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Does non-contact infrared thermometry offer an accurate means of measuring canine and feline body temperature?

Clinical Scenario

You work in a busy city centre small animal hospital. Today you are on isolation duty.  You are thrilled to see that Roxy, the 12 week old Staffordshire Bull Terrier puppy with parvo virus, appears to have improved overnight and is sitting up in her kennel looking a lot brighter.  As you begin her morning health check, it becomes clear that she will no longer tolerate the rectal thermometer without additional restraint, so you phone for assistance from the kennel nursing team.  Whilst you wait for your colleague to complete the isolation entry protocol you wonder if there is an alternative to rectal thermometry?  You’ve seen non-contact infrared thermometers (NCITs) for sale in the supermarket and seen them used for children in hospitals.  They appear to offer a non-invasive method of monitoring body temperature and reduced risk of transmitting infectious material between patients. Could NCITs provide an equally accurate (comparable to rectal thermometry), less invasive option of monitoring body temperature for your canine and feline patients?

3-Part Question (PICO)

In [dogs and cats] do [non-contact infrared thermometers, compared to rectal thermometers] provide [accurate measurements of body temperature]?

Search Strategy and Summary of Evidence

Search Strategy

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) 1946 to Present using the OVID interface

(dog.mp. OR dogs.mp. OR exp dogs/ OR canine.mp. OR canines.mp. OR canis.mp. OR cat.mp. OR cats.mp. OR exp cats/ OR feline.mp OR felines.mp. OR felis.mp.)

AND

(non contact infrared thermometer.mp. OR non-contact infrared thermometer.mp. OR NCIT.mp. OR non contact thermometer.mp. OR infrared thermometer.mp. OR infra-red thermometer.mp. OR non-contact infrared thermomet*.mp.)

AND

(rectal thermometer.mp. OR rectal temperature.mp. OR rectal thermomet*.mp. OR exp thermometers/ OR rectal digital thermometer.mp.)

CAB Abstracts 1910 to Present using the OVID interface

(dog.mp. OR dogs.mp. OR exp dogs/ OR canine.mp. OR canines.mp. OR canis.mp. OR cat.mp. OR cats.mp. OR exp cats/ OR feline.mp OR felines.mp. OR felis.mp.)

AND

(non contact infrared thermometer.mp. OR non-contact infrared thermometer.mp. OR NCIT.mp. OR non contact thermometer.mp. OR infrared thermometer.mp. OR infra-red thermometer.mp. OR non-contact infrared thermomet*.mp.)

AND

(rectal thermometer.mp. OR rectal temperature.mp. OR rectal thermomet*.mp. OR exp thermometers/ OR rectal digital thermometer.mp.)

Search Outcome

MEDLINE

  • 5 papers found in MEDLINE search
  • 1 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 0 papers excluded as they are review articles/in vitro research/conference proceedings
  • 4 total relevant papers from MEDLINE

CAB Abstracts

  • 8 papers found in CAB search
  • 3 papers excluded as they don't meet the PICO question
  • 2 papers excluded as they are in a foreign language
  • 0 papers excluded as they are review articles/in vitro research/conference proceedings
  • 3 total relevant papers from CAB

Total relevant papers

4 relevant papers from both MEDLINE and CAB Abstracts

Comments

Studies using tympanic membrane infra-red thermometry were excluded as these require patient contact.  All types of non-contact infra-red thermometry (human, non-medical and veterinary) were included. 

Summary of Evidence

Kreissl and Neiger (2015) Germany

Title:

Measurement of body temperature in 300 dogs with a novel noncontact infrared thermometer on the cornea in comparison to a standard rectal digital thermometer.

Patient group:

300 dogs (mixed breed, Labrador and Beagle were the most common breed types) presenting to a single small animal clinic, aged 2.5 months to 17.2 years, including 153 males (97 entire, 56 neutered) and 147 females (77 entire, 70 neutered).

Study Type:

Diagnostic testing study

Outcomes:
  • Rectal digital thermometer reading (by both experienced and inexperienced operators)

  • NCIT reading (by both experienced and inexperienced operators)

  • Sensitivity and specificity of NCIT for varying body temperatures

Key Results:
  • NCIT resulted in significantly less patient discomfort when compared to rectal thermometry.

  • Poor correlation between NCIT and rectal thermometry means that if used in clinical practice, both hypothermia and hyperthermia would go undetected.

  • Measurements taken by an experienced and non-experienced operator correlated well (P<0.001) for both thermometers.

  • Repeatability was better for rectal thermometry when compared to NCIT.

Study Weaknesses:
  • A human NCIT device was used (Thermofocus 01500); there are now animal specific models available.

  • Effect of ambient temperature on rectal/NCIT difference was not reported.

  • The figure presented as a Bland Altman plot was not compliant with Bland Altman methodology.

  • The NCIT device was only used on the cornea; the use of NCIT on other anatomical locations was not investigated.

  • Whilst the dogs had a range of body temperatures including both hypo- and hyperthermia, only 13.7% of the dogs had hyperthermia meaning the device's ability to detect hyperthermia was not robustly explored.
Attachment:
Evidence appraisalEvidence appraisal

Nutt et al. (2016) USA

Title:

Comparison of non-contact infrared thermometry and rectal thermometry in cats.

Patient group:

188 adult short haired cats from animal shelters (113), veterinary clinics (57) and private homes (18).  No further information was provided on gender, age, bodyweight etc.

Study Type:

Diagnostic testing study

Outcomes:
  • Rectal digital thermometer reading.

  • NCIT reading using 3 (from an initial 6 trialled) human devices on 3 (from an initial 15 sites investigated) anatomical locations.

  • Ambient temperature also measured.

Key Results:
  • Out of 6 tested human NCIT devices, 3 were found to have better correlation with rectal temperature in a pilot study of 14 healthy cats.

  • Perineum, gingiva and pinnae temperatures were found to be the anatomical locations that best correlated to rectal temperature (however ocular surface temperature was not investigated).

  • Overall NCIT was poorly correlated with rectal temperature.

  • NCIT did not identify hypothermic or hyperthermic patients reliably.

Study Weaknesses:
  • Although infrared thermography showed that the warmest body temperature is recorded at the eyes, this was not investigated using NCIT.

  • Only human NCIT devices were investigated.

  • The figures presented as Bland Altman plots were not compliant with Bland Altman methodology.

  • No detail regarding study population demographics.

Attachment:
Evidence appraisalEvidence appraisal

Rizzo et al. (2017), Italy

Title:

Monitoring changes in body surface temperature associated with treadmill exercise in dogs by use of infrared methodology

Patient group:

Ten healthy Jack Russell Terrier cross Miniature Pinscher dogs (3 females and 7 males; 1–4 years; mean body weight 8±1.8 kg) with short coat, deemed to be clinically healthy following clinical examination and laboratory blood test analysis.

Study Type:

Diagnostic testing study

Outcomes:
  • Rectal temperature measured pre and post exercise on a treadmill.
  • Non-contact infra-red thermometry performed at points throughout the period of exercise, measuring surface temperature at six anatomical locations (neck, shoulder, ribs, flank, inner thigh and eye).
Key Results:
  • Only eye and inner thigh surface temperatures showed good correlation with rectal temperature.
  • Mean surface temperatures at every anatomical location, throughout the period of exercise remained below the normal reference range for canine rectal temperature.
Study Weaknesses:
  • No direct comparison between rectal and surface temperature was performed, meaning there is no reported information regarding the reliability of the non-contact thermometer to detect hyperthermia.
  • Results are not reported fully, e.g. there is no reported information regarding the mean rectal temperatures pre and post exercise, individual dogs' rectal temperatures or temperature comparisons.
  • Whilst this paper compares rectal temperature to temperature measured with a NCIT device, the study aim was not the same as the aim of this BET; this paper looked to investigate the use of NCIT in exercising animals rather than veterinary patients.
Attachment:
Evidence appraisalEvidence appraisal

Omóbòwálé et al. (2017) Nigeria

Title:

A comparison of surface infrared with rectal thermometry in dogs

Patient group:

150 dogs of mixed breeds (unknown sex), aged 5 weeks to 8 years old presenting to a veterinary hospital.

Study Type:

Diagnostic testing study

Outcomes:
  • Rectal temperature measured with a glass mercury thermometer
  • Surface temperature of the nasal region measured with a non-contact infrared thermometer at 20, 30 and 50cm distance from the dog
  • Surface temperature of the forehead region measured with a non-contact infrared thermometer at 20, 30 and 50cm distance from the dog
Key Results:
  • The nasal region surface temperature measured on average 7.6oC lower than rectal temperature.
  • The forehead region surface temperature measured on average 5.3oC lower than rectal temperature.
Study Weaknesses:
  • There is no description of who performed the temperature readings or what training they had received.
  • The surface temperatures were measured at three different distances, then averaged rather than using a fixed distance from the patient to standardise results.
  • Reporting of the study methods, statistical significance and basic data are limited.
  • A non-medical infrared thermometer was used to measure surface temperature.
  • The mean rectal temperature (39.27oC) is high compared to normal UK dogs, and is above the normal temperature range commonly stated (39.2oC often stated to be the upper limit). This could perhaps reflect the clinical population of animals used, or potentially the relatively higher ambient temperature, but as the proportion of hypothermic, normothermic and hyperthermic dogs is not stated this is not clear.
  • The ambient temperature was not reported, which could potentially influence the readings obtained with the NCIT device.
Attachment:
Evidence appraisalEvidence appraisal

Comments

The four studies are difficult to compare as each used different NCIT devices, surface temperature was measured at different anatomical locations using slightly different methods, and basic data describing the study population and factors that may influence the performance of the NCIT were poorly reported. Three studies included only dogs (Kreissel, Rizzo and Omóbòwálé); one included only cats (Nutt). With the exception of the 300 canine patients described by Kreissel and Neiger (2015), the study populations and conditions were either not adequately described (Nutt, Omóbòwálé) or were not representative of the UK pet population (Rizzo). 

All four studies found the correlation between rectal temperature and NCIT temperature to be poor, but Nutt, Omóbòwálé and Rizzo each identified different specific measurement sites and/or rectal temperatures at which the devices did appear more accurate in their own population. It is unclear whether the differences between studies were as a result of the device used, the measurement methodology, the population assessed, the sample sizes included or other unidentified factors. 

These studies used only human or non-medical NCIT devices, so there is no current evidence on the reliability of animal specific NCIT models which are now available commercially to both veterinary staff and pet owners.

Bottom line

Human and non-medical non-contact infrared thermometry (NCIT) devices cannot be recommended for measuring canine or feline body temperature in clinical practice as they are not sufficiently accurate. There is no available peer-reviewed evidence on the reliability of animal-specific NCIT devices.

Disclaimer

The BETs on this website are a summary of the evidence found on a topic and are not clinical guidelines. It is the responsibility of the individual veterinary surgeon to ensure appropriate decisions are made based on the specific circumstances of patients under their care, taking into account other factors such as local licensing regulations. Read small print

References

Kreissl, H, Neiger, R, (2015). Measurement of body temperature in 300 dogs with a novel noncontact infrared thermometer on the cornea in comparison to a standard rectal digital thermometer.  Journal of Veterinary Emergency and Critical Care 25: 372-378.

Nutt, KR, Levy, JK, Tucker, SJ, (2016). Comparison of non-contact infrared thermometry and rectal thermometry in cats.  Journal of Feline Medicine and Surgery 18: 798-803.

Omóbòwálé, TO, Ogunro BN, Odigie EA, Otuh, PI, Olugasa BO, (2017). A Comparison of Surface Infrared with Rectal Thermometry in Dogs. Nigerian Journal of Physiological Sciences 32: 123-127.

Rizzo, M, Arfuso, F, Alberghina, D, Giudice, E, Gianesella, M, Piccione, G, (2017). Monitoring changes in body surface temperature associated with treadmill exercise in dogs by use of infrared methodology. Journal of Thermal Biology 69: 64-68.

About this BET

First author:
Emily Hall
Second author:
Zoe Belshaw
Institution:

School of Animal, Rural and Environmental Sciences

Nottingham Trent University

Brackenhurst

Southwell

Nottinghamshire

NG25 0QF

 

CEVM, University of Nottingham

Search last performed:
2018-08-30 16:25:24
Original publication date:
2018-08-30 16:25:24
Last updated:
2018-08-30 16:25:24
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