A massive health care strike over wages and staff shortages is heading into its final day without a deal between industry giant Kaiser Permanente and the unions representing the 75,000 workers who picketed this week. The three-day strike will officially end on Saturday morning. Workers are scheduled to return to their jobs in Kaiser’s hospitals and clinics that serve nearly 13 million Americans. The two sides did not have any bargaining sessions scheduled after concluding their talks midday Wednesday. Union officials and Kaiser representatives say they both want an agreement.