TORONTO -- Nurse Manpreet Kainth knows every patient being treated under her team's care in Humber River Hospital's intensive care unit

Even with her 16 years of experience, the ever-growing workload and the daily scenes unfolding before her eyes - more acutely ill COVID-19 patients and young people fighting for their lives - weigh heavily on her.

There is no escaping that reality even when she's home with her family, who she tries not to burden with her worries.

"Sometimes when I sleep, I just keep thinking," she says during a short break after her team has intubated another COVID-19 patient struggling to breathe. "Those things are going through my mind and I just want to shut it down, just shut it off for a minute."

Another worry that keeps her up at night is the ICU staffing crunch and her team's high level of turnover at this stage of the third wave of the pandemic.

"The thing is, we are not only taking care of the patients," she says. "We have to take care of our staff. Everybody's burned out."

Severely ill COVID-19 patients are being hospitalized in Ontario in higher numbers than ever, as the province and health-care sector scramble to increase capacity through transfering patients to other hospitals, cancelling non-essential procedures and setting up field units.

As COVID-19 cases continue to soar - 4,250 new infections were reported Sunday, with 741 patients in intensive care - the provincial government has promised to add between 700 and 1,000 additional ICU beds.

"It's fine to add a bed, but not so much if you don't have people that can care for the person in the bed," says Vicki McKenna, president of the Ontario Nurses Association.

She says there is already a shortage of nurses in hospital ICUs and adding more beds will only exacerbate the problem.

"The nurses are going to be further stretched than they already are, and that takes a physical and emotional toll on people when they are placed in these situations," she says.

The nurses McKenna speaks with compare the situation to a battlefield. They are used to having patients die, but the duration of the crisis and their inability to connect with friends and family due to infection risk has pushed nurses to the brink.

"I am worried about staffing," says Raman Rai, manager of ICU at Humber River. "Every single day, every single shift, we wish we had more ICU-trained nurses."

The hospital has redeployed nurses from other units as well as nursing students to support ICU staff, but those with critical-care certificates are in short supply.

A year into the pandemic, Rai says burnout is taking a toll on staff.

"The pandemic has been long and hard on the entire ICU team, and we are having nurses who are feeling that they need some time off," she says. "It's been difficult to try to get vacation, and they are a bit overworked."

Rai said she's seeing an increase in people taking sick time, or staff requesting a day away. If it can't be accommodated, they're encouraged to switch shifts.

The team also takes time each shift to decompress and discuss difficult situations they're witnessing - like the recent deaths of two COVID-19 variant patients from the same family, on the same day.

Doctors are feeling the strain, too.

"People get tired all the time, and it has impact on the family as well. You don't have much time to spend with them," says Dr. Ali Ghafouri, an intensivist at Humber River.

"We used to have some vacation time, but now we can't even go, because first of all, nowhere to go. And second of all, they're asking for more help, so we are spending more of our vacation time in the hospital."

On Friday, the government pleaded with other provinces to send urgently needed medical personnel. In a letter to her provincial counterparts, deputy health minister Helen Angus estimated Ontario will be short 4,145 hospital nurses over the next four months.

McKenna says the government's plea for help is "a precarious strategy" as all provinces are facing a surge in cases of COVID-19 variants.

"I'm really worried about our workforce today and what they're facing going into the workplaces right now, and how long they can keep up this pace," she says.

This report by The Canadian Press was first published April 18, 2021.