A growing number of hospitals around the U.S. have canceled or delayed some planned medical procedures to preserve staff and beds for a surging number of Americans sick with COVID-19.

Conditions remain especially acute in the Midwest and West. From Illinois to Idaho, health systems are limiting non-emergency surgeries as the pandemic’s strain on personnel grows. Putting off planned procedures that patients can defer safely is one of the few levers hospitals have to adjust their capacity as the virus spreads unchecked.

“COVID is like a sink: The faucet is on full blast, and we only have so much ability to open the drain,” said Eric Borgerding, chief executive officer of the Wisconsin Hospital Association.

All Wisconsin’s major hospital systems are postponing some non-emergency care, Borgerding said. Some have set up beds in ambulance bays, hallways and waiting rooms. Hundreds of patients are stuck in hospitals because COVID-stricken nursing homes can’t receive them, he said.

Hospitals have worked with regulators to add around 1,400 beds statewide. “Even with that, the sink is overflowing,” Borgerding said.

Surgeries scheduled in advance are often considered elective, but delaying operations to replace joints or remove tumors can harm patients. These procedures are also typically among the most profitable for hospitals.

Medical staff attending to COVID-19 patients wear protective equipment in a unit dedicated to treatment of the coronavirus at UW Health in Madison, Wis., on Nov. 5. Conditions in the nation’s hospitals are deteriorating by the day as the coronavirus rages through the country at an unrelenting pace. John Hart/Wisconsin State Journal via AP

In the spring, health-care providers halted most non-urgent in-person care on orders from state and federal authorities. Medical supplies were running short, and the U.S. feared a national crush of COVID patients filling emergency wards and intensive-care units.

Much of the country averted that in the pandemic’s first weeks, leaving some hospitals strangely quiet. Even the usual stream of patients with urgent needs like strokes and heart attacks seemed to dwindle.

Since spring, hospitals have learned how to treat COVID patients while safely resuming other care. They’ve encouraged patients spooked by the virus to return for other needed care. Now, even without orders from states, some facilities are dialing back what they can.

As of Nov. 23, more than 85,000 patients were hospitalized with COVID, according to data compiled by COVID Tracking Project. The U.S. is recording more than a million new cases per week, prompting the Centers for Disease Control to tell Americans not to travel for Thanksgiving.

On Tuesday, groups representing surgeons, nurses, anesthesiologists and hospitals released principles for continuing surgery during the pandemic that acknowledged “health care facilities are again struggling to meet the needs of patients presenting for essential surgery.”

There are no comprehensive data on suspensions of elective care. A tally by the trade publication Becker’s Hospital Review found 66 hospitals and health systems delaying some procedures.

More than 1,000 hospitals, or over 20% of the nation’s total, reported a critical staffing shortage on Nov. 22, according to federal data.

The biggest factor limiting hospital capacity isn’t physical bed space, protective gear or ventilators. It’s the personnel needed to care for patients.

In Minnesota, at least 6,800 patient care staff were out for COVID-related reasons two weeks ago, and that increased by 11% the following week, according to the state’s hospital association. That counts workers ill themselves, in quarantine after exposure or caring for someone else.

Hospitals monitor capacity hour-by-hour, balancing the available staff and beds, with the flow of emergencies like traumas, heart attacks and strokes, said Rahul Koranne, CEO of the Minnesota Hospital Association.

They want to avoid the negative health effects of deferring care. Clinicians saw patients whose conditions deteriorated following the spring shutdowns. “Their tumors had grown, their joints were in much worse shape, their hernias had gotten worse,” Koranne said.

But performing those procedures depends on having the nurses, doctors, technicians and other staff to do it. South Dakota-based Sanford Health, which operates 46 hospitals, has idled some operating rooms to free up workers.

Twice as many staff were out in October compared to typical levels, said Allison Suttle, Sanford’s chief medical officer. With COVID admissions increasing, “you need more staff and we’re already behind,” she said.

Hospitals around the country have taken similar steps. St. Luke’s, a major hospital system in Idaho, said it won’t schedule new procedures that require overnight stay until January. Some of its hospitals canceled cases already scheduled through the end of November. Mayo Clinic has reduced procedures in many of its Midwest hospitals, and UW Medicine in Seattle is actively reaching out to patients who can safely postpone non-urgent surgeries.

At Advocate Aurora Health, a large system in Illinois and Wisconsin, some elective surgeries in some areas have been cut back by as much as 50%, said Robert Citronberg, executive medical director of infectious disease and prevention. Two large publicly traded hospital systems, HCA Healthcare Inc. and Tenet Healthcare Corp., said last week that some procedures were being deferred in El Paso, Texas, but not in other markets.

If COVID forces broad reductions in planned procedures, it could have ripple effects across the health-care business, including for device manufacturers and insurers.

Medtronic PLC CEO Geoff Martha said he’s optimistic that hospitals won’t close down wholesale during this surge as they did early in the outbreak. And people aren’t as terrified of the virus as they were early on. That should reduce the number of critically ill patients who skip essential care.

Still, Martha acknowledged a concern that the sheer number of COVID patients could overwhelm hospitals and derail elective procedures. “It becomes a real estate issue within a hospital that would impact obviously elective cases,” he said. “In some cases, we’re seeing that we’re getting closer to that level of capacity, so that’s what we’re watching.”

Michael Neidorff, CEO of insurer Centene Corp, predicted fewer visits for procedures and even emergencies as COVID rates increase. “Colonoscopies and endoscopies, things like that, people don’t need lots of reasons, if a doctor says: ‘How do you feel about delaying it?'” he said at a conference last week.