Every now and then, a case crops up which is far from straightforward. Medicolegal expert Bill Madden explains.

The law, perhaps like medicine, seems easy enough to apply in many circumstances.

In medical negligence law, more than 90% of cases don't require a judge to make a formal decision.

But every now and then a case arises that isn't straightforward — a court decision is then required and we learn a little more about the legal framework.

We've seen that recently in the Liverpool Hospital case where doctors treating a boy for an open fracture decided, in line with clinical guidelines, to prescribe flucloxacillin but not gentamicin. The boy's thumb was subsequently amputated after it became gangrenous.

At the first hearing, the trial judge ruled in favour of the boy, finding that South Western Sydney Local Health District, where the doctors worked, was negligent. [ Read the full story here]

Having heard testimony from a number of expert witnesses during the hearing, the judge had asked whether guidelines should be "adhered to slavishly, as in a box-ticking exercise" or if they required interpretation on a case-by-case basis.

The first point here is that when judges are determining if a doctor has been negligent, they will want to hear evidence from other doctors.

When these expert witnesses disagree, the judge must still reach a decision, somehow.

Since about 2002, judges have had the benefit of some legislative guidance, phrased along the lines of "a professional does not incur a liability in negligence arising from the provision of a professional service if it is established that the professional acted in a manner that [at the time the service was provided] was widely accepted in Australia by peer professional opinion as competent professional practice".

This wording from NSW varies in other states.

Of course, the trial judge may still have the potential problem of the expert medical witnesses disagreeing as to whether the defendant did or did not act in a widely accepted manner.

Usually, that sees the judge carefully scrutinising the stated opinions, the reasoning of the witnesses, and perhaps other useful material such as guidelines and peer-reviewed articles.

Most interesting, however, is the legislative exception where a court may decide that there is plausible evidence of widely accepted medical opinion. The caveat is that such opinion cannot be relied on as a defence to a claim asserting negligence if the court considers that the opinion is "irrational".

"Irrational" is the term used in NSW. Again the wording differs in other states.

More than 15 years have passed since those legislative exceptions were created, but there has been little need for their application to date.

But this was precisely the issue that came up in the Liverpool Hospital case.

The trial judge's ruling was overturned. The Court of Appeal decided that the non-administration of gentamicin in the particular circumstances was widely accepted in Australia by peer professional opinion as competent professional practice. In the circumstances of this particular case, that treatment decision could not be judged "irrational". [ Read the full story here]

The court said that it would be a seriously pejorative and exceptional thing to find that a professional person had expressed an opinion that was irrational, and even more exceptional if the opinion was widely held.

To consider a body of opinion to be irrational is a stronger conclusion than merely disagreeing with it, or preferring a competing body of peer-professional opinion.

That seems clear enough, but it does raise some interesting issues.

We need to bear in mind that in most parts of Australia, the provisions don't only apply to doctors. For instance, Zhang v Hardas NSWSC 432 held that chiropractors were professionals for the purposes of the relevant section.

Midwives will no doubt be held to be professionals as well.

So how will the courts assess the practises of those in some professions or groups who could show their practises are in line with at least some of their peers, even if they are not seen as appropriate by the medical profession? Will this require the court to apply the irrational exception when considering civil liability cases?

This brings me back to where I started this article. The law, perhaps like medicine, seems easy enough to apply in many, but not all, circumstances.

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