The target population was adult patients undergoing anaesthesia. Twenty-eight departments of anaesthesia were randomized to one of two groups. Intervention departments used the SARI score for preoperative airway assessment. The intervention group additionally did an assessment of risk factors for difficult mask ventilation as described by Kheterpal and colleagues[14-16]. Departments in the control group continued normal practice of preoperative airway assessment. All data were registered in the DAD. A more detailed trial protocol describing background, design and rationale has been published in TRIALS[17].