Medical Errors and Open Disclosure — Written Clinical Reasoning

SAQ 1 — A tenfold insulin overdose and a failure to adjust metformin in acute kidney injury (25 marks, 35 minutes)

Model answer

Classification of the event (5 marks) [1]

This patient sustained a preventable adverse event — an injury caused by medical management rather than by the underlying pneumonia, comprising two distinct errors. The first is the failure to cease metformin in the setting of acute kidney injury (day-two creatinine 230), a monitoring error that placed him at risk of lactic acidosis. The second is a tenfold insulin overdose (40 units instead of 4) caused by the use of the prohibited abbreviation "U" for units at the prescribing stage, not intercepted by an independent check at the administration stage. The overdose reached the patient and caused harm (profound hypoglycaemia and ICU transfer), so it is an adverse event rather than a near miss [1].

In Reason's taxonomy, the abbreviation error is an error of execution (the plan to give 4 units was correct; the execution failed through the ambiguous prescription) and, more specifically, a rule-based mistake (the doctor applied a non-compliant local habit of abbreviating units) compounded by a lapse at the administration step (no independent check). It is NOT a near miss (the harm occurred), NOT a never event (insulin abbreviation error is not on the never-event list, which includes wrong-site surgery, retained foreign object, and incompatible transfusion), and NOT an unpreventable complication (the error is preventable by writing units in full). [1]

Immediate management (4 marks) [1]

The clinical priority precedes the disclosure and the investigation. [1]

1. Stabilise the patient. Treat the hypoglycaemia with 50 per cent intravenous dextrose (50 to 100 mL) and ongoing glucose monitoring for at least 24 to 48 hours because subcutaneous depot insulin continues to act. The patient was appropriately transferred to ICU for neuroglycopenia. Concurrently, cease the metformin and manage the acute kidney injury with intravenous fluids, treat the pneumonia, and monitor the creatinine.
2. Preserve the evidence. Do not discard the medication chart or the insulin pen. Secure the prescription, the administration record, and any pump or pen involved.
3. Inform the senior clinician in charge and the treating team — the consultant, the nurse unit manager, and (for a serious adverse event requiring ICU transfer) the medical defence organisation before any formal statement. [1]

The structured open disclosure process (7 marks) [1]

I would conduct disclosure under the Australian Open Disclosure Framework (ACSQHC), operationalised through the National Safety and Quality Health Service Standards. The process is staged [4].

Initial disclosure — as soon as practicable (within 24 hours), once the patient is stable and able to participate. In a private setting, with the treating consultant and (ideally) an open disclosure facilitator present, I would: open with an apology — an expression of regret for what happened and for the impact, which is explicitly NOT an admission of legal liability under Australian civil liability legislation; give a factual, plain-language account of what is known (that an insulin dose ten times the intended amount was given overnight due to a prescribing abbreviation, and that the metformin was not stopped when the kidneys failed); acknowledge the impact (the hypoglycaemia, the ICU stay, the fear); state what is being done to investigate (a formal root cause analysis) and to prevent recurrence; offer support (a second opinion, counselling, advocacy); and invite questions. I would not speculate about the cause or blame the nurse or the registrar. I would document the conversation in the medical record. [1]

Ongoing communication — keep the patient and his family informed as the investigation proceeds, with a single point of contact. [1]

Formal open disclosure meeting — once the root cause analysis is complete, reconvene to present the full factual account, the contributory factors found, the actions taken to prevent recurrence, and ongoing support. [1]

Follow-up — provide the written outcome, confirm the actions, and offer continued support. [1]

The apology is the most-tested element. The largest single driver of complaints and litigation is not the harm itself but the perception of a cover-up; open disclosure with a genuine apology reduces the number and value of civil claims [3].

Root cause analysis and the contributory factors (5 marks) [1]

I would convene a formal root cause analysis (RCA) using the London Protocol contributory-factor domains. [1]

• Patient factors: complex comorbidity (diabetes, ischaemic heart disease, CKD), making the dose critical and the margin for error narrow.
• Task factors: the sliding-scale insulin protocol and the dose-adjustment task in AKI lacked an embedded forcing function.
• Individual factors: the prescribing registrar used a non-compliant abbreviation; the overnight nurse read it without an independent check — both are active failures, but neither is reckless.
• Team factors: handover at the evening shift change did not flag the rising creatinine or the need to review insulin and metformin dosing.
• Environment: the ward was the site of the prescribing and administration error; staffing and workload at night may have contributed.
• Organisation: the latent conditions — the persistence of the U abbreviation in practice despite policy; the absence of an independent double-check for high-alert medicines on the ward; the absence of a hard alert in the prescribing system when insulin is prescribed above a threshold dose for a patient with renal impairment.
• Institutional context: the availability of decision support and the accreditation of the insulin-prescribing process against the NSQHS Standards. [1]

The durable fixes are at the latent-condition level: a hospital-wide ban on the U abbreviation with audit; mandatory independent double-checks for all high-alert medicines including insulin; computerised physician order entry with a hard dose-range alert for insulin in renal impairment; and a renal-dose-adjustment prompt when the creatinine rises. The active failures (the abbreviation, the missing check) are proximate, but the latent conditions are the root causes [1].

I would apply the just culture algorithm: this was a human error (an inadvertent abbreviation, a missing check), so the response is to console the individuals and fix the system, not to discipline. Both the registrar and the nurse are second victims who will require peer support, debriefing, and a structured re-entry to practice. [1]

Medico-legal and reporting obligations (4 marks) [1]

1. Internal incident report — filed for every adverse event regardless of severity; it triggers the severity assessment and the RCA.
2. Medical defence organisation — notified of the serious adverse event and before any formal statement; the MDO supports the clinician through the disclosure and investigation.
3. AHPRA mandatory notification — NOT required here. The threshold is notifiable conduct (intoxication, sexual misconduct, impairment placing the public at risk, or a significant departure from professional standards). An unintentional abbreviation error by an otherwise competent clinician is an error, not notifiable conduct, and mandatory notification is distinct from the internal incident report.
4. Coronial referral — NOT required here because the patient recovered. Had the patient died from the hypoglycaemia, the death would have been reportable to the coroner as an unexpected death resulting from a medical intervention; the ordinary death certificate would not have been issued, and the record would have been preserved. [1]

The distinction among a complaint (an expression of dissatisfaction), a claim (a formal demand for compensation pleaded in negligence), and a mandatory notification (a report to the regulator about fitness to practise) must be kept clear, as the three pathways require different documentation and different responses. [1]

SAQ 2 — The diagnostic error and the duty of candour (10 marks, 20 minutes)

Question

A 58-year-old woman is referred to you with newly diagnosed stage 4 lung cancer. Reviewing her records, you find that a CT scan performed 18 months ago for renal colic incidentally noted a 12 mm spiculated pulmonary nodule with a recommendation for three-month follow-up imaging. The result was filed in the radiology system but no clinician acted on it and the patient was never recalled. Outline the classification of this event, the disclosure you would conduct, and the system changes you would recommend. [1]

Model answer

Classification (2 marks) [1]

This is a diagnostic error — specifically a missed diagnosis — caused by a system failure in result handling and follow-up. It is a preventable adverse event: the harm (the progression from a small resectable nodule to stage 4 lung cancer) was preventable by a reliable recall and follow-up system. In Reason's terms, the active failure is that no clinician took ownership of the incidental finding; the latent condition is the absence of a result-handling system that assigns a responsible clinician, flags the result for follow-up, and recalls the patient. The radiology report documented the finding, so this is NOT a near miss (the harm occurred). [1]

Disclosure (4 marks) [1]

I would conduct open disclosure under the Australian Open Disclosure Framework. In a private setting with the patient and her support person, the treating team, and an open disclosure facilitator, I would: apologise (an expression of regret that is NOT an admission of liability); give a factual, plain-language account — that the nodule was documented on the CT scan 18 months ago with a recommendation for follow-up, that the result was not acted upon, and that the cancer has since progressed; acknowledge the profound impact; explain that a formal investigation (root cause analysis) is underway to understand why the result was not followed up; and offer support including a second opinion, oncology referral, counselling, and advocacy. I would not speculate about whether earlier treatment would have changed the outcome (that is a matter for the investigation and, potentially, the courts). I would document the conversation and arrange follow-up. Because the harm is serious and a claim is likely, I would notify the medical defence organisation and the hospital executive before the formal disclosure [3].

System changes (4 marks) [1]

The root cause analysis would focus on the result-handling system. The durable fixes address the latent conditions: [1]

• A result-handling policy that assigns every significant incidental finding to a named responsible clinician at the time of reporting, with documented acknowledgement.
• A recall system that tracks recommendations for follow-up imaging or review, flags overdue items, and recalls the patient directly if the clinician does not respond.
• Patient communication — the patient is told of the incidental finding and the need for follow-up in writing, so that the patient themselves becomes a defence in the system.
• Decision support — a flag in the radiology and clinical information systems for any report containing the terms nodule, follow-up, or recall.
• Audit — regular review of the proportion of significant incidental findings that are followed up within the recommended interval. [1]

The point of the Swiss cheese model is that a single clinician's vigilance is an unreliable defence; the durable fix is a system that does not depend on any one person remembering [1].