Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03656315 |
| Other study ID # |
247781 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
September 14, 2018 |
| Est. completion date |
February 25, 2022 |
Study information
| Verified date |
March 2021 |
| Source |
University Hospitals Coventry and Warwickshire NHS Trust |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
This study looks to devise a scoring system that can be used to predict difficult front of
neck access due to increased depth of cricothyroid membrane. This study will recruit elective
patients undergoing operations for a variety of procedures and correlate their measured (by
ultrasound) cricothyroid depth with other difficult airway predictors (such as Mallampatti
score).
Description:
A 'can't intubate can't oxygenate scenario (CICO) is defined as a situation when there is a
failed intubation and failure to adequately oxygenate using facemask ventilation or
supraglottic airway device resulting in increasing hypoxemia in an anaesthetised and
paralysed patient. Although this situation is rare, if not managed appropriately it can
result in hypoxic brain damage and death. The successful management of CICO includes timely
decision making to perform front of neck access (FONA) via the cricothyroid membrane (CTM).
The currently recommended technique in the UK is surgical cricothyroidotomy.
Successful FONA depends on the ease of anatomy of the neck and the ability to locate the
cricothyroid membrane. In cases where the cricothyroid membrane is not palpable, front of
neck access is difficult. The clinical procedure involves an 8 cm long skin incision and
finger dissection to palpate the cricothyroid membrane. In a real-life situation, this will
be compounded by profuse bleeding and no structure would be visible. Therefore, prediction of
difficult FONA and appropriate preparation is essential for safe airway management.
Routine airway assessment includes mouth opening measured as inter-incisor gap, Mallampatti
score, thyromental distance, sternomental distance, jaw protrusion and neck movements. In
addition, ability to perform front of neck access should be ascertained prior to induction of
general anaesthesia. Depth of cricothyroid membrane is one of the factors leading to
technical difficulties in front of neck access. In situations where the CTM is deep and not
palpable, FONA is technically difficult and takes longer. A previous observational study has
shown a positive correlation between patient's weight, height, body mass index and neck
circumference with depth of cricothyroid membrane. A scoring system to assess the depth of
cricothyroid membrane based on the patient's height, weight, neck circumference and other
airway assessment parameters would be useful in predicting the depth of CTM. Hence
difficulties with front of neck access can be anticipated and appropriate measures can be
taken in the event a CICO situation arises.
DAS 2015 guideline recommend airway assessment and preparation for all patients presenting
for surgery. Routine airway assessment includes mouth opening measured as inter-incisor gap,
Mallampatti score, thyromental distance, sternomental distance, jaw protrusion and neck
movements. In addition, ability to perform front of neck access should be ascertained prior
to induction of general anaesthesia. Depth of cricothyroid membrane is one of the factors
leading to technical difficulties in front of neck access. In situations where the CTM is
deep and not palpable, FONA is technically difficult and takes longer. A previous
observational study has shown a positive correlation between patient's weight, height, body
mass index and neck circumference with depth of cricothyroid membrane. A scoring system to
assess the depth of cricothyroid membrane based on the patient's height, weight, neck
circumference and other airway assessment parameters would be useful in predicting the depth
of CTM. Hence difficulties with front of neck access can be anticipated and appropriate
measures can be taken in the event a CICO situation arises.
