Clinical Recognition A history of exposure in a closed space should heighten concern for smoke inhalation Need for CPR at the site implies significant carbon monoxide poisoning and/or hypoxia secondary to decreased ambient oxygen concentration or severe respiratory disease The physician should also consider the types of material involved to determine the risk of poisoning from carbon monoxide or other toxins Important elements from the patient’s history include the mechanism of inhalation injury, duration of exposure, location, and pre-existing comorbidities Physical examination that reveals facial burns, singed nasal hairs, pharyngeal soot, or carbonaceous sputum justifies a presumption of smoke inhalation Any sign of neurologic dysfunction, including irritability or depression, should be presumed related to tissue hypoxia until proven otherwise Signs of respiratory dysfunction, including tachypnea, cough, hoarseness, stridor, decreased breath sounds, wheezing, rhonchi, or rales may be detected on presentation or may be delayed for 12 to 24 hours, depending on the severity of the insult Auscultatory findings often precede chest radiograph abnormalities by 12 to 24 hours Radiographic changes may include diffuse interstitial infiltration or local areas of atelectasis and edema ( Fig 90.3 ) Acute respiratory failure may occur at any point ABG analysis provides the ultimate assessment of effective respiratory function Fiberoptic bronchoscopy can document the extent and severity of injury by assessing for the presence of hyperemia, edema and soot, and can help remove debris In general, it is respiratory function, not the appearance of surface lesions, that guides supportive care; therefore, most patients can be treated effectively without bronchoscopy