Cooper v Royal Berkshire NHS Foundation Trust  EWHC 664 (QB) required the court to assess expert evidence so as to determine whether the claimant’s cardiac arrest and consequent hypoxic neurological damage was caused by the occurrence of a cerebral venous thrombosis (CVT). The defendant asserted otherwise, saying that the cause was postpartum eclampsia.
It was conceded by the defendant that the lack of consistent post-natal provision of Heparin amounted to a lack of reasonable medical care of the claimant and, that if the cause of her cardiac arrest and consequential hypoxic neurological damage was a CVT, the admitted negligence would have been causative of her current condition.
Ultimately the court determined that the cause was CVT.
In doing so, reference was made to the court’s approach to the assessment of expert evidence; in particular the helpful guidance provided by Stuart Smith LJ in Loveday v Renton & Wellcome Foundation Limited  1 Med LR 117, in relation to the court’s approach to the assessment of expert evidence,
“The mere expression of opinion or belief by a witness, however eminent…….does not suffice. The court has to evaluate the witness and the soundness of his opinion. Most importantly this involves an examination of the reasons given for his opinions and the extent to which they are supported by the evidence. The judge also has to decide what weight to attach to a witness’s opinion by examining the internal consistency and logic of his evidence; the care with which he considered the subject and presented his evidence; his precision and accuracy of thought as demonstrated by his answers; how he responds to searching and informed cross-examination and in particular the extent to which a witness faces up to and accepts the logic of a proposition put in cross-examination or is prepared to concede points that are seen to be correct; the extent to which a witness has conceived an opinion and is reluctant to re-examine it in the light of later evidence, or demonstrates a flexibility of mind which may involve changing or modifying opinions previously held; whether or not a witness is biased or lacks independence.”