Table 1

Author, date and countryPatient groupStudy type (level of evidence)OutcomesKey resultsStudy weaknesses
Nolan JP, 1993, UK157 patients undergoing elective surgeryPRCTNumber of grade 3 views in neutral position34/157 (22%)Small number of truly difficult laryngoscopies in whom differences are likely to be the greatest
Median time for intubation20 secs for direct intubation v 25 seconds for use of the bougie
No grade 4 views
Patients were intubated in the neutral c-spine positionSuccess rate for intubation5/78 (6.4%) direct intubation patients could not be intubated (they were subsequently intubated using the bougie). 0/79 patients could not be intubated using the bougie
Patients were either intubated direct (just with the ETT) or using a bougie.Number of patients requiring prolonged time for intubation (>45 seconds)11 in direct visualised group v none in the bougie group.