Depth to the airway lumen at the level of the cricothyroid membrane measured by ultrasound

Abstract

Background: Knowing the likely depth to the airway before emergency cricothyroidotomy may improve success in cases where it cannot be measured. Our aim was to measure the depth to the airway at the cricothyroid membrane by ultrasound in a large group of adult patients.Method: Prospective, observational study in two centres, Oxford and Gloucester.Patients presenting for a large variety of surgical operations were studied. Patients under 18 years; pregnant; critically ill; had a history of neck surgery were not included. Ultrasound examination was performed pre-operatively while participants lay supine with their head and neck extended, with light transducer pressure. We measured depth to the airway lumen in mm; age; weight; height and sex. Results:In total 352 patients were studied. We found that depth to the airway lumen strongly correlated with weight (r = 0.855, P < 0.001) and to a lesser extent body mass index (r = 0.781, P < 0.001). Statistical analysis produced an equation to predict upper 95% CI of depth to the airway from the patient's weight: Depth to the airway lumen in mm = (0.13 × weight in kg) + 0.86.Conclusions: If ultrasound measurement is not possible before emergency cricothyroidotomy, the clinician could use our results to predict the depth to the airway by using the patient's weight. If the upper 95% CI were used as the depth of incision, it would enter the airway in 39 out of 40 patients of that weight, without damage to posterior structures in those with a shallower airway. | 49ATHANASSOGLOU eT AL.

Observation on Application Effect of Arterial Puncture and Catheterization under Guidance of Intelligent Medical Care Ultrasound in Clinical Anesthesia

“…BPNN has three layers: an input layer, a hidden layer, and an output layer. There is one input layer and one output layer, as well as the possibility of many hidden levels [ 16 – 18 ]. Each layer is connected by multiple neuron nodes, although nodes within the same layer are connected.…”

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Ultrasound identification of the cricothyroid membrane: the new standard in preparing for front-of-neck airway access

“…Pre-emptive use of ultrasonography also reveals the depth to the airway lumen to guide incision requirements. If no ultrasonography equipment, experience in using it, or time is available, a recent study provided clinicians with an algorithm to estimate the depth to the airway lumen at the level of the cricothyroid membrane (DACM) based only on the weight of the patient 25 : upper 95% CI of DACM (in mm)¼(0.13Âweight in kg)þ0.86.…”

Palpation Versus Ultrasonography for Identifying the Cricothyroid Membrane in Case of a Laterally Deviated Larynx: A Randomized Trial

“…The depth of the cricothyroid membrane from the surface of the ballistic gel was 2 cm, which corresponds to the upper limit of what would be found in a 150-kg patient. 16 A coordinate system frame was used to measure the coordinates of the position identified by the participants. The coordinate system frame was placed with the reference at the lower left corner of the model.…”