The “Oscar” communication model is a key component in the Marine Corps’ “Combat and Operational Stress First Aid” training manual. The guide helps Marines and support professionals provide a timely and preclinical response to stress injured individuals. - The “Oscar” communication model is a key component in the Marine Corps’ “Combat and Operational Stress First Aid” training manual. The guide helps Marines and support professionals provide a timely and preclinical response to stress injured individuals.