If you recently had a surgical procedure that was considered fairly ­minor—such as cataract removal—you might have gone to what’s called an ambu­la­tory surgery center (ASC).

These freestanding centers, which may be at least partly owned by private physicians, are becoming increasingly widespread.

We’re awaiting newer statistics, but 10 years ago, of the estimated 35 million annual outpatient surgeries, about 15 million were done in ASCs. (Many are also performed in the outpatient departments at hospitals.)

The most common procedures at ASCs—such as cataract surgeries and lumpectomies—tend to be simpler ones.

However, these facilities are starting to take on more complicated procedures. The percentage of hysterectomies done at such centers, for example, rose from 36 percent to 64 percent between 2010 and 2014. Some ASCs are also performing total joint replacement and spine surgery.

If your doctor recommends that you have a procedure at an ambulatory surgery center, you might wonder whether it's the best option. Here's what the research suggests and what our experts say.   

The Advantages of Outpatient Surgery

Outpatient surgery, whether done at an ASC or the outpatient surgery department of a hospital, can offer some significant benefits. It not only involves a shorter stay at a medical facility but also is usually less expensive than inpatient surgery.

A recent Blue Cross Blue Shield analysis of the claims data of approx­i­mately 43 million people found that those who chose to have angio­plasty in an out­patient facility rather than inpatient saved an average of $1,062 out of pocket.

And according to a 2016 study in the Journal of Bone & Joint Surgery, people who had outpatient surgery for ankle fractures, for example, had lower rates of urinary tract infections, pneumonia, and blood clots, and required fewer blood transfusions than those who had the surgery in a hospital.

Know Whether You're a Good Candidate for an ASC

If you’re in good health, experts say, an ambulatory surgery center procedure may work for you.

“We’ve made so many advances with surgery—smaller incisions, so patients lose less blood; better instruments so that there’s less soft-tissue damage; more effective pain medications—that it’s feasible now to safely do these surgeries on an out­patient basis,” says Claudette Lajam, M.D., assis­tant professor of orthopedic surgery and chief safety officer for orthopedics at NYU Langone Medical Center in New York City.

But not everyone is a good candidate for outpatient surgery, no matter where it’s done.

Older adults who are frail may take longer to heal, have stronger and longer-lasting reactions to anesthesia, and be more likely to experience surgical complications than younger people.

In addition, even a simple procedure could be problematic if you have a serious medical condition.

“These patients have a higher risk of complications and will be better off in a hospital that can quickly respond to emergencies,” says Daniel Mendelson, M.D., a geriatric specialist at the University of Rochester Medical Center in New York and spokes­man for the American ­Geriatrics Society.

About 1 in 1,000 people experiences significant complications—or even dies—within 72 hours of surgery at an ASC or a hospital outpatient center, according to a 2013 University of Michigan study.

The researchers pinpointed seven main risk factors: being overweight, being obese, obstructive lung disease, hypertension, past history of heart attack or stroke, previous cardiac intervention, and prolonged operating room time.

What to do: If you meet any of the above criteria, talk with your doctor about whether an inpatient procedure, or at least a hospital-based outpatient procedure, might be more appropriate for you. (Check with your health insurer to determine whether it will cost you more out of pocket to go inpatient for a pro­cedure that is usually done on an out­patient basis.)

Study Up on Your Surgery

It's important to understand the potential risks of your particular surgery before deciding whether to have it at an ASC or elsewhere. That's because research suggests certain procedures may be more problematic when done on an outpatient basis.

When researchers from the Agency for Healthcare Research and Quality and other groups conducted a survey on six common outpatient procedures, they found that trips to the emergency room, ambulatory surgery, and hospital admissions were more common ­after two of the six: prostatectomies and hernia repairs.

The research, published in 2015 in JAMA, found that such complications were lowest for anterior cruciate ligament (ACL) repair and spinal surgery.

Postsurgery infections shake out a little differently. According to a 2014 JAMA study, these tend to be highest for hysterectomies and hernia surgeries, and lowest for prostatectomies, spine surgeries, and anterior cruciate ligament (ACL) repairs.

What to do: Ask for your surgeon’s infec­tion and complication rates for your surgery. (You can check these against inpatient and outpatient hospital rates here.)

Pick Your Center Carefully

When you’re considering outpatient surgery, whether it’s at a hospital or an ambulatory surgery center, do some research first.

If you’re having outpatient surgery at a hospital, you can check the hospital’s infection rate here.

However, “Consumers should be aware that they (ASCs) may not be held to the same standards as hospitals,” says ­Patricia Kelmar, J.D., senior policy adviser for the New Jersey Health Care Quality Institute. “For example, in New Jersey, safety and health inspections differ depending on whether a facility has more than one surgery room and whether it’s CMS [Centers for Medicare and Medicaid Services] certified.”

What to do: If you’re having surgery at an ASC that's not affiliated with a hospital, ask if it is CMS-certified. This means that for the center to be reimbursed by Medicare, it must meet standards related to anesthesia administration, operating and recovery rooms, medical staff, and nursing services.

In addition, CMS-certified ASCs are required to report certain quality standards, such as statistics on patient falls, burns, and hospital transfers after a procedure, to receive Medicare payment.

And ask the following questions before you go under the knife:

How much experience does the surgeon have? Look for someone who has performed the procedure at least 50 times in the past year, says Lisa ­McGiffert, director of Consumer Reports’ Safe Patient Project.

For the anesthesiologist: What's the best anesthesia for me and who will check on me during the procedure? In many cases, local anesthesia or conscious sedation (where you are awake but feel no pain), may suffice. The anesthesiologist should check on you during the procedure. (Be sure he or she accepts your insurance, is board-certified, and has hospital admitting privileges too.)

What’s the emergency plan? Ask whether emergency medications and resuscitative equipment are on-site, if there is a procedure for using them, and whether your doctor is certified in advanced resuscitation techniques. The facility should also have a plan for transferring you to a hospital, if necessary.

How many patients have to be hospitalized as a result of infections after having this procedure? Your doctor should be able and willing to share that information with you. “The goal should be zero,” McGiffert says.

Make Going Home Safer

Adults who are age 60 or older are more likely than younger people to be admitted to a hospital within 30 days of outpatient surgery, according to an analysis published in 2015 in the Journal of the American Geriatrics Society. To prevent this:

Get written discharge instructions. These should cover diet, medications, the activities you should and shouldn't do, follow-up appointments, and who and when to call about complications.

Be sure you're ready to go home. Your blood pressure and temperature should be normal and your pain and nausea under control. You should also be able to move without dizziness.

Have the right help at home. You may need to have someone with you, at least initially. And for more complicated procedures, such as a joint replacement, you might need another adult on hand for at least a week.

Pass on key information in your follow-up call. (You should get a call from the ASC within 24 to 72 hours of surgery.) Tell the caller if you’re unable to eat, drink, or use the bathroom; have a fever or bleeding; or have pain or nausea that is not well-controlled by medication.

Editor's Note: This article also appeared in the April 2017 issue of Consumer Reports on Health.