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The death of Margaret O’Doherty — a 72-year-old patient who suffered a fatal cardiac arrest midway through a seven-implant procedure under conscious sedation at a Dublin specialist clinic in August 2020 — has concluded in the civil courts following a settlement reached without admission of liability. The case, and the inquest that preceded it, raises issues that every clinician performing implantology under sedation should carefully consider.
This article provides a balanced overview of what is known about the case, the findings from the 2023 inquest, and the clinical and regulatory questions that follow. It concludes with a practical patient safety checklist for practitioners.
Case Overview
Ms O’Doherty attended Dublin Specialist Dentistry in Sandyford, Co Dublin, on 18 August 2020 for a planned procedure to place seven dental implants under conscious sedation with Midazolam. The procedure followed dental injuries she had sustained in a fall. Her family subsequently stated that she had contacted the clinic in the days prior to surgery to enquire whether a more conservative treatment alternative was available, and was advised that implants were the most appropriate option.
Approximately midway through the procedure, after five implants had been placed, Ms O’Doherty experienced a cardiac arrest. Emergency services were contacted and she was transferred to St Vincent’s University Hospital, where she died five days later on 23 August 2020.
In 2023, a coroner’s inquest returned a verdict of medical misadventure. The inquest heard evidence that the most probable cause of the cardiac arrest was an adverse response to Midazolam. Ms O’Doherty’s family maintained that she had a documented and communicated history of hypersensitivity to sedative medications — a contention disputed by the clinic’s representatives. The pathologist noted that Ms O’Doherty had an unusually healthy cardiovascular system for her age, with no underlying cardiac pathology identified at post-mortem.
In early 2026, the family’s High Court action settled via mediation. The case came before the court solely for the purpose of apportioning a €35,000 solatium payment among the family. No admission of liability was made. In approving the division, the presiding judge expressed his sympathy to the O’Doherty family.
Inquest Findings and Regulatory Response
The 2023 inquest produced several notable outputs for the profession. Coroner Clare Keane issued a recommendation that the Dental Council of Ireland urgently review its conscious sedation guidelines, which at the time of the incident dated to 2005. In a field where sedation pharmacology, monitoring standards, and patient demographics have all evolved considerably over two decades, the currency of such guidance is not merely a regulatory formality — it has direct clinical significance.
The inquest also surfaced questions about the adequacy of pre-operative risk documentation, the process by which patient-reported sensitivities are recorded and acted upon, and whether the duration and scope of the planned procedure was appropriate given the patient’s age and physiology. These are systemic issues as much as individual clinical ones.
Clinical Considerations for Practitioners
The O’Doherty case does not lend itself to simple lessons, partly because many of the core factual disputes remain unresolved. What it does offer is a framework for reflection across several areas of practice.
Sedation risk in the elderly patient. Midazolam pharmacokinetics differ significantly in older patients. Reduced hepatic clearance, altered volume of distribution, and age-related changes in benzodiazepine receptor sensitivity can all prolong and intensify sedative effects. Weight and frailty compound these factors. Dosing decisions must be individualised, not protocol-driven.
Pre-operative history-taking and documentation. A reported history of medication sensitivity — whether to sedatives, anaesthetics, or other agents — must be formally captured, clinically assessed, and reflected in the treatment plan. Where any uncertainty exists, specialist anaesthetic input should be sought before proceeding.
Procedure scope and patient capacity. Placing seven implants in a single session under conscious sedation represents a significant physiological challenge for any patient. In a 72-year-old patient of small stature, the cumulative sedation load and procedural duration require careful justification. Clinicians should consider whether staged approaches better serve the patient’s risk profile, even when the single-session option is technically feasible.
Informed consent and treatment alternatives. The allegation that Ms O’Doherty sought information about less invasive alternatives prior to surgery is an important detail, whatever its ultimate resolution. Robust informed consent requires that clinicians document not only what the patient agreed to, but that alternatives were discussed and the patient’s questions were fully addressed.
Patient Safety Checklist: Implant Procedures Under Conscious Sedation
The following checklist is offered as a practical prompt for clinicians undertaking implant procedures under conscious sedation, particularly in older or medically complex patients. It should be supplemented by current national guidelines and individual clinical judgement.
Pre-Procedure
- Conduct and document a full medical history, including all current medications and any history of adverse reactions to sedative, anaesthetic, or analgesic agents.
- Assess the patient’s ASA physical status classification. Consider whether conscious sedation is appropriate for ASA III and above without specialist input.
- Record body weight, height, and BMI. Adjust Midazolam dosing accordingly. Use minimum effective doses with titration-based administration.
- Confirm that all reported drug sensitivities are documented in the clinical record and visible to all members of the treatment team.
- Review whether the planned procedure scope is appropriate for a single session given the patient’s age, physiology, and anticipated sedation load.
- Ensure that informed consent documentation reflects a discussion of treatment alternatives, risks specific to sedation, and the patient’s own questions and concerns.
Intra-Procedure
- Ensure continuous monitoring of oxygen saturation, heart rate, blood pressure, and level of consciousness throughout. Appoint a dedicated team member for monitoring, separate from the operating clinician.
- Establish clear escalation thresholds in advance. Document what observations will trigger suspension of the procedure and/or emergency response.
- Confirm that resuscitation equipment — including a defibrillator and Flumazenil (Midazolam reversal agent) — is immediately accessible and that all team members are trained in its use.
- Reassess sedation depth at each clinical stage. Do not assume that a stable patient early in the procedure will remain stable as sedative accumulation occurs over a longer session.
Post-Procedure & Systems
- Ensure adequate monitored recovery time before discharge. Do not rely on patient self-report of readiness; use a validated discharge scoring tool such as the Modified Aldrete Score.
- Conduct regular team drills for medical emergencies, including cardiac arrest scenarios. Ensure all clinical staff hold current BLS and, where appropriate, ILS certification.
- Review your practice’s conscious sedation protocols against current national guidelines. If your guidelines predate 2015, they are likely overdue for review.
- Following any critical incident, carry out a structured case review using a recognised framework such as root cause analysis. Document findings and any resulting changes to practice.
Conclusion
The O’Doherty case is a tragedy, and its legal resolution does not diminish its significance as a clinical event. For practitioners working in implantology and sedation dentistry, it serves as a prompt — not to practise defensively, but to practise deliberately. Rigorous patient selection, individualised risk assessment, meticulous documentation, and up-to-date emergency preparedness are not aspirational standards. They are the baseline.
Perioperative safety in dentistry has historically received less systematic attention than in medicine. Cases like this one make the argument, compellingly, that it deserves more.
Editorial note: The civil settlement in this case was reached without any admission of liability. Clinical allegations referenced in this article were pleaded in legal proceedings and aired at inquest; they do not constitute findings of fault against any named individual or institution. This article is intended for educational purposes for dental professionals and does not constitute legal or clinical advice.
