Managing a hospital or health care facility almost always includes working under a relatively large amount of uncertainty. Hospitals, physicians and other providers of care rarely know for sure about such things as what they will be paid for the care they provide or what their patient outcomes will be like.

But in the last few weeks it's felt like we've entered one of those phases where the stakes are even higher and the outlook even less certain. The news coming out of the Centers for Medicare & Medicaid Services that nine of 32 participants were dropping out of the Medicare Pioneer Accountable Care Organization program has got to have others working on ACOs feeling a little nervous. Certainly, it is encouraging that 13 of the ACOs saved money, a sign that the program can work, but having 28 percent drop out after a year is not exactly a ringing endorsement for the care and reimbursement model.

Similarly, with enrollment in the new health insurance marketplaces set to start for 2014 on Oct. 1, and Medicaid expansion starting next year in at least 24 states, health care administrators are going to have more to be concerned about. The influx of patients could stress hospitals' ability to provide care, particularly if the subsequent reimbursement is at money-losing levels.

I expect there to be be a lot of discussion and problem-solving regarding those matters at the upcoming Health Forum-American Hospital Association Leadership Summit this week in San Diego.

Most of the sessions at the Summit are going to cover ACOs, clinical integration, population health or some aspect of one or more of those subjects. Those sessions should lead to some interesting presentations and Q&A sessions, even if there turns out to be more Q's than A's.

I'm also looking forward to a keynote by Massachusetts gubernatorial candidate Don Berwick, M.D., former head of both the CMS and the Institute for Healthcare Improvement. I'm wondering if his time on the campaign trail has altered his view of what health care should be.

Those interested in the Summit's happenings can check out H&HN Daily, where we'll be blogging and conducting video interviews Thursday and Friday. Also keep an eye out for video interviews with Berwick and with AHA President and CEO Rich Umbdenstock. Plus, my colleague Matt Weinstock and I will both be tweeting from the Summit under the handles @PGBarr and @HHNmag. Summit-related tweets will include the hashtag #HFSummit13.

Keynoters on the schedule include futurist and researcher Eric Topol, M.D., the Pulitzer Prize-winning biographer of Thomas Jefferson, Jon Meacham, and the needs-no-introduction speaker Magic Johnson.

That's a trio I'd like to sit down with over lunch — if I can make it happen, I'll let you know.