A managed care says it will refuse to pay hospitals when the hospitals make mistakes that seriously threaten patient safety.

Aetna Inc., Hartford, is adding language to its hospital contracts that frees it from responsibility for paying for the kinds of mistakes on a list of “never events” developed by the National Quality Forum, Washington.

The mistakes include incidents in which hospitals perform surgery on the wrong body part of a patient or leave foreign objects inside the patient’s body after surgery.

Hospitals in which such errors occur must report them to the appropriate authorities, take action to prevent similar events from occurring in the future, waive all costs related to the event, and apologize to the patient or the patients family, Aetna says.