Akron-based Summa Health System said Wednesday that it is exploring a partnership with a larger, nonprofit health system as it prepares for changes in the way hospitals will be reimbursed by federal and commercial insurers. Summa, which has 11,000 employees at eight owned or affiliated hospitals, is one of the largest health systems in Northeast Ohio with $1.6 billion in revenue. Ideally, Strauss said, a partner would help the system better serve patients and prepare for the health industry shift from being paid for each individual service provided to reimbursement based on the kind of care given.