Condition category
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Air containing oxygen, normally passes in and out of our nose or mouth to the lungs during normal breathing. In the event of rare and life-threatening emergency, this passage may become blocked or obstructed, and an alternative route that bypasses the nose or mouth is needed. This can be done with a small cut or window made in the front of the neck (the cricothyroid membrane) overlying the windpipe. Without this life-saving procedure, the patient will be starved of oxygen and may come to serious harm, or die. This is a very rare event, and many doctors will never perform even one of these in their lifetime. Correctly locating this point on the neck can be difficult, especially when a patient is very overweight. The current way of finding this point is by feeling for landmarks on the neck with fingers, known as “palpation”. This is known to be more difficult when the patient is very overweight and the landmarks of the windpipe underneath the neck are less easy to feel. Another way to find this point on the neck is by using ultrasound. This is a machine that can produce an image or picture of tissues underneath the skin onto a screen, so that a trained doctor can see the correct spot to aim for, even if they may not be able to feel it by the finger method. Our study is going to look at which of these two techniques is more accurate.

Who can participate?
Anaesthetists working at University College London Hospital ( UCLH).

What does the study involve?
Participants are randomly allocated into one of two groups. Those in group 1 are asked to locate the cricothyroid membrane using the finger "palpation" technique on an actor who is overweight.
Those in group 2 are asked to locate the cricothyroid membrane using ultrasound on an actor who is overweight. Assessments are made as to how quickly and easily the membrane is located.

What are the possible benefits and risks of participating?
There are no specific benefits for the participants, though they will receive education on ultrasound guided interventions in the neck. There are no risks to participants.

Where is the study run from?
University College London Hospital (UK)

When is the study starting and how long is it expected to run for?
May 2016 to July 2016

Who is funding the study?
University College Hospital NHS Trust (UK)

Who is the main contact?
Dr Kirstie McPherson

Trial website

Contact information



Primary contact

Dr Kirstie McPherson


Contact details

Dept of Anaesthetics
235 Euston Road
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Randomised control trial of ultrasound versus palpation-technique in identifying the cricothyroid membrane (CTM) in simulated can’t intubate, can’t ventilate scenario


Study hypothesis

The principle research question is which of two methods is more accurate at correctly identifying the spot on the neck, under which lies the windpipe. At this point a "cut" or window can be made accessing the windpipe, providing a route for air to pass down into the lungs, bypassing the nose or mouth, where a blockage or obstruction lies. The first method relies on examining the neck with hands and fingers to locate this spot correctly, the second uses ultrasound, a machine that produces a picture or image of structures below the skin and invisible to the human eye. We will measure how accurate both methods are by randomly allocating anaesthetists to one of two groups (finger palpation and using ultrasound). We will ask them to find the correct point on the neck of an actor, marking this with "invisible ink". An experienced doctor will have marked this area beforehand (with invisible ink), enabling a measurement of how accurate and close to the expert's mark the subject has been using one of either techniques.

Ethics approval

On pre-review by ethics, it was decided that full ethical review was not required

Study design

Single-centre randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Can't intubate, can't ventilate scenarios


Doctors are randomly assigned to one of two groups.
Group 1: Participants are asked to locate the cricothyroid membrane using the finger "palpation" technique on an actor who is overweight
Group 2: Participants are asked to locate the cricothyroid membrane using ultrasound on an actor who is overweight

Intervention type



Drug names

Primary outcome measure

Ease of identification of the cricothyroid membrane with ultrasound in a simulated CICV scenario.

Secondary outcome measures

Speed of identification of cricothyroid membrane using ultrasound

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)

Objectives no longer viable


Participant inclusion criteria

Anaesthetists working at UCLH

Participant type

Health professional

Age group




Target number of participants


Participant exclusion criteria

Unwilling to consent to taking part

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University College Hospital
235 Euston Rd
United Kingdom

Sponsor information


University College Hospital NHS Trust (UK)

Sponsor details

235 Euston Rd
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type

Hospital/treatment centre

Funder name

University College Hospital NHS Trust (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

We anticipate the results of the trial will be published in an international anaesthetic journal for dissemination of the lessons learned.

Intention to publish date

Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

12/03/2019: This trial was abandoned pre-data collection as airway guidelines changed during its design period, making the design outdated. 20/04/2016: The following changes were made to the trial record: 1. The overall trial start date was changed from 01/06/2015 to 01/05/2016. 2. The overall trial end date was changed from 30/06/2015 to 01/07/2016.