How do we show negligence has caused harm?

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If you have been harmed by negligent medical care, you may be entitled to damages. But you need to show that negligence caused the harm; that it would not have happened in any event.


How do we prove negligence caused harm?

In most cases, the courts simply ask what would have happened but for the negligence. This ‘but for’ test is easy to understand but can be difficult to apply. What happens for instance if your diagnosis of cancer was missed a year before? What stage would the cancer have been? What would the prognosis have been? How can anyone know? The answer is that there will probably be different views but experts have to use the research and evidence available, alongside their own experience, and do their best to guide the court.

There are, however, cases where gaps in our scientific knowledge mean no one can answer the ‘but for’ question.

What if there is a gap in our knowledge?

In two areas of these scientific gaps, the courts replace the ‘but for’ test with a different test. This makes life easier for people bringing claim and can lead to surprisingly large awards.

‘All or nothing’ injuries

The first is what you might think of as an ‘all or nothing injury’. The courts have sometimes called these ‘trigger injuries’. This is an injury which has a single trigger. The injury does not get worse just because there are more triggers. It either happens or it doesn’t. It is ‘all or nothing’. Think of malaria, which is caused by a single mosquito bite. You may have many bites but still not get malaria. Just one bite from the right mosquito is enough. You either get malaria or you don’t but more bites do not make it worse.

There are some injuries from medical mistakes which are like that. In one case, a woman was weak after surgery. She vomited and was too weak to clear her airways. She breathed in her vomit, had a heart attack and was left with brain damage. The court heard that her weakness – which was the ‘trigger’ – had two causes. One was an underlying illness (pancreatitis). The other was that her care after surgery had been negligent. The experts were asked whether she would have been too weak to clear her airways but for the negligent care. They couldn’t say. But they could say that the negligence was a cause. It contributed to her weakness. The court used this contribution test rather than the but for test (the technical legal term is ‘material contribution’.) The court ruled that she was entitled to recover for all the loss arising from her brain injury. John White, Partner at Enable Law, ran that case to the Court of Appeal. It has proved to be a very important one for patients.

Other cases where the courts have allowed patients to recover in full this way include sepsis, meningitis, brain damage from ischaemia (reduced blood supply to the brain), brain damage from raised intra-cranial pressure, hydrocephalus and post-traumatic stress disorder (PTSD).

We act for many people with injuries from sepsis and different forms of brain damage. This way of proving that negligence has caused harm is important on these cases.

Dose-related injuries

The second area where the courts replace the ‘but for’ test with this easier contribution test is more complicated. These are what you might think of as dose-related injuries. The more the negligence, the worse the injury. For instance, if the blood supply to your brain is stopped, brain tissue will gradually die. The longer this goes on for, the worse the damage. We sadly see this where babies suffer birth injuries leading to cerebral palsy. In many of these cases, there are a few minutes where no one is to blame for the disrupted blood supply and then a few minutes where negligent delays make the situation worse.

The courts have to decide how much a baby would have been injured anyway and how much extra harm the negligence caused. For instance in one recent case, the blood supply to a baby’s brain was disrupted for 16 minutes. The first 10 minutes did not cause harm – baby’s brains can survive 10 minutes without blood supply. After that ‘every minute counts’ and there were six minutes. The judge asked himself, ‘What do I do if only two of those six minutes were caused by negligence and there would have been four minutes of damage anyway?’ The experts thought it impossible to say exactly what damage each minute caused. Different areas of the brain suffer damage but not at a uniform rate. In those circumstances, the child would recover for all her loss even though she would have suffered some of it anyway.

Fairness to patients

That may sound unfair. Where there is uncertainty, why should the law favour patients? Why should hospitals have to pay for damage they have not caused as well as damage they have? The answer is that the gaps in our knowledge mean that it has to be unfair to one party or the other. It chooses to favour the innocent patient who has done nothing wrong over the party who caused harm, particularly where the harm is seriously disabling.

Surprising results

What it means for disabled patients is that we are sometimes able to reach surprisingly good results for them.

Medical negligence is a very technical area of law and medicine. It has become very complex and the courts have spent a long time grappling with these questions. Managing these claims requires specialists with experience and expertise, who really understand these difficult issues.

Enable Law has a team of expert lawyers who specialise in the complex claims. If you or someone you love has been injured by medical mistakes, please get in touch.

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