The decision in CNZ v Royal Bath Hospitals NHS Foundation Trust provides important judicial consideration and conclusions on the issues of how the Supreme Court’s Montgomery principle on informed consent applies to historical cases involving obstetrics and gynaecology as well as that of material contribution in Cerebral Palsy negligence matters.
What were the facts in CNZ v Royal Bath Hospitals NHS Foundation Trust?
The Claimant’s mother (M) was pregnant with twins in 1996. She repeatedly requested a Caesarean birth but this was denied or delayed. M was admitted and induced on 2 February 1996. At 00:01 on 3 February 1996 the first twin (the Claimant’s sister) was delivered vaginally. The Claimant’s head remained high in the pelvis; therefore at 00:35 M was sent to theatre for an artificial rupture of membranes (ARM) procedure. M stated she did not want the ARM procedure; however, the obstetrician ignored her preference and request for a Caesarean and went ahead with the ARM. In the end, the Claimant was delivered by Caesarean at 01:03.
The Claimant suffered hypoxia and was subsequently diagnosed with quadriplegic Cerebral Palsy.
The Claimant argued that if M’s request for a Caesarean had been actioned sooner, she (the Claimant) would have been delivered earlier and therefore not suffered damage.
What was the Court’s decision in CNZ v Royal Bath Hospitals NHS Foundation Trust?
Mr Justice Ritchie had to decide on two key issues, namely:
• What constituted informed consent.
• Material contribution in relation to causation of the birth injuries.
The leading case is the Supreme Court decision in Montgomery v Lanarkshire Health Board  UKSC 11. The mother in this case was just above five feet tall and suffered from diabetes.
Women with diabetes are likely to have babies that are larger than normal, with a particular concentration of weight on the shoulders.
In 1999, the mother became pregnant. Because of her diabetes, the pregnancy was regarded as high risk, requiring intensive monitoring. The mother questioned her obstetrician on whether her baby’s size would present difficulties if it was delivered vaginally. Despite her concerns, the obstetrician failed to disclose the risks of a vaginal birth to the mother. Her son subsequently experienced complications owing to shoulder dystocia, resulting in hypoxic insult with consequent Cerebral Palsy. The mother sued for negligence claiming that if she had been informed of the risks she would have demanded a Caesarean.
Overturning the existing House of Lord’s precedent in Sidaway v Board of Governors of the Bethlem Royal Hospital  AC 871 the Supreme Court found for the Claimant, thus changing the law around informed consent before surgery. In Sidaway, the House of Lords rejected the idea that a patient should be informed of all risks associated with a procedure.
Lord Scarman summarised his conclusions as follows (pp 889-890):
“To the extent that I have indicated I think that English law must recognise a duty of the doctor to warn his patient of risk inherent in the treatment which he is proposing: and especially so, if the treatment be surgery. The critical limitation is that the duty is confined to material risk. The test of materiality is whether in the circumstances of the particular case the court is satisfied that a reasonable person in the patient’s position would be likely to attach significance to the risk. Even if the risk be Page 16 material, the doctor will not be liable if upon a reasonable assessment of his patient’s condition he takes the view that a warning would be detrimental to his patient’s health.”
In Montgomery, the Court ruled that a patient should be told whatever they want to know and the extent of the information provided was not a matter for clinical judgment unless the obstetrician:
“…reasonably considers that its disclosure would be seriously detrimental to the patient’s health. The doctor is also excused from conferring with the patient in circumstances of necessity, as for example where the patient requires treatment urgently but is unconscious or otherwise unable to make a decision.”
Ever since Montgomery, the Courts have had to tackle the issue of how far back the principle can be applied. In CMZ, Mr Justice Ritchie concluded:
“I doubt it can be taken as far back as the 1950s or 1960s..”
He also doubted whether it could be applied to clinical practice in the 1980s. However, in CNZ he deduced, although cautiously, that the Montgomery principle “probably does” apply.
Mr Justice Ritchie stated that the Obstetrician ignored M’s wishes to have a Caesarean and adopted an approach that was “too paternalistic” and contrary to the Mongomery principle.
Material contribution is where the law awards 100% compensation to a Claimant who, in certain circumstances, only needs to prove to a civil standard that negligence materially contributed to the harm they suffered as opposed to causing all of it.
Expert witnesses sometimes apply the Aliquot theory as a method of applying disability using the duration of the PHI as a measure.
For example, a person exposed to 10 – 15 minutes of PHI will have mild to moderate disability; 15 – 20 minutes leads to severe injury.
The Claimant’s expert witness in CNZ was uncomfortable applying the Aliquot theory as a blanket rule because every Cerebral Palsy patient is different. In addition, the Aliquot theory proposes that each five minute chunk of PHI was likely to result in a specific type of harm. Mr Justice Ritchie rejected this approach on the grounds that it lacked sufficient evidence-based certainty on the extent of the injuries that may be suffered during such timeframes.
“I consider that on logical analysis the Aliquot theory falls apart. On the hypothetical assumption (which I am not prepared to make in any event) that the theory is applied when the total PHI is 20 minutes (10 of which were damaging) and the negligent PHI is 5 minutes, then using Doctor Rosenbloom’s Aliquot approach the quantum would be apportioned in line with the attached chart. The relevant claimant would be in the moderate category and the damages would be assessed on the difference between the actual symptoms and the symptom pattern set out in the mild category. However if the negligent PHI was only 3 minutes, in my judgment that would still make a material contribution to the extent and severity of the Claimant’s brain injury but apportionment would not be possible in relation to functional outcome so recovery would be 100%. This is plainly illogical. Less damage/injury results in more damages. I raised this problem before submissions but the Defendant could provide no resolution for the inherent unfairness in that approach.” at para 385
Given the difficulty in obtaining evidence to support the application of the Aliquot theory, it was concluded that the Courts must continue to award full damages when PHI resulting from some negligence made an undefined contribution to the infant’s injuries. However, Mr Justice Ritchie left open the possibility of apportioning damages where expert evidence allowed findings to be made concerning the functional nature of the disability which would have occurred regardless of the negligence.
Leave to appeal the decision has been given.
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