Optimal Positioning of Nasopharyngeal Temp Probe

Optimal Positioning of Nasopharyngeal Temperature Probes in Pediatric Patients: A Prospective Cohort Study

The purpose of this study is to determine the optimal range of insertion depths for a nasopharyngeal probe in anesthetized pediatric patients as a function of age.

Study Overview

• Status: Completed
• Conditions: Pediatric Temperature
• Intervention / Treatment: Other: Nasopharyngeal temperature probe

Detailed Description

Before surgery, the esophageal and nasopharyngeal probes (DeRoyal GP/Nasopharyngeal Probe, 9F, 400 series [REF 81-025409] to be used in a given patient will be connected to the two channels of the clinical monitor in the designated room. The tips will be inserted at least five centimeters into a well stirred container of water maintained near 370 Celsius. Temperatures will be recorded from each, and the offset (if any) used as a correction factor in the statistical analysis below.

After anesthetic induction and intubation, patients will be positioned per clinical routine for the selected operation. An esophageal temperature probe (DeRoyal General Purpose Temperature Probe, SOFT 9 French, 400 series [REF V81-010400]) will be inserted. The optimal placement of the esophageal temperature probe varies based on the height of the patient8. Broad consensus is that the measurement is most accurate in the distal third of the esophagus. The use of acoustic criteria for optimal placement is not a reliable method9. Bloch et al.,5 proposed the use of a simple formula of one quarter of the patient's height plus 4.5 centimeters with the upper incisors as the starting point. This technique reliably locates the tip of the probe 2 centimeters above the lower esophageal sphincter.

For the two groups of infants aged up to twelve months, the nasopharyngeal probe will be marked with indelible ink from 2-10 cm in 1-cm increments and inserted 10 cm. For the two groups of children between 1 and 5 years, the nasopharyngeal probe will be marked with indelible ink from 2-15 cm in 1.5-cm increments and inserted 15 cm. For older children, a nasopharyngeal probe will be marked with indelible ink from 2 to 20 cm at 2 cm increments from its tip, and inserted 20 cm. In each case, investigators will confirm under direct vision that the probe tip is visible in the oropharynx. Insertion will be repeated if necessary; the contralateral nostril or a new probe can be used.

Both nasopharyngeal and esophageal temperatures will initially be recorded 30 minutes after induction of anesthesia. Nasopharyngeal probes will then be withdrawn at the designated increment for each age group and will be equilibrated for 3 minutes before the temperature is recorded. Thereafter, the nasopharyngeal withdrawal sequence will be repeated. The number of measurement will depend on the initial depth of insertion; with measurements continuing until only 2 centimeters remain in the nostril.

Temperature in the operating room will be maintained per clinical routine. Normothermia will be maintained with forced-air warmer and if necessary with overhead warming lights per clinical routine.

• Study Type: Observational
• Enrollment (Actual): 158

Contacts and Locations

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75235
      • Children's Health Children's Medical Center Dallas

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 second to 12 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

The subjects will be pediatric patients having elective non-cardiac surgery with general anesthesia and endotracheal intubation at the Children's Health.

Description

Inclusion Criteria:

1. Elective non-cardiac surgery in children to last at least 1.5 hours;
2. Supine position anticipated;
3. General endotracheal anesthesia.

Exclusion Criteria:

1. Nasopharyngeal disease (e.g. sinusitis), upper airway abnormalities, or planned oral or facial surgery;
2. History of genetic or congenital anomalies leading to facial dimorphism;
3. History of recent substantive epistaxis or suspected bleeding disorder;
4. Therapeutic-dose anti-coagulation;
5. Contraindication to esophageal temperature probe insertion (i.e., esophageal varices, congenital anomalies).

Study Plan

How is the study designed?

Number of groups / cohorts

5

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
0 to 6 months	Other: Nasopharyngeal temperature probe; Nasopharyngeal temperatures will initially be recorded 30 minutes after induction of anesthesia. Nasopharyngeal probes will then be withdrawn at the designated increment for each age group and will be equilibrated for 3 minutes before the temperature is recorded. Thereafter, the nasopharyngeal withdrawal sequence will be repeated.
7 months to less than 1 year	Other: Nasopharyngeal temperature probe; Nasopharyngeal temperatures will initially be recorded 30 minutes after induction of anesthesia. Nasopharyngeal probes will then be withdrawn at the designated increment for each age group and will be equilibrated for 3 minutes before the temperature is recorded. Thereafter, the nasopharyngeal withdrawal sequence will be repeated.
1 to less than 2 years	Other: Nasopharyngeal temperature probe; Nasopharyngeal temperatures will initially be recorded 30 minutes after induction of anesthesia. Nasopharyngeal probes will then be withdrawn at the designated increment for each age group and will be equilibrated for 3 minutes before the temperature is recorded. Thereafter, the nasopharyngeal withdrawal sequence will be repeated.
2 to less than 6 years	Other: Nasopharyngeal temperature probe; Nasopharyngeal temperatures will initially be recorded 30 minutes after induction of anesthesia. Nasopharyngeal probes will then be withdrawn at the designated increment for each age group and will be equilibrated for 3 minutes before the temperature is recorded. Thereafter, the nasopharyngeal withdrawal sequence will be repeated.
6 to 12 years	Other: Nasopharyngeal temperature probe; Nasopharyngeal temperatures will initially be recorded 30 minutes after induction of anesthesia. Nasopharyngeal probes will then be withdrawn at the designated increment for each age group and will be equilibrated for 3 minutes before the temperature is recorded. Thereafter, the nasopharyngeal withdrawal sequence will be repeated.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference between esophageal temp and nasopharyngeal temp	Nasopharyngeal probe will be withdrawn incrementally, with 5 minutes to equilibrate at each depth.	5 minute increments at each position

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Investigators: Principal Investigator: John Zhong, MD, UTSouthwestern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): June 9, 2017
• Primary Completion (Actual): December 2, 2020
• Study Completion (Actual): August 3, 2021

Study Registration Dates

• First Submitted: November 9, 2016
• First Submitted That Met QC Criteria: November 9, 2016
• First Posted (Estimate): November 15, 2016

Study Record Updates

• Last Update Posted (Actual): January 6, 2022
• Last Update Submitted That Met QC Criteria: January 5, 2022
• Last Verified: January 1, 2022

More Information

Terms related to this study

• Other Study ID Numbers: STU 072016-059