Wilsher v Essex Area Health Authority [1988] AC 1074 (HL)

Facts

A premature baby required oxygen therapy shortly after birth. A junior doctor mistakenly inserted a catheter into a vein rather than an artery, resulting in excessive oxygen being administered.

The child later developed retrolental fibroplasia, a condition causing blindness. However, medical evidence showed that there were multiple possible causes of the condition, including several unrelated natural complications of prematurity. The claimant argued that the doctor’s negligence caused the blindness.

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Issue

Is a junior doctor judged by the same standard as a fully qualified doctor? Can causation be established where there are multiple possible causes of harm, and it is uncertain which one caused the injury?

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Decision

The House of Lords held that a junior doctor is judged by the same standard as a reasonably competent doctor in that post. Inexperience is not a defence.

The claimant failed on causation because it could not be proven on the balance of probabilities that the excessive oxygen caused the blindness rather than one of the other possible causes.

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Legal Principle

Professionals, including junior doctors, are judged objectively against the standard of a reasonably competent person performing that role. Inexperience does not lower the standard of care.

Where multiple independent possible causes exist, the claimant must prove that the defendant’s breach was the probable cause of harm.

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Importance

• Reinforces the objective professional standard seen in Bolam.

• Frequently cited in both professional negligence/medical causation cases.

• Important distinction from cases involving cumulative exposure (e.g., material contribution cases).

• Demonstrates strict application of the balance of probabilities test in medical negligence.