Fig. 1
Fig. 2
Fig. 3
Demographics of the study population
| Mdn | IQR | |
|---|---|---|
| Age (yr) | 26.5 | 24.5–41.3 |
| Height (cm) | 176.5 | 173.6–179.5 |
| Weight (kg) | 81.5 | 79.5–87.3 |
| BMI (kg/m2) | 27.0 | 24.3–29.4 |
| n | % | |
| Male | 5 | 80 |
Comparison of LMA and no LMA US measurements (cm)
| INL | No LMA | With LMA | p – value | ||
|---|---|---|---|---|---|
| Mdn | IQR | Mdn | IQR | ||
| HMD | 3.48 | 3.27–3.86 | 3.04 | 2.92–3.48 | 0.046 |
| TMD | 5.27 | 5.17–6.44 | 5.02 | 3.86–5.34 | 0.046 |
| SMD* | 13.50 | 13.19–13.99 | 11.75 | 11.53–11.90 | 0.028 |
| HTD | 1.88 | 1.76–2.04 | 2.09 | 1.67–2.25 | 0.917 |
| HCD | 6.33 | 5.95–6.88 | 5.73 | 5.18–6.05 | 0.075 |
| TH* | 3.18 | 2.83–3.71 | 2.79 | 2.58–2.96 | 0.028 |
| TCD* | 4.38 | 4.29–4.66 | 3.69 | 3.57–3.85 | 0.028 |
| TW* | 3.72 | 3.06–3.94 | 4.14 | 3.92–4.72 | 0.028 |
LMA compared with INL
| Anatomy dimmension | LMA Unique | |||||
|---|---|---|---|---|---|---|
| Outer dimension | Inner dimension | |||||
| Concordance (%) | Difference (LMA-INL) | Concordance (%) | Difference (LMA-INL) | |||
| Mdn (cm) | IQR (cm) | Mdn (cm) | IQR (cm) | |||
| HMD | 0.0 | 5.8 | 5.4–6.0 | 0.0 | 2.9 | 2.6–3.0 |
| TMD | 0.0 | 3.7 | 2.8–4.3 | 16.7 | 1.0 | −0.1–1.3 |
| SMD | 0.0 | −4.4 | −4.6–3.9 | 0.0 | −7.2 | −7.5–6.9 |
| HTD | 0.0 | 7.6 | 6.9–7.7 | 0.0 | 4.6 | 4.1–4.7 |
| HCD* | 0.0 | 2.9 | 2.2–3.6 | 33.3 | −0.1 | −0.5–0.6 |
| TH | 0.0 | 5.9 | 5.7–6.4 | 0.0 | 3.1 | 2.8–3.5 |
| TCD | 0.0 | 4.9 | 4.5–5.2 | 0.0 | 1.9 | 1.7–2.2 |
| TW | 0.0 | 2.8 | 2.6–3.1 | 0.0 | 2.1 | 2.1–2.4 |
Guidelines for measuring external and internal landmarks
| Landmark | Description |
|---|---|
| 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 criteria | LMA Unique – dimensions (cm) | ||||
|---|---|---|---|---|---|
| Size | Masa ciała (kg) | Outer cuff width (OW) | Outer cuff width (OW) | Inner cuff width (IW) | Inner cuff length (IL) |
| 3 | 30–50 | 5 | 7.5 | 4.5 | 5 |
| 4 | 50–70 | 6 | 8.5 | 5 | 6 |
| 5 | 70–100 | 6.5 | 9.5 | 6 | 6.5 |