Trial to compare two airway ultrasonography techniques for speed and accuracy
- Conditions
- Difficult cricothyroid membrane localisation (during airway emergency with failure to oxygenate requiring cricothyroidotomy)Anaesthesiology - Anaesthetics
- Registration Number
- ACTRN12617001131347
- Lead Sponsor
- niversity of Tasmania
- Brief Summary
The cricothyroid membrane (CTM) is the site of emergency front of neck airway access (cricothyroidotomy) during anaesthesia. Cricothyroidotomy is required when a patient cannot be oxygenated using facemask, laryngeal mask or endotracheal intubation, a rare emergency. Locating the CTM in obese females by palpation can be impossible, whereas ultrasonography is more accurate but slower. We found that a new 2-Level transverse ultrasonography technique is significantly faster than the previously fastest known technique (the “thyroid-airline-cricoid-airline”, TACA, technique) to locate the CTM. We also found that the 2-Level technique is significantly more accurate within 27s (a window of time to perform the scan that is considered to still allow cricothyroidotomy to be performed before morbidity could occur in obese female patients due to low oxygen in the body). Overall accuracy though, not considering time, was not significantly different between the two techniques. So, overall, the 2-Level technique was found to be superior in speed, and in accuracy at 27s. This result was found despite simple randomisation, and one scanning participant’s error (unintentionally performing scans in reverse order to allocation), resulting in a skewed distribution with the 2-Level technique performed initially (before crossover) more (62%) than the TACA (38%), that could possibly favour the TACA technique due to recall bias in this study. Concluding, the 2-Level technique may reduce morbidity in obese female patients during anaesthesia by reducing the time taken from the declaration of an airway emergency until the successful performance of cricothyroidotomy.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Completed
- Sex
- All
- Target Recruitment
- 26
Medical student participants: 5th year medical students at University of Tasmania's Launceston Clinical School, must be aged over 18 years of age.
Mock patient participants: must be over 18 years of age and BMI>30
<18 years, Aboriginal or Torre's Straight Islanders, pregnant, incompetent to give informed consent, hospital inpatients.
Study & Design
- Study Type
- Interventional
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method Time taken (speed) to locate the cricothyroid membrane will be assessed for watch scan by a blinded timing observer. This observer will not watch the scan, but will face the other way. This observer will measure with a stop watch from when the scanning participant says start” (when the ultrasound transducer contacts the ultrasound transmission gel on skin of the neck) to when they say done” (when they believe they have located the CTM on the image).[At the end of each airway ultrasounography examination (less than 2 minutes per scan) ]
- Secondary Outcome Measures
Name Time Method Accuracy will be assessed by a single blinded accuracy observer (blinded to which scan technique is performed, and will therefore also not observe the scans being performed). After scans are completed this accuracy observer will assess the accuracy of each student participants' scans by looking at the ultrasound image saved at the completion of each scan, to assess if each image displays the cricothyroid membrane or not.[Also at the end of each airway ultrasonography examination.]