Fig 1.
Flow chart of the literature screening process.
Table 1.
Characteristics of the included trials.
Table 2.
Assessment of bias risk items for each included study.
Table 3.
Meta-analysis of oropharyngeal leak pressure.
Fig 2.
Forest plot of the oropharyngeal leak pressure in the flexed neck position compared with the neutral neck position.
Fig 3.
Forest plot of the oropharyngeal leak pressure in the extended neck position compared with the neutral neck position.
Table 4.
Meta-analysis of peak inspiratory pressure (cmH2O).
Table 5.
Meta-analysis of the worst fibreoptic view.
Table 6.
Meta-analysis of the best fibreoptic view.
Table 7.
Meta-analysis of ventilation score.