A failure to properly sterilise surgical equipment at Hawke's Bay hospital was caused by "many errors", an external review has found.
The Hawke's Bay District Health Board released, on Wednesday, internal and external reports on the incident that saw the equipment used on up to 55 patients over nine days in February.
It covered all aspects of the sterilisation failure and subsequent use of unsterile instruments on patients, risk mitigation and recall of potentially affected patients.
The external review found that all three sterilisation checks failed and that staff failed to follow sterilisation policy.
Those errors included the reliance on a printer that hadn't been working for months, a switch on the sterilising machine that was know to not work, and a raft of human and other mistakes.
The report highlighted that at 10.45pm, on February 1, the sterilising technician who put the load into one of the autoclaves did not recall hearing the steriliser begin its cycle after pressing the start button.
The four autoclaves are connected to individual printers which signal when the machine has started and when the process has been completed.
As the printer for Autoclave "3" had not been working for several months, no signal was given and no printout was available at completion.
Staff instead had to check on a computer to see if the machine had been operating.
The next morning, the responsibility for the unloading of the autoclaves fell on nursing staff who are not trained in sterilising technology.
The staff member did not check the computer to see if the equipment had completed the full sterilisation cycle before dispatching the equipment for use in theatres.
Furthermore, the staff member failed to check that sterilisation codes on the packages had not changed colour, indicating they had been sterilised.
Clinical staff who were taking the equipment from their packs failed to check the colour codes before use.
There were 91 pieces of equipment that were cleaned and heated to high temperatures, but failed to go through the third and final stage of sterilisation overnight between February 1 and 2.
It wasn't until February 11 that the alarm was raised after a theatre nurse noticed the colour coding on a surgical tools packet was wrong, and notified a manager.
Up to 55 patients from across Hawke's Bay underwent tests for blood-borne viruses – including HIV and hepatitis B and C, because the inadequately sterilised surgical equipment may have been used on them. However, none of them have shown any sign of infection.
Of those affected, 18 people were operated on in the main theatre block of Hawke's Bay Hospital.
The remaining packs were also sent to oral health and gynaecological clinics throughout Hawke's Bay, where they were then used by district nurses.
More than half the packs that were sent out were recalled before being used.
Three children under the age of 16 and four people over the age of 70 were included in the group.
In the aftermath of the incident, several changes to systems have been put in place and both the printer and start button have been replaced.
Tape on small pouches has been made much larger so the change in colour couldn't be missed, and the move to a paperless environment has been delayed until checks were well embedded.
The reviewers concluded that there was a "system wide failure across all departments to complete correct sterilisation checks".
They found that sterilisation services around the country has for "too long been ignored by the health service management due to it not being a source of revenue, but rather requiring high cost investment".
It recommended that going forward, the Ministry of Health should put several systems in place to prevent further incidents occurring, including that electronic tracking and traceability systems be installed at all sterile units and operating theatres throughout the country as soon as possible, with tracking identifiable to individual instrument level.
They also called for this tracking system to be extended out to include all wards and outpatient clinics within 18 months.
They have also made national recommendations that sterile services should undergo external auditing in conjunction with robust internal auditing.
Executive director provider services Dr Colin Hutchison said the review "made it clear that no-one person or department can be held accountable for this, as there were many errors across a number of systems and processes".
Dr Hutchison said many of the issues would not have occurred if policies and processes had been embedded.
"We have caused distress to the patients affected and we apologise to those people for the anxiety this has caused.
"The DHB will work towards appointing an educator specifically to sterile technician training and professional development as well as system-wide retraining to ensure clinical staff understood and followed all steps and protocols regarding the handling of sterile equipment," Dr Hutchison said.
Alongside this, he said the DHB was also in the process of upgrading its electronic tracking system of reusable medical devices, which was due to be completed this month.