The national commission that accredits hospitals is investigating how administrators at Sacramento's Mercy General handled a power failure that may have left some surgery patients and their doctors in the dark during a massive storm in January. The Joint Commission made an unannounced visit to the hospital in early February to conduct an "on-site survey" related to the hospital's actions during the storm, which left an estimated 370,000 customers in the Sacramento region without power. The commission can remove accreditation if it finds a hospital violated established standards of care.