The purpose of the present study was to evaluate the optimal insertion depth of an esophageal stethoscope with a thermistor for core temperature monitoring.
Monitoring core temperature is crucial for maintaining normothermia during general anesthesia. During anesthesia, an esophageal stethoscope with a thermistor for monitoring esophageal temperature is frequently used. There are several researches on the depth or position of the esophageal stethoscopes, but there is only limited information (known as about 40-45 cm or T8-T9). The purpose of the present study was to evaluate the optimal insertion depth of an esophageal stethoscope with a thermistor for core temperature monitoring.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
40
Core temperatures will be measured with a tympanic thermometer as a reference. When the tympanic membrane (TM) temperature is constant after measuring three consecutive times at 10 seconds intervals, the temperature will be assumed as the core body temperature. Initially, the esophageal stethoscope (ES) will be inserted to a depth of 45 cm from the incisor. After 30 minutes of monitoring, when the changes in the body temperatures stabilized, initial temperatures of the TM and ES thermistor will be assessed. After 5 minutes, ES will be taken out 2 cm back, and the temperatures of each site will be measured when the temperature change of the ES thermistor stabilized below 0.1°C. Eventually, the depth of ES will be changed from 45 to 27 cm with a 2 cm interval, and the temperature at each position will be measured.
For the further evaluation of the optimal insertion depth of GDT, anatomical landmarks such as distance from the cricoid cartilage to the carina (CCD) and distance from the carina to the intervertebral disc between T8 and T9 (CDD) will be measured using an electronic caliper on a preoperative chest X-ray.
Chosun University Hospital
Gwangju, South Korea
RECRUITINGDesired insertion depth of ES thermistor
To evaluate the desired insertion depth, we will assess the accuracy of temperatures of the ES thermistor at each location by estimating the difference between the esophageal temperature using ES thermistor and the core body temperatures of TM.
Time frame: 1 day
Correlation analysis
The secondary outcome of the study is to assess the correlation between the characteristics of patients including gender, height, weight, BMI, CCD, or CDD, and the actual insertion depth of the ES which showed the most minor difference in temperature between TM and ES thermistor.
Time frame: Through study completion, 1 year
Optimal depth analysis
We will calculate a mathematical model to predict the optimal insertion depth of ES for the esophageal temperature monitoring, and further analysis for the accuracy and correlation will be done.
Time frame: Through study completion, 1 year
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