I-Gel Size Selection for 73 kg Elderly Female
For an elderly female patient weighing 73 kg, use I-Gel size 4, which is the manufacturer's recommended size for patients weighing 50-90 kg. 1
Weight-Based Sizing Recommendation
The manufacturer's weight-based formula provides the primary guidance for I-Gel selection 1:
- Size 3: < 50 kg
- Size 4: 50-90 kg
- Size 5: > 90 kg
Your patient at 73 kg falls squarely within the size 4 range. 1
Alternative Sex-Based Approach
Recent evidence suggests that sex-based selection may reduce the need for device size changes 1:
- Males: Size 5
- Females: Size 4
This sex-based approach aligns with the weight-based recommendation for your patient, further supporting size 4 selection. 1 A prospective study of 900 patients found that sex-based sizing required device changes in only 3% of cases compared to 7% with weight-based sizing, though both approaches achieved adequate ventilation in the vast majority of patients. 1
Clinical Performance Expectations
With size 4 I-Gel in this patient, you should expect 1, 2, 3:
- First-attempt success rate: 93-97% 1, 3
- Insertion time: Approximately 14 seconds (median) 4
- Airway leak pressure: 27-30 cmH₂O 2, 3
- Gastric tube placement success: 90-100% 4, 3
Key Technical Considerations
The I-Gel is a second-generation supraglottic airway with high oropharyngeal seal pressure, making it suitable for critically ill patients and rescue airway scenarios. 5 The device features a non-inflatable thermoplastic elastomer cuff and an esophageal drainage channel. 4, 3
Important Insertion Points
- Insert after loss of consciousness to avoid coughing 5
- The device has a tendency to displace upward out of the mouth, requiring careful fixation 4
- Flexion and extension of the proximal tube can alter airway quality—maintain neutral positioning 4
- Confirm placement with waveform capnography 5
When Size Change May Be Needed
If initial ventilation is inadequate with size 4 1:
- Consider size 5 if there is excessive leak or inadequate seal pressure
- Consider size 3 if insertion is difficult or the device appears too large
- Success rate after size change is approximately 90% 1
Critical Airway Management Context
If using the I-Gel as a rescue device after failed intubation, limit yourself to one optimal attempt at SGA placement before considering front-of-neck access. 5 The British Journal of Anaesthesia guidelines emphasize that second-generation SGAs like the I-Gel are preferred for airway rescue due to their superior seal pressures and esophageal drainage capability. 5
The I-Gel can serve as a conduit for fiberoptic-guided intubation if needed, though this should be limited to a single attempt. 5 When used for this purpose, a 6.0 mm internal diameter endotracheal tube can typically be passed through the device. 5