A patient presenting with bluish-black non-deformable skin and hemorrhagic blisters is suffering from which degree of cold injury?

The characteristics of bluish-black non-deformable skin and hemorrhagic blisters are indicative of a third-degree cold injury. This level of cold injury involves significant tissue damage where the skin becomes frozen and may also become necrotic. In cases of third-degree cold injury, there is often a loss of sensation in the affected area due to nerve damage, and the appearance of the skin can include blisters and discoloration.

Identifying the correct degree of cold injury is crucial for appropriate treatment and management. First-degree cold injuries typically exhibit redness and swelling without blisters or tissue necrosis. Second-degree injuries present with blisters but do not reach the extent of necrosis seen in third-degree injuries. Fourth-degree cold injury is the most severe and extends into deeper tissues like muscle and bone, which is not yet represented in this case. Therefore, the observed symptoms clearly fit the criteria for a third-degree cold injury.