In this extreme and life-threatening situation, the emergency responders would need to employ different techniques to control the massive bleeding:
Direct Pressure: The first and most critical action would be to apply direct, firm pressure to the wound site, deep into the axilla (armpit) and the shoulder. This pressure would be used to compress the major blood vessels against the shoulder blade and chest wall.
Wound Packing with Hemostatic Agents: In modern trauma care, medical personnel would likely use hemostatic gauze or other agents. These are special dressings that contain chemicals to help the blood clot faster. The responder would pack the deep wound with this gauze and continue to apply firm pressure.
Immediate Transport: With this type of catastrophic injury, every second counts. The patient would be stabilized with direct pressure and, if available, hemostatic dressings, and then transported immediately to the nearest trauma center.
The goal is to get the patient to a surgical team as quickly as possible. The only definitive way to stop the bleeding from the severed major artery at the shoulder is through a surgical procedure called ligation, where the artery is surgically tied off. The ambulance crew would be focused on keeping the patient alive until they can get to a surgeon who can perform this life-saving procedure.