Thorley v Sandwell & West Birmingham Hospitals NHS Trust [2021] EWHC 2604 (QB) (01 October 2021)

This is the trial of the issues of breach of duty and causation… In February 2002 he was diagnosed with atrial fibrillation (AF)… his treatment for this condition included a daily 3.5mg dose of warfarin… In March 2005 C suffered chest pain. A review at D concluded that investigation by coronary angiogram was necessary. This was arranged to take place on 27 April 2005. In accordance with the advice given to him… C stopped his daily dose of warfarin for the 6-day period 23-28 April (inclusive) and restarted on 29 April at a reduced dose of 3mg. The angiogram on 27 April was uneventful and he was discharged home that day. However on 30 April he suffered an ischaemic stroke which has resulted in permanent and severe physical and cognitive disability. [1]

C alleges that D was in negligent breach of duty in that the cessation of warfarin should have been limited to the 3-day period 24-26 April (inclusive) and restarted at the usual 3.5mg, not 3mg. These breaches caused or materially contributed to the occurrence of the stroke. [2]

D denies breach of duty, save to admit that warfarin should have been restarted by no later than the day after the angiogram (i.e. 28 April) and at the previous dose of 3.5mg. As to causation, and whatever the conclusion on breach of duty, it contends that C would have suffered the stroke in any event. [3]

D would not have been in breach of its duty of care if it had restarted warfarin on 28 April; and in consequence was not in breach of duty beyond the extent which the D has admitted. [80]

D’s case on causation is put on two alternative bases, namely by reference to the tests commonly described as (i) ‘but for’ and (ii) material contribution. [81]

In the light of my findings on breach of duty… resolution of the ‘but for’ case on causation is academic. The alternative case of ‘material contribution’ remains live, but only to the extent of the admitted breaches. However, in each case I consider the causation issues in full. [82]

if the omission of warfarin for a period of more than 3 days did constitute a breach of duty, I would reject the case of ‘but for’ causation and hold that C would have suffered his stroke in any event. [137]

The alternative case on material contribution raises two particular issues : (i) whether this modified test of causation can be applied to a case where (as admittedly here) the injury is indivisible; if so, (ii) whether negligent over- omission of warfarin for 1, 2 or 3 days of the total 6 made a material contribution to the occurrence of the stroke. [138]

the claim of material contribution must fail on the basis that this modified test of causation does not apply when there is a single tortfeasor and an indivisible injury. [151]

the claim must be dismissed [164]