Perioperative Accuracy of the Raiing Wireless Axillary Thermometer
Condition: Major Surgery Under General Anesthesia
Study type: Observational

Summary: 
      A new wireless axillary thermometer from Raiing Medical uses a proprietary system,
      iThermonitor (WT701), to provide better estimates of core temperature than a conventional
      axillary probe. Improvement results in part because the axillary probe measures and records
      temperatures continuously every 4 seconds and includes software to compensate for ambient
      temperature and positional changes including arm abduction.

      Whether the iThermonitor is sufficiently accurate for clinical use remains unknown. The
      investigators thus propose to evaluate the system in perioperative patients who often
      experience thermal perturbations over a range of several °C. Specifically, the investigators
      propose to determine the precision and accuracy of iThermonitor in surgical patients and
      during the initial hour of recovery. As in previous studies, the investigators will consider
      the thermometer sufficiently accurate for clinical use if most Raiing temperatures are within
      ±0.5°C of the reference temperature.
    

Detailed description: 
      Patient characteristics, including age, height, weight, sex, and ASA status, and details of
      the surgery, including procedure and postoperative diagnosis will be recorded. The
      investigator will record the time of anesthesia induction and emergence. At 10-minute
      intervals during surgery, the investigator will record inspired volatile anesthetic
      concentration, mean-arterial pressure, type of thermal management device(s), and urine output
      over the previous 10-minute interval.

      After induction of general anesthesia (without restriction as to type), the anesthesiologist
      will insert a temperature sensor into the distal esophagus. The distance will be determined
      by maximal heart sounds (if a stethoscope is used), or the probe will be inserted
      0.48.(sitting height) - 4.4 cm. If an esophageal probe cannot be used, a thermometer can be
      inserted to between 10 and 20 cm into the nasopharynx. The surgical team will position a
      Foley catheter with temperature sensor into the urinary bladder. Ambient temperature will be
      recorded from an electronic probe situated at the height of the patients, well away from any
      heat-producing equipment.

      Axillary temperature will be recorded by iThermonitor, a Raiing Medical wireless module,
      paired to an iPhone. An adhesive patch provided by Raiing will be used to securely position
      the Railing probe in a shaved axilla before the anesthesia induction. Patients will be asked
      to adduct the ipsilateral arm for up to 5 minutes after the probe is inserted, or until the
      temperature displayed on the paired iPhone is stable. Thereafter, patients will be free to
      move their arms.Monitored arm position during surgery will be recorded (arm tightly tucked,
      arm loose at side, arm abducted).

      Temperatures will be recorded at 10-minute intervals during surgery and during the initial
      postoperative hour. Just before anesthetic emergence, the esophageal or nasopharyngeal
      thermometer will be removed, but the Foley catheter retained. The axillary device will then
      be removed after an hour of recovery, and the study concluded. The Foley catheter can be
      removed or retained per clinical need.
    

Intervention name(s): iThermonitor (WT701)
Intervention type(s): Device
Intervention description(s): Continuously monitor the axillary temperature during surgery
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Adult surgery patients
      
Keywords: open abdominal surgery; anesthesia, general