Dr. Mohammad Siddiqui said Trooper Alex Douglass had internal bleeding and organ damage from the shooting, allegedly perpetrated by 33-year-old Eric Frein.
Prosecutors say Douglass will testify when the trial resumes next week. Prosecutors say he's undergone 18 surgeries and will likely require more.
Cpl. Bryon Dickson II also was shot outside the barracks in the Pocono Mountains. Dickson died in the attack.
Frein was captured after a 48-day manhunt.