Inhalation injury - Emerging treatments

Nebulised heparin

Heparin may help to prevent fibrin deposition in the airways and alveoli of acute respiratory distress syndrome (ARDS) patients.[37] Preliminary clinical and animal data show promise, but multi-centre prospective trials are lacking.[49][50] One retrospective case-control study of nebulised heparin found that patients on mechanical ventilation who received this therapy within 48 hours of diagnosis had decreased duration of mechanical ventilation, increased ventilator-free days, and no differences in 28-day mortality, length of hospitalisation, or bleeding rates.[51] One multi-centre extension of this trial found similar outcomes regardless of dose of nebulised heparin that was used.[52] In 2023, an international Delphi panel recommended the use of nebulised heparin in patients with moderate to severe burn inhalation injury.[32]

Tocopherols

Tocopherols scavenge reactive oxygen and nitrogen species, and have shown efficacy in animal models.[38] Tocopherols, with the exception of alpha-tocopherols, are not currently approved for use in humans.

Corticosteroids

Several studies in ARDS have demonstrated the potential benefit of corticosteroids, but their use in inhalation injury is unclear.[39][53] No data have supported a role for systemic corticosteroids in reducing inflammation in inhalation injury.[54]

Vitamin C

High-dose vitamin C has demonstrated improvement in oxygenation in small trials, although the mechanism is unknown and large trials are lacking.[42] One retrospective case-control study (38 patients who received the intervention and 42 matched controls) found no difference in the rates of inhalation injury or other clinical outcomes in patients treated with vitamin C during burn shock resuscitation.[55]

Antithrombin-III

Patients with burn injuries have been noted to develop deficiency of antithrombin, a serine protease inhibitor with anti-inflammatory properties. Repletion of antithrombin-III is under clinical investigation; however, it has not been proven effective in large clinical trials.[43]

Anti-inflammatory agents

Inhibition of the cyclooxygenase (COX) and lipoxygenase inflammatory pathways with agents such as non-steroidal anti-inflammatory drugs and leukotriene inhibitors have demonstrated promise in animal models, but human trials are lacking.[54] Tranilast, a tryptophan analogue with anti-inflammatory properties, has been shown to ameliorate the development of acute respiratory distress syndrome in a rat model of smoke inhalation, but no human studies have been published.[56]