Six operating theatres at Waikato Hospital are too hot to work in according to surgeons who want better air-conditioning at a cost of $200,000.

The theatres are required to be less than 22 degrees Celsius and 60 per cent humidity but last summer they became so stuffy doctors cancelled some surgeries in the orthopaedic department.

Executive director of Waikato Hospital services, Brett Paradine, said the hotter than usual summer caused the theatres to creep up to 24 degrees which is one factor contributing to a backlog of patients waiting for elective surgeries.

"There were some concerns at the end of the hot summer we had last year that the theatres were warmer than ideal," Paradine said.


The surgeons wanted the temperature to sit at 20 degrees or lower.

"That's been looked at and a plan developed and approved to upgrade the heating-ventilation air-conditioning system for theatres."

Paradine said $200,000 had been earmarked to upgrade the current air-conditioning in the six theatres in the Kempthorne Building, but the work could not be scheduled to begin until Christmas when there would be less elective surgeries taking place.

This was because the upgrade would affect a whole theatre suite including 12 operating rooms across two levels of the older building, even though only six of them needed upgrading.

That would put half of the hospital's 24 operating theatres out of action.

"There's been a fair bit of work to look at what the ideal time is and to minimise disruption across all our different specialities it was decided that we go into a lower activity period over Christmas so that's when we're looking at doing that work."

Winter had provided a reprieve from the situation but Paradine said Waikato District Health Board was developing contingency plans in case of a hot December.

"There is the risk that if we have a very hot December there may be lists [of elective surgery patients] that surgeons feel they can't proceed with. If that's the case we will have to look at other options."

These included using other operating theatres at the three private hospitals in Hamilton.

The work would include new vents, ducting and chillers and was hoped to be completed by January.

A Hamilton-based surgeon said he was unaware of the temperature requirements at Waikato Hospital and found operating in New Zealand a breeze compared to tropical climates where being in a gown, mask and gloves made for hot work.

He said if temperatures were too cold in operating theatres patients were at risk of becoming hypothermic and his theatre team used blankets with circulating hot air to keep patients warm.

Christchurch plastic surgeon Dr Sally Langley said an ambient theatre temperature was around 21 degrees but the right temperature for patients depended on the type of surgery.

"The theatre does need to be at a certain warm temperature to keep the patient warm but different types of operations dictate how warm or cool the temperature should be."

Paediatric and burns patients, microsurgery and longer operations needed warmer conditions while cardiac and neurosurgery patients needed a cooler temperature.

Surgeon and staff comfort and safety was also a factor, with dehydration a real possibility, she said.

"But what they really need is to be able to adjust the temperature in the operating theatre to suit their requirements."

Langley said there was a "big problem" nationwide with the quality of heating and cooling in operating theatres.

"It's surprising in this day and age that with air-conditioning in operating theatres, you dial it up to what you want but it doesn't match what you get."

She said temperatures of 24 and 25 degrees were common for operating but anything higher would be too hot and anything in the 30s would pose a risk of infection for the patient.