Background

Coroner King of the Western Australian Coroner’s Court conducted an inquest into the death of Myosotis Julianna Moriarty (patient) who died two days after having teeth extracted by experienced dentist, Dr Colgan (dentist).1

In 1987, the patient developed sub-acute bacterial endocarditis2 following a dental procedure that was performed without antibiotic prophylaxis. As a result, the patient was required to undergo surgery to insert an aortic valve prosthesis. The patient subsequently avoided doctors until 2000, when she was diagnosed with atrial fibrillation and prescribed Warfarin.3

On 9 November 2009, the patient attended an appointment with her dentist. During the consultation, she expressed that she was anxious about consulting a dentist given her history and advised that she had not seen a dentist in a long time. She advised the dentist that she was on long term warfarin therapy with stable INR4 levels of between 3 and 3.4. The dentist conducted an oral examination, recommended that she have at least two extractions and advised her to discuss the extractions with her GP to ensure that her INR levels were within acceptable levels.

Following the appointment with her GP, the patient did not return to the clinic for over a year. At the subsequent appointment on 8 December 2010, the patient told the dentist that she was still on warfarin and her INR levels were stable. The dentist arranged for the patient to attend his clinic on 16 December 2010 for the extractions.

Although absent from the medical record, the dentist asserted that the patient advised him that in the previous week her INR was 3.5. The extractions were performed and the patient was given verbal post-operative instructions - no written instructions were provided. Two days later the patient died from gastrointestinal haemorrhage secondary to bilateral dental extraction.

Findings

The Coroner’s findings focussed on two issues: 1) adherence to Therapeutic Guidelines; and 2) post-operative management instructions.

The Coroner found that the Guidelines, whilst not a set of rules or instructions, represented best practice. The Guidelines provided a number of steps to manage risks of bleeding from warfarin. The Coroner found that the dentist did not comply with critical steps of the Guidelines, including organising a blood test for INR within 24 hours before the surgery and applying the transexamic5 mouthwash protocol (protocol).

The Coroner found that the dentist ought to have adhered to the protocol. Whilst not able to conclude that the failure to adhere to the protocol caused or contributed to the patient’s death, the Coroner was unequivocal that the management of the patient was deficient. Accordingly, the Coroner referred the dentist to the Dental Board of Australia.

The Coroner was also critical of the dentist for not providing the patient with any written post-operative instructions. The Coroner referred to a publication on the Dental Protection (a dental insurer) website which endorsed post-operative instruction sheets as a useful adjunct to the communication process. Given the patient’s history, the Coroner found that the patient was likely to be very anxious about the surgery and found that the dentist should have provided her with clear written instructions that ought to have included the importance of seeking prompt treatment in the event of bleeding or any other problem, as well listing an after-hours emergency telephone number.

The Coroner provided a copy of his finding to the Australian Dental Association, suggesting that it advise its members to provide patients undergoing extractions, especially those on warfarin, with written post-operative instructions.

Comment

This inquest highlights the need for practitioners to be up to date with current guidelines and best practice and, more importantly, to apply relevant guidelines to their practice, especially when the consequences to the patient are potentially fatal.

The comments made by the Coroner in his findings serve as a reminder of the critical importance for practitioners to take accurate and detailed notes in case questions are raised at a later date. In this inquest, the Coroner specifically mentioned a number of assertions made by the dentist in oral evidence (four years following the death) that were not recorded in the patient’s notes, implicitly calling into question the reliability of the dentist’s assertions.