Three times within a week, 34-year-old Michael Granillo went to the emergency room at Northridge Hospital Medical Center in Los Angeles because of intense back pain. Each time, Granillo, who didn’t have insurance, stayed for less than an hour before leaving without being seen by a doctor.

“I was in so much pain I wanted to be taken care of now,” said Granillo, who runs a hot-dog-cart business. “I didn’t want to sit and wait.”

On a recent Wednesday morning, he woke up feeling even worse. This time, Granillo’s wife, Sonya, tried something different: Using a new service offered by the hospital, she was able to make an ER appointment online, using her mobile phone.

When they arrived at the hospital, he was seen almost immediately.

“That was my last resort, and it worked,” she said. “He would have probably been at home in pain if not for the service.”

In an era of increased competition, hospitals around the country are hoping that online ER appointments will help attract patients anxious to avoid long waits in a crowded and often chaotic environment.

“It makes for a happier camper,” said Susan Dubuque, a national expert in hospital marketing. “When it comes to health care, consumers want more control over everything.”

The system adopted by Northridge and other hospitals in the Dignity Health chain about a year ago is intended only for patients without life-threatening or debilitating emergencies. To check in online, patients must explain the reason for their visit and check a box indicating that they can wait for treatment.

Patients having chest pain or trouble breathing, for instance, are instructed to call 911 or go directly to an ER. Those with an ankle sprain or a fever, however, might be able to make an appointment.

When scheduled patients get to the hospital, they still may be bumped by people who are more seriously ill.

The approach makes business sense, hospital executives say, because it lets the medical staff know what types of cases may be coming through the door, and it makes patients more comfortable.

Patients want to access health care the same way they do services in other industries, such as retail and travel, said Chris Song, a spokesman for InQuicker, a Nashville-based company that offers online scheduling in California and 25 other states.

“When is the last time someone bought plane tickets at the gate?” he said.

Some critics say the online check-in system may be convenient but is not necessarily cost-effective. If the country wants to decrease health-care costs, patients need to be treated at the right place at the right time, said Del Morris, president of the California Academy of Family Physicians. Patients who can make appointments should be seen at their doctors’ offices, he said.

“Emergency rooms are there to take care of people who have emergencies,” said Morris, medical director of the Stanislaus County Health Services Agency in Modesto.

The Dignity Health chain says roughly 12,000 patients have scheduled visits for emergency rooms at hospitals in California, Arizona and Nevada. Recently, Dignity stepped up marketing, with billboards, print advertisements and online and radio spots. One features a woman sitting in a waiting-room chair, then cuts to her on a living room couch with a dog as words on the screen read, “Wait for the ER from home.”

On the day of his appointment at Northridge, Granillo winced and shifted uncomfortably in the ER exam room.

“How are you feeling?” asked physician Stephen Jones. “Do you need more pain medicine?”

Granillo nodded and told him that his back and stomach both hurt.

After a CT scan, doctors told the couple that Granillo had a very serious condition: lymphoma, a type of cancer.

Jones, the medical director for the emergency room, said some patients who come in through the appointment service probably should be seen by a primary-care doctor but either don’t have one or can’t get a timely appointment. Others, such as Granillo, shouldn’t wait for care, he said.

Dignity Health, which is also offering the online reservations at urgent care centers and doctors’ offices, hopes that the new service will minimize wait times and boost patient satisfaction scores, said Page West, the chain’s chief nursing officer. Under the Affordable Care Act, Medicare reimbursements for hospitals are tied to results on patient surveys.

Others say hospitals need to do more to fix the emergency room process in which people show up and wait for hours, said Bridget Duffy, chief medical officer at Vocera Communications, which develops technology for improving patients’ experiences. Besides offering online appointments, Duffy said, hospitals need to assess patients more quickly, improve communication with them and better manage their pain.

As it stands, she said, “it’s ridiculous … it’s like herding cattle.”

Kaiser Health News is an editorially independent program of the Henry J. Kaiser Family Foundation, a nonprofit, nonpartisan health-policy-research and communication organization not affiliated with Kaiser Permanente.