The San Diego County Medical Examiner’s Office said that 9-year-old Silvanna Moreno passed away on March 18 this year just hours after being placed under anesthesia for dental surgery at Dreamtime Dentistry in Vista, California.
She had been complaining of a toothache

The girl first complained of a toothache in October 2024 and was referred for dental surgery after a consultation, according to the autopsy report.
Dreamtime Dentistry’s Dr Ryan Watkins released a statement obtained by People, saying, “The patient was referred to our office for dental treatment under general anesthesia due to her young age and acute situational anxiety.”
Silvanna developed a fever

The autopsy report also stated that Silvanna developed a 101-degree fever and ‘complained of a headache’ the next day before the procedure took place.
The report stated that the girl was described as ’out of it’ after the surgery, but later left with her mother ‘after she was awake with stable vital signs’.
Records from the dentistry were examined

“Dreamtime Dentistry’s records show that the patient’s mother completed and signed a pre-operative check-in form indicating ‘No’ when asked if the patient was sick,” said a spokesperson for the dentist.
“Dr. Watkins follows standard protocol. Had he been informed of any recent fever or illness, especially within 24 hours of the procedure, it would have been rescheduled until the patient was healthy.”
The dentist office said she went through review

Dr Watkins said that the girl went through a ‘thorough review of her medical and dental history’ before undergoing the surgery.
Silvanna fell asleep in the car on the way back from the dentist and then once more at home, but she remained ‘unresponsive’ which prompted her family to call 911 and rush her to Rady Children’s Hospital.
She passed away at the hospital

The medical examiner’s report said that at the hospital, the girl was ‘provided additional medications, ongoing chest compressions, and was intubated but her condition did not improve’.
She was sadly pronounced dead at 5:44pm local time after that.
Her cause of death was listed as methemoglobinemia

Silvanna’s cause of death was listed as ‘methemoglobinemia in the setting of recent nitrous oxide administration’.
According to Cleveland Clinic, methemoglobinemia is a rare blood disorder which affects the performance of red blood cells in their transportation of oxygen throughout the body.
The doctor explained her condition

Dr Watkinds claimed that Silvanna ‘never exhibited’ signs of the condition, adding, “In patients experiencing this condition, there is typically a refractory hypoxemia, which means that even when breathing 100% oxygen with no airway obstruction, pulse oximetry readings will show abnormally low levels in the 80s instead of the normal high 90s.”
A GoFundMe was made for her

A GoFundMe campaign was set up in the wake of the girl’s tragic death, reading, “It is with heavy hearts that we share the tragic loss of 9-year-old Silvanna Moreno.”
“Silvanna was a bright and loving third grader at Sherman Elementary School in San Diego. She was the sunshine in every room she entered, always greeting staff and classmates with a big smile and an even bigger hug.”