What action should you take after applying a field dressing to a casualty's forearm to help control bleeding?

Applying manual pressure after placing a field dressing on a casualty's forearm is an essential step for controlling bleeding. This action aids in creating direct pressure on the wound site, which is crucial in minimizing blood loss. By maintaining consistent pressure, you can help the blood clot and reduce the chances of a more severe hemorrhage.

While other actions, like notifying medical personnel or elevating the arm, may be helpful in certain situations, they do not provide the immediate control over bleeding that manual pressure does. Elevation can assist in reducing blood flow to the area to a degree, but only manual pressure directly addresses the wound. Removing the dressing to check the wound can disrupt any clotting process that may have started and expose the wound to infection or further bleeding. Therefore, applying manual pressure is the most effective immediate action to take in this scenario.