What is one sign of internal bleeding that a corpsman should be aware of?

Increased heart rate and reduced blood pressure are significant indicators of internal bleeding that a corpsman should be vigilant about. When internal bleeding occurs, the body attempts to compensate for the loss of blood volume by increasing the heart rate in order to maintain adequate circulation and oxygen delivery to tissues. At the same time, reduced blood pressure is a critical sign that can indicate severe blood loss, as the volume of circulating blood decreases. Monitoring these vital signs is crucial in assessing a patient who may have sustained an injury leading to internal bleeding.

Other signs such as blue discoloration of the skin, pain at the site of injury, and swelling in the abdomen may also indicate issues related to trauma or injury, but they may not be as definitive as the changes in heart rate and blood pressure that directly reflect the body's response to internal bleeding.