From the Middle District of Pennsylvania:
In Pennsylvania, an individual who sustains injury in a motor vehicle collision that is aggravated by subsequent medical negligence may recover damages for both injuries either from the driver exclusively or from the driver and the negligent medical practitioner in tandem. See RESTATEMENT (SECOND) TORTS § 457 (s1965) [hereinafter "RESTATEMENT"]; Smialek v. Chrysler Motors Corp., 290 Pa. Super. 496, 434 A.2d 1253, 1258 (Pa. Super. Ct. 1981) (stating that "the original tortfeasor[ in an automobile collision] is . . . fully responsible . . . for the negligent manner in which a physician or surgeon treats the case"). The plaintiff may recover all damages solely from the negligent driver because subsequent faulty treatment is deemed to be a foreseeable consequence of the automobile accidence. See RESTATEMENT § 457 cmt. a ("[D]amages assessable against [a negligent driver] include not only the injury originally caused by the [driver’s] negligence but also the harm resulting from the manner in which the medical, surgical, or hospital services are rendered"); Boggavarapu v. Ponist, 518 Pa. 162, 542 A.2d 516, 517 (Pa. 1988).
However, if the plaintiff sues both the driver and the physician, liability should be allocated according to each tortfeasor’s separate negligence. 1 See Frazier v. Harley Davidson Motor Co., 109 F.R.D. 293, 295-96 (W.D. Pa. 1985) (stating that negligent motorists and subsequently negligent physicians commit separately identifiable acts of negligent); Smith v. Pulcinella, 440 Pa. Super. 525, 656 A.2d 494, 497 (Pa. Super Ct. 1995); Harka v. Nabati, 337 Pa. Super. 617, 487 A.2d 432, 434 (Pa. Super Ct. 1985) (quoting Voyles v. Corwin, 295 Pa. Super. 126, 441 A.2d 381, 383 (Pa. Super. Ct. 1982)) ("[T]o the extent that the acts of the original tortfeasor and those of the physician are capable of separation, the damages should be apportioned accordingly."). The court determines as a matter of law whether injuries are capable of apportionment; however, the jury determines the value of the claim against each defendant. Voyles, 441 A.2d at 383.
Trout v. Milton S. Hershey Med. Ctr., 2008 U.S. Dist. LEXIS 65553 (emphasis added).
If the medical malpractice causes a catastrophic injury, there are very few situations in which you would want to proceed only against the car driver, not least because they likely have far less available insurance than the medical provider. Indeed, in this case the plaintiff’s leg became necrotic and had to be amputated allegedly due to medical malpractice, an injury that, when combined with the accident itself, likely exceeds the insurance coverage of most drivers.
Then again, if neither the auto accident nor the medical malpractice was catastrophic, and the damages are within the coverage limits, the action can be substantially simplified by proceeding only against the car driver. You will still need expert medical testimony, but you might not get nearly the same fight as you would going against the medical provider directly. You might also have more settlement leverage against the car driver’s insurance company because they run the risk of eating all of the damages at trial.