Former Kailua dentist Lilly Geyer told a state jury Thursday that she did everything she could to save 3-year-old Finley Boyle.

Boyle died in January 2014 of an infection, a month after going into cardiac arrest at Geyer’s Island Dentistry for Children where her mother had taken her to have baby root canals performed on several of her teeth.

Geyer, 41, is on trial for manslaughter and assault.

She said Boyle had large cavities on four lower teeth and smaller cavities on two upper teeth. Geyer said she had recommended to Boyle’s mother, Ashley Puleo, that the girl have the required dental work done in Boston, where Puleo was planning to move with Finley. But, she said, Puleo insisted on having all of the work done in one session before leaving for the mainland because she was involved in a bitter divorce and custody fight with Boyle’s father.

Geyer said she started on the upper teeth and was about to work on the lower ones when Boyle’s oxygen level started dropping. She said she got certified for pediatric advanced life support every two years and did everything she was trained to do.

She said she had not yet started CPR by the time pediatrician Dr. Brit Reis arrived from across the hall to help because Boyle still had a pulse. Geyer demonstrated for the jury how she was able to provide Boyle bursts of oxygen by squeezing the bag reservoir on the tank that was providing Boyle oxygen. She also said she had sealed the oxygen mask around Boyle’s mouth and pinched the girl’s nose shut.

Geyer said she was the one who directed one of her dental assistants to get Reis for help and who directed her other assistant to call 911.

“Every single person that was involved tried their best. We all did,” she said.

She said she decided to shut down her practice after the Dec. 3, 2013, incident because “there would be no way for any of us involved in that situation to practice ever again. It was the most tragic and devastating event that we’ve been through, and it was heartbreaking.”

Geyer said she went over everything to try to find out what happened and even checked with her pharmacy if there was anything wrong with the sedatives. She said it was only after she read all of the medical records following her indictment in 2016 that she realized what happened.

On Nov. 7, 2013, just hours before Puleo scheduled the Dec. 3 appointment for her daughter, another doctor had diagnosed Boyle with an upper respiratory infection that Puleo failed to disclose.

“When that came up, my heart sank (because) I knew that was the cause,” Geyer said.

She said she would have delayed Boyle’s appointment had she known about the diagnosis.

Defense expert witnesses have testified that lingering effects of the infection caused Boyle’s vocal cords to slam shut under sedation, cutting off her supply of air.

State expert witnesses said Boyle showed no sign of the infection and that she stopped breathing because of the sedative drugs given to her.

The state says Geyer caused Boyle’s death by directing one of her dental assistants to administer a cocktail of sedatives that caused Boyle to stop breathing. Deputy Attorney General Michael Parrish says Geyer also caused Boyle’s death as an accomplice to the dental assistant in failing to get Boyle medical help and, in the same manner, caused the brain damage that put Boyle in a coma from which the girl never recovered.

The dental assistant, Kathleen Cacal, is not charged with any crimes.

Circuit Judge Paul B.K. Wong dismissed Thursday two counts accusing Geyer of distributing, administering or dispensing drugs without a written prescription. Geyer’s lawyers argued that no prescription is needed when the drugs are administered in a doctor’s office.

Parrish had told the jurors in opening statements that Geyer could not distribute, prescribe, administer or dispense drugs on Dec. 3, 2013, because her state license to do so had expired. Her lawyers told the jury that Geyer updated her registration and had it retroactively renewed after the incident.