Final answer:
A cautery during a surgical procedure is primarily used for controlling bleeding by cauterizing tissue to seal blood vessels.
Step-by-step explanation:
During a surgical procedure, a cautery is mainly used for controlling bleeding. This medical device utilizes heat from electrical current, lasers, or a flaming substance to burn tissue, which causes blood vessels to seal shut. This process, known as cauterization, helps to prevent excessive blood loss during surgery. Cautery can also be used to remove unwanted or harmful tissue and, in some cases, to make precise incisions, though its primary use is hemostasis.