A randomised cross-over comparison of the transverse and longitudinal techniques for ultrasound-guided identification of the cricothyroid membrane in morbidly obese subjects

Abstract

A randomised cross-over comparison of the transverse and longitudinal techniques for ultrasound-guided identification of the cricothyroid membrane in morbidly obese subjects SummaryWe compared the transverse and longitudinal approaches to ultrasound-guided identification of the cricothyroid membrane, to determine which was faster and more successful. Forty-two anaesthetists received a one-hour structured training programme consisting of e-learning, a lecture and hands-on training, and then applied both techniques in a randomised, cross-over sequence to obese females with body mass index 39.0 -43.9 kg.m À2. The mean (SD) time to identify the cricothyroid membrane was 24.0 (12.4) s using the transverse technique compared with 37.6 (17.9) s for the longitudinal technique (p = 0.0003). Successful identification of the cricothyroid membrane was achieved by 38 (90%) anaesthetists using either technique. All anaesthetists were successful in identifying the cricothyroid membrane with at least one of the techniques. We advocate the learning and application of these two techniques for identification of the cricothyroid membrane before starting anaesthesia in difficult patients, especially when anatomical landmarks are impalpable. Further use in emergency situations is feasible, if clinicians have experience and the ultrasound machine is readily available.

Evaluation of a novel cricothyroidotomy introducer in a simulated obese porcine model: a randomised crossover comparison with scalpel cricothyroidotomy

“…). However, pre‐procedural ultrasound scanning could assist in identifying the cricothyroid membrane more accurately, especially in obese patients . The Ambu‐aScope (single‐use flexible intubation scope) was used to determine correct tracheal tube placement within the trachea and to visualise false passage creation.…”

Determining the amount of training needed for competency of anesthesia trainees in ultrasonographic identification of the cricothyroid membrane

“…It is possible that learning curves might be affected by the different techniques. However, the same authors showed the success rate between techniques were similar [26]. Lastly, we also performed the ultrasound scan in a controlled non-stressful environment.…”

“…In our study ultrasound scans were assessed using the longitudinal technique. Kristensen et al demonstrated the transverse technique was significantly faster than the longitudinal technique to identify the cricothyroid membrane [26]. It is possible that learning curves might be affected by the different techniques.…”

Through a glass darkly - ultrasound imaging in obstetric anaesthesia

“…Kristensen et al compared the transverse and longitudinal approach to ultrasoundguided identification of the cricothyroid membrane, to determine which was faster and more successful, utilising a one-hour training program consisting of e-learning, a lecture and hands-on training. Both approaches were associated with high success rates, though it was faster with the transverse approach [5].…”

“…Pre-operative frailty in patients has been linked with increased postoperative morbidity [5], including delirium [6], sepsis [7], prolonged hospital stay [5] and postoperative re-admission [8], compared with non-frail counterparts. Moreover, Fried et al [4] suggest that frail patients may also suffer from a 'vulnerability to stressors'.…”