Registered nurses at 10 Northern California hospitals operated by Sutter Health are planning a one-day strike Wednesday, involving some 4,500 registered nurses and several hundred respiratory, X-ray and other technicians, union officials said.

The strike is being called by the California Nurses Association, which is protesting demands from Sutter for contract concessions, some of which union representatives say could affect the quality of patient care.

Sutter Health wants nurses to begin paying a portion of the cost of their health care coverage and is seeking elimination of paid sick leave and retiree health plans, implementation of mandatory overtime, and freedom to require nurses to work in hospital areas for which they lack appropriate clinical expertise, union officials said.