Value of ultrasonography in predicting difficult airway: a meta-analysis

Objective To systematically review the value of ultrasonography in predicting difficult airway. Methods Databases including PubMed, Embase, Cochrane Library and CNKI were searched for trials involving the value of ultrasonography in predicting difficult airway.Outcome parameters were true positive, false positive, true negative and false negative.The pooled estimates and heterogeneity among the included studies were performed with Meta-DiSc 1.4 software.The evaluation indexes including sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and the 95% confidence interval (CI) were calculated according to true positive, false positive, true negative and false negative extracted from selected studies.The receiver operating characteristic curves were plotted according to sensitivity and specificity, and the area under the curve was calculated.The overall pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, 95% CI and area under the curve were used to assess the value of ultrasonography in predicting difficult airway. Results Nine trials involving 3 525 patients were included in this meta-analysis.The overall pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio of the included studies were 0.69 (95% CI 0.63-0.74), 0.84 (95% CI 0.82-0.85), 5.79 (95% CI 3.67-9.14), 0.36 (95% CI 0.27-0.46), 22.04 (95% CI 10.68-45.45), respectively.The area under the curve was 0.89 (95% CI 0.84-0.94). Conclusion Ultrasonography can accurately predict difficult airway. Key words: Ultrasonography; Intubation, intratracheal; Forecasting