A few minutes before Ellen MacInnis of Brighton was due at her overnight rotation as a nurse in the emergency department at St. Elizabeth’s Medical Center in Boston, she acknowledged how she was feeling — scared.

“I'm very concerned,” she said. “I'm frightened honestly. I know it sounds dramatic, right? I don't want to go in there. I don't want to do this. I will.”

As she said, MacInnis will go to work. She said all nurses will report to work, because that’s what nurses do. But she couldn’t help feeling that she’s in the midst of the calm before the storm.

“I'm 60 years old,” she said. “My children are grown. I would go into work no matter what. If I get sick, I get sick. I wouldn't blame people. I wouldn't blame nurses if they didn't go in.”

Nurses and other health care professionals are preparing for an onslaught of Covid-19-infected patients, studying up on equipment and technology while trying to keep their families and themselves safe.

MacInnis said nurses at St. Elizabeth’s have enough gowns and gloves, for now, but not enough of the N-95 respirator masks that hospital professionals need.

MacInnis added that some of them were stolen from a hospital supply closet. Boston police were notified, she said.

“I don't know who's stealing it,” she said, adding that whomever did it put everyone at risk.

MacInnis has watched reports coming out of New York — ground zero for COVID-19 — and she's getting anxious. So, she’s been studying nursing journals to refresh her skills around caring for patients with severe respiratory issues.

“It's been a long time since I took care of a patient, for any extended time, on a ventilator,” she said.

MacInnis knows that’s what’s coming and the sickest people will need to be placed on ventilators, which are in short supply. And she said she expected there will be many, many sick people in the coming days and weeks — no one knows quite how many.

“There's still the underlying fear of knowing that we will be working days on end, taking care of the sickest of the sick. Not everybody will survive,” she said. "The frightening part is the volume, the volume of patients I know that we'll have. And how quickly this happens.”

But MacInnis said the hospital is intensely preparing. For example, specific areas of the hospital have been designated for certain patients.

“It feels good to actually plan for it,” she said. “It's empowering to know when the onslaught happens that we actually do have some tools. We do have a systematic approach to this.”

MacInnis knows what’s ahead of her, and so does her family. One daughter asked her to retire rather than go work in the hospital. That daughter is now sewing facemasks.

MacInnis lives alone, but she said many nurses have sent family to live elsewhere in an effort to limit their exposure to the virus. MacInnis, who became emotional talking about it, said this is a lonely time for nurses.

“I miss my children,” she said. “And I miss my grandson's most of all, I would give anything to … I'm really looking forward to when I can see them again.”