This article examines the Supreme Court of Victoria Court of Appeals' decision in Grazilda Odisho v Marcia Bonazzi  VSCA 11 in the context of:
- A medical practitioner's duty of care to warn a patient of a rare risk associated with the medical treatment; and
- The role of factual causation
The appellant, Ms Odisho sought treatment from the respondent Dr Bonazzi, gynecologist, for menorrhagia when aged 46 years. It was accepted evidence that when she presented before the respondent she was very anxious about her menorrhagia. The respondent outlined the available treatment options for menorrhagia to the appellant who accepted that in her circumstances the only available medical treatment was tranexamic acid (an antifibrinolytic agent) at least until further investigation as to endometrial abnormalities could be performed at the Royal Women's Hospital in 3 months' time. The appellant presented as a patient with no risk factors. The appellant felt a strange sensation after ingestion of one single tranexamic acid tablet. The appellant continued to take the tranexamic acid tablets at the recommended dose over a week to two week period and subsequently thereafter was diagnosed with pulmonary embolus.
The appellant commenced proceedings alleging that the respondent had been negligent in her care of her by failing to warn of the likelihood, however remote, that the ingestion of tranexamic acid at the recommended dose could cause pulmonary embolus and that the tranexamic acid caused the pulmonary embolus.
A Doctors duty to warn of a material risk
Following Rogers v Whitaker (1992) 175 CLR 497 it is well accepted law in Australia that a medical practitioner has a duty to warn a patient regarding 'material risks': "The law should recognize that a doctor has a duty to warn a patient of a material risk inherent in the proposed treatment, a risk is material if, in the circumstances of a particular case, a reasonable person in the patient's position, if warned of the risk, would be likely to attach significance to it or if the medical practitioner is or should reasonably be aware that the particular patient, if warned of the risk, would be likely to attach significance to it." (ibid 489-490)
The objective and subjective approach.
The High Court in Rosenberg v Pericval (2001) HCA 18 provided further explanation as the practical application of the duty to warn of a material risk:
An objective approach; requires an analysis as to whether in the circumstances of the particular case, a reasonable person in the patients position if warned of the risk, would be likely to attach significance to it.
A subjective approach; requires an analysis as to whether the medical practitioner is or should reasonably be aware that the particular, if warned of the risk, would be likely to attach significance to it.
Grazilda Odisho v Marcia Bonazzi (2012) VCC 558 (8 May 2012)
The respondent defended the County Court of Victoria trial as follows:
The duty to warn of a material risk did not require a gynecologist to warn a patient as to a risk of pulmonary embolus prior to prescribing tranexamic acid.
Had, in any event, a warning been given the appellant would not have placed any significance on the warning and would have accepted the treatment.
There was no available medical literature or factually based evidence that the ingestion of tranexamic acid tablets at the prescribed level could cause a thrombosis.
Expert evidence was called at the trial which concluded: Tranexamic acid was a drug very commonly used to treat or prevent excessive blood loss during surgery and in various other medical conditions such as trauma and menstrual bleeding.
There is a tentative association of tranexamic acid with pulmonary embolus by nature of the way the medication works. The 2005 product literature stated that you cannot exclude it as a contributing factor, however that associated is not sufficient to say its ingestion was “a cause” of pulmonary embolus.
The association between tranexamic acid, Cyklokapron, and pulmonary embolus is not evidence based. There have been case reports of such an association, but no randomized control trials which would implicate tranexamic acid in the causation of pulmonary embolus.
In the evidenced based Lancet study published in 2010 involving 10,000 people half of whom were given tranexamic acid tablets, the placebo group recorded a minor higher degree of vascular occlusions than the group taking tranexamic acid, as such it was considered to be statistically equal.
Based on the evidence presented at trial the County Court judge found: The appellant was owed a duty to be warned of the rare side effect of a thromboembolic event associated with tranexamic acid.
The respondent did not breach the objective limb of the duty to warn by failing to warn of the rare risk.
The respondent did not breach the subjective limb of the duty to warn as the appellant would not have acted on that warning had it been given.
The appellant could not prove factual causation; that the tranexamic acid treatment was “a cause” of the pulmonary embolus from which she had suffered.
The appellant appealed to the Supreme Court of Victoria Court of Appeal stating: The trial judge erred:
By not finding find that a cause of the appellant’s injuries was the breach of duty by the respondent in failing to warn her of the remote risk that the tranexamic acid might cause pulmonary embolus (the objective test).
By not finding that the appellant was not a patient in respect of whom the respondent should reasonably have been aware that, if warned of the risk, she would have been likely to attach significance to it (the subjective test).
By not finding that the appellant had made out a “prima facie causal connection” such that the onus of proof should shift to the respondent to prove tranexamic acid was not a cause of pulmonary embolus (Chappel v Hart (1998) 195 CLR 232, Gaudron, McHugh J and Kirby J) (factual causation).
The Supreme Court of Victoria Court of Appeal, per Nettle, Beach JJA and McMillan AJA dismissed the appeal stating: The trial judge was correct in finding that the appellant had not established that the tranexamic acid she consumed was a cause of her pulmonary embolus.
That since Rogers v Whittaker was decided Parliament has enacted a number of amendments to the Wrongs Act 1958 (Vic) and that reference to the relevant sections as to duty of care, breach and causation is now the correct approach to be adopted by the Courts.
Without deciding the point that notwithstanding expert evidence presented at trial that it was not the usual practice for gynecologists who prescribe tranexamic acid to give a warning of the remote risk of thromboembolism there seems to be reasonable grounds that a warning in the terms of the product literature should be provided by a gynecologist (objective test).
Having regard to its findings on causation there was no requirement for the Court of Appeal to reconsider the application of the subjective test.
As to causation and scope of liability The Court rejected the appellant’s submission that this was a case which involved the shifting of the evidentiary onus from the appellant to the respondent as the evidence did not establish that tranexamic acid was “a cause” of pulmonary embolus.
The Court left “for another day” its answer to the question of whether any of the analysis of the High Court in Chappel v Hart on the shifting evidentiary onuses on the issue of causation survives sections 51 and 52 of the Wrongs Act 1958 (Vic).
It was not contented that section 51(2) of the Wrongs Act 1958 (Vic) required that in this instance although negligence was not established as being a necessary condition of the occurrence of harm this was an ‘appropriate case’ where the County Court ought to have taken that factual causation had been established in any event.
In summary while it was questioned by the Court of Appeal whether a warning should have been given in the context of the tranexamic product literature the fact remained that the patient could not prove that she would have acted on that warning and that the risk had in fact materialized.