Continuous Temperature Measurement by Thermal Imaging Camera: Concordance, Patterns, and Intelligent Prediction of Events in Critical Patients
Conditions: Critically Ill
Sponsor: Universidad Europea de Madrid

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COVER PAGE 
 
 
Document name: 
Continuous Temperature Measurement by Thermal Imaging Camera: Concordance, 
Patterns, and Intelligent Prediction of Events in Critical Patients. Protocol 
Title of the study: 
Continuous Temperature Measurement by Thermal Imaging Camera: Concordance, 
Patterns, and Intelligent Prediction of Events in Critical Patients 
NCT number:  
Not yet available 
Date: 
December 15, 2023 
 
 
 

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STUDY PROTOCOL - TermoCam UCI-1 
 
 
Researchers 
 
Principal Investigator 
• 
Samuel González López – Medical Specialist in Intensive Medicine, HLA Moncloa 
Hospital – Doctor in Biomedical Research - Associate Professor at UEM 
 
Other Researchers 
• Jose Luis Lafuente Carrasco – Bachelor's in Electronic and Automatic Engineering - Associate 
Professor at UEM 
• Eva Avilés Álvarez – Bachelor's in Biomedical Engineering – Associate Professor at UEM 
• Enrique Puertas Sanz – Doctor in Computer Engineering – Full Professor at UEM 
• Ana Isabel Castillo Varón – Doctor in Biological Sciences – Associate Professor at UEM 
• Ingrid Lorena Bernal González – Nursing Degree, HLA Moncloa Hospital 
• María del Carmen Sandoval Gómez - Nursing Degree, HLA Moncloa Hospital 
• Almudena Benito Fernández - Nursing Degree, HLA Moncloa Hospital 
• Gloria Sánchez Jiménez - Nursing Degree, HLA Moncloa Hospital 
• Vicente Gómez Tello - Medical Specialist in Intensive Medicine, Head of Emergency Service, 
HLA Moncloa Hospital – Doctor in Medicine – Professor at UEM 
• Juan José Oñoro Cañaveral – Medical Specialist in Intensive Medicine, Head of ICU Service, HLA 
Moncloa Hospital – Associate Professor at UEM 
• Juan José Beunza Nuin – Medical Specialist in Internal Medicine – Doctor in Medicine – 
Professor at UEM 
Code: TERMOCAMUCI1 
Version:  2 
Date:  December 15, 2023 
 
Title 
Continuous Temperature Measurement by Thermal Imaging Camera: Concordance, Patterns, 
and Intelligent Prediction of Events in Critical Patients 
 
 

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Introduction 
 
Body temperature is one of the most frequently studied physiological variables in hospitalized 
patients. The normal temperature value is around 36.7°C, with significant variability ranging 
from 35.3 to 37.7°C among different individuals or within the same person throughout the day. 
The definition of fever is established by a consensus reached by the American College of Critical 
Care Medicine and the IDSA, placing it at a central temperature of 38.3°C (1), where central 
temperature refers to the temperature of internal organs. This thermal elevation is typically 
found in approximately 50% of critical patients (2) and is not only clearly associated with 
infectious processes but can also be observed in various other conditions such as autoimmune 
diseases, oncological conditions, bleeding, inflammatory reactions, after surgical procedures, or 
drug-induced (3).   
There are multiple methods for temperature measurement in Intensive Care Units (ICUs), with 
the most common being peripheral temperature measurement every eight hours using contact 
thermometers in the axilla(4). In patients with sustained fever or those undergoing therapeutic 
hypothermia, continuous monitoring of central temperature through rectal, tympanic, vesical, 
or esophageal methods can be performed (5). However, it is considered a more invasive 
measure, and its use is limited mainly due to technical difficulties, higher economic costs, and 
potential serious complications (6, 7). 
Thermal monitoring in critical patients is essential. Many critical patients with fever will receive 
antibiotic treatment, even in the absence of evidence of infection, as early initiation of this 
treatment in septic patients clearly improves survival (8, 9). 
The wide variability of temperature between individuals, circadian changes, different methods 
of temperature measurement, the influence of medications, and deficiencies in measurement 
methods make defining fever with a single temperature value impractical (10) Therefore, other 
patient variables should also be considered before establishing the presence of fever. One of 
these variables is the thermal curve, or the evolution of temperature throughout the day, which 
can be sustained or in peaks and may or may not respond to antipyretics, antibiotics, or other 
temperature control methods. Studying a patient's thermal curve is useful even before reaching 
definitive fever values (11).  
Another issue in fever monitoring, especially with sporadic measurements rather than 
continuous monitoring, is that febrile peaks may go unnoticed or that the maximum or minimum 
values that the patient will experience may not be captured. 
Therefore, as a first step, the main purpose of this study would be to establish the concordance 
between axillary temperature measurements (widely used method) taken in patients multiple 
times a day and temperatures recorded by a thermal imaging camera at the same moments. 
Thermal imaging cameras have been widely used during the Covid-19 pandemic for fever 
screening in healthcare settings and other facilities(12). Their use in hospitalized patients could 
translate into numerous advantages compared to routine clinical practice. Firstly, it is a non-
invasive and contactless measurement, reducing the risk of pathogen transmission, especially in 
patients colonized by multidrug-resistant microorganisms, and facilitating measurement in 
patients with compromised skin integrity. Secondly, the automated and continuous acquisition 
of temperature provides valuable information that has proven useful in patient management 

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without requiring extra effort from healthcare professionals and may even reduce the nursing 
and auxiliary workload. 
However, the lack of diagnostic test validity studies for most thermal imaging cameras and 
contradictory results found in published studies (13) have led to their limited use in the hospital 
environment. Despite this, recent systematic reviews emphasize their great potential pending 
further studies to validate their utility (14, 15). Therefore, within one of the secondary objectives 
of this study, we also aim to assess the validity of these cameras as a diagnostic test for fever 
and hypothermia. 
In this regard, the use of thermal imaging cameras integrated into a system capable of 
automated and real-time peripheral temperature acquisition could potentially lead to a change 
in the standard practice for temperature monitoring in ICUs. Additionally, this system would 
provide a wealth of data that could be used to train intelligent systems through machine learning 
algorithms in the near future, with the goal of predicting events such as the onset of fever, 
nosocomial infections, or shock. 
 
Hypothesis and Objectives 
Hypothesis: 
Temperature measurements using thermal imaging cameras in critical patients show good 
concordance with those taken using contact thermometers in the axilla. 
Objectives: 
Primary Objective: 
To assess the concordance of temperature obtained continuously by a thermal imaging camera 
with that obtained by an axillary contact thermometer. 
Secondary Objectives: 
1. To describe the sociodemographic (age and gender) and clinical characteristics (HTN, 
DM, DL, reason for ICU admission, SAPS3) of the study population. 
2. To study the diagnostic test validity of the thermal imaging camera for fever and 
hypothermia. Fever is defined as an axillary temperature of ≥ 37.5°C, and hypothermia 
is defined as an axillary temperature < 34.2°C. 
3. To determine the time difference until fever detection between the SF-HANDHELD-
80TA05 thermal imaging camera or similar, and temperature measurement through the 
usual nursing practice following standard protocols in critical patients. 
4. To describe the continuous thermal curve patterns taken by the thermal imaging camera 
in patients with the following pathologies: altered level of consciousness, acute 
coronary 
syndrome, 
cardiac 
rhythm 
disturbances, 
cardiac 
arrest, 
heart 
failure/cardiogenic shock, hypovolemic shock, sepsis/septic shock, shock of other 
etiology, respiratory failure, renal failure, metabolic disorders, intoxications, trauma, 
postoperative monitoring and surveillance, non-surgical procedure monitoring and 
surveillance, and others. Thermal curves will be obtained in at least 20 patients per 
pathology. 
 

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5. To describe the continuous thermal curve patterns taken by the thermal imaging camera 
in patients with infectious complications in two cases: patients with infection upon 
admission and patients who develop infection during admission. Thermal curves will be 
obtained in at least 20 patients in each case. 
6. To determine the adequacy of regional thermal measurement by reviewing the 
complete thermal image obtained by the SF-HANDHELD-80TA05 or similar camera 
 
Materials and Methods 
 
Design: 
This is a single-center, observational, descriptive, longitudinal, and prospective study to 
investigate the concordance between temperatures obtained by the thermal imaging camera 
and axillary temperatures. 
 
Scope and Study Population: 
The study will be conducted on all patients admitted to the ICU rooms at HLA Moncloa University 
Hospital equipped with an infrared camera for continuous measurement of skin temperature. 
 
Inclusion Criteria: 
• Patients admitted to the ICU in a room with a thermal imaging camera 
• Aged 18 years and above 
• Patients who provide voluntary consent to participate in the study (Annex 2). If the participant 
is not in full physical or intellectual capacity to provide their signature in the informed consent, 
the responsible investigator will seek consent from their direct family member or the legally 
designated person to make decisions on their behalf regarding health matters. This measure is 
adopted to ensure the participant's rights are respected and the integrity of the consent process 
is maintained, even in situations where their decision-making capacity may be compromised. 
 
Exclusion Criteria: 
Patients from whom information from the thermal imaging camera cannot be obtained due to 
technical reasons. 
 
Sample Size: 
To determine the degree of concordance between the temperature recorded by the thermal 
camera and axillary temperature, a minimum of 224 pairs of data (224 temperature records by 
thermal camera vs. 224 axillary temperature records) will be required to estimate an Intraclass 

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Correlation Coefficient (expected to be 0.8 or higher) with an estimation error of +- 0.05 points, 
a confidence level of 95%, and anticipating a 10% loss. 
 
Data Collection: 
Temperature measurements will be autonomously recorded by the SF-HANDHELD-80TA05 
thermal imaging camera, or another with similar characteristics, which provides temperature 
values every second, thermal images, bed number, date, and time. 
The rest of the variables needed for the study will be manually collected by the researchers or 
through the clinical information system (CIS) "Innovian" and included in a study-dedicated 
database hosted on the hospital intranet. 
Finally, all data will be collected in a pseudonymized manner. For this purpose, two databases 
will be constructed. One will contain personal data associated with a code (one for each patient), 
which will be safeguarded by the investigator. The second database will contain the associated 
clinical data. In the case of images generated by thermal cameras, these will also be 
pseudonymized, generating images with the aforementioned association code. These coded 
images will be sent to the Computing Center of the European University of Madrid for the 
creation of temperature patterns (secondary objectives 4 and 5) and for the adequacy of 
regional thermal measurement (secondary objective 6). 
 
Standard Practice in Peripheral Temperature Measurement in Our Unit 
The standard practice for peripheral temperature measurement in the ICU at HLA Moncloa 
University Hospital is not formally documented but adheres to recommendations for monitoring 
temperature in critically ill patients. Peripheral temperature is obtained using a contact 
thermometer in the axilla every 8 hours or whenever thermal disturbances are suspected by 
healthcare personnel (both medical and nursing staff). 
Axillary temperature measurement through standard practice will be repeated every 8 hours 
and collected in triplicate to establish an average used for assessing concordance at that point 
and so forth until reaching the 224 measurements needed to complete the primary objective of 
the study. If, during the 8-hour collection, there is a difference of more than 15% between the 
first 3 measurements, a fourth measurement will be taken, and only the average of the three 
most similar measurements will be used for concordance. If all four measurements are different, 
a fifth measurement will be taken, and so on until three measurements considered similar are 
obtained. 
Definitions of Thermal Disturbances and Infectious Complications: 
• Fever: Defined as a central temperature (rectal, esophageal, vesical, or tympanic) ≥ 38.3°C. 
Peripheral temperature (cutaneous or axillary) is 0.6 to 1°C lower than central temperature; 
therefore, for this study, we will consider a peripheral temperature ≥ 37.5°C as a fever. 
• Hypothermia: Defined as a central temperature < 35°C or peripheral temperature < 34.2°C. 
• Infectious Complications: Will include both patients admitted to the ICU due to an infection 
(pre-admission infection) and patients who develop an infection during their stay in the ICU 
(infection during admission). Identification and diagnosis of either type of infection will be 

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carried out by the attending physician following established clinical practice recommendations 
and guidelines in each specific case. The task of the researchers will be limited to reviewing the 
patient's medical history and collecting data. 
 
Temporal Differences in Fever Detection: 
The time of fever detection will be identified for each measurement method (standard practice 
vs. thermal imaging camera), and the temporal difference in minutes between them will be 
determined. 
 
Creation of Temperature Patterns: 
Continuous temperature data (every second) offered by thermal cameras will be represented 
by 24-hour thermal curves and classified automatically based on patterns and patient 
characteristics using unsupervised machine learning algorithms such as clustering. For this 
purpose, the data will be physically and securely sent to the Computing Center of the European 
University of Madrid. 
 
Adequacy of Regional Thermal Measurement: 
Thermal cameras SF-HANDHELD-80TA05 or similar perform a scan across the entire thermal 
image to extract the point of maximum temperature found. It is deemed necessary for the study 
to visually check the thermal images obtained to verify the adequacy of temperature 
measurement—ensuring that the temperature is being obtained from the patient and not from 
any other high-temperature element, such as healthcare personnel or electronic devices (mobile 
phones, respirators, pumps, etc.). A direct visual check of a sample of thermal images will be 
performed by the researchers, and all thermal images will be physically and securely sent to the 
Computing Center of the European University of Madrid for automatic classification using 
convolutional image recognition algorithms (machine learning) to identify whether the 
temperature is obtained from the patient or any other element. 
 
Interventions and Procedures: 
 
1. All patients admitted to the ICU in a room with a thermal imaging camera will be 
considered potential candidates for inclusion in the study and will be verbally informed 
and provided with patient information sheets about the study, requesting their 
signature on the informed consent form for participation. 
2. If they agree to participate, compliance with inclusion and exclusion criteria will be 
confirmed. 
3. Patients will receive treatments according to the center's usual clinical practice and the 
criteria of their attending physician based on the patient's characteristics in each specific 
case. 
4. The thermal imaging camera will automatically record temperature readings every 
second and capture a thermal image. The information will be recorded in real-time on 

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the server dedicated to the study, located physically within the ICU and connected only 
to the hospital intranet. This ensures that the information collected for the study has 
the same level of security as other information related to hospitalized patients. 
Additionally, all records made on the server will be pseudonymized from personal 
information. Identifying a person through the thermal image is not possible without 
additional information; thus, for all intents and purposes, it is considered anonymized 
information.  
5. Temperature data for each patient included in the study can be accessed through a 
tablet connected only to the hospital intranet and will remain within the ICU. 
6. At the time of discharge or patient exitus, the principal investigator will review the 
patient's medical history to create a pseudonymized database that records study 
variables and patient temperature data. 
7. Once data collection is complete over the 11-month study period, the principal 
investigator will physically send pseudonymized temperature data and thermal images 
to the Computing Center of the European University of Madrid, which is committed to 
maintaining data confidentiality and destroying any possible copies of the material once 
study objectives are fulfilled. 
8. After completing the study, pseudonymized patient data will remain recorded for 5 
years on the server physically located within the ICU. This is in case data consultation is 
necessary for clinical reasons or regarding the publication of study data. 
 
Variables 
 
Primary: 
• 
Axillary Temperature 
• 
Temperature from Thermal Imaging Camera 
Secondary: 
• 
Age 
• 
Gender 
• 
Reason for Admission: 
• 
Altered Level of Consciousness and Other Neurological Disorders 
• 
Acute Coronary Syndrome 
• 
Cardiac Arrhythmias 
• 
Cardiorespiratory Arrest 
• 
Heart Failure/Cardiogenic Shock 
Figure 1. Example of Thermal Image 

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• 
Hypovolemic Shock 
• 
Sepsis/Septic Shock 
• 
Shock of Other Etiology 
• 
Respiratory Failure 
• 
Renal Failure and Metabolic Disorders 
• 
Intoxications 
• 
Head Trauma 
• 
Other Traumas without Head Injury 
• 
Postoperative Monitoring and Surveillance 
• 
Monitoring and Surveillance of Non-Surgical Procedures 
• 
Other Unspecified Medical or Surgical Conditions 
• 
Hypertension (Yes/No) 
• 
Diabetes Mellitus (Yes/No) 
• 
Dyslipidemia (Yes/No) 
• 
SAPS3 at Admission 
• 
Thermal Image 
• 
Fever (Yes/No) 
• 
Hypothermia (Yes/No) 
• 
Infectious Complications (Pre-existing or During Admission) Date and Time 
• 
Time to Fever Development 
 
 
Statistical Analysis Plan 
The degree of agreement between temperature measurements recorded with the thermal 
camera and measurements taken with the axillary contact thermometer will be assessed, as 
these are quantitative variables, through the intraclass correlation coefficient. Qualitative 
variables will be summarized based on absolute and relative frequency (n and %), while 
normally distributed quantitative variables will be described using mean ± standard deviation 
(SD), or if not normally distributed, using median and interquartile range. Normality will be 
determined using the Kolmogorov-Smirnov test. 
The validity of the thermal camera as a diagnostic test for fever and hypothermia will be 
calculated based on sensitivity and specificity, as well as Positive Predictive Value (PPV) and 
Negative Predictive Value (NPV). Considering fever is defined as ≥ 37.5ºC in axillary 
temperature, and hypothermia as <34.2ºC in axillary temperature. 
 
Limitations 
This is a single-center study; other units may have different protocols for monitoring, 
managing, and treating fever, or admit patients with different baseline characteristics than 
those in this sample, so the conclusions of this study may not be applicable to other services. 
 
Ethical and Legal Aspects 
This study will be conducted in accordance with current legislation. All participating 
researchers will adhere to strict confidentiality in accessing, collecting, and processing data in 

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the databases, and commit to strict compliance with relevant laws: Law 41/2002, of November 
14, which regulates patient autonomy and rights and obligations regarding clinical information 
and documentation, Organic Law 3/2018, on the protection of personal data and the 
guarantee of digital rights, and Regulation (EU) 2016/679 of the European Parliament and of 
the Council of April 27, 2016, on the protection of individuals concerning the processing of 
personal data and on the free movement of such data, repealing Directive 95/46/EC (General 
Data Protection Regulation). 
All information obtained will be pseudonymized before leaving the hospital network, ensuring 
the identification of any individual through this information is not possible. The transfer of 
information to the Computing Center of the European University of Madrid will be done 
physically on a hard drive guarded by the researchers and deposited at the hospital facilities 
after the study's completion. Researchers at the Computing Center of the European University 
of Madrid also commit to the strictest confidentiality in accessing, collecting, and processing 
data, even though they will always be pseudonymized, and commit to strict compliance with 
current legislation: Law 41/2002. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Cronograma 
 
 
November 
2023 
November 
2023 
December -
January 
2024 
May 
2024 
October 
2024 
November 
2024 
Protocol Study 
Drafting 
 
 
 
 
 
 
HLA Moncloa 
Hospital 
Permissions 
 
 
 
 
 
 
Presentation to 
CEIm (Ethics 
Committee) 
 
 
 
 
 
 
CEIm (Ethics 
Committee) 
validation 
 
 
 
 
 
 
Purchase and 
Installation of 
Equipment in 
ICU 
 
 
 
 
 
 
Patient 
Recruitment 
 
 
 
 
 
 
Interim Report 
 
 
 
 
 
 
Statistical 
Analysis 
 
 
 
 
 
 
Final Report" 
 
 
 
 
 
 
Article Writing 
and 
Commencement 
of Outreach 
 
 
 
 
 
 
 
 
 
 
 
 

12 
 
Economic Report 
 
Budget 
Concept  
Grant Awarded * 
Equipment 
3200€ 
Consumable Material 
200€ 
Publication Expenses 
600€ 
Total 
4000€ 
 
* Grant Awarded corresponds to the RESEARCH GROUPS JOINT GRANTS CALL 2023. ASISA 
FOUNDATION-UNIVERSIDAD EUROPEA DE MADRID CHAIR 
Budget Justification 
At the beginning of the project, €1,200 will be used to purchase 3 high-quality thermal 
cameras, valued at approximately €400 each. Additionally, a budget of €800 will be allocated 
for the purchase of a PC (€600) and consumable materials (€200) for interconnection and 
automation of image downloads. 
After 6 months, another €1,200 will be used to complete the purchase of an additional 3 
thermal cameras, along with a Tablet (€200) for data representation. Furthermore, €600 will 
be allocated for publication expenses, which may include article translation, publication fees, 
or dissemination of results at national and international conferences." 
 
 
 
 
 
 
 
 

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