In several emergency situations, doctors may run out of options. In several cases, experts may not be available when they are most required. If a physician is not the authorized person to perform an emergency procedure but has thorough experience in it should he/she go for the procedure to save the patient life if the patient’s attendants give written consent and mention the non-availability of the expert?

Or should he/she wait until the expert comes? What should a physician do in such a situation?