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LMA-Fastrach and i-gel: Generation Classification
Short Answer
| Device | Generation | Basis |
|---|
| LMA-Fastrach (ILMA) | 1st generation (with a specialized intubating function) | No gastric drainage port; cannot protect against aspiration |
| i-gel | 2nd generation | Has a gastric drainage port + high seal pressure |
Detailed Breakdown
Generation Classification of SGAs — Standard Criteria
1st-Generation SGAs
- Simple perilaryngeal seal
- No gastric drainage channel
- Not designed for aspiration protection
- Limited seal pressure (~20 cm H₂O)
- Examples: LMA Classic, LMA Flexible, LMA Unique
2nd-Generation SGAs
- Incorporates a gastric drainage tube (separates respiratory and GI tracts)
- Higher airway seal/leak pressure (up to 30 cm H₂O or more)
- Reduced aspiration risk
- Examples: LMA ProSeal, LMA Supreme, i-gel, LMA Protector, Ambu AuraGain
LMA-Fastrach (Intubating LMA / ILMA)
The LMA-Fastrach is classified as a 1st-generation SGA — specifically designed as an intubating conduit, not for aspiration protection.
"Brain et al. introduced a version of the LMA, the LMA Fastrach (Teleflex), designed specifically as a conduit to intubation."
— Barash, Clinical Anesthesia 9e
Key features:
- Rigid, curved stainless-steel/plastic barrel with a handle
- Epiglottic elevating bar to guide ETT toward larynx
- Accommodates up to 8 mm ID cuffed ETT (blindly or over a scope)
- Available in sizes 3, 4, 5 (equivalent to LMA Classic)
- No gastric drainage channel → not 2nd generation
It belongs to a separate subcategory called "Intubating SGAs" (iSGAs) — a functionally distinct subgroup, but generationally it is 1st generation since it lacks the defining 2nd-generation feature (gastric drainage + aspiration protection).
Some classification schemes list three categories:
- 1st generation (basic seal, e.g., LMA Classic)
- 2nd generation (gastric drain + higher seal, e.g., ProSeal, Supreme, i-gel)
- Intubating SGAs (conduit for intubation, e.g., LMA-Fastrach, air-Q, Aura-I)
In this scheme, the LMA-Fastrach falls outside the 1st vs. 2nd generation spectrum — it is a specialized/intubating SGA, not upgraded by aspiration-protection criteria.
i-gel
The i-gel is unambiguously a 2nd-generation SGA.
"The i-gel is considered a second-generation SGA considering the presence of a gastric drainage port and higher seal pressure."
— Miller's Anesthesia, 10th edition, Chapter 40 (Airway Management)
Key features:
- Cuffless — anatomically preshaped soft gel-like material (SEBS polymer) that conforms to the perilaryngeal anatomy
- Gastric drainage port (passes a gastric tube up to 8 Fr)
- Higher seal/leak pressure compared to 1st-generation devices
- Integrated bite block
- No need for cuff inflation — simplifies insertion
Summary Table
| Feature | LMA Classic (1st gen) | LMA-Fastrach | i-gel (2nd gen) |
|---|
| Gastric drain | ✗ | ✗ | ✓ |
| Aspiration protection | ✗ | ✗ | Partial ✓ |
| Higher seal pressure | ✗ | ✗ | ✓ |
| ETT conduit | ✗ | ✓ (primary purpose) | Limited |
| Cuff | Inflatable | Inflatable | Cuffless |
| Generation | 1st | 1st / Intubating SGA | 2nd |
Sources (Standard Textbooks)
- Miller's Anesthesia, 10th Edition, Ch. 40 — "Cuffless Anatomically Preshaped Sealers": "The i-gel is considered a second-generation SGA considering the presence of a gastric drainage port and higher seal pressure."
- Barash, Clinical Anesthesia, 9th Edition, Ch. 28 — "Supraglottic Airways": Classifies LMA Classic as 1st-generation SGA; LMA-Fastrach described as an intubating SGA (separate from the 1st/2nd generation upgrade axis)
- Miller's Anesthesia, 10th Edition, Ch. 40 — "Second-Generation Perilaryngeal Sealers": Defines 2nd-gen by gastric drainage + higher seal; LMA ProSeal as prototype
Bottom line per standard textbooks:
- i-gel = 2nd generation ✓
- LMA-Fastrach = 1st generation (or "intubating SGA" subclass) — NOT 2nd generation