On the night of Jan. 15, 2021, in a distant Arizona desert city, Christine Benton saved a life.

She and her husband, Brian Benton, have been touring the nation in a leisure car and had parked close to different R.V.ers at a vineyard in Willcox. Because the couple have been consuming dinner, somebody began shouting from an R.V. behind them. A lady had collapsed and was in cardiac arrest. She had no pulse. Frantic, her husband referred to as 911 whereas two different folks began cardiopulmonary resuscitation.

“She regarded like she was gone,” stated Ms. Benton, a retired paramedic firefighter.

However Ms. Benton had made a consequential determination earlier than she and her husband began out: She had purchased a private automated exterior defibrillator, or A.E.D., which might shock an individual’s coronary heart again to life if it instantly stops beating. Her plan was to to maintain it along with her, simply in case. It was costly, it was extremely unlikely she would ever use it and her husband was hesitant. However she was adamant.

“If I have been ever in a state of affairs the place I may save a life and I didn’t have an A.E.D., I may by no means stay with myself,” she instructed her husband on the time.

As a firefighter, Ms. Benton had been educated to make use of a defibrillator. She knew that if somebody’s coronary heart stopped, a rescuer ought to begin CPR instantly, pushing exhausting and rhythmically on the chest, whereas one other rescuer went to get an A.E.D. As quickly as that second rescuer returned, the A.E.D. ought to be used.

And Ms. Benton knew that A.E.D.s have been simple to make use of, even for somebody with no coaching. The machine speaks to rescuers and tells them learn how to proceed.

However despite the fact that all states have legal guidelines requiring that A.E.D.s be accessible in public locations, Ms. Benton nervous that if somebody had a cardiac arrest in a spot the place the closest A.E.D. was miles away, the particular person would possibly die — minutes depend when reviving somebody in cardiac arrest. For each one-minute delay in resuscitation, the probability of survival falls by as much as 10 p.c.

For Ms. Benton, the choice to purchase an A.E.D. made good sense. I additionally ordered one for myself after reporting on the soccer participant Damar Hamlin’s on-field cardiac arrest. When it arrives I’m going to inform my neighborhood’s Google group that I’ve it.

However emergency drugs specialists are divided on whether or not it is sensible for anybody to purchase one.

They know that A.E.D.s in public locations like airports, the place 1000’s of individuals cross by on daily basis, could make a distinction and so they urge folks to make use of them in the event that they see somebody who wants assist. Within the U.S., 85 to 90 p.c of people that have sudden cardiac arrests don’t survive and lots of can’t be revived, actually because resuscitation makes an attempt begin too late.

However the state of affairs is totally different within the dwelling.

For one, there may be the expense — the units usually value greater than $1,000, making them far much less inexpensive to the typical particular person than dwelling medical units like a blood stress monitor or a pulse oximeter. Whereas there are efforts to develop cheaper A.E.D.s, they’re nonetheless underway, in accordance with Monica Gross sales, a spokeswoman for the American Coronary heart Affiliation.

The value is just not the one factor that provides some specialists pause. The chances are so stacked in opposition to a dramatic save that it has proved not possible to point out that non-public A.E.D.’s make a distinction.

An estimated 1,000 folks a day within the U.S. have sudden cardiac arrests, through which the guts stops beating and the particular person is technically useless. However that represents a minuscule portion of the American inhabitants.

Even folks at excessive danger of a sudden cardiac arrest weren’t helped by dwelling A.E.D.s, a big research confirmed. It concerned 7,001 individuals who had beforehand had coronary heart assaults and who have been randomly assigned to obtain an A.E.D. or to be in a management group.

Regardless of the massive variety of research members, only a few had cardiac arrests and, even after they did, the arrests usually didn’t happen at dwelling or weren’t witnessed. Ultimately, simply eight folks in every group have been resuscitated at dwelling. The authors concluded that even when the research’s dimension have been doubled, there can be too few occasions to detect an impact of dwelling A.E.D.s.

However consider an A.E.D. like a hearth extinguisher, stated Dr. Benjamin Abella, an emergency drugs specialist on the College of Pennsylvania. You would possibly by no means use it, however having one would possibly at some point save a life.

“I believe it’s a terrific thought” to personal one, Dr. Abella stated. He not too long ago ordered an A.E.D. for himself.

For a similar motive, the American Coronary heart Affiliation helps anybody who desires to get an A.E.D., stated Dr. Comilla Sasson, a vice chairman on the American Coronary heart Affiliation and an emergency drugs doctor on the College of Colorado Denver.

“If we may simply scale back the stigma round, ‘Hey, I can’t do that as a result of I’m not a medical skilled,’” she stated. “And also you don’t have to have CPR certification to make use of an A.E.D.”

However Dr. Sumeet S. Chugh, director of the Heart for Cardiac Arrest Prevention at Cedars Sinai in Los Angeles, has his doubts.

“I don’t assume we’ve the info to help widespread prophylactic purchases of A.E.D.s even should you can afford it,” he stated. And, he added, many who go into cardiac arrest wouldn’t have a shockable situation. One instance is asystole, a flat line on the guts monitor indicating there is no such thing as a electrical exercise within the coronary heart. An A.E.D. can’t revive folks with unshockable rhythms. Different sufferers will not be found in time for his or her coronary heart to be shocked again to life.

That was the state of affairs that Mary Newman discovered herself in. Ms. Newman, co-founder of the Sudden Cardiac Arrest Basis, which promotes consciousness of cardiac arrest and has a help group for survivors, has an A.E.D. However when her mom collapsed within the toilet throughout a household trip, nobody realized she was lacking. By the point the household discovered her, it was too late to avoid wasting her.

But there are uncommon examples of people that did save a life with a private A.E.D.

One concerned Esley Thorton, Jr. of Bismarck, N.D.

At about 8 a.m. on Nov. 25, 2019, Mr. Thornton sank into his favourite chair, inexplicably drained.

A couple of minutes later his spouse, Melinda, heard an odd noise and got here working into the room. “His physique was contorted,” she stated. “He was gasping for air.”

Then he stopped respiratory. His coronary heart had stopped.

Ms. Thornton screamed for her son Rhannon, who referred to as 911 and grabbed an A.E.D. that one other son, who works for the A.E.D. maker Stryker, had given his mother and father as a present two years earlier.

Rhannon put the machine’s pads on his father’s chest. It stated, “No pulse, administer shock,” Ms. Thornton recalled.

He pressed a button.

“Shock administered,” the machine stated.

“We heard him take a deep breath,” Ms. Thornton stated. Her husband’s coronary heart was beating once more.

An ambulance got here eight minutes after the 911 name — lengthy sufficient that with out Rhannon’s assist, Mr. Thornton might need died or had critical mind injury.

One of many paramedics was astonished, telling the household that he had been a paramedic for 22 years however had by no means earlier than seen a private A.E.D. utilized in a affected person’s dwelling.

In Ms. Benton’s case, the girl whose coronary heart had stopped started respiratory once more lower than 20 seconds after Ms. Benton shocked her coronary heart with the A.E.D.

With out the A.E.D., the girl, Karen Schluter, would have died — CPR alone wouldn’t have been adequate in that distant location the place it took about half an hour for an ambulance to reach.

But nobody would have predicted that Ms. Schluter was in danger. She was 52 and athletic — an avid bicyclist.

Now Ms. Benton and Ms. Schluter are good associates. Ms. Schluter has bought an A.E.D. and so have others whose R.V.s have been parked there that night.

When the Bentons returned to their R.V. after their A.E.D. saved Ms. Schluter’s life, Mr. Benton checked out his spouse and stated, “I’m positive glad you didn’t hearken to me about shopping for that A.E.D.”