Accuracy of Conventional Digital Palpation and Ultrasound of the Cricothyroid Membrane in Obese Women in Labour

“…[8][9][10][11][12][13] Ces études se fondent sur des méthodologies semblables afin de déterminer la fréquence à laquelle les médecins évaluateurs ont correctement localisé la membrane cricothyroïdienne par palpation externe. Les estimations des évaluateurs dans ces études (tout comme dans l'étude publiée ici) ont été comparées à Deficiencies in locating the cricothyroid membrane by palpation 793 l'emplacement réel de la membrane cricothyroïdienne déterminé par échoguidage.…”

Section: Incapables De Localiser Launclassified

“…[8][9][10][11][12][13] These studies used similar methodologies to determine how often physician assessors correctly identified the location of the CTM by external palpation. The assessors' estimations in these studies (and similarly in the present one) were compared with the actual location of the CTM as confirmed by ultrasound.…”

mentioning

confidence: 99%

Deficiencies in locating the cricothyroid membrane by palpation: We can’t and the surgeons can’t, so what now for the emergency surgical airway?

Law

2016

Can J Anesth/J Can Anesth

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At times, it seems that we were never meant to discover the underlying mysteries of the neck's surface anatomy. The quest first began with the cricoid cartilage and although Sellick's maneuver 1 seemed an acceptable concept, it eventually proved somewhat disappointing in its application. Who knows how often this technique actually hit its target? Now, as Hiller et al. outline in this issue of the Journal, just north of the cricoid cartilage and sorely needed for expeditious emergency surgical airway (ESA), it seems that the cricothyroid membrane (CTM) is also keeping its exact location a closely guarded secret. 2The ESA is infrequently performed by the average anesthesiologist and has had its issues. Historically, in a can't intubate, can't oxygenate (CICO) emergency, practitioners been slow to initiate the procedure. Furthermore, some of the techniques used to execute the ESA have been less than effective, perhaps accounting for the generally poor success rates.3,4 Fortunately, recently published national airway guidelines address these matters with more definitive recommendations for both when and how ESA should occur.5-7 The trouble is, establishing an ESA generally begins with identifying the location of the CTM by external palpation. As it turns out, for the life of us (not to mention that of our patients), it seems that we can't reliably accomplish this task.At least six recently published studies from a variety of countries attest to this conclusion. [8][9][10][11][12][13] These studies used similar methodologies to determine how often physician assessors correctly identified the location of the CTM by external palpation. The assessors' estimations in these studies (and similarly in the present one) were compared with the actual location of the CTM as confirmed by ultrasound. In most studies, the assessor's attempt to localize the CTM was defined as a failure if the estimation was either outside the vertical confines of the CTM or [ 5 mm from the midline. The results are sobering. Correctly identifying the CTM location using external palpation is no better than a 50:50 proposition, give or take, even in nonobese subjects. Most of the studies include scatter plots of the assessors' estimates, and in some cases, localization is off by at least 3 cm above, below, or lateral to the actual CTM location. Not surprisingly, there is a trend towards worse results in females and obese subjects given their less distinct thyroid cartilage anatomy. These findings occurred in the relatively stress-free conditions of a clinical study in volunteer subjects. We can probably expect even worse results when we add the anxiety-related performance degradation in an actual CICO situation.By adding trauma surgeons to the mix, Hiller et al. add fuel to the fire with their study of the accuracy of CTM identification by external palpation in female subjects. 2Notwithstanding their greater experience in performing ESA, the surgeons failed to demonstrate a significantly better success rate at CTM identification than their anesthesia ...

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“…The 4th National Audit Project similarly identified a 64% failure rate of when anaesthetists utilised this 'rescue' technique [23]. This may in part be related to anaesthetists' relatively poor ability to correctly identify the cricothyroid membrane [24,25]. In one study, physician accuracy in identifying the cricothyroid membrane was 10 of 41 in non-obese female subjects but none of 15 obese subjects [24].…”

Section: Airway Managementmentioning

confidence: 99%

“…Studies investigating ultrasound localisation of the cricothyroid membrane have produced some encouraging results. In a study in labouring women, anaesthetists palpated and identified the cricothyroid membrane of obese and non-obese women [25]. Ultrasonography was then used to assess the accuracy of digital palpation.…”

Section: Airway Managementmentioning

confidence: 99%