A woman who had had her right lung removed was sent home from hospital without anyone diagnosing the other lung had collapsed - and died days later.
A senior medical doctor has been found in breach of the Code of Health and Disability Services Consumers' Rights over the case, and a second doctor has been reprimanded for the part he played.
The 58-year-old woman had a recent history of a chesty cough, chest tightness, and shortness of breath, and had previously had a lung removed. She awoke in the early hours with a dull ache in her left shoulder, tight chest, and inability to catch her breath, according to the report from Health and Disability Commissioner Anthony Hill says.
She was taken to hospital by ambulance and seen around 4.30am by the sole doctor on duty, a consultant emergency physician who ordered a chest X-ray "for when available".
The doctor discussed possible diagnoses but did not write down his clinical impression and the diagnoses he had considered. When the shift changed at 7am a senior medical officer took over the woman's care.
That doctor looked at the X-ray and saw nothing new, so decided to send the woman home - despite having found no cause for her breathing difficulties.
Shortly after the decision was made to discharge the woman, the radiologist's formal review of her X-ray found a large left pneumothorax, or collapsed lung. But that report was emailed to the woman's GP and the consultant emergency physician, not to the senior medical officer, who never saw it.
He sent her home at 10am with advice to follow up with her GP or to "come back if any concerns".
The woman's GP practice saw the report and sent the woman back to hospital around 6pm. She was seen by a different doctor who ordered her pneumothorax drained and the lung reinflated.
During the operation, the woman began struggling to breathe. When the needle was removed from her chest she went into cardiac and respiratory arrest. She was resuscitated but died some days later after suffering a second cardiac arrest.
Both doctors came under fire from the Health and Disability Commission, with the second doctor being found in breach of the Code. Hill criticised the doctor for discharging the woman without excluding significant diseases or documenting much of the diagnostic process.
The senior medical officer acknowledged that reviewing X-rays was a key part of a senior emergency physician's job.
"I deeply regret that the pneumothorax was missed by me and I apologise unreservedly for this," he said. He had made changes to his practice including being more careful in his interpretation of X-rays, and was more likely to get a radiologist to check them if unsure.
Hill also criticised the first emergency doctor who saw the woman overnight, and recommended his clinical documentation be audited to see if any other patients had been discharged without a diagnosis.
The emergency physician apologised to the family, saying he distinctly remembered admiring the woman for facing serious challenges, including having her right lung removed, and continuing to live a full life.
The DHB has also made changes, including training its ED staff in how to spot a pneumothorax on an X-ray.