CLAIR Score: A Risk-Screening Tool for Unanticipated Difficult Airways — A Retrospective Case– Control Study

Background Unanticipated difficult airways are a major cause of perioperative morbidity. Existing bedside airway assessments often fail to predict difficulty when anatomical predictors are absent, highlighting the need for a pragmatic tool that integrates physiological, procedural, and demographic factors to flag patients at risk for unanticipated difficult intubation. Results In this retrospective case–control study of 62,111 anesthetized patients between 2015 and 2020, we identified 98 unanticipated difficult airway events and matched them 1:3 to 294 controls. The incidence of unanticipated difficult airways was 0.16%. Multivariate logistic regression determined four independent predictors: coagulopathy or hypocalcaemia, female sex, potentially difficult airway on physical exam, and intubation by a less-experienced resident. These variables were combined into the CLAIR score which demonstrated an area under the receiver operating characteristic curve of 0.633, with high sensitivity (98%) despite low specificity (16%). A cutoff of 0 effectively stratified patients into high (≥ 1), and low (≤-1) risk groups to airway management strategies while a web-based risk calculator and QR code enhanced accessibility for real-time clinical applications. Conclusion The CLAIR score, based on routinely available preoperative and procedural data, provides a high-sensitivity screening tool to identify patients at risk of unanticipated difficult airway. Although external validation is required, its simplicity and reliance on routine information make it a valuable tool in routine anesthetic practice to prompt preparedness and risk mitigation.