Difficult Airway Management in Oncology: An International Delphi Consensus Study (DAMO)

Overview

Airway management in patients with cancer carries risks that general difficult-airway guidelines do not address. Tumour in the head, neck, or mediastinum can distort or narrow the airway; previous radiotherapy causes fibrosis and restricts neck movement; low platelet counts increase bleeding during instrumentation; and obstruction may sit below the point at which a breathing tube ends, so that intubation alone does not restore ventilation. Existing international airway guidelines are written for general populations and contain little cancer-specific guidance. This study uses a modified Delphi method to develop an international expert consensus statement on the prediction, preparation for, and management of the difficult airway in adults with cancer. An international panel of clinicians with expertise in anaesthesiology, intensive care, interventional pulmonology, head and neck surgery, and emergency medicine votes anonymously on a set of candidate statements across ten clinical domains, using a seven-point agreement scale with free-text comment. Voting takes place over a minimum of three rounds. Between rounds, panellists receive anonymised group results and a summary of comments, and statements are revised accordingly. Consensus is defined a priori as agreement by at least 80 percent of respondents together with a median score of 5 or above; strong consensus requires at least 90 percent agreement with a median of 6 or 7. Statements that do not reach consensus are reported as such and form a prioritised research agenda. Reporting follows the ACCORD reporting guideline for consensus methods.

BACKGROUND Failure of airway management causes hypoxaemic brain injury and death within minutes. Outside the operating theatre, tracheal intubation carries a substantially higher rate of severe complications, including cardiovascular collapse and cardiac arrest, than intubation under elective conditions. In patients with cancer this baseline risk is compounded by disease- and treatment-related factors: anatomical distortion by head, neck, or mediastinal tumour; airway and facial oedema from superior vena cava obstruction; mucosal friability and bleeding risk from thrombocytopenia; restricted neck mobility from radiation fibrosis; and supraglottic or glottic stenosis. National audits of airway complications repeatedly identify head and neck pathology and obstructive airway lesions among the recurring contributors to death and brain damage, yet patients with cancer fall outside the population addressed in detail by existing airway guidance. Several features distinguish this population. Anatomical distortion is acquired, progressive, and often occult, so that an assessment made weeks earlier may not describe the airway encountered. Anterior mediastinal masses can precipitate cardiorespiratory collapse on induction through loss of the negative intrathoracic pressure maintaining airway patency and venous return. Prior radiotherapy raises the likelihood of difficult laryngoscopy, failed facemask ventilation, and difficult surgical access simultaneously, removing the redundancy on which conventional algorithms depend. Where extrinsic compression or oedema is present, a supraglottic airway may fail to seal, so that the principal rescue device of every published algorithm is unreliable in exactly the patients most likely to need it. In malignant central airway obstruction the pathology may lie distal to the tube tip, making rigid bronchoscopy, stenting, or debulking the definitive intervention rather than an adjunct. Randomised evidence on these questions does not exist and is unlikely to be generated, since the events are uncommon, the situations emergent, and equipoise difficult to sustain. Formal consensus methods are therefore the appropriate means of structuring expert judgement. OBJECTIVES The primary objective is to develop an international consensus statement providing explicit criteria and a procedural framework for the prediction, preparation, and management of the difficult airway in adults with cancer, across the settings in which such airways are encountered. Secondary objectives are to specify an oncology-specific airway assessment and preparation approach; to provide recommendations on pharmacological strategy including induction agents and neuromuscular blockade; to outline a tiered approach to primary airway management and rescue including videolaryngoscopy, awake technique, flexible and rigid bronchoscopy, and front-of-neck access in the irradiated neck; to address malignant central airway obstruction as a distinct entity; to address extubation, tracheostomy decannulation, post-procedural care, and system-level preparedness, training, human factors, and documentation; and to publish the questions on which the panel finds insufficient evidence or fails to agree as a prioritised research agenda. DOMAINS Candidate statements are grouped into ten pre-specified domains: (1) oncology-specific airway assessment and risk prediction; (2) pre-procedural preparation and multidisciplinary coordination; (3) pre-oxygenation and peri-procedural oxygenation; (4) pharmacological optimisation; (5) primary airway management devices and approaches; (6) management of malignant central airway obstruction; (7) rescue strategies and front-of-neck access; (8) extubation and tracheostomy decannulation; (9) post-procedural care and follow-up; (10) system preparedness, training, human factors, and documentation. METHODS A Steering Committee of 10 to 12 members … \[full text copies via the button\] ANALYSIS Quantitative responses are summarised as counts and percentages … Consensus requires a median of 5 or above with at least 80 percent of votes in the 5 to 7 range … REPORTING Reporting follows the ACCORD reporting guideline for consensus methods in biomedicine, with a completed checklist accompanying submission.