Personnel from American Medical Response and D.C. Fire and EMS load a patient onto an AMR ambulance after a March 2016 call at an apartment in Northeast. (Ricky Carioti/The Washington Post)

Under a change taking effect Friday, D.C. residents who call 911 no longer will be guaranteed an ambulance ride to hospitals if responding medics and a nurse determine their ailments are minor, D.C. Fire and EMS Department officials said.

Instead, after an assessment by firefighter and EMT crews, patients who are not in serious straits will be put on a phone call with a nurse, who will help them to find care at a clinic or a primary care facility. The medics will remain on scene and talk to the nurse after an agreement on care has been made.

“We’ll dispatch like we normally do. An ambulance or firetruck will show up your door,” Fire Chief Gregory Dean said. “They’ll come in. They’ll talk with you and figure out what’s going on, take your vitals, your blood pressure, your heart rate. The nurse will have your vitals to help make a better decision on the best care for you.”

The new policy is part of the department’s Right Care, Right Now nurse triage line that launched in April in the city’s 911 center. That line has nurses available to diagnose 911 callers who appear to have non-life-threatening symptoms or injuries.

The nurses will book an appointment for those in need with a primary-care doctor or clinic in the caller’s neighborhood that can see the caller within two hours. The nurses also send Lyft drivers to take Medicaid-covered patients to and from those appointments.

One aim of the phone line was to divert medics or fire crews from unnecessary calls and trips to the emergency rooms with patients who suffered minor ailments such as insect bites and sore throats. Officials hope the new policy will expose more patients to the nurse line, which has had a limited impact since it began.

“What we learned is we weren’t getting as many patients as we thought,” Dean said. “In talking to the nurses and 911 call takers there was something missing.”

Dean said that “until we get better at this we are going to reaffirm the decision-making by having the firefighters, paramedics and EMTs on scene to help give additional information to help make a better decision for the patient.”

The stemming of ambulance rides, even after medics arrive to a call, is the latest attempt by fire officials to deal with a crippling call volume that frequently caused the department to be short on available units for life-threatening situations. In March 2016, the department began employing a private fleet of ambulances with contractor American Medical Response to help transport patients with less-serious symptoms, injuries and conditions after they were assessed by fire department medics.

City officials and D.C. Council members have said that these efforts have stabilized the response system but that far more work needs to be done to eliminate needless trips to hospitals, which siphon the availability of emergency resources. Before the creation of the nurse triage line, officials estimated that as many as 70 percent of medical dispatches from 911 calls involved patients with conditions that were not life-threatening emergencies.

Last fall, Dean sent a letter to the department stating that the nurse triage line showed modest improvement on trimming the non-emergency runs but hadn’t yet drastically reduced caseload stress on the system.

Officials want this month’s rollout to help in educating citizens to use 911 only for serious matters.

Dabney Hudson, president of the firefighters union, said the policy change is welcome because the city is taking another step to prevent misuse of 911 resources. However, he said union officials remain concerned that the on-scene phone calls may tie up units too long and could potentially put staff in confrontations with unhappy residents.

“We support getting the right people to the appropriate care. However, I’m worried about the amount of time this will keep units on the scene,” Hudson said. “I think it could put our providers in a precarious position. I think in certain places that’s not going to be received very well.”

He added that “if the patient still demands they go, I don’t think we will have a choice, because they will just call back.”

Hudson said the initial version of the nurse triage line did not divert hundreds of calls from being dispatched as officials had predicted, and he questioned how much the new policy will improve that. He suggested the city needs a larger messaging and education program to help residents learn when to call 911.

“I’m glad they’re doing something. Nobody has done anything to tackle this problem,” Hudson said. “Let’s get the education piece out there so people are calling their doctors [for minor ailments]. Handouts, leaflets, pamphlets — those are the things that we have seen work.”