From arm wrestling gone wrong to flying pocket knives, district health boards have reported on "adverse events" affecting 525 patients in the year to June.

This is 16 per cent more than the 454 national adverse events in 2013/14, according to data collated by the Health Quality and Safety Commission, which says the increase is probably due to better reporting.

Seventy-three of the patients in the latest annual tally died, although not necessarily because of the adverse event.

Falls causing serious harm were again the most commonly reported event, accounting for 277 cases, followed by 205 cases attributed to problems with clinical management which included misdiagnosis, failure to act on lung x-ray abnormalities that turned out to be cancer, delays in treatment, misinterpretation of electronic fetal monitoring in labour, and leaving swabs and instruments in patients.


An adverse event is defined as one that causes serious harm or death, or could have done so.

Some of the incidents reported by DHBs include:

Arm wrestling: When a Northland DHB staff member agreed to a patient's request for an arm-wrestle, the patient suffered a fractured upper arm. Arm-wrestling and other "contact sports" are now banned.

Flying pocket knife: A Counties Manukau patient was allowed to wear trousers during a magnetic resonance scan and didn't know there was a pocket knife in a pocket. The scanner's powerful magnet sucked the knife out of the pocket "at speed" and it hit the patient's right eye, causing a tear in the retina and fracturing the bone around the eye, requiring ongoing operations. MRI patients must now change into a hospital gown and a metal detector will be installed.

Also at Counties Manukau, an eye patient was kept waiting 15 weeks instead of being seen as intended within four, despite phoning to express concerns about worsening sight. The person was left with permanent deterioration of eyesight. The mistake was blamed on "critical workforce shortages".

Wrong tooth, wrong kidney: A Hutt Valley dental therapist extracted the wrong tooth after reading an x-ray the wrong way around.

Also in Hutt Valley, a patient was left with a significant reduction in renal function after the removal of the larger rather than the smaller kidney for live-donor transplantation.

Lost vision: A Whanganui teenager was treated for a squint but his retina and optic nerve weren't checked. In the absence of that baseline check to allow assessment of progressive damage, a misdiagnosis was later made of a non-progressive congenital eye condition that would require special contact lenses and the patient was discharged. In fact, a large benign cyst was pressing on the optic nerve and blood supply which caused loss of vision which was irreversible, despite surgery.