the manufacturer and the Medicines and Healthcare products Regulatory Agency, and are waiting for a reply from the former. T. A. Wimalaratne S. Setty Barnet Hospital Barnet, UK Email: aselawimal@gmail.com No external funding and no com- peting interests declared. Previously posted on the Anaesthesia corres- pondence website: www.anaesthesia correspondence.com. References 1. Richardson PB, Turner MW, Callander CC. The Portex Epifuse TM connector: lessons on first use in a large district general hospital. Anaesthesia 2011; 60: 948–9. 2. Philip A, Bourne TM. Epifuse TM failure causing epidural disconnection. Anaes- thesia 2012; 67: 306. 3. Riebe E. A reply. Anaesthesia 2012; 67: 306–7. 4. Farrell C. Occluded Portex Epifuse TM epidural connector. Anaesthesia 2012; 67: 307. 5. Evans R, Baraz R, Joseph A. Portex Epi- fuse TM connector blockages. Anaesthesia 2012; 67: 307–8. doi:10.1111/anae.12651 Ultrasonographic identification of the cricothyroid membrane Commenting on Hui and Tsui’s work [1] correlating the imagingof the hyoid bone using bedside sublin- gual ultrasound with easy laryngos- copy, Greenland and Irwin [2] queried whether another innovative use of ultrasound could indeed improve airway management. They pointed out that despite more than 100 years of laryngoscopy and tra- cheal intubation, many aspects of dif- ficult airway training remain largely unstructured and anecdotal, with juniors learning an airway technique from their seniors/airway experts, without appreciation of the subtleties that led the experienced practi- tioner to employ that specific method of airway management. Trainees approach an airway problem from a ‘treatment’ perspective, without a clear understanding of airway pathol- ogy, when a paradigm shift is needed towards a ‘diagnosis/management’ perspective, in which diagnostic ultrasound might play a role. Oxygenation via the cricothyroid membrane is the common rescue manoeuvre recommended by all diffi- cult airway management algorithms, but only 0-30% of anaesthetists can correctly identify the relevant anat- omy by palpation [3, 4], resulting in considerable morbidity and mortality [5]. Ultrasonography represents the best method currently available for locating the cricothyroid membrane before initiating difficult airway man- agement. We have devised a simple, step-wise structured approach to ultrasonographic identification [6, 7], with a 98% success rate in prelimi- nary results involving non-obese individuals [8], which surpasses pre- viously reported results obtained using inspection/palpation alone [3]. We teach this method at courses available annually worldwide (see www.airwaymanagement.dk). The ultrasound probe in the hands of a trained anaesthetist is a powerful new point-of-care tool, that personifies the paradigm shift towards the ‘diagnosis/management’ approach in difficult airway man- agement. In addition to locating the cricothyroid membrane, ultrasound can help rule out intra-operative pneumothorax, locate the optimal level for dilatational tracheostomy, distinguish between tracheal and oesophageal intubation and judge whether the stomach is empty [7], Contrary to Greenland and Irwin’s views, we commend its extended use as a fundamental tool in diffi- cult airway management. W. H. Teoh KK Women’s & Children’s Hospital Singapore Email: teohwendy@yahoo.com M. S. Kristensen Rigshospitalet Copenhagen, Denmark No external funding and no com- peting interests declared. Previously posted on the Anaesthesia corres- pondence website: www.anaesthesia correspondence.com. References 1. Hui CM, Tsui BC. Sublingual ultrasound as an assessment method for predicting difficult intubation: a pilot study. Anaes- thesia 2014; 69: 314–9. 2. Greenland KB, Irwin MG. Airway man- agement –‘spinning silk from cocoons’ (Chinese idiom). Anaesthesia 2014; 69: 296–300. 3. Elliott DS, Baker PA, Scott MR, Birch CW, Thompson JM. Accuracy of surface landmark identification for cannula cric- othyroidotomy. Anaesthesia 2010; 65: 889–94. 4. Aslani A, Ng SC, Hurley M, McCarthy KF, McNicholas M, McCaul CL. Accuracy of identification of the cricothyroid mem- brane in female subjects using palpa- tion: an observational study. Anesthesia and Analgesia 2012; 114: 987–92. 5. Cook TM, Woodall N, Frerk C. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. British Jour- nal of Anaesthesia 2011; 106: 617–31. 6. Kristensen MS. Ultrasonography in the management of the airway. Acta © 2014 The Association of Anaesthetists of Great Britain and Ireland 649 Correspondence Anaesthesia 2014, 69, 640–652