The chemicals Péchier added triggered cardiac arrest or haemorrhaging in patients, which required emergency intervention in the operating theatre.
This was often provided by Péchier himself, who was then able to pose as the patient’s saviour.
But in 12 cases he was unable to intervene, or it was too late, and the patient died.
The prosecution argued that Péchier acted in order to discredit fellow anaesthetists against whom he bore a grudge.
In most of the operations, he was not the primary anaesthetist. It was alleged he came in early to the clinic to tamper with the infusion bags.
Then, when things went wrong, he was able to step in after diagnosing the problem and ordering an antidote.
Péchier was first placed under investigation eight years ago, when he was suspected of poisoning patients at two clinics in Besançon between 2008 and 2017.
The alert was raised in 2017 after a surfeit of potassium chloride was found in the infusion bag of a woman who had a heart attack while being operated on for a back complaint.
Investigators found a pattern of “serious adverse events” at the Saint-Vincent private clinic in Besançon. While the national average for fatal heart attacks under anaesthetic was 1 in 100,000, at the clinic it was more than six times that.
And in most cases nationally, an explanation for the heart attack was subsequently found, whereas at Saint-Vincent the cause remained a mystery.
It was also found that the “serious adverse events” ceased when Péchier left for a short period to work at another clinic, which itself then saw an uptick. Then when he returned to Saint-Vincent, the emergencies resumed there. When he was disbarred from practising in 2017, the anomaly stopped.
Péchier’s first known victim, Sandra Simard, was 36 when she experienced a sudden cardiac arrest in the middle of spine surgery. She survived thanks to intervention by Péchier, although she went into a coma.
Tests on her infusion bags showed concentrations of potassium 100 times the expected dose and the alarm was sounded with local prosecutors.
During the 15 weeks of the trial, Péchier sometimes acknowledged that some of the patients who fell ill or died may have been poisoned but he denied any wrongdoing.
“I have said it before and I’ll say it again: I am not a poisoner… I have always upheld the Hippocratic oath,” he stated.
Péchier will now spend a minimum of 22 years behind bars, having been at liberty throughout the trial.
He has 10 days to lodge an appeal, which would entail a second trial within a year.
According to the trial prosecutor: “His colleagues said he always seemed to have the answer. That he made himself out to be the best, that he created this character of the saviour, so that colleagues would instinctively turn to him.”
Péchier denied the charges and his lawyers argued that there was no hard proof linking him to the crimes. But his own testimony varied in the trial, and he ended up admitting there must have been a poisoner at large in the clinic, but it was not him.
The son of two parents in the medical profession, Péchier was described by a court psychologist as having a Dr Jekyll and Mr Hyde personality – one side respectable, the other side capable of doing great harm. In 2014 and again in 2021 he made attempts to kill himself.
A divorced father of three children, he told the court before the verdict that his sole concern was to protect his family. His children wept as the sentence was read but he remained impassive.
“It’s the end of a nightmare,” said survivor Sandra Simard.
Another patient who survived, Jean-Claude Gandon, said: “We can have an easier Christmas now.”
