AimTo evaluate variations in diagnostic criteria and management recommendations for Smoke Inhalation Injury (SII) amongst the burn networks of England, Scotland, and Wales. MethodsA descriptive cross-sectional study examining SII guidelines provided by adult burn units and centres in England, Scotland and Wales. ResultsAll 16 adult burn units and centres responded. Fourteen (87.5%) had guidelines. Due to sharing of guidelines, ten unique guidelines were assessed. Diagnostic criteria showed variability with no universal criterion shared amongst guidelines. Bronchoscopy was recommended by 90% of guidelines, but the timing varied. The use of bronchoscopy scoring systems was recommended by four guidelines. Bronchoalveolar lavage (BAL) was recommended by four, with considerable variation in frequency and choice of lavage fluid. All guidelines advised at least one nebulised agent: heparin (n=8); N-acetyl cysteine (NAC) (n=8); salbutamol (n=8). All guidelines included advice on carbon monoxide poisoning, however, carboxyhaemoglobin (COHb) cut-off levels for treatment varied (5% [n-4], 10% [n=3], 15% [n=1]). All recommended high-flow oxygen. Seven (70%) guidelines offered guidance on cyanide poisoning. Reduced/altered consciousness was the only consistent diagnostic criterion. Five (50%) guidelines provided intubation guidance, emphasising the role of a ‘senior clinician’ as the intubator. Ventilatory guidance appeared in eight guidelines, focusing on: lung protective ventilation (n=8); oxygenation goals (n=3); and permissive hypercapnia (n=3). Within lung protective ventilation, advice on tidal volume (6, or 6-8ml/kg) and ventilatory plateau pressures (>30 cmH2O) were presented most commonly (n=7). ConclusionThis study has outlined the substantial variations in guidance for the management of SII. The results underscore the need for a national guideline outlining a standardised approach to the diagnosis and management of SII, within the limitations of the current evidence.