The accuracy of a disposable noninvasive core thermometer

Abstract

Purpose Perioperative hypothermia is still a common occurrence, and it can be difficult to measure a patient's core temperature accurately, especially during regional anesthesia, with placement of a laryngeal mask airway device, or postoperatively. We evaluated a new disposable double-sensor thermometer and compared the resulting temperatures with those of a distal esophageal thermometer and a bladder thermometer in patients undergoing general and regional anesthesia, respectively. Furthermore, we compared the accuracy of the thermometer between regional and general anesthesia, since forehead microcirculation might differ between the two types of anesthesia. Methods We assessed core temperature in 36 general anesthesia patients and 20 patients having regional anesthesia for orthopedic surgery. The temperatures obtained using the double-sensor thermometer were compared with those obtained with the distal esophageal thermometer in the general anesthesia population and those obtained with the bladder thermometer in regional anesthesia patients. Results In our general anesthesia patients, 90% (95% confidence interval [CI] 85 to 95) of all double-sensor values were within 0.5°C of esophageal temperatures. The average difference (bias) between the esophageal and double-sensor temperatures was -0.01°C. In patients undergoing regional anesthesia 89% (95% CI 80 to 97) of all double-sensor values were within 0.5°C of bladder temperatures. The average difference (bias) between the bladder and double-sensor temperatures was -0.

Accuracy of zero-heat-flux thermometry and bladder temperature measurement in critically ill patients

“…Many studies that compare new temperature monitoring devices with a gold standard use a definition that the combined inaccuracy (bias and limits of agreement) should be smaller than 0.5 °C 27 to be accurate enough. In our opinion this objective is very high and most of the studies that have investigated new non-invasive thermometers 13 , 28 , 29 did not find an accuracy that met this criterion. Still they came to the conclusion that the new devices agree sufficiently enough for clinical practice 13 , 28 , 29 .…”

“…Some studies have used more complex statistical methods 29 like population analysis 30 . However, very often these complex analyses do not add very much new information about the accuracy of the studied devices.…”

Increased core body temperature in astronauts during long-duration space missions

“…CBT was determined using a novel, non-invasive heat flux sensor 20 , 21 , 23 , 25 , 26 . Major advantages and limitations of the different methods including the Double Sensor, their anatomical site, their applicability in the clinic and in the field, and the role of the hypothalamus in thermoregulation, as well as the ambiguous brain temperature concepts, have been intensively reviewed and discussed in the recent literature 20 , 30 – 34 .…”

“…The sensor is fixed using a two-sided adhesive ring tape as well as an additional adhesive tape to securely affix it to the astronaut’s skin on the forehead. A detailed description of the sensor design and its precision, accuracy, and validity is described elsewhere 20 – 23 , 25 , 26 . Data were recorded and stored at 0.5 Hz using a miniaturized mobile system specifically adapted for spaceflight operations (Health Lab-System, Koralewski Industrie-Elektronik, Hambuehren, Germany).…”

A prospective observational study testing liquid crystal phase change type thermometer placed on skin against oesophageal/pharyngeal placed thermometers in participants undergoing general anesthesia

“…oral) and non-invasive (e.g. SpotOn Thermometer [5], DoubleSensor thermometer [6] and Temple Touch Pro [7]), however these are not widely endorsed or available for use at our institution.…”