Acute lung injury after inhalation of nitric acid

We report two cases of acute lung injury after the inhalation of nitric acid fumes in an industrial accident. The first patient, who was not using a respirator and standing in close proximity to the site of spillage of concentrated nitric acid, presented within 12 h with worsening dyspnea and required noninvasive ventilation for type 1 respiratory failure. The second case presented 1 day later with similar symptoms, but only required supportive treatment with high-flow oxygen. Both patients' chest radiographs showed widespread bilateral airspace shadows consistent with acute lung injury. Both received treatment with systemic steroids. They were discharged from hospital 5 days postexposure. Initial lung function test showed a restrictive pattern that normalized by 3 weeks postexposure. This case series describes the natural history after acute inhalation of nitric acid fumes, and demonstrates that the severity of lung injury is directly dependent on the exposure level. It also highlights the use of noninvasive ventilatory support in the management of such patients.