In Sparks v Hobson; Gray v Hobson  NSWCA 29, the Plaintiff suffered from Noonan Syndrome, a genetic disorder that prevents normal development in various parts of the body. Due to this disorder, his ability to fill his lungs with air, and hence to breathe, was restricted. Surgery to correct this problem was arranged to take place in two stages. The first operation was successful. The second operation had to be terminated before its intended conclusion and resulted in the Plaintiff becoming a paraplegic.
The Plaintiff commenced proceedings in negligence against both the orthopaedic/spinal surgeon and the anaesthetist involved in the surgery.
At first instance, the trial judge found that both doctors had breached their duties of care to the Plaintiff and were liable in negligence for damages in the amount of $3,828,075. It was held that, in light of adverse blood gas readings obtained during the operation, the doctors should have stopped the operation earlier than they did. If this had occurred, the Plaintiff would not have suffered a significant cardio-vascular collapse during the operation, his spine would not have been damaged and he would not have become a paraplegic.
Both doctors appealed against the trial judge’s decision on liability. In contending that the trial judge had erred in finding that they acted negligently, the appellants relied on sections 5I and 5O of the Civil Liability Act 2002 (NSW) (CLA).
On appeal, the orthopaedic/spinal surgeon was successful in having the findings of liability against him overturned. However, the Court considered that the anaesthetist had acted unreasonably and breached his duty of care to the Plaintiff in not stopping the operation at an earlier time. His appeal was therefore dismissed.
Of note in the decision is the discussion by the Court of the correct interpretation of s.5O of the CLA, the equivalent of s.5PB in the Civil Liability Act (WA).
At trial, both practitioners had raised s5O as a defence. However, Counsel for the Plaintiff relied upon the decision in McKenna v Hunter & New England Local Health District  NSWCA 476 as an answer to the defence. In McKenna, Macfarlan JA stated (at ) that:
“To establish a defence under s5O a medical practitioner needs to demonstrate, first, that what he or she did conformed with a practice that was in existence at the time the medical service was provided and, secondly, to establish that that practice was widely, although not necessarily universally, accepted by peer professional opinion as competent professional practice.”
On appeal, Counsel for the anaesthetist submitted that McKenna was wrong in holding that it was necessary to demonstrate the existence of “a practice” extant at the time of the conduct in question. The Court of Appeal accepted this submission, stating:
"31. Although it is uncertain how this reasoning in McKenna will operate in particular cases, there is a risk in reformulating the statutory language. To speak of “a practice” adopted by a group of professional persons suggests a regular course of conduct adopted in particular circumstances. By contrast, the phrase “competent professional practice” is apt to cover the whole gamut of professional services provided by the practitioner, whether or not the particular circumstances have arisen sufficiently often to result in an established practice. For example, although opinions may differ as to the conclusion to be drawn, there is no grammatical or semantic difficulty in describing an argument run by counsel in a novel case as demonstrating competent or incompetent professional practice. The same judgment may be offered about the failure of counsel to call a defendant in a criminal trial, where no settled practice exists. Where an acquittal depends on establishing an affirmative defence and there is no other evidence to support the defence, it may be described as incompetent professional practice not to call the defendant who could have given such evidence. Where an opinion is given and challenged, it will be supported (or attacked) not by reference to some established practice, but by reference to how an assessment of the circumstances (which may be unique) would be undertaken by a knowledgeable and experienced practitioner.
32. There are other reasons for thinking that the reference to “competent professional practice” does not require evidence of “a practice”. First, it is the “manner” in which the defendant acted which must be the focus of the opinion. Secondly, if it were necessary to establish a practice, one might expect subs (3) to refer to “opinions … concerning that practice”, rather than “opinions … concerning a matter”.
33. To take an example closer to the present case (but still hypothetical) an anaesthetist might allow an operation to proceed on the basis that two indicators remained within acceptable limits but a third indicator did not. An expert might express an opinion that such conduct was not competent practice, not because he or she had experienced the same circumstance in the past, or had read about it in a textbook, but because basic principles of human physiology led to that conclusion.
34. Accordingly, although the language used in McKenna may well sufficiently describe many circumstances in which s 5O is invoked, I would not understand it as a general proposition as to the constraints imposed by s 5O(1).
35. If that understanding is too restrictive and it is necessary to go further, I would not follow McKenna. The decision in McKenna having been overturned in the High Court, the reasoning of the majority in this Court is no longer binding."
Western Australian courts have not as yet provided any significant guidance with respect to the operation of s.5PB of the Civil Liability Act (WA) and to date, its application has been guided by decisions relating to similar provisions in other states. It is expected that a similar approach to that adopted by the NSW Court of Appeal in this matter would also be applied to our legislation.