What is the test for objecting to expert testimony in a medical malpractice case?

The holdings of Sanchez restrict the use of hearsay in expert witness testimony. Defendant seeks reversal in light of those holdings, but the People contend his claims were forfeited by a failure to object below. The point of contention is whether objecting would have been a futile act. (See People v. Sandoval (2007) 41 Cal.4th 825, 837, fn. 4 ["An objection in the trial court is not required if it would have been futile"].)