In surgery, blood is always a problem.  If a blood vessel is punctured and blood rushes out, they cauterize it with electricity, blocking the blood vessel.  This is the fastest and most effective method.  Another way is to tie the bowl closed with sewing.  There is always a gauze cloth to get rid of the blood.  You can also temporarily secure the bowl with a hemostat fixator (also known as a snap).  Another option is to reduce blood flow, either by injecting epinephrine.  Another option is to use hemostatic agents/powders/gels that seal the area.  Sometimes we use a tourniquet to limit blood flow to the extremities.

   In rare cases - such as a ruptured liver - surgeons place gauze in the rupture to have a hemostatic (liver-coating) effect.  After some time, the gauze should be removed (unless an absorbable material is used).

   Gauze remaining inside the patient is a source of inflammation and a potential site of infection.

   A gauze bandage should be used on a tight wound because if it is applied to a new wound with pus and blood leaking, it should be changed before the exudate dries up and sticks because when you change the bandage, you will need to get wet.  water to remove it or take a shower.  If the wound is stitched up (stitched or stapled), you can cover it with sterile gauze dressings, but for most wounds that happen at home, gauze can stick to the exudate, and untreated Tylvan dressings are better for greater coverage than a bandage.  Because Telefan does not do that.  Do not stick.

   It really depends on your degree level and your environment.  An accomplished Thoracic Surgeon at a Level 1 Trauma Center would be significantly different from Boy Scout with EMS less than 10 minutes away.

   For the layman (I assumed a chest surgeon or EMT wouldn't ask), it's pretty simple:

   Call for immediate advanced medical assistance

   Be prepared to help with breathing

   Providing high-flow oxygen, if available (medical grade and with an appropriate device)

   Treat shock / prepare for CPR