Some 4,800 nurses working at Allina Health’s four hospitals walked off the job early Sunday morning, handing off their patients to 1,400 temps hired to carry on in their stead.

The transition was rushed and uncoordinated in some units, the nurses say. Though Allina ordered everyone to be clocked out by 7 a.m., managers were slow to bring in the reinforcements. Nurses stayed late to avoid abandoning patients. Surgeries were cancelled and rescheduled.

Irena Tabakova is a nurse of 10 years who works in the cardiovascular intensive care unit. When she signed off Sunday morning, she was supposed to brief a replacement nurse — face to face — about every patient under her care. Instead, she was told to simply report to her supervisor.

She hopes the message was eventually relayed to someone who is actually working directly with the patients.

"It was very hard to leave the patients today," Tabakova says. "I had tears almost come to my eyes ... We have to take care of ourselves too, so that we can take care of the patients."

About two-thirds of Allina nurses voted to strike after months of contract negotiations ended in a bitter deadlock over the nurses' health insurance.

Most Allina nurses are currently enrolled in one of several hard-fought union health plans, for which they voluntarily sacrificed wage increases in previous years. Allina wants to get rid of all those other options and move nurses to the Allina corporate plan, saving $10 million. Nurses would have to find new doctors for themselves and their families and pay more out of pocket for anything more serious than basic care.

"There were a couple years where we got a zero percent raise, a one percent raise, because we thought it was more important to have our insurance," says Loellen Grzeskowiak, a nurse of 30 years. "Nurses know how important health insurance is. We see it every day, the unexpected that happens, and we need to know that insurance is there."

For its part, Allina held a press conference Sunday afternoon to say that things are running smoothly throughout its hospital system despite being short-staffed by about 3,400 nurses. From the start of the strike to about 2 p.m. Sunday, Allina's four hospitals delivered 12 babies and helped 67 ER patients, said CEO Penny Wheeler.

"While I’m incredibly proud of the way we have come together in support of our patients, I’m also frustrated that it has come to this. Let me be clear: Allina Health is eager to get back to the negotiating table with the union. We believe we can solve these issues through a constructive dialog."

Nurses have accused their bosses of stonewalling on other important contract issues like staffing ratios and workplace violence because of the impasse on healthcare. Wheeler blamed the union for refusing to cave on the health plans.

"The union has said we have been unwilling to discuss issues that are important to them," Wheeler said. "That is not true. Through 13 bargaining sessions beginning in February, we have brought forward proposals related to staffing, workplace safety and other issues."

On staffing, Allina proposes using analytics software, Health Catalyst, to objectively predict how many nurses would be needed for each unit based on the number of patients. Allina signed a 10-year, $100 million contract with Health Catalyst in January.

Allina CEO Wheeler also sits on the Health Catalyst board of directors.

Nurses are skeptical of the apparent conflict of interest. They also doubt that a computer would be able to replace nurses' judgment and experience when it comes to what patients need in real time.

"If there are not enough nurses, call lights don't get answered, pain meds aren't given on time, you don't realize changes in critical things in patients, so we don't believe it's safe for patients," Grzeskowiak says.

As for workplace safety, she says that nurses shared stories around the negotiating table of being kicked, hit, spit on, and scratched every day. As a result of certain illnesses, patients who aren't thinking clearly might lash out in ways they normally wouldn't. Some family members take their frustrations out on nurses when things don't go well.

"Nurses were talking about all these recent experiences they had. We were talking, and it was like they didn't have a response for us," Grzeskowiak says.

Nurses are prepared strike for one week.