A court in Singapore sentenced a doctor to 18 months in jail after finding him responsible for the death of a 31-year-old woman who suffered a cardiac arrest during an aesthetic procedure in 2019.

Dr Chan Bingyi, 38, was convicted of committing a negligent act not amounting to culpable homicide over the death of Lau Li Ting, a property agent who died five days after taking chelation treatment at Revival Medical & Aesthetics Centre in Bras Basah.

The court heard that Chan had intravenously administered ethylenediaminetetraacetic acid, or EDTA, a chemical generally used to treat heavy metal poisoning or dangerously high calcium levels though there was no medical need for it.

He then “wilfully” withheld that EDTA had been administered from Lau’s family, paramedics and treating doctors, the judge said, calling it “deplorable conduct” carried out for “self-preservation”.

The court also learned that Chan did not keep proper clinical notes or items used during the procedure.

Prosecutors said the substance was administered at “too high a concentration and too quickly”, causing Lau to develop EDTA toxicity. This led to a cardiac arrest, and eventually her death in a local hospital on 13 March 2019.

Deputy public prosecutors Thaddeus Tan and Jiang Ke Yue noted that chelation treatment involved the use of EDTA “to bind to metallic ions and extract them from the body.

“Disodium EDTA, which the accused used in this case, binds preferentially to calcium, a mechanism that makes it inherently dangerous,” the prosecutors explained. “This is because ionic calcium plays a critical role in essential bodily functions including neurotransmission and neuromuscular function.”

When EDTA depletes calcium levels, the patient can suffer impaired muscle function and even heart failure.

According to court documents, Lau visited the clinic at Esplanade Xchange on 8 March 2019 asking for an aesthetic procedure. Chan later told the health ministry that she wanted to reduce the fine lines on her forehead. He claimed that the patient then asked whether he provided chelation treatment, which she had previously undergone with another doctor.

“I told her that she was not suitable to undergo this ‘chelation’ treatment, but she insisted, as she had undergone this treatment,” he said, “and she was happy with the outcome.”

Chan later described how he prepared the intravenous treatment by adding sodium bicarbonate and EDTA into a saline drip before monitoring Lau during the procedure.

“I was monitoring the drip rate and speed to time it for at least an hour’s duration and at the same time monitoring side-effects, like burn sensation and nausea. Ms Lau was talking about her plan for the day,” he recalled, according to the court records.

“After about five minutes, Ms Lau suddenly stopped talking. I tried to speak to her, but there was no response. I checked on her and realised that she was having a seizure.”

The doctor said he stopped the drip immediately and attempted emergency intervention while staff brought in resuscitation equipment.

When paramedics arrived, though, Lau was reportedly not breathing and had no detectable pulse.

During the trial, however, Chan denied administering EDTA. He claimed his statements to the health ministry soon after the incident were unreliable because of his “poor mental state” at the time, and a “misunderstanding of the question”.

Prosecutors rejected that explanation.

“It is baffling that a well-educated doctor with a degree and multiple graduate diplomas would claim to misunderstand this question,” they said.

The defence argued Lau’s collapse could have been caused by other substances, pointing to “400g of yellowish pill residue” found in her stomach during the autopsy.

Professor Johan Duflou, a defence witness, had earlier suggested the residue could have come from slimming products or supplements.

But prosecutors said there was “no evidence that the deceased was consuming such slimming products prior to her collapse”.

Senior district judge Ong Hian Sun ruled that Chan’s actions were the “sole and direct cause” of Lau’s death.

The judge said that Chan had known the risks associated with chelation therapy, including death, yet failed to ensure Lau was a suitable candidate or take necessary safeguards during the procedure.

Chan, who remains registered as a medical practitioner in the country, is expected to appeal both his conviction and sentence.