Fairfax County school officials said the district will begin adding portable defibrillators, devices that could save the life of someone in cardiac arrest, in all schools and administration buildings during the next school year.

The automated external defibrillators, or AEDs, will be bought jointly by the county and the school system, officials said. Inova Health System has tentatively agreed to provide free training.

Sandy Canfield, a Burke mother who has lobbied for AEDs in schools, said she hopes the devices will never be needed but that they will reassure parents, teachers and coaches. Canfield's 15-year-old daughter, Danica, went into cardiac arrest during a crew practice at Robinson Secondary School in January 2002 and later died. The family wonders if an AED would have saved her life.

"By having the units in schools, families will know that everything possible is being done," Canfield said. "I would definitely not want someone else to go through what we went through."

AEDs, laptop-size devices that provide a jolt of electricity that can restore a heartbeat to a normal rhythm, have become increasingly common in public places such as government buildings, stadiums and airports. Alexandria school officials announced last month that the district had completed outfitting all schools with AEDs and had trained staff members. Arlington and Loudoun schools also are equipped with the easy-to-use devices.

In April, the Fairfax County School Board unanimously approved a policy that endorsed the installation of the AEDs and called for staff members to develop a plan for training and maintenance. The county Board of Supervisors had set aside a little more than $1 million for AEDs in schools and other county buildings, and the School Board is poised to approve a $500,000 contribution this month.

"It took a lot of talking because several things had to be resolved for this to be up and running on a large scale," said School Board member Jane K. Strauss (Dranesville). "We're confident now we will be able to equip the buildings and that the training and maintenance and even the placement will be appropriate so they really can save a life."

According to the American Red Cross, sudden cardiac arrest strikes about 220,000 people in the United States each year and only about 5 percent survive. Advocates say quick use of an AED can greatly increase the chance of survival.

The devices use voice commands to guide the responder though the process. In addition, AEDs analyze heart rhythms automatically and deliver a shock only if needed.

School staff members have said that about 580 AEDs, which cost about $1,650 each, will be needed to ensure that one could be reached in minutes from any office, classroom or gymnasium in any school or administrative building.

Jon Almquist, an athletic training specialist in the schools, said staff members at each building will be trained to use the devices and to administer cardiopulmonary resuscitation. In addition, the district is developing a maintenance plan to ensure that each unit functions properly.

Almquist said the schools will launch a program to teach staff members and students about the AEDs and the appropriate response to a medical emergency.

"We want to do it right, and that's why it's going to take a while," Almquist said. "We do think these devices eventually will save a life."