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NCT Number: NCT03105037

The Effect of Supraglottic Airway Insertion on the Accuracy of Cricothyroid Membrane Identification in Females

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.

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Key information

Conditions

Airway Obstruction Respiration Disorders Respiratory Insufficiency Respiratory Tract Diseases

Age range

18 year and older

Sex eligibility

Female

Study type

Observational

Primary location

The Rotunda Hospital

Dublin, Ireland

About this study

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.

Who can participate

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Primary outcomes

  1. accurate identification of the cricothyroid membrane

    Time frame: At clinician assessment, on the day of patient recruitment.

    accuracy of cricothyroid membrane identification, measured as either successful identification or unsuccessful (binary outcome). A successful identification is within 5mm of the midline and within the upper and lower borders of the cricothyroid membrane as measured using ultrasound.

Secondary outcomes

  1. Accurate identification of the midline of the neck

    Time frame: At clinician assessment, on the day of patient recruitment.

    Accurate identification of the midline of the neck, binary outcome. A successful identification is within 5mm of the midline of the cricothyroid membrane as measured using ultrasound.

  2. Difficulty of cricothyroid membrane assessment

    Time frame: At clinician assessment, on the day of patient recruitment.

    Difficulty of assessing the cricothyroid membrane as graded subjectively by the clinician using a visual analogue scale (VAS) where '0' is the easiest possible assessment of the location of the cricothyroid membrane and '10' is the most difficult possible assessment of the location of the cricothyroid membrane.

  3. Time taken to attempt localisation of the cricothyroid membrane

    Time frame: At clinician assessment, on the day of patient recruitment.

    The time taken in seconds to attempt localisation of the cricothyroid membrane

  4. Distance from clinician assessment to actual cricothyroid membrane location

    Time frame: 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

    The distance measured from the clinicians estimate of where the cricothyroid membrane is to where the actual location of the CTM is using ultrasound and measured in millimetres

  5. The distance from the skin to the first tracheal ring

    Time frame: 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

    The distance from the skin to the superficial surface of the first tracheal ring measured in millimetres using digital analysis of ultrasound images

  6. The distance from the skin to the cricoid cartilage

    Time frame: 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

    The distance from the skin to the superficial surface of the first tracheal ring measured in millimetres using digital analysis of ultrasound images

  7. The angle between the surface tissue interface of the cricothyroid membrane and the trachea

    Time frame: 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

    The angle between the surface tissue interface of the cricothyroid membrane and the trachea measured in degrees using digital analysis of ultrasound images

Sponsors and collaborators

Lead sponsor

The Rotunda Hospital

Other

Registry information

Official study title

The Effect of Supraglottic Airway Insertion on the Accuracy of Cricothyroid Membrane Identification in Females- a Prospective Observational Study.

Important dates

Study start
2017
Primary completion
2017
Study completion
2017
First posted
Apr 7, 2017
Registry last updated
Sep 25, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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