Clinical trial NCT03105037: The Effect of Supraglottic Airway Insertion on the Accuracy of Cricothyroid Membrane Identification in Females
Official title: The Effect of Supraglottic Airway Insertion on the Accuracy of Cricothyroid Membrane Identification in Females- a Prospective Observational Study.
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Airway Obstruction
Lead sponsor: The Rotunda Hospital
Sponsor class: OTHER
First posted: 2017-04-07
Enrollment: 64
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Observational model: CASE_CROSSOVER
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: women attending for routine gynaecological surgery

Brief summary: Prospective, observational, study that will examine if a sited supraglottic airway (the igel) will increase the accuracy of identifying the cricothyroid membrane in female patients.

Consented patients that meet inclusion criteria are assessed by clinicians under general anaesthesia with and without a supraglottic airway in situ. The accuracy of CTM identification by palpation will be evaluated using ultrasound.

Detailed description: Palpation of the airway structures results in misidentification of the cricothyroid membrane (CTM) in a high proportion of women. Female front of neck anatomy is less distinct compared to males with reduced angulation of the laryngeal cartilages making it harder to distinguish the relevant landmarks. In obese patients, overlying subcutaneous tissue compounds this problem and several studies have demonstrated poor success identifying the CTM by palpation in this population. Supraglottic airway device (SAD) insertion precedes emergency front of neck access attempts in the stepwise progression from failed intubation to cricothyroidotomy. The nature and clinical implication of SAD insertion on cricothyroidotomy remain unstudied.

Sixty four patients will undergo front of neck airway assessment by volunteer clinicians with and without a SAD in situ (control and SAD assessments, within-subjects design). The patients are fasting women presenting for routine gynaecological surgery. Eight anaesthetists, at different levels of training, will perform eight individual CTM assessments with and without the SAD in situ.

Ultrasound images will be captured in the sagittal plane immediately before and after supraglottic airway insertion. Images are then downloaded, anonymised and randomised for blinded digital analysis.

Eligibility criteria: Inclusion Criteria:

* Women attending for routine surgery

Exclusion Criteria:

* unable to give informed consent
* abnormal neck anatomy
* history of gastroesophageal reflux
* history of neck surgery or radiotherapy
* contraindication to supraglottic airway device insertion

Primary outcomes:
measure: accurate identification of the cricothyroid membrane
timeFrame: At clinician assessment, on the day of patient recruitment.
Secondary outcomes:
measure: Accurate identification of the midline of the neck
timeFrame: At clinician assessment, on the day of patient recruitment.
measure: Difficulty of cricothyroid membrane assessment
timeFrame: At clinician assessment, on the day of patient recruitment.
measure: Time taken to attempt localisation of the cricothyroid membrane
timeFrame: At clinician assessment, on the day of patient recruitment.
measure: Distance from clinician assessment to actual cricothyroid membrane location
timeFrame: On blinded, retrospective ultrasound analysis of images captured at the time of clinician assessment of the cricothyroid membrane. Blinded retrospective ultrasound assessment is to take place within 3 months of patient recruitment
measure: The distance from the skin to the first tracheal ring
timeFrame: On blinded, retrospective ultrasound analysis of images captured at the time of clinician assessment of the cricothyroid membrane. Blinded retrospective ultrasound assessment is to take place within 3 months of patient recruitment
measure: The distance from the skin to the cricoid cartilage
timeFrame: On blinded, retrospective ultrasound analysis of images captured at the time of clinician assessment of the cricothyroid membrane. Blinded retrospective ultrasound assessment is to take place within 3 months of patient recruitment
measure: The angle between the surface tissue interface of the cricothyroid membrane and the trachea
timeFrame: On blinded, retrospective ultrasound analysis of images captured at the time of clinician assessment of the cricothyroid membrane. Blinded retrospective ultrasound assessment is to take place within 3 months of patient recruitment
Other outcomes:
Locations:
city: Dublin
country: Ireland
facility: The Rotunda Hospital
Study officials:
affiliation: Prof
name: Conan McCaul
role: STUDY_DIRECTOR
References: