Comparison of Glottic Views and Intubation Times in the Supine and 25 Degree Back-up Positions

April 5, 2017 updated by: Raj M Reddy, Betsi Cadwaladr University Health Board
Our hypothesis is that the view of the glottis may be improved by putting all patients requiring intubation in the ramped or back up position while maintaining the classic sniffing position.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The sniffing position has traditionally been considered the optimal head position for direct laryngoscopy and is the usual patient position preferred by most anaesthetists. In theory, neck flexion aligns the pharyngeal and laryngeal axes, and head extension at the atlanto-occipital joint aligns the oral axis with these two axes allowing the line of sight to fall on the glottis. It is recognized as the starting head position for direct laryngoscopy because it provides the best chance of adequate exposure.

However the sniffing position does not guarantee adequate exposure in all patients because many other anatomical factors control the final degree of visualization.

To achieve a proper sniffing position in obese patients, the "ramped" (or the back-up) position has been used as this produces better neck flexion and head extension in these patients when compared to the horizontal supine position. Also the forces required to elevate and move the tongue and other tissues out of the line of sight are less when the patients are ramped.

Our hypothesis is that the view of the glottis may be improved by putting all (ie not only obese) patients requiring intubation in the ramped or back up position while maintaining the classic sniffing position.

Study Type

Observational

Enrollment (Actual)

781

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Adult patients who required intubation as part of their routine anaesthesia

Description

Inclusion Criteria:

  • Adult surgical patients who required intubation as part of their routine anaesthesia

Exclusion Criteria:

  1. Patients less than 18 years old,
  2. Patients recognised to have difficult airways where an alternative method of intubation (e.g. fibre optic) was the method of choice,
  3. Patients undergoing emergency surgery where patient positioning and data collection might cause delay (e.g. exsanguinating patients) or where the supine position is not optimal (e.g. brisk bleeding into the upper airway),
  4. Patients requiring rapid sequence induction of anaesthesia

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Supine
A baseline group of adult patients who required intubation as part of their routine anaesthesia who were intubated in the standard horizontal sniffing position.
Back-up
A subsequent group of similar the patients who had their anaesthesia induced and tracheas intubated in a 25 degree back-up position achieved by flexion of the operating table at the hips
Procedure: 25 degree back-up position
To test whether a 25 degree back-up position improves laryngeal views and makes intubation easier compared to the standard horizontal position

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The Best Glottic View Obtained During Laryngoscopy
Time Frame: The view of the glottis was measured once while the patient was being intubated

The best glottic view obtained during laryngoscopy was assessed using the Cormack and Lehane classification by the anaesthetist performing the laryngoscopy.

The Cormack and Lehane classifies glottic views as follows: Grade 1: Most of the glottis is visible, Grade 2: At best almost half of the glottis is seen, at worst only the posterior tip of the arytenoids is seen., Grade 3: Only the epiglottis is visible, Grade 4: No laryngeal structures are visible.
The view of the glottis was measured once while the patient was being intubated

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The Number of Attempts at Both Laryngoscopy and Tracheal Intubation
Time Frame: Once at intubation
The number of attempts at both laryngoscopy and tracheal intubation were recorded
Once at intubation
The Use of Ancillary Equipment
Time Frame: Once at intubation
The use of ancillary equipment (e.g. bougie, alternative laryngoscope blades) and manoeuvres (e.g. laryngeal manipulation) were recorded but applied at the intubating anaesthetist's discretion
Once at intubation
The Time Between the Beginning of Laryngoscopy and Detection of Carbon Dioxide on the End-tidal Carbon Dioxide Monitor
Time Frame: Once at intubation
The time between the beginning of laryngoscopy and detection of carbon dioxide on the end-tidal carbon dioxide monitor after the successful placement of the tracheal tube was recorded
Once at intubation

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Betsi Cadwaladr University Health Board

Investigators

  • Principal Investigator: Raj M Reddy, FRCA, Anaesthetic Department, Glan Clwyd Hospital, Betsi Cadwaladr University Health Board

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 2012

Primary Completion (Actual)

November 1, 2014

Study Completion (Actual)

January 1, 2015

Study Registration Dates

First Submitted

October 13, 2016

First Submitted That Met QC Criteria

October 13, 2016

First Posted (Estimate)

October 17, 2016

Study Record Updates

Last Update Posted (Actual)

May 11, 2017

Last Update Submitted That Met QC Criteria

April 5, 2017

Last Verified

April 1, 2017

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • BetsiCUHB

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Publish anonymised raw data as supplementary file

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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