All of the following are indicators of inhalation injury EXCEPT:

Inhalation injuries can occur due to exposure to heated air, chemicals, or smoke during a fire, and several clinical indicators can help in the assessment of such injuries. An indicator that would not necessarily be associated with inhalation injury is a carboxyhemoglobin level greater than 4%.

Inhalation injuries primarily arise from direct thermal damage or chemical exposure affecting the respiratory tract, which is often evidenced by physical signs like singed hairs, carbon deposits in the oral cavity, or changes in voice, such as hoarseness. While elevated carboxyhemoglobin levels indicate carbon monoxide exposure, which is a separate concern, it does not specifically indicate an inhalation injury itself but rather highlights a systemic issue from carbon monoxide poisoning. A level greater than 4% can occur in various situations of carbon monoxide exposure not specifically related to inhalation injury from heat or smoke inhalation.

This distinction is essential in clinical practice, as management and treatment plans are significantly differentiated based on signs indicative of direct inhalation trauma versus systemic effects from inhaled toxins. If the level is elevated, it may suggest carbon monoxide poisoning, but it doesn’t necessarily correlate with physical damage to the lung parenchyma or airway that characterizes inhalation injuries.