Accuracy of Core Body Temperature Measurement Depending on Oesophageal Probe Tip Location (ESO-TIP)

Background An accurate measurement of the core body temperature (CBT) is of pivotal importance in the management of severely hypothermic patients. For instance, triage decisions for or against extracorporeal rewarming of hypothermic patients in cardiac arrest strongly depend on CBT. CBT measurement with an oesophageal probe is currently considered the gold standard in hypothermic patients with a secured airway in the prehospital setting, with the tip of the probe placed into the distal third of the oesophagus (i.e., posteriorly to the heart and distal to the tracheal bifurcation). However, the correct placement of the probe tip cannot be verified in the prehospital setting, and it is unknown how incorrect placement affects temperature readings.

Hypothesis and aim The investigators hypothesise that an incorrect placement of the oesophageal temperature probe tip could lead to inaccurate measurements (i.e., temperature readings not reflecting the real CBT). Particularly, a tip location too high in the oesophagus in close proximity to the trachea could lead to falsely low temperature readings, especially when the patient is ventilated with cold air. The aim of the proposed study is to investigate the influence of oesophageal temperature probe tip location on CBT measurement.

Methods Experimental, interventional study on 16 healthy volunteers. During the test oesophageal temperature is measured while participants are breathing ambient air first at 20°C (baseline) followed by cold (-20°C) ambient air in supine position for 20 minutes each test in an environmental simulator (terraXcube). Each participant repeats the 20-min test two times with the oesophageal temperature probe tip placed either in the lower third of the oesophagus (i.e., correct position) or too high in the oesophagus, i.e. behind the trachea.

Study Overview

• Status: Completed
• Conditions: Emergencies; Hypothermia
• Intervention / Treatment: Diagnostic test: Oesophageal temperature measurement

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Bolzano, Italy
    • terraXCube

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Volunteers with an American Society of Anaesthesiologists (ASA) score ≤2.

Exclusion Criteria:

• ASA >3
• Age < 18 and age >75
• Pregnant women
• No signed informed consent
• Signs and symptoms of an acute illness on the study day
• History of oesophageal and nasopharyngeal disorders
• Allergies to Local Anaesthetics (i.e. Lidocain).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Correctly placed oesophageal probe at +20 degrees celsius ambient temperature; Oesophageal probe tip located in the lower third of the oesophagus, i.e. behind the left atrium, +20°C ambient temperature, outside terraXcube	Diagnostic test: Oesophageal temperature measurement; Oesophageal temperature measurement
Experimental: Oesophageal probe tip too high at +20 degrees celsius ambient temperature; Oesophageal probe tip located too high the oesophagus, i.e. behind the trachea, 1-2 cm above the level of the tracheal bifurcation, +20°C ambient temperature, outside terraXcube	Diagnostic test: Oesophageal temperature measurement; Oesophageal temperature measurement
Active Comparator: Correctly placed oesophageal probe at -20 degrees celsius ambient temperature; Oesophageal probe tip located in the lower third of the oesophagus, i.e. behind the left atrium, -20°C ambient temperature, inside terraXcube	Diagnostic test: Oesophageal temperature measurement; Oesophageal temperature measurement
Experimental: Oesophageal probe tip too high at -20 degrees celsius ambient temperature; Oesophageal probe tip located too high the oesophagus, i.e. behind the trachea, 1-2 cm above the level of the tracheal bifurcation, -20°C ambient temperature, inside terraXcube	Diagnostic test: Oesophageal temperature measurement; Oesophageal temperature measurement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in core body temperature between the two tip positions	Difference in core body temperature between the two tip positions (i.e. in the lower third of the oesophagus (behind the left atrium) and in the middle third of the oesophagus (behind the trachea)	20 minutes after cold air exposure

Collaborators and Investigators

• Sponsor: Institute of Mountain Emergency Medicine
• Investigators: Principal Investigator: Simon Rauch, MD, PhD, Institute of Mountain Emergency Medicine, EURAC Research

Study record dates

Study Major Dates

• Study Start (Actual): May 23, 2024
• Primary Completion (Actual): December 31, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: April 11, 2024
• First Submitted That Met QC Criteria: April 16, 2024
• First Posted (Actual): April 17, 2024

Study Record Updates

• Last Update Posted (Actual): August 8, 2025
• Last Update Submitted That Met QC Criteria: August 5, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Body Temperature Changes; Emergencies; Hypothermia
• Other Study ID Numbers: ESO-TIP

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No