, Krep H, Bernhard M. Coagulation management in multiple trauma. Intensive Care Medicine. 2011;37:572-82.
  25. Karalapillai D, Story D, Calzavacca P, Licari E, Liu Y, Hart G. Inadvertent hypothermia and mortality in postoperative intensive care patients: retrospective audit of 5050 patients. Anaesthesia. 2009;64(9):968-72.
  26. Adams HP, Del Zoppo G, Alberts MJ, Bhatt DL, Brass L, Furlan A, et al. Guidelines for the Early Management of Adults with Ischemic Stroke. Circulation. 2007;115:e478-e534.


The information on this page is general in nature and cannot reflect individual patient variation. It reflects Australian intensive care practice, which may differ from that in other countries. It is intended as a supplement to the more specific information provided by the doctors and nurses caring for your loved one. ICNSW attests to the accuracy of the information contained here but takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.