RAE tube in anesthesia
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RAE tube anesthesia endotracheal tube types uses
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RAE tube oral nasal preformed endotracheal anesthesia
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Here is a comprehensive overview of the RAE tube in anesthesia, sourced from major anesthesia textbooks:
RAE Tube (Ring-Adair-Elwyn Tube)
What Is It?
The RAE tube is a preformed, right-angle-bend endotracheal tube named after its inventors Ring, Adair, and Elwyn. It is made from clear polyvinyl chloride (PVC) and has a fixed contour designed to keep the proximal end of the tube and the breathing circuit away from the surgical field.
Two variants exist:
- Oral RAE (South-facing / "south-pole") — The preformed bend sits at the level of the teeth; the tube exits downward to rest on the patient's chin.
- Nasal RAE (North-facing / "north-pole") — The preformed bend sits at the level of the nares; the tube is directed upward over the patient's forehead.
Indications / Surgical Applications
| Type | Primary Uses |
|---|---|
| Oral RAE | Ophthalmic surgery, tonsillectomy & adenoidectomy, nasal surgery, oral surgery, any case where the circuit must exit away from the face |
| Nasal RAE | Dental surgery, oral & maxillofacial surgery (orthognathic surgery, Le Fort osteotomies), cleft palate repair — tube directed over the forehead |
Key Properties & Design Features
- Preformed contour maintains a low profile and prevents surgical interference.
- The proximal segment connects to the breathing circuit while the distal segment intubates the trachea — the bend keeps both ends clear of the operative site.
- Equipped with a high-volume, low-pressure cuff and pilot balloon.
- Standard 15 mm male connector for circuit attachment.
- Most are PVC — this is both a practical and a safety consideration (see Limitations below).
Clinical Considerations
Sizing / Depth:
- For nasal RAE tubes, the bend is fixed at a set depth for each tube size — size selection must be careful to ensure the tube reaches far enough into the trachea without being too shallow. Nasal tubes are typically positioned 20–30% deeper than the equivalent oral tube.
- For oral RAE tubes, the bend should sit at the level of the teeth; if too shallow, accidental extubation is a risk; if the tube is too long, endobronchial intubation may occur. This is particularly critical in pediatric patients, where glottis-to-carina distance is very small.
Ophthalmic surgery:
"The risk of endotracheal tube kinking and obstruction can be minimized by using a preformed oral RAE (Ring-Adair-Elwyn) endotracheal tube." — Morgan & Mikhail's Clinical Anesthesiology, 7e
Because the anesthesiologist is often positioned away from the airway during eye surgery, kinking of the circuit at the face is a real hazard, and the oral RAE eliminates it.
Maxillofacial / oral surgery:
"Nasal intubation with a straight tube with a flexible angle connector or a preformed nasal RAE tube is usually preferred in dental and oral surgery. The endotracheal tube can then be directed cephalad over the patient's forehead." — Morgan & Mikhail's Clinical Anesthesiology, 7e
Nasal intubation should be used with caution in Le Fort II and III fractures because of possible coexisting basilar skull fracture.
Tonsillectomy/Adenoidectomy:
Oral RAE tubes are commonly used. The groove in most tongue blades of mouth gags accommodates the oral-down RAE to prevent compression and keep the tube clear of the field. (Barash's Clinical Anesthesia, 9e; Miller's Anesthesia, 10e)
A reinforced (armored) tube is preferred when tube kinking from surgical retraction or head rotation is a greater risk (e.g., ear surgery with head rotation, tonsillectomy with heavy retraction). The RAE tube is not kink-resistant because of its PVC construction.
Limitations & Hazards
- Fixed bend depth — cannot be adjusted; wrong size → risk of endobronchial intubation (too long) or extubation (too short). Critical in pediatric patients.
- Kinking / compression risk — PVC construction makes it susceptible to kinking, especially if compressed by surgical instruments or retractors. Armored tubes are preferred when kinking is a major concern.
- Fire risk — PVC is combustible. RAE tubes are relatively high risk for airway fire in transoral laser or electrocautery surgery. Laser-resistant tubes should be used when high-energy devices are used near the airway. (Cummings Otolaryngology, 6e)
- Nasal tissue pressure — with prolonged nasal intubation, the preformed nasal RAE must be positioned carefully to avoid pressure necrosis at the naris.
- Nasotracheal RAE severed by surgical instruments — case reports exist of the tube being cut by osteotomes during Le Fort I osteotomies.
RAE vs. Other Specialized Tubes
| Feature | Oral/Nasal RAE | Armored (Reinforced) | Laser-Resistant |
|---|---|---|---|
| Kink resistance | Low (PVC) | High (spiral wire) | Variable |
| Fire resistance | Low | Low–moderate | High |
| Best for | Surgical field clearance | Head rotation, retraction | Laser/electrocautery cases |
| Fixed depth | Yes (limitation) | No | No |
Sources:
- Morgan & Mikhail's Clinical Anesthesiology, 7e, Chapters 36 & 37
- Miller's Anesthesia, 10e, Chapter on Tracheal Intubation
- Barash, Cullen & Stoelting's Clinical Anesthesia, 9e, Chapter on Endotracheal Tubes
- Cummings Otolaryngology Head & Neck Surgery, Chapter 97
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