Mass. Gen. Laws ch. 271 § 44
Except as provided below, no settlement or general release or statement in writing signed by any person confined in a hospital or sanitarium as a patient with reference to any personal injuries for which said person is confined in said hospital or sanitarium shall be admissible in evidence, used or referred to in any manner at the trial of any action to recover damages for personal injuries or consequential damages, so called, resulting therefrom, which statement, settlement or general release was obtained within fifteen days after the injuries were sustained and such settlement or release shall be null and void unless at least five days prior to the obtaining or procuring of such general release or statement such injured party had signified in writing his willingness that such general release or statement be given. This section shall not apply to statements or releases obtained by police officers or inspectors of motor vehicles in the performance of their duty, members of the family of such person or by or on behalf of his attorney. The provisions of this section shall not apply to chapter one hundred and fifty-two.
Mass. Gen. Laws ch. 271, § 44