Atlanta-based Grady Memorial Hospital officials approved a plan that would close its outpatient dialysis unit and shift the patients to a private care provider. The Grady board instructed management to draft a contract with Fresenius, a major provider of dialysis services in the United States, with about 60 centers in metro Atlanta. The plan would close the existing clinic at Grady and shift its 90 patients to a new location by Sept. 14. The financial burden on the patients would not change.