Over the past four months, Amber Retzloff, a critical care nurse in Florida, requested to work 50 specific 12-hour shifts. But over half the time, she says her hospital’s Palantir-powered scheduling software assigned her to different shifts, often putting her on back-to-back-to-back days and leaving her mentally drained. Retzloff doesn’t expect to always get the slots she wants, but by her count the tool does a far worse job honoring her preferences than managers did when they assigned shifts by hand.

Retzloff’s experience mirrors that of other nurses across HCA Healthcare, the largest hospital chain in the US. Since 2023, HCA has rolled out an AI scheduling tool it co-developed with Palantir called Timpani at roughly 130 of its 190 locations. Retzloff’s hospital adopted it nearly two years ago.

“No one is happy with Timpani,” says Retzloff, echoing what five nurses at other locations reported in interviews with WIRED. “Everyone complains all the time.” Other purported HCA workers have expressed similar gripes about the tool on platforms like Reddit.

The nurses who spoke with WIRED allege that Timpani has potentially harmed patients by causing care teams to be understaffed, imbalanced, and exhausted. Operating with minimal oversight, they say the tool routinely schedules too few nurses or not enough experienced veterans during shifts, particularly on Sundays. It also frequently ignores nurses’ stated preferences for spacing out shifts, working nights and weekends, or taking specific days off.

As a result, nurses say they are being forced to waste more time trying to trade shifts or appeal their schedules than prior to the arrival of the software. They also believe colleagues are increasingly calling out, using paid or unpaid time to skip assignments, though doing so more than a few times annually puts them at risk of termination.

Retzloff, 34, a National Nurses United labor union leader with a decade of bedside experience, recalls recent shifts where all four of her colleagues were junior. Because she was the only senior nurse working, Retzloff says she had to delay care for the sickest patients to guide the novices through milder cases.

HCA is “letting AI dictate,” Retzloff says. “We are overriding clinical judgment and the human-to-human piece of health care with an app.”

Previously, managers handled scheduling manually and generally consulted nurses well in advance when overriding requests. With Timpani, nurses report needing to make alternative arrangements on shorter notice and an increase in temporary reassignments to different teams. “I can’t remember any issues before,” says a non-union nurse in Texas who asked to remain anonymous out of fear of retaliation from HCA. “Everything came out on time.”