Surgery
Conditions
Keywords
Anatomic Landmarks, Body Temperature, Monitoring, Intraoperative
Brief summary
The purpose of the present study was to evaluate the optimal insertion depth of an esophageal stethoscope with a thermistor for core temperature monitoring.
Detailed description
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.
Interventions
DEVICEEsophageal temperature monitoring according to the depth
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.
OTHERAnatomical landmark
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.
Sponsors
Chosun University Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
20 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* The patients with ASA class 1-2 (20-65 years old) who are undergoing elective surgery with supine or lithotomy position, without position change scheduled to last more than 90 min.
Exclusion criteria
* anatomical abnormality with the upper airway * risks of a difficult airway * abnormal central anatomical structures such as airway, diaphragm, or spine on the chest X-ray * history of disease or surgery on the stomach or esophagus * risks of bleeding or coagulopathy on the preoperative laboratory results * obese patients with BMI over 30 * contraindication to insertion of ES for the surgery * who did not take a standing chest PA X-ray before surgery * position change during the surgery * open chest surgery
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Desired insertion depth of ES thermistor | 1 day | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Correlation analysis | Through study completion, 1 year | 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. Radiographic landmarks On the preoperative chest radiograph, the cricoid-to-carina distance (CCD) and the carina-to-T8/9-intervertebral-disc distance (CDD) will be measured. |
| Optimal depth analysis | Through study completion, 1 year | 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. To quantify tolerance to positioning error, the difference was modeled as a quadratic function of the offset from the MHS position (depth - MHS) using a linear mixed-effects model with a random intercept per patient. From the fixed-effect curve and the total (within- plus between-patient) standard deviation, the probability that a single reading fell within ±0.5 °C of core was computed across offsets to define ≥90% and ≥85% "safe zones." |
Countries
South Korea
Contacts
STUDY_DIRECTORKi Tae Jun, M.D., Ph.D.
Chosun University Hospital
Outcome results
None listed