Evaluation of a Licensed Double-sensor-heat-flux (DHF) Non-invasive Core Temperature Sensor in Small Children and Toddlers Undergoing Surgery
Condition: Hypothermia; Anesthesia
MeSH terms: Hypothermia
Study type: Observational

Summary: 
      Title: Evaluation of a licensed double-sensor-heat-flux (DHF) non-invasive core temperature
      sensor in small children and toddlers undergoing surgery.

      CI/PS identification code: DHF-TaSC Device Name: Tcore™ system (Tcore-Adapter MP00999 &
      Tcore-Sensor MP 00989) Manufacturer: Drägerwerk AG & CO KGaA Study design: Prospective,
      single arm, clinical study

      Patients:

        -  Number: 72

        -  Age / gender: females and males between 0 and 7 years

        -  Patients of a tertiary referral, university-affiliated hospital undergoing surgery

      Exclusion Criterions:

        -  Operation site, rash or infection that prevents the application of the heat flux
           thermometers.

        -  Patients and/or legal guardians not willing to participate in the trial.

        -  Patients older than 7 years Setting: ORs of a tertiary referral, university-affiliated
           hospital. Study variables: measurement triplets measured via two double-sensor-heat-flux
           (DHF) thermometer the Tcore™ (Dräger, Drägerwerk AG & Co KG, 23558 Lübeck, Germany) one
           placed on the forehead and one on the upper belly and temperature measured by a rectally
           placed temperature probe.
    

Detailed description: 
      Body temperature is important for maintaining normal physiological functions. Inadvertent
      hypothermia as well as pyrexia are associated with higher morbidity and mortality.
      Consequently, continuous measurement of body temperature is standard of care at intensive
      care units (ICUs) and in operation rooms (ORs). The use of core temperature measurements such
      as pulmonary catheter (gold standard), esophageal or urinary probes is recommended because of
      higher accuracy than non-invasive measuring methods. The double-sensor-heat-flux (DHF)
      thermometer the Tcore™ (Dräger, Drägerwerk AG & Co KG, 23558 Lübeck, Germany). The DHF
      thermometers consist of two sensors separated by a known thermal resistance. One side is
      placed directly at the patient's skin and the other is facing the environment. After some
      equilibration time the core temperature can then be calculated. To date no study, exist for
      the use of the Tcore™ thermometer in children or toddlers. Children are at higher risk for
      hypothermia and perioperative hypothermia is still common in children.(8) The objective is to
      find a non-invasive core temperature measurement for children to guide perioperative
      temperature management.

      Primary Objective (Hypothesis):

      Evaluation of the accuracy of the licensed double-sensor-heat-flux (DHF) thermometer the
      Tcore™ (Dräger, Drägerwerk AG & Co KG, 23558 Lübeck, Germany) when used for intraoperative
      core temperature measurement in small children and toddlers.

      The Hypothesis is that each of the two temperature measurements obtained with the Tcore™
      (forehead, upper belly) have a high level of agreement(<0.5°C) with the standard of care
      temperature measurements via rectal temperature probe.

      Our primary objective is to investigate the agreement between the two temperature
      measurements obtained with the Tcore™ (Dräger, Drägerwerk AG & Co KGaA, 23558 Lübeck,
      Germany) placed on the forehead and the upper belly and temperature measured via a rectally
      placed Medical Level 1 disposable General Purpose Temperature Probe (Smiths Medical
      Österreich GmbH, Brunn am Gebirge, Austria). Measure triplets of the two Tcore™ sensors and
      the rectally placed probe are obtained every 3 minutes for up to 12 consecutive hours or for
      the duration the patient spends in the OR and the recovery room. If the observed limits of
      agreement (± 1.96 SD around the mean difference), within which 95% of the differences are
      expected to fall, are clinically acceptable, the methods are considered to agree. We define
      deviations of +/-0.5°C, a priori, to be acceptable for the Bland Altman method comparison
      analysis as was done in previous studies.

      Intended use The Tcore system is a thermometer intended for non-invasive, continuous
      measurement of the core body temperature of children from 5 years of age, adolescents, and
      adults. The Tcore system consists of a sensor and an adapter. The adapter is reusable. The
      sensor is intended for single use. The Tcore system works in adjusted mode, i.e., the core
      body temperature is determined by a dual sensor.

      Off-Label/Investigational Use In context of this clinical study the Tcore-system will be
      investigated outside its approved and intended use, namely in children below the age of five
      and toddlers.

      Descriptive statistics:

        -  For nominal and ordinal data absolute frequencies and percentages, fraction, rate, and
           incidence will be calculated, if appropriate.

        -  Continuous data are described by mean ± standard deviation (SD) in case of approximate
           normal distribution, or by median, interquartile range otherwise.

      Endpoint analysis:

      For the primary objective, a scatterplot of differences between Tcore and standard
      measurements and their mean will be produced for each of the two Tcore measurements in
      relation to the measurement standard (rectal temperature). If the differences prove to be
      approximately independent for the observed range of temperatures, limits of agreement will be
      calculated using the method by Zou (2013).(23) If these limits are contained within the
      acceptable deviation of +/-0.5°C the respective Tcore measurement method will be considered
      acceptable. Irrespective of the success of the investigation of agreement the results for
      both Tcore measurement locations will be reported.

      For the secondary objective sensitivity and specificity will be calculated with 95%
      confidence intervals for each Tcore measurement in relation to the measurement standard.

      All study data will be queried from the ICCA and from the database of electronic health
      records the Vienna General Hospital information management system (AKIM; "Allgemeines
      Krankenhaus Informationsmanagement") (Siemens AG Österreich, Vienna, Austria). Intellispace
      Critical Care and Anesthesia. After acquisition, patient data will be anonymized, cleaned,
      and stored in a study database.

      Patient identification will contain name, sex, and birthdate. This data will be documented in
      an excel sheet, protected with a password. All patients will be given a number for
      pseudonymization. The verification key will be stored on a separate computer in our
      laboratory. Only specially authorized persons (Dr. Sebastian Zeiner and Prof. Oliver
      Kimberger) will have access to the data.

      All data will be stored on a password secured computer in the laboratory of our department
      (Department for Anesthesia) at the Medical University of Vienna.

      At any time, medical confidentiality will be fulfilled by all persons involved in this
      project.
    

Intervention name(s): Tcore™ system
Intervention type(s): Device
Intervention description(s): The Tcore sensor is a double-sensor-heat-flux (DHF) thermometer and consist of two sensors separated by a known thermal resistance. One side is placed directly at the patient's skin and the other is facing the environment. After some equilibration time the core temperature can then be calculated. The sensors are placed above the eye and the sinus frontalis.
Intended use The Tcore system is a thermometer intended for non-invasive, continuous measurement of the core body temperature of children from 5 years of age, adolescents, and adults. The Tcore system consists of a sensor and an adapter. The adapter is reusable. The sensor is intended for single use. The Tcore system works in adjusted mode, i.e., the core body temperature is determined by a dual sensor.
Off-Label/Investigational Use In context of this clinical study the Tcore-system will be investigated outside its approved and intended use, namely in children below the age of five and toddlers.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Study population: toddlers and small children undergoing surgery at a tertiary referral,
        university-affiliated hospital