Final answer:
The burn can be classified as critical based on the age of the patient, location of the burn, amount of BSA involved, and the type/source of the burn, hinting at a severe third or fourth-degree injury requiring specialist medical care.
Step-by-step explanation:
The burn described affects 2/3s of the arm, with a center area that is dry and leathery, which could be classified as critical due to several factors.
Notably, the age of the patient is essential; elderly patients have a higher risk for complications and slower healing. Additionally, the location of the burn is crucial as burns on joints like the elbow can impair functionality and mobility.
The amount of BSA (Body Surface Area) involved suggests a substantial injury, and large burns over a significant percentage of body area often require specialized treatment.
Lastly, the type or source of the burn, in this case, an electric heating pad, indicates continuous, direct heat which often causes deeper tissue damage.
Overall, the severity of the burn, presented through the symptoms like blistering, oozing, and leathery skin, point towards a third or possibly fourth-degree burn, which affects not only all skin layers but also the underlying tissues and requires immediate medical attention.