In case of uncontrolled bleeding, what is the first action a Hospital Corpsman should take?

Applying direct pressure to the wound is the immediate and most effective first action when managing uncontrolled bleeding. This technique helps to stabilize the situation by reducing blood flow from the wound, which is crucial in preventing shock and further complications. Direct pressure encourages clot formation by compressing the blood vessels and surrounding tissues, thus promoting hemostasis.

In cases of uncontrolled bleeding, timely intervention is vital. While other options like calling for a blood transfusion or administering oxygen are important in a broader first aid or emergency care scenario, they would not be the initial step taken in response to uncontrolled bleeding. Starting CPR is also not appropriate unless the patient is unresponsive and in cardiac arrest, which is a separate issue from managing hemorrhage.