The latest upheaval in the U.S. bond market is threatening two major Minnesota hospital chains with serious financial pain. Park Nicollet Health Care Services will pay an extra $86,000 in interest on its outstanding debt in one week alone. And if Fairview Health Services can't refinance its $450 million in debt, the chain of hospitals and clinics could see a jump in its interest rates that would cost it an extra $3.5 million a month.