Those hospitalised 50% more likely to get blood clots during surgery

Covid patients are more than twice as likely to develop life-threatening blood clots during surgery compared to those not infected with the virus.

That's according to a new Royal Australasian College of Surgeons (RACS) and CovidSurg Collaborative study involving 140,000 patients from around the globe. Of those, 1000 were from 11 New Zealand hospitals - both regional and in our city centres.

Patients who develop blood clots were also five times more likely to die 30 days after surgery, the study found.

Experts spoken to by the Herald said the findings were a stark warning of the devastating impact that could hit New Zealand if the Delta outbreak got out of control.

It comes as the number of people with Covid in the community jumped to 148, with 41 new cases announced yesterday.

The youngest case to date is a baby under the age of one, director-general of health Ashley Bloomfield said. The number of close contacts has also sky-rocketed to 14,000, which is 10 times more than last year's nationwide lockdown.

University of Otago researcher Dr Deborah Wright - who is also a surgeon at Dunedin Hospital and took part in collecting data for the study - said it was a crucial reminder for New Zealanders to get vaccinated and follow all precautionary measures to avoid contracting Covid.

Hospitals were already operating at or very close to capacity, and with an influx of Covid patients they wouldn't be able to cope, she said.

"We don't have resources standing by, currently not being utilised, to swing into action if this outbreak gets out of control.

"I would find it very hard to imagine you would have a single hospital doctor who would say otherwise," Wright said.

The research - which collected data from all surgeries performed in October last year at hospitals taking part - found a 2.2 per cent chance of getting a blood clot in Covid patients.

That's compared to a 0.5 per cent chance in non-Covid patients.

It comes after a health chief from the European Medicines Agency (EMA) identified a link between AstraZeneca's Covid-19 vaccine and blood clots in April.

All of the 1000 New Zealand patients that took part in the study were part of the controlled group, which meant none of them had Covid and they had required surgery for other conditions.

New Zealand's study lead Chris Varghese, a fifth-year medical student at the University of Auckland, said the study showed that if anyone in the country got Covid and required surgery they were far more at risk of getting a dangerous blood clot.

"We know that patients having surgery are at increased risk of clots in their legs and lungs. What this shows is, if they have Covid on top of that their risk for the clots increases even more, and their subsequent risk of death increases further in the next 30 days."

Varghese said in New Zealand this hasn't been a focal point because we hadn't seen many Covid cases needing surgery.

"But with this Delta outbreak, it's now time for us to be mindful of this building body of evidence in relation to the benefits of vaccinations, pre-op isolation, how much to delay surgery in Covid patients and now this study taking into consideration the risk of blood clots."

Varghese said he hadn't come across a Covid patient in his medical training but the RSV spike at Middlemore Hospital gave a scary glimpse of what hospitals overseas were facing with the virus.

"I was shocked at the sheer volume of kids coming in at all hours of the day with awful coughs - we tend to see the milder end of the illness at home. But when they are coming into hospital and requiring oxygen, ventilation and ICU support, which are all real risks with Covid, that kind of paints a picture of what things could get to."

* The New Zealand hospitals involved in this study were: Auckland, Middlemore, Waikato, Christchurch (one public, one private), Masterton, Wellington, Dunedin, Taranaki, Hawke's Bay, Whangarei, North Shore and Palmerston North.