In which scenario is applying direct pressure likely to be the most effective intervention?

Applying direct pressure is especially effective in scenarios involving external bleeding, as it helps to control the blood flow from the wound by promoting clot formation and sealing off the damaged blood vessels. In the case of an open fracture with significant bleeding, there is likely to be an external wound where blood can escape from the body. By applying direct pressure to this site, you can help stop the bleeding while providing time for more advanced care to arrive.

In contrast, scenarios like internal bleeding without an external wound do not benefit from direct pressure, as there is no external access to the bleeding area. Similarly, bruises over major organs do not involve a break in the skin and would not respond to direct pressure applied externally. Minor abrasions might be treated with direct pressure, but their bleeding is generally less significant compared to what is seen in an open fracture situation. Therefore, applying direct pressure to an open fracture with significant bleeding is the most effective intervention in this context.