The principle of "res ipsa loquitur" is a legal doctrine used in certain types of negligence cases where the exact cause of the accident or injury is not known, but it is clear that the injury would not have occurred without negligence. It allows for the presumption of negligence on the part of the defendant, shifting the burden of proof from the plaintiff to the defendant. This means that, instead of the plaintiff having to prove how the defendant was negligent, the situation itself implies negligence, and it becomes the defendant's responsibility to prove they were not negligent.
For example, in a medical malpractice case, if a surgical instrument is left inside a patient after surgery, the principle of res ipsa loquitur could be applied. The very fact that the instrument was left inside the patient suggests negligence, as such an event would not typically occur in the absence of negligence. Thus, the court allows the argument that the situation itself ("The thing speaks for itself") indicates negligence, making it easier for plaintiffs in challenging cases where direct evidence of negligence is hard to obtain.
| Doctrine or argument | Central question | Illustration |
|---|---|---|
| Foreseeability | Was it reasonably predictable that the action could result in harm? | A lower leg pressed against a metal bar in lithotomy; a potassium bolus given over ten minutes rather than an hour |
| Limits of foreseeability | Could the provider have anticipated the reaction at all? | Hodge v. State Hospital — anaphylaxis to Valium in a patient with no recorded allergies; the suit was dismissed |
| "But for" negligence | Would the injury have happened but for one specific action? | An airway fire during tonsillectomy with FiO2 at 70% while bovie cauterization is in use |
| Response as defense | Even if the event was unpredictable, did the provider respond promptly and within the standard of care? | An airway fire at FiO2 of 25% shifts focus to how quickly and effectively it was extinguished |
| Res ipsa loquitur | Does the situation itself imply negligence, shifting the burden to the defendant to prove they were not? | A surgical instrument left inside a patient after surgery |
