Final answer:
In the case described, the most critical concern is the potential for airway swelling due to inhalation injury, which can lead to rapid airway obstruction and respiratory failure. It is more immediately life-threatening than hypothermia or infection and requires prompt assessment and possible interventions.
Step-by-step explanation:
In the scenario where a patient has sustained burns to his face and chest, has singed nasal hairs, and is coughing up sooty sputum, the most concerning factor is the potential for airway swelling. The presence of soot and singed nasal hairs indicates that the patient has likely inhaled hot gases, which can lead to upper airway edema (swelling) and compromise the airway.
While estimating the extent of burns using the "rule of nines" and preventing infection are important aspects of care, they are not as immediately life-threatening as a compromised airway. In cases of inhalation injury, the respiratory tract can swell rapidly, leading to obstruction and respiratory failure, requiring rapid assessment and potential treatments such as humidified oxygen, corticosteroids to control swelling, or even intubation if necessary.
Although treating for hypothermia and preventing the risk of infection are important in burn treatment, they are secondary to establishing a patent airway, as hypothermia generally presents a threat over a longer period of exposure and infection is a concern that develops over a number of days following the burn injury.