Kara Spike has been a nurse at St. Joseph’s Hospital in St. Paul for a quarter century, but she never imagined she’d find herself in the position she’s been in this week after her neuro/spine unit was converted into a unit for COVID-19 patients.

Instead of the preferred N95 respirator masks that filter out 95% of airborne particles, Spike and other nurses have been forced to wear paper surgical masks while they care for coronavirus patients. Instead of masks that are fit-tested annually to adhere to their faces, the surgical masks have gaps and provide minimal protection. The N95 masks at the hospital are reserved for ICU patients getting aerosol medications, Spike said.

“You sign up to be a nurse, yes — but you also expect to be protected in what you’re doing, and we are not,” Spike said. “It’s like going to a war without a gun.”

So this week Spike and her colleagues started posting on Facebook about their dire need for masks. Nurses are driving to Home Depot and Menards to find them — when they’re not sold out. Nurses’ parents are posting on Nextdoor for mask donations. Spike posted online about a health system in Boston that’s sewing covers over N95 masks so they can be reused instead of disposed of regularly; several seamstresses replied that they’re on it. On Wednesday, a neighbor in Victoria who works in construction dropped off five N95 masks at Spike’s house.

And on Friday afternoon, the 45-year-old mother of three drove to a parking lot near Ridgedale Center in Minnetonka to meet her brother, who works in the automotive industry. He handed her a box of 20 or so N95 masks out his car window. She began to cry. Spike plans to bring her newly procured masks to her Saturday shift to share with colleagues. She assumes they will last about two days.

The mask dilemma is far from restricted to St. Joseph Hospital or to Minnesota. Nationwide, health care professionals have sounded the alarm for what is quickly becoming an acute mask shortage. Maplewood-based 3M Co. is doubling global production of N95 respirator masks to about 100 million a month, which will be directed toward government and public health response. The Centers for Disease Control and Prevention has “as a last resort” suggested homemade masks such as bandannas or scarves for health care providers where face masks are unavailable.

The problem has been building for weeks as the pandemic has spread. Public health officials warned about supply-chain issues in late February. Nonmedical professionals have hoarded masks and respirators for personal use, contributing to the shortage in an increasingly overwhelmed health care system.

The Minnesota Department of Health is coordinating offers of mask donations for health care workers, such as Friday’s donation by Twin Cities Habitat for Humanity of 7,500 masks to Hennepin Healthcare and M Health Fairview.

“The N95 mask shortage is an issue all health care systems are facing across the country,” M Health Fairview, which operates St. Joseph Hospital, said in a statement that thanked local organizations for mask donations.

The mask problem will only worsen, some fear. “We have the supplies right now,” said Bobbie Bertram, a nurse practitioner for the trauma service team at CentraCare St. Cloud Hospital. “But we’re going to deplete the stockpile. When we hit the peak, we need to make sure we have the supplies to make us safe.”

On March 10, the CDC relaxed its guidelines for protective medical equipment use, saying the supply chain cannot meet demand. Surgical masks, like the ones that Spike and her colleagues have been using, are now considered “an acceptable alternative,” according to health officials. And Vice President Mike Pence said new legislation will ramp up mask production immediately, with health care workers receiving tens of millions more each month.

In the meantime, Spike and other nurses are doing what they can with what they have even as they try every avenue to get more masks. But Spike worries it’s already too late for her and her colleagues, who have been exposed to COVID-19 since the hospital admitted its first patient last weekend.

Spike’s whole family is quarantined and she is practicing social distancing in her own home. Her 6-year-old daughter, Maggie, has asthma so severe that every cold or virus turns into pneumonia. Just last month, on a family vacation, Maggie ended up in the emergency room. Spike and her husband give the child nebulizer treatments multiple times a day. In the face of this pandemic, Maggie keeps asking why she can’t snuggle and watch television with her mother.

When Spike ends a shift, she changes clothes at work, and as soon as she gets home she puts her scrubs on hot in the laundry and takes a shower. Her husband has become the primary parent.

Some colleagues have taken more extreme measures, like one nurse, the sole breadwinner in his family, who is living in a tent in his garage.

In recent days, Spike has thought about not going to work to protect herself and her family. But for her, nursing is a calling — the only job she’s wanted to do since she was a young girl — and she loves her work and colleagues.

She grew up chronically ill in New Hope. A disorder called cyclic vomiting syndrome started at age 5, and was at its worst between age 9 and 12, keeping her hospitalized for months at a time. She was fed through a tube. The family traveled all over the Midwest to get a diagnosis. During that time, she had mean nurses and she had good nurses.

“And ever since I was 9 years old, I wanted to be a nurse, because I wanted to be one of the good ones,” she said.

Spike has read about health care workers in China who died from the virus because they weren’t protected. She’s read about American health care workers who have been infected. When she’s gone to work this week, she’s felt it in her chest: anxiety, and fear. She’s angry at a lack of forethought and planning — by the government, by the health care industry — to not have a larger stockpile. She’s most worried about exposing her family to the virus. Spike signed up to be a nurse, she said; her family did not.

But still, on Saturday morning, she’ll get in her car with her mask stockpile, drive to St. Paul and walk into the COVID-19 unit for her 7 a.m. shift.

“There’s a sense of duty, a sense of guilt when you’re not there,” Spike said. “We take an oath to do good and take care of people, and I will honor that, whether I’m covered or not. Because that’s the only thing I know how to do.”