Quantification of the effect of Body Mass Index on Cricothyroid Membrane Depth: a cross-sectional analysis of clinical CT images

Sadia Ghaffar, Tom Blankenstein, Dilip Patel, Catherine Theodosiou, David Griffith

Research output: Contribution to conferencePosterpeer-review

Abstract / Description of output

The recommended front of neck access (FONA) procedure in can’t intubate, can’t ventilate (CICO) scenarios relies on palpation of the cricothyroid membrane (CTM), or dissection of the neck down to the larynx if CTM is impalpable. The CTM palpation is particularly challenging in obese patients, with CTM identified reliably in only 39% of obese compared with 71% in the non-obese necks. 1, 2 This is most likely due to an increased distance between the skin and the CTM (CTM depth). The primary aim of this study was to quantify the CTM depth in a clinical sample. In this retrospective study, all CT scans performed at a teaching hospital over an 8-month period were examined, and the distance between the skin and CTM measured by two radiologists independently. The patients’ age, gender, height and weight were noted, and the relationship between these variables and the CTM depth analysed. Requirement for research ethics committee approval was waived by the Academic and Clinical Central Office for Research and Development (ACCORD), as the study was considered to be an evaluation of clinical practice and not research. Three hundred and fifty-five of the 394 CT scans performed were included in the analysis. Mean CTM depth was 8.12mm (IQR 6.36, 11.70). There was no association between CTM depth and patient height ( 0.01cm (95% CI -0.05 to 0.06) p=0.79) or age ( -0.01(95% CI 0.10 to 0.15) p=0.62). Increasing weight (0.12kg (95%CI 0.10 to 0.15) p<0.001) and BMI (0.52kg/m2 (95% CI 0.44 to 0.60) p<0.001) were strongly associated with CTM depth. There was a significant association between both weight and BMI and CTM depth. Our finding have potential clinical benefits in that a simple measure of BMI preoperatively could be used to identify patients that may require careful planning, with possible utilisation of advanced airway techniques for airway management.
Original languageEnglish
Publication statusPublished - 28 Nov 2018
EventDifficult Airway Society Annual Scientific Meeting - Edinburgh International Conference Centre, Edinburgh, United Kingdom
Duration: 28 Nov 201830 Nov 2018


ConferenceDifficult Airway Society Annual Scientific Meeting
Country/TerritoryUnited Kingdom


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