Clinical Negligence News

Causation: The Hurdle is lowered? David Tweedie

Alternative and Cumulative Causes in Clinical Negligence

Causation is often the battleground in clinical negligence cases. Even if the claimant can demonstrate breach of duty of care (i.e. that the care given by the defendant fell below a reasonable standard), he/she must still prove that the injury complained of was caused by that breach of duty. This is the issue of causation.

The standard test for causation is the "But For" test i.e. but the claimant must prove that but for the breach of duty, the injury would not have happened. Put another way, the claim is for the difference (expressed in money - damages) between the claimant's present condition on the one hand and the condition in which he/she would have been in had there been no breach of duty of care.

In many situations that is the appropriate test. It is easy enough to demonstrate that if the claimant had not been hit by a car, he would not have suffered his broken leg. In clinical negligence cases, in practice the test is hard to answer. The claimant is already in the doctors' hands because of an underlying medical condition. How much of the injury complained of is really the result of that underlying condition? This is always a matter for expert evidence.

But where there are potentially several causes for the injury, the problem from the claimant's perspective is even more difficult.

In the leading case of Wilsher -v- Essex Area Health Authority 1988 (House of Lords) a baby was negligently given an overdose of oxygen. He was rendered blind by reason of fibroplasia which the claimant alleged was caused, as can happen, by an excess of oxygen. At trial, the Judge found that this was only one potential cause - along with four non-negligent causes - each one of which was distinct and could have caused the injury. The House of Lords decided that the claimant must prove (on the balance of probabilities) that the negligent cause was probable. This is now known as the "alternative risk" situation.

The recent case of Bailey -v- Ministry of Defence 2008 (Court of Appeal) deals with the "cumulative causes" situation. The claimant underwent an unsuccessful gall- stone operation in the Royal Haslar Hospital run by the Ministry of Defence. There was extensive bleeding. There was substandard care in the postoperative period, in particular a failure to resuscitate. She developed pancreatitis and was transferred to an intensive care unit in Portsmouth. She was later put on the renal unit in the Portsmouth Hospital were she aspirated her vomit leading to a cardiac arrest resulting in hypoxic damage to her brain.

At trial, the Judge found that there were ultimately two reasons for the claimant's inability to stop the aspiration of her vomit. One was the pancreatitis, which was not negligent. The other was her weakened state which, had she been treated properly including her resuscitation, would have been avoided. He could not decide on the available evidence of the experts which was the dominant cause but he concluded that each made a "material contribution".

On appeal, the MOD argued that the "But For" test should apply, i.e. the claimant must prove that without the negligence, the injury would not have happened. On the evidence, this would have meant that the claim failed.

The Court of Appeal unanimously found that the Judge had been right, on the evidence, to conclude that the weakness of the claimant had made a material contribution to the injury and found in her favour. Lord Justice Waller said: -

"In a case where medical science cannot establish the probability that "but for" an act of negligence the injury would not have happened but can establish that the contribution of the negligent cause was more then negligible, the "but for" test is modified, and the claimant will succeed".

Comment

The law in relation to causation is complex and often presents practical difficulties of proof from the claimant's perspective. There is a distinction between the "alternative causes" situation in which one of several distinct, competing causes must have caused the injury (and the claimant has to prove that the "negligent" cause was the one), and the Bailey situation in which more than one cause may have contributed to the injury. In that latter situation ("cumulative causes") the claimant now has to prove simply that the negligent cause made a material contribution to the injury. "Material" merely means that it was not a purely theoretical or negligible contribution but, most significantly, it does not need to be the dominant cause.

If Bailey -v- Ministry of Defence remains the law, it will make it possible for claimants to establish causation in certain cases in which it was previously impossible.

David Tweedie

This article provides a summary of a recent case/change in law/news item. It is intended for general information purposes only and is not to be relied upon. It does not constitute legal advice and should not be treated under any circumstances as a substitute for legal advice. Lees Solicitors LLP does not accept any responsibility for any loss that may arise from reliance upon the information contained within this article. The copyright in this article is owned by Lees Solicitors LLP and permission must be sought before reproduction or publishing.

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