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Ultrasound comparison of external and internal neck anatomy with the LMA Unique

Steven M. Lee
Steven M. Lee
, 
Jacek A. Wojtczak
Jacek A. Wojtczak
 and 
Davide Cattano
Davide Cattano
   | Dec 29, 2017
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Article Category: research-article
Published Online: Dec 29, 2017
Page range: 229 - 234
Received: Aug 22, 2017
Accepted: Nov 17, 2017
DOI: https://doi.org/10.15557/jou.2017.0033
Keywords
© 2017 Steven M. Lee et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial 3.0 Public License.

Fig. 1

A. Submandibular sagittal view no LMA. B. Submandibular sagittal view with LMA. H – hyoid bone, MH – mylohyoid, GH – geniohyoid, HMD – hyoid-mental distance
A. Submandibular sagittal view no LMA. B. Submandibular sagittal view with LMA. H – hyoid bone, MH – mylohyoid, GH – geniohyoid, HMD – hyoid-mental distance

Fig. 2

A. Midline transverse view of upper thyroid no LMA. B. Midline transverse view of upper thyroid with LMA. SM – strap muscles, TC – thyroid cartilage, TW – hyroid width
A. Midline transverse view of upper thyroid no LMA. B. Midline transverse view of upper thyroid with LMA. SM – strap muscles, TC – thyroid cartilage, TW – hyroid width

Fig. 3

Comparison of INL (ultrasound) and ENL (tape measure) measurements. The dotted line represents a 1:1 conversion of ENL and INL measurements. Most ENL measurements are greater than INL measurements
Comparison of INL (ultrasound) and ENL (tape measure) measurements. The dotted line represents a 1:1 conversion of ENL and INL measurements. Most ENL measurements are greater than INL measurements

Demographics of the study population

MdnIQR
Age (yr)26.524.5–41.3
Height (cm)176.5173.6–179.5
Weight (kg)81.579.5–87.3
BMI (kg/m2)27.024.3–29.4
n%
Male580

Comparison of LMA and no LMA US measurements (cm)

INLNo LMAWith LMAp – value
MdnIQRMdnIQR
HMD3.483.27–3.863.042.92–3.480.046
TMD5.275.17–6.445.023.86–5.340.046
SMD*13.5013.19–13.9911.7511.53–11.900.028
HTD1.881.76–2.042.091.67–2.250.917
HCD6.335.95–6.885.735.18–6.050.075
TH*3.182.83–3.712.792.58–2.960.028
TCD*4.384.29–4.663.693.57–3.850.028
TW*3.723.06–3.944.143.92–4.720.028

LMA compared with INL

Anatomy dimmensionLMA Unique
Outer dimensionInner dimension
Concordance (%)Difference (LMA-INL)Concordance (%)Difference (LMA-INL)
Mdn (cm)IQR (cm)Mdn (cm)IQR (cm)
HMD0.05.85.4–6.00.02.92.6–3.0
TMD0.03.72.8–4.316.71.0−0.1–1.3
SMD0.0−4.4−4.6–3.90.0−7.2−7.5–6.9
HTD0.07.66.9–7.70.04.64.1–4.7
HCD*0.02.92.2–3.633.3−0.1−0.5–0.6
TH0.05.95.7–6.40.03.12.8–3.5
TCD0.04.94.5–5.20.01.91.7–2.2
TW0.02.82.6–3.10.02.12.1–2.4

Guidelines for measuring external and internal landmarks

LandmarkDescription
Hyoid mental distance (HMD)Lower midline border of mandible in jaw occlusion extended to upper border of hyoid bone
Thyroid mental distance (TMD)Mentum as per HMD extended to thyroid notch
Sternal mental distance (SMD)Mentum as per HMD extended to sternal notch
Hyoid thyroid distance (HTD)Upper border of hyoid bone extended to thyroid noth
Hyoid cricoid cartilage distance (HCD)Hyroid bone to upper border of cricoid cartilage
Thyroid height (TH)Thyroid notch to lower border of cricoid cartilage
Thyroid cricoid distance (TCD)Thyroid notch to upper border of cricoid cartilage
Thyroid width (TW)Lateral border of upper thyroid cartilage

Extraglottic airway device sizing criteria

Sizing criteriaLMA Unique – dimensions (cm)
SizeMasa ciała (kg)Outer cuff width (OW)Outer cuff width (OW)Inner cuff width (IW)Inner cuff length (IL)
330–5057.54.55
450–7068.556
570–1006.59.566.5
eISSN:
2451-070X
Language:
English
Publication timeframe:
4 times per year
Journal Subjects:
Medicine, Basic Medical Science, other
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