In a tragic case, a nine year old girl has died after undergoing anesthesia. She was supposed to have a dental procedure.

According to the San Diego County Medical Examiner's office, Silvanna Moreno, "underwent dental surgery under anesthesia in Vista and transitioned to a recovery room afterwards. She was later discharged from the facility. She fell asleep during her ride home. Upon arrival, she stayed sleeping and was transitioned into her bed at home. Family checked on her throughout the day to later find her unresponsive in bed and called 911 for emergency services assistance. Responding paramedics contacted the decedent and provided lifesaving measures while transporting her to the Rady Children's Hospital Emergency Department. Upon her arrival, medical staff assumed the provision of lifesaving measures to no avail with death being pronounced." She died on March 18.

The report mentions her cause of death to be "Methemoglobinemia in the setting of recent nitrous oxide administration."

What is Methemoglobinemia?
Methemoglobinemia is a rare but serious blood disorder where your red blood cells can’t carry oxygen. Normally, hemoglobin works like a delivery agent, bringing oxygen to all the tissues in your body. But when someone has methemoglobinemia, a form of hemoglobin called methemoglobin starts to build up. This version can’t carry oxygen like it’s supposed to. It’s like your oxygen delivery system broke down halfway through the job.

Now here’s where it gets tricky: this condition can be genetic (you’re born with it), or it can happen because of exposure to certain drugs, chemicals, or even foods high in nitrates (like well water or too much spinach in babies). People with methemoglobinemia might look blue or gray-ish (a condition called cyanosis), feel short of breath, dizzy, or super tired all the time. In severe cases, it can cause seizures or even death if left untreated.

Yes, anesthesia can sometimes cause methemoglobinemia, especially certain types of local anesthetics like benzocaine, prilocaine, or even lidocaine in high doses. These drugs can trigger the formation of methemoglobin in the blood, making it harder for red blood cells to carry oxygen. This risk is higher in babies, people with genetic susceptibility, or those getting large doses during surgery or dental work. Symptoms might show up shortly after exposure—like bluish skin, shortness of breath, or fatigue.

She was administered anesthesia by Dr. Ryan Watkins. "The patient was referred to our office for dental treatment under general anesthesia due to her young age and acute situational anxiety," he told PEOPLE. "Throughout the procedure, she was continuously monitored by our dentist anesthesiologist ... with no complications observed." New reports say Dr Watkins had faced disciplinary action before.