Comparison of plastic and metallic single-use and metallic reusable laryngoscope blades: a randomised controlled trial.

CONTEXT: Plastic single-use laryngoscope blades have been found to increase the difficulty of intubation. Metallic single-use blades may represent an alternative.

OBJECTIVE

To compare the rates of intubation failure at first laryngoscopy using metallic single-use, plastic single-use and metallic reusable laryngoscope blades.

DESIGN

Randomised, superiority, single-centre, controlled trial.

SETTING

Operating theatres at a University Hospital from January 2008 to August 2009.

PATIENTS: A total of 1863 adults requiring general anaesthesia.

INTERVENTION: Patients were randomised to one of three laryngoscope blades: metallic single-use, plastic single-use or metallic reusable.

MAIN OUTCOME MEASURE: The primary end-point was the number of intubation failures at first laryngoscopy. Secondary end-points were glottic exposure and the Intubation Difficulty Scale.

RESULTS

The failure rate (absolute difference: 95% confidence interval) at the first attempt was greater for the plastic single-use blades (8.1%) than for the metallic reusable [3.2% (4.9%: 2.2 to 7.6%); P < 0.001] and metallic reusable blades [4.0% (4.0%: 1.2 to 6.9%); P < 0.006]. No difference was found between the metallic reusable and metallic single-use groups (0.9%: -1.3 to 3.1%). Scoring on the Intubation Difficulty Scale [median (interquartile range)] was higher in the plastic single-use group [1 (0 to 2)] than in the metallic groups [metallic reusable: 0 (0 to 1); P < 0.001 and metallic single-use: 0 (0 to 1); P < 0.007] groups. Glottic exposure was significantly better in the metallic reusable group (modified Cormack & Lehane score III and IV: 3.7%) compared with the plastic single-use group (modified Cormack & Lehane score III and IV: 9.4%; P < 0.03).

CONCLUSION

The rates of failed intubation at first laryngoscopy were similar in the metallic reusable and metallic reusable groups, but greater in the plastic single-use group.