The duty to warn and the limited application of Chester v Afshar

The Court of Appeal’s decision in Duce v Worcestershire Acute Hospitals NHS Trust [2018] EWCA Civ 1307

Overview

In finding that an NHS trust had not breached its duty of care by failing to warn a patient of the risk of developing chronic post-surgical pain following a total abdominal hysterectomy and bilateral salpingo-oophorectomy, the Court of Appeal has provided useful guidance on the duty to disclose material risks to a patient post-Montgomery v Lanarkshire Health Board as well as some helpful commentary on the use of the ‘but for’ causation test following the decision in Chester v Afshar.

Background

The appellant Ms. Duce appealed against the dismissal of her personal injury claim against the respondent NHS trust. In 2008, she had undergone a total abdominal hysterectomy and bilateral salpingo-oophorectomy after suffering from heavy and painful periods. After surgery, she suffered neuropathic post-operative pain and argued that the defendant trust had negligently failed to warn her of the risk of developing chronic post-surgical pain (CPSP). The judge however found that the trust had not been negligent and, in any event, that causation had not been established.

On appeal, Ms Duce sought to argue that the judge had:

1. Failed to consider whether the risk of CPSP was "material" as per the test in Montgomery v Lanarkshire Health Board [2015] UKSC 11;
2. Failed to apply the test of causation set out in Chester v Afshar [2004] UKHL 41;
3. Erred in finding that even if she had been warned of the risk of CPSP, she would still have proceeded with the operation.

In response, the trust argued that at the material time, knowledge of chronic, neuropathic pain was not commonplace and not well-understood by gynaecologists, upon which both parties’ experts agreed, hence doctors could not be expected to warn patients of its risks. The trust also argued that the appellant’s interpretation of the Chester decision constituted a disapplication of the conventional principles of causation.

The court’s decision

Unanimously rejecting the appeal, the Court of Appeal held that the trial judge had correctly applied the Montgomery test and upheld his findings that Ms. Duce had been suitably warned of the risks of the surgery and would have proceeded to have it anyway, even if the risk of the neuropathic pain had been explained.

An especially helpful aspect of the judgment was the court’s reaffirmation that the modified test for causation, per Chester, in cases involving consent did not remove a claimant’s need to show a ‘but for’ causative effect of the breach of duty and specifically that the surgery would not have happened at the material time. The court followed an earlier Court of Appeal decision (Correia v University Hospital of North Staffordshire NHS Trust [2017] EWCA 356) in which the court stressed that if the exceptional principle which Chester established were to be relied upon, it had to be pleaded and proved that a claimant would have deferred the surgery if warned of the risk.

Comment

Both medical and legal practitioners will be relieved and reassured by the Court of Appeal’s reiteration that the application of the Chester decision as an exception to the usual principles of causation can only be in limited and clearly set-out circumstances. Another welcome aspect of the judgment is the court’s confirmation that medical staff cannot be expected to warn patients about risks of which they are unaware. Although this was self-evidently a very distressing set of circumstances for the claimant, the court’s clarity will be appreciated by all those involved in dealing with consent cases post-Montgomery.