Cause of death revealed for 9-year-old who died after dental procedure under anesthesia
The cause of death of the 9-year-old girl who passed away after being placed under anesthesia for a dental procedure has been disclosed.
According to an autopsy report obtained by PEOPLE, Silvanna Moreno died due to methemoglobinemia in the setting of recent nitrous oxide administration.
Methemoglobinemia is a rare condition that "affects how red blood cells deliver oxygen throughout your body," per Cleveland Clinic.
The autopsy report by the San Diego County Medical Examiner's Office stated that nitrous oxide was one of the anesthetics she had during the surgery.
Silvanna underwent the dental procedure in March at Dreamtime Dentistry in Vista, California.
She started complaining of tooth pain in October 2024 and eventually agreed to have it removed via surgery, the media outlet reported.
Silvana had fever but she felt better after taking Tylenol ahead of her procedure. She got a headache "without appearing distressed" on the day of her surgery, so it pushed through as planned. She was placed under anesthesia for the procedure that lasted for three hours.
The young girl was moved to a recovery room upon waking up and was later discharged. Dreamtime's dentist Ryan Watkins noted she was, at the time, "in stable condition—awake, with stable vital signs and protective reflexes intact—into her mother’s care, following our standard post-anesthesia protocols."
Authorities said that she slept in the car and snored heavily on the way home. She was then transitioned into her bed, where she stayed asleep for more than an hour.
After noticing that her snoring "got noticeably quieter and slower," her grandmother decided to check her heart rate and saw that she was unresponsive in the second reading.
Her relative called 911 late afternoon and administered CPR while waiting for the medical staff. Silvana was rushed to Rady's Children's Hospital, where she was declared dead.
Watkins, in a new statement, noted that Silvana "never exhibited" warning signs throughout the surgery.
He stressed that they made sure to look through her medical and dental history before the procedure and "maintained our standard of care with continuous monitoring by me."
Watkins said Dreamtime Dentistry is now looking into the matter internally.
"We are committed to learning from this tragic event and will implement any additional safety measures that may help prevent such occurrences in the future. We extend our deepest condolences to Silvanna's family and ask for continued respect for their privacy during this time of grief," he continued.
