Cooper & Anor v Royal Berkshire NHS Foundation Trust

In clinical-negligence litigation involving competing medical diagnoses, the court must determine which explanation is more likely on the evidence. Population prevalence is relevant, but it must be adjusted to reflect the claimant’s individual circumstances and the timing of the event. Expert opinion is not accepted merely because it is expressed by an eminent expert. The court must examine the reasons given, their evidential support, internal consistency, logic, the expert’s care and accuracy, response to cross-examination, willingness to revise opinions, and independence. A normal diagnostic test may weaken a diagnosis without excluding it where the test has recognised limitations. The court must weigh all relevant factors and decide causation on the balance of probabilities.

The claimant suffered an asystolic cardiac arrest five days after giving birth following an emergency caesarean section for uterine rupture. She sustained irreversible hypoxic neurological damage and remained minimally responsive.

The defendant admitted that inconsistent post-natal provision of Heparin amounted to negligent medical care. It was also agreed that, if the claimant’s collapse had been caused by a cerebral venous thrombosis (CVT), that negligence would have been causative. The only liability issue was whether the claimant had proved that a CVT, rather than post-partum eclampsia (PPE), caused the cardiac arrest.

1. The claimant succeeded on the only issue requiring determination. On the balance of probabilities, she suffered a CVT which caused a focal seizure, followed by a generalised seizure, asystolic cardiac arrest and hypoxic neurological damage.
2. The court applied the guidance in Loveday v Renton & Wellcome Foundation Limited [1990] 1 Med LR 117. Expert opinion was assessed by reference to the reasons given, evidential support, internal consistency, logic, care, precision, response to cross-examination, willingness to reconsider opinions and independence.
3. The mechanism by which either PPE or CVT could cause cardiac arrest required a generalised seizure affecting the autonomic parts of the brain. The judge rejected Dr Sawle’s view that PPE could directly cause cardiac arrest without a seizure.
4. General population prevalence favoured PPE, but the relevant comparison had to reflect the claimant’s circumstances. PPE occurred predominantly within 48 hours of delivery, whereas the claimant’s event occurred on the fifth post-partum day, during a period of heightened thrombotic risk. The resulting differential was insignificant.
5. The normal CT scan favoured PPE but did not determine the issue. CVT may produce a normal CT scan, and the scan’s limitations had to be balanced against the other evidence.
6. The claimant’s prothrombotic post-partum condition was increased by the traumatic delivery, blood loss, emergency caesarean section, pyrexia, vomiting, possible dehydration, immobility and absence of consistent Heparin. These factors supported CVT. The lack of prior or ante-natal pre-eclampsia and the well-developed baby reduced the likelihood of PPE. Headache, mild hypertension and absence of other neurological symptoms were compatible with either diagnosis and did not materially alter the conclusion.

Liability was established against the defendant.

Not stated in the judgment.