26 September 2011

On 7 September 2011, Justice Garling of the Supreme Court of New South Wales handed down his decision in King v Western Sydney Local Health Network [2011] NSWSC 1025.

The plaintiff, Tamara King, by her tutor, commenced a claim for damages in the Supreme Court of New South Wales against the Western Sydney Local Health Network (the defendant).

The plaintiff alleged that the defendant breached the duty of care it owed to her while she was in utero by failing to administer Varicella-Zoster Immunoglobulin (VZIG) to her mother, Phillippine King.  Mrs King presented to Blacktown Hospital on 6 May 2002 and advised staff that she had been exposed to her eldest child Shania who had developed chickenpox (varicella). Mrs King advised staff that she did not believe that she  had previously had chickenpox. The plaintiff alleged that had the injection been administered at that time, her mother would not, on the balance of probabilities, have become infected with chickenpox, and consequently she (the plaintiff) would not have developed congenital varicella syndrome (CVS).

FACTS

On 5 May 2002, when Mrs King was just under 13½ weeks’ pregnant with the plaintiff, Mr and Mrs King observed a rash on Shania’s left arm. Shania was subsequently diagnosed with chickenpox.

At 10.15am on 6 May 2002, Mrs King presented to Blacktown Hospital due to vaginal bleeding that had commenced that morning.  Mrs King was admitted and seen by Dr Jane Davidson. Mrs King informed Dr Davidson that Shania had developed chickenpox the day before and that she did not believe that she had previously had chickenpox herself.

Dr Davidson discussed the case with an obstetrician and gynaecologist, in particular the need for Mrs King to be administered VZIG, a human blood product that, while not a vaccination, strengthens the recipient’s immune system and reduces the severity of chickenpox symptoms.

The obstetrician and gynaecologist advised Dr Davidson that VZIG did not need to be administered on that day, but that a blood test should be performed to check for the presence of antibodies to chickenpox to ascertain whether Mrs King was in fact immune to chickenpox. A blood sample was taken for testing and Mrs King advised that the results would be discussed with her when she attended the antenatal clinic on 9 May 2002.

On 9 May 2002, Mrs King attended the antenatal clinic. The entry in her medical record for that attendance makes no reference to her potential chickenpox exposure or her diagnosis with a viral infection the day before.  On 17 May 2002, Mrs King presented to her general practitioner with chickenpox symptoms that had developed since the day before.

The plaintiff was born on 1 November 2002. Following her birth it was suspected that she had suffered a congenital varicella infection.

ISSUES

An order was made for liability to be determined separately to quantum. There were four questions to be answered.

1. Whether the hospital owed the plaintiff a duty of care, and if so, its nature and content

The plaintiff pleaded that the defendant owed her a duty of care which became enlivened upon her birth. It was pleaded that the extent of that duty included an obligation to advise Mrs King on the availability of VZIG, its potential benefits and risks, and to have offered her an injection of VZIG.

The defendant admitted that it owed the plaintiff a duty of care. This position is accepted in Queensland; see, for example, Bowditch (by his next friend Bowditch) v McEwan [2001] QSC 448 at [11] where her Honour Justice White stated that it is a well-accepted principle that once a child is born he or she may sue in respect of an injury caused to him or her whilst in utero by the negligence of a third party.

2. Whether the hospital was in breach of that duty of care

The issue of breach fell to be decided by reference to section 5B of the Civil Liability Act 2002 (NSW) (the NSW Act), the equivalent of which is section 9 of the Civil Liability Act 2003 (Qld) (the Qld Act).

His Honour observed that the three elements of section 5B(1) reflect the concepts of foreseeability, probability and reasonableness of precautions respectively, and found that the plaintiff made out her case in respect of each.

In relation to foreseeability, his Honour found that the defendant, through its agents was aware that there was a risk of the child being born with CVS if the child’s mother were exposed to varicella during the course of the pregnancy. It was this knowledge that led Dr Davison to seek the opinion of an obstetrician and gynaecologist on 6 May 2002.

In relation to probability, his Honour found this established in view of the known rate of children born with CVS to mothers who contracted chickenpox during the course of their pregnancy and the range, severity and permanence of the symptoms that CVS could potentially cause.

In relation to the reasonableness of precautions, his Honour found that the risk of harm was indeed one against which a reasonable person in the position of the hospital (acting through its staff) would have taken precautions, based on:

  • the opinion of five of the six experts who agreed Mrs King should have been warned of the risk and offered an injection of VZIG;
  • numerous medical publications in circulation at the time that strongly supported the administration of VZIG to a pregnant woman who was exposed to a person with active chickenpox within 96 hours of exposure; and
  • the fact that none of the experts or the publications identified any possible serious adverse effects that could arise from the administration of VZIG.

In its defence the defendant pleaded that it had not breached its duty of care to the plaintiff as it had acted in accordance with section 5O of the NSW Act, the equivalent of which is section 22 of the Qld Act.

The defendant submitted that the actions of hospital staff on 6 May 2002 in not administering VZIG to Mrs King but instead recommending blood tests and then review at the antenatal clinic was acting in accordance with a manner contemplated by section 5O(1) on the basis that:

  • since Mrs King had, as a matter of fact, being exposed to  varicella more than 96 hours before she attended the hospital on 6 May 2002, widely accepted professional practice did not require the administration of VZIG; and
  • the treatment provided to Mrs King accorded with that recommended in a guideline issued by the Royal College of Obstetricians and Gynaecologists, in circumstances where it was agreed in the joint expert report that the guideline was competent professional practice, widely accepted in Australia by peer professional opinion.

His Honour found that the defendant failed to establish a defence under section 5O on either of the above two grounds.

In relation to the first ground, his Honour found that at the time of Mrs King’s presentation on 6 May 2002, the staff at the hospital were aware that she had been exposed to her daughter who had developed chickenpox symptoms the day before, and that her daughter was likely to have been the most infectious in the 24 to 48 hours leading up to this. As such Mrs King was within the 96 hour window during which VZIG should have been administered.

In relation to the second ground, his Honour found that the approach taken by staff would have been in accordance with the guideline if the results of the blood test were available within six hours of the sample being taken. As it were, the results were not to be available until Mrs King attended the antenatal clinic three days later on 9 May 2002, at which point she would be outside the 96 hour window.

3. Whether the features of the plaintiff’s condition observed, prior to and after her birth, amounted to CVS

His Honour found that the plaintiff established that she suffered from CVS, and that this was caused by her mother Mrs King becoming infected with chickenpox during the course of her pregnancy when she was exposed to her daughter Shania during the period in which Shania was infectious with chickenpox.

4. Whether the plaintiff’s CVS was caused by, or else materially contributed by, the hospital’s breach of duty

Section 5D of the NSW Act prescribes the legal test to be applied to determine causation in such cases. The equivalent is section 11 of the Qld Act.

The issue of causation was summarised at [151] as follows:

Had, on 6 May 2002, the medical staff at Blacktown Hospital appropriately advised about and administered 600 international units of VZIG to Mrs King, the plaintiff’s mother, she would, on the balance of probabilities, not have contracted varicella on 16 May 2002.

Before determining this issue his Honour made the necessary prerequisite finding that Mrs King would have accepted the VZIG injection if she had been offered it on 6 May 2002.

The expert evidence was provided concurrently by a panel of six expert witnesses, who produced a joint report following a conference prior to the hearing. Out of the six experts, only Professor Curtis, a paediatric infectious diseases specialist, expressed the opinion that, on the balance of probabilities, Mrs King’s chickenpox would have been prevented if she had received an injection of VZIG on 6 May 2002.

The plaintiff submitted that his Honour should accept the view of Professor Curtis over that of the other experts. In considering whether Professor Curtis’ opinion should be accepted his Honour examined the basis on which that opinion had been formulated. Primary among the material relied upon by Professor Curtis were the statistics contained in an article published in 2000 and referred to in the judgment as the ‘Enders table’.

Professor Curtis interpreted the Enders table as demonstrating that, in a study of 212 pregnant women who were administered VZIG after exposure to varicella, 98 women or 46% became infected whilst 114 women or 54% did not become infected.  That is, a greater number of women did not become infected than the number who did.

The remaining experts identified three features of the Enders table that were important to note:

1. The data was derived from one or more observational studies and not from the results of a randomised controlled clinical trial. The latter is of a higher evidentiary level and would provide a more comprehensive basis from which to draw scientific conclusions.

2. The data was derived from a study of patients in Germany where the routine dosage of VZIG is 1750 international units, which is just under three times greater than the routine dosage in Australia in 2002 which was 600 international units.

3. The Enders table did not take into account the virus strike rate, being the number of women who would have not have become infected with varicella in any event, even if they had not been administered VZIG.  If the table were adjusted to account for this rate (accepted by his Honour as 10%), then the number of women who would not have become infected after being administered VZIG (and due to its administration) dropped to 93 women, or 44%.

His Honour noted that even if he had accepted the Ender table as supporting the conclusion that VZIG was successful at preventing chickenpox across a population, this would not, by itself, have been sufficient to support Professor Curtis’ conclusion that it was probable that in this case VZIG would have prevented Mrs King from becoming infected with chickenpox.

In reaching this finding his Honour discussed that, while epidemiological evidence may be relied upon to establish the possibility of a particular outcome occurring in a particular class of persons, further evidence in relation to the individual person in question (in this case Mrs King) was required to convert that possibility into a probability of the particular outcome occurring.

His Honour concluded that while it was possible that Mrs King would have not become infected with varicella if administered VZIG, the evidence did not established that this would probably (that is, more likely than not) have been the outcome.

JUDGMENT

While his Honour found that the defendant had breached the duty of care it owed to the plaintiff, the plaintiff had failed to establish that that breach had, more likely than not, caused or materially contributed to her loss. Accordingly judgment was given for the defendant and the plaintiff ordered to pay the defendant’s costs.

KEY LESSONS

The decision in this case reinforces two key lessons for healthcare providers and health lawyers.

First, the weight that a court will likely give to medical record as a contemporaneous record of events should not be underestimated. In many cases, in particular those involving infant plaintiffs, the claim will not be commenced until many years after the alleged negligence has occurred. The claim process itself can then also take upwards of several years to resolve.

Even if the honesty of a witness is not in question, the accuracy and reliability of his or her evidence as to something that may have occurred many years ago may be such that limited weight can be attached to it. Often in such cases the medical record will be relied upon as the primary factual record. In circumstances where the evidence contained in the record varies to that of a witness, it is open for a judge or jury to prefer the evidence contained in the record. In this case, his Honour accepted the contemporaneous hospital and medical records where they conflicted with the evidence of the plaintiff’s parents.

Second, while the role of scientific studies and epidemiological evidence in relation to causation remains important, the limitations of that evidence must be recognised and carefully assessed. The present case demonstrates that the outcome reported by a particular study can be analysed, disassembled and then reassembled to arrive at a conclusion opposite to that which the study was relied on to establish in the first instance.

Finally, evidence must be led to establish or refute the link between the possibility demonstrated by epidemiological evidence and the probability of a particular outcome occurring in a particular case.

For more detailed information regarding this case please click here for the case study.

Please contact Andrew Mansfield (andrew.mansfield@cgw.com.au) for further enquires relating to this alert.

Acknowledgement
The author wishes to thank Bianca Kabel for her assistance with preparation of this article.

 

This publication is for information only and is not legal advice. You should obtain advice that is specific to your circumstances and not rely on this publication as legal advice. If there are any issues you would like us to advise you on arising from this publication, please let us know.