| Laurent SC et al, 1996, UK | 167 elective patients intubated in the neutral c-spine position. | Controlled clinical trial | Cormack view at laryngoscopy | Grade 3 or 4 view in 33% of cases with Macintosh v 5% with McCoy (p<0.001). | Elective setting. Only a size 3 blade used. There were no grade 4 views in this study. |
| Each patient had laryngoscopy performed with both Macintosh and McCoy (both size 3 blades) | | Number of patients whose Cormack score improved | View improved by one or more Cormack grades in 57% of patients using McCoy laryngoscope | |
| Uchida T et al, 1997, Canada | 50 female patients undergoing elective surgery. patients were kept in the neutral position by an assistant using in-line cervical immobilisation.Either a size 3 Mackintosh or a size 3 McCoy blade was used | Controlled clinical trial | Percentage of grade 3 or 4 views at laryngoscopy Number of patients in whom view improved with McCoy | 76% with Macintosh v 16% with McCoy blade (p<0.01) View was improved in 74% of cases using Cormack score. The 2 patients scoring grade 4 with the Macintosh did not improve with the McCoy | Only female patients studied. Elective setting. |
| | | | | All patients were first examined using the Macintosh before using the McCoy. |