Facts
- Sandra Carlson drove through a stop sign and blinking red light at an intersection in Spencer, Massachusetts, and struck the passenger side of another vehicle.
- The passenger, Carol Suprenant, had severe chronic obstructive pulmonary disease and used supplemental oxygen; she had expressed that she did not want to be kept alive on a ventilator.
- The collision caused Suprenant multiple chest wall fractures (ribs and sternum) and a lung contusion.
- Suprenant was hospitalized, intubated, and placed on a ventilator.
- Suprenant requested discontinuation of the ventilator and was removed from intensive care; she later agreed to re-intubation as breathing worsened.
- When her kidneys began to fail, Suprenant again chose to discontinue the ventilator and decline dialysis after being advised death was likely without them and that continued treatment offered a reasonable chance of survival.
- Suprenant died several hours after the ventilator was removed, from respiratory failure.
- A treating physician testified that, but for the crash injuries, Suprenant likely would not have needed a ventilator and would not have faced the decision whether to accept life-sustaining treatment.
Issues
- Whether Carlson’s negligent operation of a motor vehicle was a proximate cause of Suprenant’s death when Suprenant later refused life-sustaining treatment that likely would have prolonged her life.
- Whether the trial court’s intervening/superseding-cause instructions were inadequate, creating a substantial risk of a miscarriage of justice.
Decision
- The Supreme Judicial Court affirmed Carlson’s conviction for motor-vehicle homicide by negligent operation.
- The court held the evidence permitted a finding beyond a reasonable doubt that Carlson’s negligence was a proximate cause of death.
- The victim’s refusal of life support was not, as a matter of law, a superseding cause that relieved Carlson of criminal liability.
- The jury instructions, considered as a whole, adequately conveyed causation and intervening-cause concepts; any arguable imprecision did not create a substantial risk of a miscarriage of justice.
Legal Principles
- A defendant is a legal cause of death when her conduct, in a natural and continuous sequence, produces death and death would not have occurred without it.
- An intervening event breaks the causal chain only if it is a superseding cause that is independent of the defendant’s conduct and sufficiently extraordinary and unforeseeable to relieve criminal liability.
- A defendant takes the victim as found; preexisting vulnerabilities do not bar liability when the defendant’s conduct sets in motion the chain leading to death.
- A competent victim’s decision to refuse or discontinue medical treatment, including life-sustaining treatment, ordinarily is a foreseeable consequence of the condition created by the defendant and does not itself sever proximate causation.
Conclusion
The court concluded that negligent driving that caused injuries leading to ventilator dependence could be found a proximate cause of death even when the competent victim later refused life-sustaining care, because that decision did not constitute an independent, extraordinary superseding cause.