The Hoa Binh People's Court in northern Vietnam on Wednesday accepted parts of an appeal made by Dr Hoang Cong Luong, a nephrologist at Hoa Binh General Hospital who was charged with "involuntary manslaughter."

Two hospital managers, charged with "lacking responsibility and causing serious consequences," got their sentences reduced by six months. The director of a company responsible for cleaning the water filter system for the hospital's dialysis machines had his jail term commuted to suspended sentence.

The court said Luong was a certified doctor trained in kidney dialysis and in line with regulation, he did not have to take responsibility for the source of water used for the process.

However, as one well aware of the importance of the water filter system for dialysis, he did not check if the system was ready to use though he had known it had just been repaired, the court said.

On May 29, 2017, 18 patients were undergoing kidney dialysis treatment at the hospital, 80 kilometers (50 miles) southwest of Hanoi. After 45 minutes some reported nausea, abdominal pain and shortness of breath. Eventually, nine died.

Minister of Health Nguyen Thi Kim Tien quickly pronounced the incident the "most serious" healthcare disaster in Vietnam in many years.

Hoa Binh police concluded that the water used in the dialysis treatment was the cause of the incident, as concentrations of fluoride in the water were up to 260 times above the permitted level.

In January, the first-instance court said Luong had been "negligent, confident in his own experience and performed duty out of habit."

The doctor then said he was "shocked" at the sentence of three and a half years and that he would "appeal against the conviction at all costs because I’m innocent."

The appeals court said Truong Quy Duong, director of Hoa Binh hospital, 80 kilometers (50 miles) southwest of Hanoi, had to take full responsibility, and his original sentence of two and a half years was upheld.

Earlier, the Ministry of Health wrote to the People's Court and People's Procuracy of Hoa Binh, saying the charge for doctor Luong was "forced, not suitable, and even unjust."

"It is inappropriate to punish doctor Luong for 'involuntary manslaughter' because the elements are not there to constitute a crime," the ministry said. It had also warned that in case the appeals court sticks to the original decision, it would set an extremely dangerous precedent, causing insecurity among all doctors and medical staff in the country.