Cal. HSC § 1799.104

(a) No physician or nurse, who in good faith gives emergency instructions to an EMT-II or mobile intensive care paramedic at the scene of an emergency, shall be liable for any civil damages as a result of issuing the instructions. (b) No EMT-II or mobile intensive care paramedic rendering care within the scope of his duties who, in good faith and in a nonnegligent manner, follows the instructions of a physician or nurse shall be liable for any civil damages as a result of following such instructions.