TissueDB/Simulators/Neonatal ETT Ultrasound Simulator (Qaim Ali)

The Neonatal ETT Ultrasound Simulator is a low-cost ultrasound phantom for training point-of-care ultrasound identification of tracheal versus esophageal endotracheal tube placement in a newborn. The original phantom recipe was described by Seguin and Tessaro in 2017.^[1] Merali et al. adapted the phantom for a neonatal ultrasound protocol,^[2] and Qaim Ali et al. later used the neonatal configuration for provider training and evaluation.^[3] The simulator is a beef-gelatin and psyllium-fibre block containing two staggered cored lumens that reproduce the ultrasound geometry of the trachea and esophagus.

This build has three distinct source roles:

• Seguin and Tessaro 2017 — original phantom and quantitative recipe.
• Merali et al. 2019 — neonatal ultrasound protocol/adaptation.
• Qaim Ali et al. 2020 — provider training and evaluation.

Use the quantitative recipe reported by Seguin and Tessaro:

• 90 mL beef gelatin powder
• 60 mL orange psyllium fibre
• 500 mL boiling water

Step 1. Bring or maintain the required water at boiling temperature for preparation.

Step 2. Combine 90 mL beef gelatin powder and 60 mL orange psyllium fibre with 500 mL boiling water using the source method.

Step 3. Mix the materials until the phantom mixture is prepared for moulding.

Step 4. Pour the mixture into the mould or container used to form the phantom block.

Step 1. Place the filled mould in refrigeration at 4 °C.

Step 2. Refrigerate the block overnight.

The overnight refrigeration is the setting time only. The sources give no total build time.

After the block has set, use a cut syringe barrel as the coring tool.

The sources differ on the syringe size:

• Seguin and Tessaro 2017 use a 10 mL syringe.
• Merali et al. 2019 Methods specifies a 5 mL syringe.
• Merali et al. 2019 Figure 1 depicts a cut-off 10 mL syringe.

No source says which size to prefer, or that the two sizes are interchangeable.

Step 1. Core the upper lumen that represents the tracheal position, following the source-specific configuration being reproduced.

Step 2. Retain the gelatin plug expelled during lumen formation.

Step 3. Core the second lumen below and offset from the first to represent the esophageal position.

The two lumens are staggered rather than directly superimposed.

Use the retained gelatin plug to change the ultrasound configuration of the lower lumen.

Insert or remove the plug according to the source training configuration being demonstrated.

The purpose is to allow the same block to present sonographic appearances used for recognising tracheal versus esophageal tube placement.

Qaim Ali et al. used:

• a Philips Lumify 12-2 MHz linear transducer; and
• a Samsung Galaxy Tab A, with a depth setting of 2.5 cm.

Scan the model transversely as described by the training protocol.

Qaim Ali et al. evaluated provider training using the simulator.

The study supports improvement in provider simulator-test performance.

Participants also had opportunities to practise ultrasound with intubated NICU patients.

However, the study does not establish that:

• simulator-acquired localization skill transferred to measured newborn clinical performance;
• patient outcomes improved;
• ultrasound replaced clinical confirmation standards; or
• the gelatin–psyllium block has histologic tissue fidelity.

Merali et al. give a material cost of approximately US$2 for the neonatal simulator.^[2] Seguin and Tessaro give US$5 for their original beef gelatin model.^[1]

• The upper lumen represents Trachea in this simulator.
• The lower lumen represents Esophagus in this simulator.
• Gelatin and psyllium form the surrounding ultrasound phantom medium.
• The cut syringe barrel is a fabrication tool, not anatomy.
• The gelatin plug is a configuration component, not a separate tissue.