A verdict of medical misadventure has been recorded at the inquest into the death of a woman with an “unusually healthy” heart after she suffered a cardiac arrest while undergoing a routine procedure at a dental clinic in Dublin.
Margaret O’Doherty (72) died five days after becoming ill during dental implant surgery at the Dublin Specialist Dentistry in Sandyford in August 2020. The inquest heard that the most likely cause of her sudden cardiac arrest was the effect of a sedative, Midazolam, used during the procedure.
The two-day hearing at Dublin District Coroner’s Court was told that Ms O’Doherty and her family had alerted two dental surgeons during several consultations in advance of the procedure to the fact she was “extremely sensitive” to sedative medication.
The claim was disputed by oral surgeon Seamus Rogers and prosthodontist Maurice Fitzgerald, who said they were unaware before the surgery of Ms O’Doherty having any issue with sedatives.
Ms O’Doherty, a mother of three from Merrion, Gorey, Co Wexford died at St Vincent’s University Hospital in Dublin on August 23rd, 2020 – five days after the dental surgery.
Following the verdict, coroner Clare Keane said she would recommend to the Dental Council of Ireland that it urgently review its existing guidelines on conscious sedation, which date back to 2005; ensure that the existing guidelines were “robustly adhered to” and publish standards for treatments involving more than one dose of a sedative.
The coroner said she had no doubt that everyone involved in Ms O’Doherty’s care had the “best intention”.
Pathologist Tom Crotty said Ms O’Doherty had an “unusually healthy” heart for a woman of her age and there was no evidence that she had any cardiac disease that could have caused her death. Dr Crotty said the postmortem results showed she died from a lack of oxygen to the brain due to the cardiac arrest.
Dr Crotty told the coroner he believed what happened to the patient was “most likely” linked to her sedation with a drug known to cause slow and ineffective breathing as well as cardiac arrest in rare cases. He acknowledged that Ms O’Doherty had a narrowing in a small area of a coronary artery, but said it was “unlikely that was enough to explain her sudden death”.
Members of the O’Doherty family explained she had asked about having a more conservative form of treatment for injuries to her teeth suffered in a fall on the driveway of her home in February 2020.
However, they were told the proposed procedure was the best option and her daughter, Clodagh O’Doherty, said her mother was reassured as Dr Fitzgerald told her his own mother, who was of a similar age, had undergone the same surgery.
The deceased’s husband, Michael O’Doherty, a GP who runs the Gorey Medical Centre, told the inquest he was “amazed” to learn there was nothing in the clinic’s notes about his wife’s issue with sedatives as they had “laboured” the point during consultations with Mr Rogers and Dr Fitzgerald.
Dr O’Doherty said his wife had suffered a previous fall in 2019 after taking a dose of Night Nurse and would not even take a Panadol because of her sensitivity to such medicine.
Sara Antoniotti SC, for the family, said they believed she had been given too much Midazolam during the procedure and she had suffered all the complications associated with the drug.
Mr Rogers said he “would not have given sedatives to someone who told me they were sensitive to them”. Dr Fitzgerald also said he had no recollection of the couple noting any issue regarding sedatives as it would have “raised a large red flag”.
Counsel for Mr Rogers, Nathan Reilly BL, claimed the complexity of the case warranted a narrative verdict.
‘Most likely cause’
A consultant in intensive care medicine at SVUH, Donal Ryan, said Midazolam could lead to the obstruction of a patient’s airway but it was not an issue by the time Ms O’Doherty arrived at the hospital. However, he said it was “the most likely cause” to explain her cardiac arrest.
Dr Tom Schnittger, a consultant anaesthetist called as an expert witness, said there was often quite a wide variation in how patients reacted to Midazolam and that it could have a bigger impact on patients aged over 60.
Following the verdict of medical misadventure, Dr O’Doherty, who was accompanied by his children Clodagh, Niamh and Cian, said: “Losing my wife has been an extremely devastating event for my family and I. It was tragic and we believe avoidable.” He said they wanted lessons to be learned from what had happened “to ensure that this never happens to any other family”.