R (Chidlow) v HM Coroner for Blackpool and Fylde & Others  EWHC 581 (Admin)
Human bodies being such complex things it is unsurprising medical causation is often extremely complicated. Legal causation of medical injury is a minefield for clinical negligence lawyers to navigate: “indivisible injuries”, “multifactorial causation”, “material contribution”, “loss of a chance”, etc.
But there is good news for all who must negotiate these causation booby-traps. It comes in the form of Mr Justice Pepperall’s judgment – arising out of an inquest – about whether a jury could reach a safe conclusion on the causative link between delay in treatment and death where the medical cause of death is unascertained.
It’s a brilliant exposition of two fundamental points on causation:
- Causation is more than a matter of medical statistics – even where survivors are a majority category.
- There is a difference between identifying what caused death and whether life could have been saved with earlier medical attention.
Carl Bibby was only 38 when he died at his home on 28 July 2009. Police officers in attendance, aware he had fallen ill, repeatedly called for an ambulance. At the inquest the ambulance service acknowledged that the failure to upgrade the case in response to the Police’s second telephone call was an error. It should have been prioritised with a ‘red’ (8-minute) response time. That would have led to attendance 26 minutes sooner than actually occurred. During that delay, Mr Bibby suffered cardiac arrest and died.
Cause of death unascertained
Detailed evidence available to the inquest from five pathologists could not identify the precise cause of death. Without a cause of death, understanding the causation of death was always going to be complex.
A Consultant in Critical Care & Emergency Medicine gave extensive evidence. He could exclude some causes of death but concluded it was impossible to reach a final diagnosis. What he could say was that Mr Bibby became critically ill for at least 25 minutes before his cardiac arrest and that an arrhythmia was the most likely cardiac event.
The inquest heard much statistical information about likely survival given various possible scenarios, with a marked difference in survival – from below 50% to above 50% – depending upon whether an ambulance crew attended after or before cardiac arrest.
There was particular focus upon the extent to which the expert was able to identify likely outcomes whilst the cause of death remained unascertained. It was suggested to the expert that he was, in effect, speculating as to what a paramedic could have done. Establishing medical cause of death would plainly have assisted, but it was not essential to being able to form an opinion as to the effect of delayed treatment. As the expert said; “You don’t have to have a diagnosis…to provide emergency care and…save a patient”.
Causation and statistics
In reviewing the Coroner’s decision the Divisional Court considered the vexed question of whether causation can be proved by statistical evidence alone.
First, as Pepperall J explained, causation evidence relating to the particular deceased may include general statistical evidence drawn from population data such as the rate of survival in a particular group. But care has to be exercised when relying on statistics as a means of establishing causation. The court must look at the deceased’s individual and specific circumstances rather than generalised statistics alone: to be a figure in a statistic does not, in itself, prove causation.
Second, whilst research may show that the majority of patients survive an event with prompt treatment, the fact that a patient dies following delayed treatment does not of itself establish causation: it does not show whether or not he would have been one of the minority who would not have survived regardless. Whether delay contributed to death turns upon all available medical evidence, both overall statistical chances of survival and information about the particular condition and specific circumstances of the patient.
In this case, the expert’s opinion that Mr Bibby was more likely than not to fall into the group of severely unwell patients who are nevertheless expected to survive with prompt treatment, was rooted in a number of factors, including:
- The expert’s experience of dealing with critically ill patients;
- The expert’s reading of other medical evidence relating to Mr Bibby and specifically the post-mortem findings that meant he could exclude a number of underlying health problems;
- The expert’s understanding of Mr Bibby’s condition when he was attended upon;
- Statistics on survival data taken from a number of studies.
Ultimately the court concluded the expert in emergency medicine and the pathologists were addressing different things. Ascertaining the cause of death, whilst helpful, was not essential to form an opinion about the likely consequences of delay in treatment. The expert’s view was that with prompt treatment it was more likely than not that Mr Bibby would have survived. The jury did not have to accept that view. But it was not so obviously unreliable that it was not safe to leave them to consider the possible causative consequences of delay.
There are three main points to take away from this case.
First, this is a helpful judgment on causation, and on Galbraith Plus for those that do inquests. It is a good one to have in the toolkit. On causation as it pertains to statistics, it is required reading.
Second, the inability to ascertain cause of death does not necessarily prevent consideration of whether treatment could have prevented that death, however it came about. On the one hand, this feels odd – how can you conclude death could have been prevented if you cannot establish what caused it? On the other, it is obvious – of course people are treated, and lives saved, in circumstances where clinicians are not certain what the actual problem is.
Third, statistics alone are not enough. What is needed is something on top of the statistics. One might say the rule is ‘statistics plus’.