This story was originally published on RNZ.co.nz and is republished with permission.

Most people severely burned in the Whakaari/White Island volcanic eruption do not yet know what has happened to them.

One week on, 14 patients remain in burns units around New Zealand; eight of them in Middlemore Hospital.

Plastic surgery consultant Michelle Locke told RNZ National's Checkpoint host Lisa Owen there are many weeks of work ahead.

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"The first time a patient with burns goes to theatre, it is to clean them, to assess the limit of their burns, and certainly to start removing the burn wound. We call that debridement.

"To start with, the surgeries are to debride them and remove any of the burnt tissue, then the rest of the surgeries after that are to reconstruct them and to perform skin grafting to reconstruct their skin.

"But some of the challenges we have with the major burns is that they don't have enough unburnt skin for us to graft them straight away.

"You can take the amount of unburnt skin and place it in an area of their body, but there will be large areas that we can't graft straight away."

Surgeons have to use donated cadaver skin in many cases to cover those areas, she said. Millions of dollars' worth of skin has been ordered from the United States and Australia.

"The cadaver skin is only temporary because it's not matched to the patient. In the same way you couldn't do an organ donation to someone who wasn't matched to you, you can't put someone else's skin on it and leave it on forever," Locke told Checkpoint.

TVNZ/Pool The 2.11pm moment of silence was observed nationwide and was exactly a week after the volcano erupted.

"In the burns situation, we use that cadaver skin almost as a biological dressing, and it usually will stay in place for up to two weeks.

"It keeps that area dressed and healthy. If we needed to replace it with fresh cadaver skin, or if they've got areas of unburnt skin that have healed, we can harvest the skin from that again and do some more grafting."

The area of the body where skin is harvested from is called the donor site, she said.

"That area takes about 10 days to two weeks to heal up, and it would be quite normal in a major burn for us to harvest that area multiple times, and let it heal and then harvest it again."

Long, hot days in the operating theatre

Some survivors of the Whakaari/White Island eruption have extremely serious burns, and have been in theatre most days, she said.

"But what we'll often do is spend the whole day on one person in the theatre, do as much work with them as we can, do as much grafting as we can, dress them well, and then it may be two to four days before they need to come back again."

Locke said it can take many hours to treat just one patient.

"Our normal operating day would be 8:30-4:30pm but with these sorts of cases our theatres have routinely been running late and we've often been operating until 9pm, 10pm, 11pm."

AP Waikato Hospital took on eight critical patients after White Island erupted on Monday.

Normally the skin regulates body temperature, but the burns victims have very little skin functioning normally.

Locke said the rooms are kept very warm for the patients.

"The rooms are kept warm, particularly the operating room because when we take them to the operating theatre and take the dressings off it does expose them and they can't regulate the temperature.

"The operating theatres are routinely kept at around 32 degrees Celsius. That way the patient doesn't cool down so much while we're doing their surgery and their dressing changes."

The surgeons are working in that heat for hours at a time, wearing their scrubs, impervious gowns, gloves, hats and masks.

"It is a lot of hard work, and when we have been running our burns theatres we've been trying to staff each theatre with four doctors, which might be two consultant burns surgeons or plastic surgeons and two of our registrars or junior doctors helping out.

"You can imagine the amount of work we have, to run those theatres, four theatres, a day, because as well as the doctors there's the same number of nursing staff in there. There might be two anaesthetists and an anaesthetic tech for every burns theatre that we run.

"The amount of staff just in one burns theatre is really incredible. And then there's the workload on the ward, looking after the patients between the theatre times in our intensive care unit and the national burns unit. The nursing staff do an incredible job looking after them there, it's very labour intensive."

ROSA WOODS/STUFF Another man has died after the Whakaari/White Island eruption in December.

Family are also able to visit, without endangering the patients' treatment, she said.

"The national burns centre has individual rooms with … an antechamber which is a room you go into, they're all appropriately air-pressured to prevent infections, and we ask any visitors to cover up, we have gowns and gloves that we expect people to put on before they go into the room."

What goes into a burns dressing?

"Our burns surgeons are trained to deal with all areas of the body, but certainly areas like the hands and the face we consider to be special areas.

"It may be that we do the grafting slightly differently in those areas. We would put a sheet graft on where you just lay on the sheet of skin rather than meshing the skin to try and spread it and cover more area, so that we get a better cosmetic result."

Farrah Fuerst/Unsplash Whakaari/White Island.

The dressings keep the patients skin from drying out.

"Each of the burnt areas are dressed with multiple layers of dressings. There are some dressings for example, with like a paraffin oil beside the skin so that the skin doesn't dry out, then layers of wet dressings that may have antibiotics or antimicrobials in them, and then drier dressings with padding to absorb any fluid that comes out of them.

"When we're putting dressings on they're usually multiple layers of different types of dressing, and that's what we use to keep the wounds moist and to absorb any fluid coming from them.

"Some of the patients have had quite different burns because the burn has been, in some cases, more of a chemical burn [like hydrochloric acid].

"They've also had inhalational injuries because the patients have inhaled toxic gas from the volcano.

"They've got injuries to the lungs and airways as well that are a bit different than we've seen before.

"And a lot of the burns are really very deep."

In terms of internal burns, patients are given treatment like breathing assistance as the body heals itself.

"Although when you get bad injuries to the lungs and airways, sometimes those are fatal. That's part of the burn injury that can be a bit unpredictable."

CHECKPOINT/RNZ A Workplace Health and Safety investigation into the Whakaari/White Island eruption could take a year to complete. (Video first published December 16, 2019)

Most patients still not aware of what happened

Most patients are not conscious enough to realise the severity of their burns, Locke said.

"Of the eight burns that we have at Middlemore, five of them are still in a critical condition, many of them are still intubated and ventilated and are in our intensive care unit. At the moment, many of them have not yet woken up."

This story was originally published on RNZ.co.nz and is republished with permission.