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

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.

Inclusion criteria

• Substantial current clinical practice involving airway management in patients with cancer, in anaesthesiology, intensive care medicine, interventional pulmonology, head and neck surgery, or emergency medicine

At least five years of independent practice following completion of specialist training

Demonstrated scholarly contribution to the field, evidenced by peer-reviewed publication, invited lecturing, or a leadership role in a relevant professional society or guideline-development body

Willingness to complete all planned Delphi rounds and to review the final manuscript

Sufficient written English to complete the survey instrument without translation Membership of the study Steering Committee, whose members do not vote in any round

Fewer than five years of independent practice following specialist training

No current clinical practice involving airway management in patients with cancer

Participation as a pilot tester of the Round 1 instrument, whose responses are excluded from all consensus calculations

Exclusion criteria

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