## Facts

- Mary Blatz underwent arthroscopic knee surgery and, three days later, awoke with breathing difficulty and severe chest pain.
- Her husband called 911; dispatch notified the sheriff’s office and Allina Health System’s contracted ambulance/paramedic service.
- A sheriff’s deputy arrived first and began CPR.
- Allina’s paramedics became lost and arrived several minutes after the deputy; Blatz was not breathing and had no pulse when they arrived.
- Paramedics provided advanced life support, and Blatz’s heart regained effective pumping shortly thereafter.
- Blatz had a heart attack and suffered severe brain injury from inadequate oxygenation, resulting in permanent cognitive and physical impairments.
- Experts disputed causation: plaintiffs attributed the additional delay to the brain injury; Allina’s experts opined the injury occurred before paramedics arrived.

## Issues

1. Whether the evidence was sufficient to sustain the jury’s findings of negligence and causation.
2. Whether a jury may be instructed that, if it cannot apportion damages between a preexisting medical event and negligent aggravation, it should impose all damages on the defendant.
3. Whether the trial court abused its discretion in evidentiary rulings, denying a mistrial, and denying a post-verdict juror-misconduct inquiry (*Schwartz* hearing).

## Decision

- The Minnesota Court of Appeals affirmed the judgment for Blatz and affirmed denial of JNOV and a new trial.
- The court held that conflicting expert testimony on causation presented a jury question and that the record supported the negligence and causation verdict.
- The court rejected challenges to evidentiary rulings and denial of a mistrial as within the trial court’s discretion.
- The court affirmed denial of a *Schwartz* hearing, finding an insufficient showing to justify that procedure.
- The court stated the trial court’s damages-apportionment instruction misstated Minnesota law to the extent it suggested a single defendant could be liable for all damages solely because damages could not be separated between a preexisting condition and negligent aggravation; the judgment was nonetheless affirmed.

## Legal Principles

- When reasonable jurors could credit a plaintiff’s expert opinion on causation, appellate courts do not reweigh expert conflicts; resolving them is the jury’s role.
- A negligent actor who aggravates a preexisting, non-tortious condition is liable only for the damages caused by the aggravation, not for the full natural course of the underlying condition.
- Joint-and-several concepts applicable to multiple tortfeasors causing an indivisible injury do not automatically extend to a case involving one tortfeasor and a preexisting condition.
- If damages cannot be apportioned between a preexisting condition and negligent aggravation, the inability to apportion does not, by itself, justify imposing all damages on the single defendant; the plaintiff bears the burden to prove the extent of aggravation attributable to the defendant’s negligence.
- A *Schwartz* hearing is an exceptional remedy; it requires a substantial preliminary showing of juror misconduct, and denial is reviewed deferentially.

## Conclusion

The court affirmed a large negligence verdict against an ambulance provider based on evidence that response delay could have caused the patient’s brain injury, while clarifying that a single defendant is not automatically responsible for all damages merely because a jury cannot separate harms due to a preexisting medical event from harms due to negligent aggravation.


Blatz v. Allina Health Sys., 622 N.W.2d 376 (Minn. Ct. App. 2001)