We are talking about semi-automatic defibrillator equipment that is present in many public places like supermarkets, gyms, airports, stadiums etc. Everywhere except medical facilities.
Whether you are permitted to use that equipment on another person in case of an emergency, depends on the Comunicad Autonomo where you live and the legislation in place there. The law in Valencia for example is very strict, there only accredited persons that have received adequate training are allowed to use the equipment and every use of the machine must be documented and reported to the authorities, stating the name of the accredited person as well.
In Catalunya the law allows non-accredited persons to use the equipment as well ´for therapeutic purposes´, but only when no trained personnel is available.
If the legislation of your region limits the use of the defib machine to accredited persons only, and you would try to help out in an emergency situation where the person involved does not survive, and it is later proved that your actions actually harmed that person, the consequences can be very serious, even leading to a charge of manslaughter.
The difference in the regional laws could have to do with the date the presently valid laws were approved, and the evolution in semi-automatic defib equipment, assuming that with the newer generations the risks involved when used by a person that has not been trained to do so, are smaller.
The law in place in Valencia dates from 2007 and the one in Catalunya from 2012.
Here´s a
to download the relevant laws for all regions.