Accuracy and Precision Test of TempTraq® Compared to Pulmonary Artery Catheter for Monitoring Temperature in Adults in Intensive Care Unit
Conditions: Temperature
Sponsor: The Cleveland Clinic

Accuracy and Precision Test of TempTraq® compared to Pulmonary Artery Catheter for 
Monitoring Temperature in Adults in Intensive Care Unit 
7/7/2020 
 
Principal Investigator:  
• Sandra L. Siedlecki Ph.D RN CNS, Senior Nurse Scientist, Office of Research & 
Innovation, Cleveland Clinic, siedles@ccf.org 
Co-Investigators: 
• Mark McClelland DNP RN, Nurse Scientist, Office of Research & Innovation, 
Cleveland Clinic 
• Robert (Sam) Butler MS, Biostatistician Quantitative Health Sciences, Lerner 
Institute, Cleveland Clinic 
Introduction 
Temperature monitoring is an important assessment tool for healthcare providers. Over 
the years a number of changes have been made to improve our ability to accurately and 
precisely measure and monitor a patient’s temperature (Sund-Levander, & Grodzinsky, 
2013).  However, most of these new technologies have limitations and many provide 
readings that are too variable under different conditions and thus cannot be relied upon 
to provide a true measure of a patient’s temperature.  Inaccurate temperature 
monitoring can result in delayed treatment or administration of treatment not actually 
needed. To be useful a thermometer must demonstrate precision and accuracy.   
Background 
The gold standard against which all thermometer devices are compared in the core 
temperature as measured by the pulmonary artery (PA) catheter (Farnell et al. 2005).  
Although body temperature measured using a PA catheter is the most accurate 
measure to date, it is an invasive procedure and the risks of inserting and maintaining a 
PA catheter may not be justified (Pinsky, & Vincent, 2005). Chemical thermometers are 
a non-invasive method for obtaining a temperature orally, rectally, inguinal, or axillary. 
Chemical thermometers are affected by many variables and each route has different 
limitations. Previous studies identify accuracy and precision issues with chemical 
thermometers.  Electronic thermometers (if calibrated often) are a bit more accurate; but 
they also have limitations. Some electronic thermometers are non-invasive (, oral, 
tympanic & temporal), but others require invasive methods to insert the thermistor 
(esophageal, rectal, or urinary bladder). None of these methods have been found to be 
as accurate or reliable for patients as the PA catheter temperature measurement 
(Farnell et al. 2005; Lawson, et al. 2007). 

One alternative to the use of invasive temperature monitoring that may be more 
accurate and reliable that either chemical or electronic thermometers is the TempTraq® 
thermometer. This thermometer developed by Blue Spark Technologies (Westlake, 
Ohio) is applied to the skin as a patch. The TempTraq® thermometer is a thin, single-
use, battery-powered skin patch that monitors and records skin temperature.  Previous 
studies have demonstrated that it is reliable and accurate for monitoring temperature in 
children and in healthy adults. However, it has not been tested in ill adult patients.  
 
Methods 
 
Purpose 
The purpose of this feasibility study is to assess the accuracy and precision of the 
Temp-Traq thermometer for monitoring body temperature in adult patients under three 
conditions (hypothermia, normothermia, and hyperthermia). 
Specific Aims 
1.  To assess the accuracy of the Temp-Traq thermometer as compared to a gold  
      standard (Core temp measured by Pulmonary Artery Catheter) 
2.  To assess the precision of the Temp-Traq thermometer over repeated measures 
3.  To determine if accuracy &/or precision is consistent in three conditions  
      (hypothermia, normothermia, or hyperthermia) 
Design 
A repeated measures within-group comparative design will be used for this study. 
Sample/Setting 
To address the specific aims of this study we will identify patients (N = 40) who have a 
pulmonary artery (PA) catheter in place (patients in intensive care units). Letters of 
support are attached from the unit managers where the study will take place (see 
attached). 
Inclusion Criteria 
Adult patient (male or female) in intensive care unit who will have a PA catheter in place 
for at least the next 8 hours; and who have no visible skin condition to the axillary region 
upon inspection by the research nurse are eligible for this study 
Exclusion Criteria 
1. Patients younger than 21 
2. Patients who will not have a PA catheter in place for the next 8 hours 
3. Patients who have a visible skin condition to the axillary region upon inspection by  

    the research nurse 
4. Patients who will be going for procedures or for some reason will not be available for     
    the 6 hours of the study 
Procedure 
Once a patient is identified, the researcher will record basic demographic data (see data 
collection form attached) and the axillary area will be assessed for visible signs of any 
skin conditions. If there are no visible signs of a skin condition the researcher will apply 
the Temp-Traq thermometer to the right or left axilla of the subject and record the 
location of the placement. The researcher will record both the PA and Temp-Traq 
recordings of subject’s temperature (taken at the same time) on the data collection form 
(see attachment) at four data points; baseline (5 minutes post application of Temp-Traq) 
and every two hours (+/- 15 minutes) after baseline X 3 (See Protocol attachment). 
Previous testing of the TempTraq® on children and healthy adults has not resulted in 
any adverse skin reactions. However, as this is a new thermometer format and there is 
not a significant body of literature on potential skin reactions, we will assess skin before 
and after application. Thus, at the end of the last reading the Temp-Traq thermometer 
will be removed and the skin will be assessed for erythema. If erythema is present the 
patient’s nurse and physician will be notified by the researcher.   
Protection of Human Subjects 
Since non-invasive temperature monitoring poses no risk to patients and is part of usual 
care and since we will not collect or record any protected health information (PHI), 
written informed consent will not be sought. Patients will be identified by their study ID 
number only. The data will be collected by a registered nurse data collector familiar with 
the intensive care setting and data will be stored in a locked file cabinet in the 
researchers locked office.  Temperature data for the Temp-Traq is collected through the 
Temp-Traq Application (AP) which will be placed on a Cleveland Clinic Approved and 
encrypted i-pad. Once the study is completed and all data has been transferred to the 
study database, the Temp-Traq application and all of its data will be deleted from the  i-
pad.  
Analysis 
We will use the TOST (Two One Sided t-tests) method for equivalence testing.  This 
method requires a defined range of mean differences between two test methods, an 
estimate of the precision of the measurement of the two systems, and an estimate of 
the size of the possible difference in the means of the two methods under consideration. 
The TOST null hypothesis is a joint null hypothesis that the mean measurement 
differences between the two methods is greater than a critical lower bound and less 
than a critical upper bound.  If the null is rejected then we can conclude that the 
absolute difference of the means for the two groups falls within the specified range.  It 
was determined that to be considered equivalent with respect to accuracy the mean 

measurements of the two methods should be within ± 0.2 degrees of each other.  
Precision tests for Temp-Traq thermometer using accepted ASTM test methods for 
various combinations of temperature and humidity provided a range of measurement 
variation between .0000435 and .019928 with a mean of 0.000254500.  If we assume 
both test methods exhibit the same levels of precision then the variance of the 
differences between their two means will reduce to two times the values listed 
previously.  This will result in estimates of the standard deviations of the mean 
differences of .0093, .032, and .063 respectively. 
The two methods for body temperature that will be examined are core temperature 
measurements with a PA catheter and temperature measurements using the Temp-
Traq.   Paired temperature measurements for both methods will be taken 
simultaneously every 2 hours for a 6 hour period.  This will provide 4 repeated 
temperature measures per patient. The simultaneous measurements within a given 
patient should exhibit a high degree of correlation.  If .7 is chosen as the lower bound 
for the correlation between the paired readings (higher correlations would result in an 
estimate of fewer patient samples thus the choice of .7 is conservative) and if the 
average standard deviation of the mean of the differences is used as an estimate of the 
expected variability, then it would be possible to declare measurement equivalence for a 
difference of ±.19 with a sample size of 40 patients.  This assumes the ASTM 
measurements of instrument variation are representative of the within patient variance.  
Given the vagaries of patient-to-patient this may be too optimistic an estimate.  Table 1 
(attached) is a summary of patient sample sizes for standard deviations equal to the 
average standard deviation and for 5 and 10 fold increases in this value.   
  
 
 A sample size of 40 patients will provide 80% or greater power for testing for 
equivalence between methods where the mean difference is .1 or less for up to a ten-
fold increase in the estimates of the variability of the differences based on the ASTM 
precision measures and for a mean difference of .15 for up to a five-fold increase in 
these same measures.  If the sample size is 40 then the power for the test of 
equivalence, where the difference is .15 and the standard deviation is a ten-fold 
increase, is 35%. Agreement testing:  The Bland-Altman test will be used to test the 
agreement of the two methods.  This test will permit a check for significance of bias 
between the two measures (the average difference between the two measures) as well 
as a check for significant trending over the range of the measurements.  If the bias is 
significant then the results of the two differ by an overall offset in their measurements. If 
the trending (slope of the regression line) is significant then the difference between the 
two measurements changes as their magnitude changes which means the two methods 
are not in agreement. 
 

The only measurements of instrument precision are those provided by the ASTM 
assessment.  It is reasonable to assume the within patient measurement variation will 
be greater than the measurements from the controlled testing.  A sample size of 40 
patients is, from a statistical standpoint, a reasonable number and, as indicated in Table 
1, this sample size provides acceptable power for a mean difference of .1 for a ten-fold 
increase in the estimate of minimum test variability.  This sample size will also provide 
enough data for the Bland-Altman test for agreement. 
 
Eliades, A, Stoner, K. and Frisone, J. (unpublished paper) Use of skin patch device to 
obtain temperature measurements.  
Farnell, S., Maxwell, L., Tan, S., Rhodes, A., & Philips, B. (2005). Temperature 
measurement: comparison of non‐invasive methods used in adult critical care. Journal 
of clinical nursing, 14(5), 632-639. 
Lawson, L., Bridges, E. J., Ballou, I., Eraker, R., Greco, S., Shively, J., & Sochulak, V. 
(2007). Accuracy and precision of noninvasive temperature measurement in adult 
intensive care patients. American Journal of Critical Care, 16(5), 485-496. 
Pinsky, M. R., & Vincent, J. L. (2005). Let us use the pulmonary artery catheter correctly 
and only when we need it. Critical care medicine, 33(5), 1119-1122. 
Sund-Levander, M & Grodzinsky, E. (2013). Assessment of body temperature  
measurement options. British Journal of Nursing, 22(6), 942-50.