The severity of an inhalation injury is determined by all of the following EXCEPT ________.

The severity of an inhalation injury is influenced by factors such as the age of the patient, the type of burn, and the duration of exposure to harmful substances. Age is important because younger and older patients may have different respiratory capacities and vulnerability to airway damage. The type of burn can determine the nature of the inhaled materials, which can vary in their toxicity and effects on lung tissues. Additionally, the duration of exposure plays a critical role; prolonged exposure to heated air, smoke, or chemicals can lead to worse outcomes.

In contrast, the gender of the patient does not have a direct impact on the extent of inhalation injury. While biological differences may affect certain aspects of health, they are not critical determinants in assessing the severity of inhalation injuries specifically. Therefore, the correct choice highlights that gender is not a factor in evaluating the seriousness of an inhalation injury.