SURGICAL patients are being put at risk of suffocation because of out-of-date equipment, according to a study by North-Eastern anaesthetists.

A research project involving a random sample of 51 hospitals in the UK found that around one in three anaesthetic machines did not have an anti-hypoxia device to safeguard against accidental suffocation.

Without such machines there is a risk that patients may be suffocated by being given pure nitrous oxide (laughing gas) rather than a mixture of nitrous oxide, oxygen and other gases.

Earlier this year three-year-old Najiyah Hussein died after she was given nitrous oxide, instead of a mixture of gases, at Newham General Hospital in the East End of London.

The doctors estimate that it would cost £60m to replace all the obsolete machines, which tend to be more than ten years old.

The research was carried out by Dr Tim Meek and Dr David Saunders, both specialist registrars in anaesthesia at the Northern Schools of Anaesthesia in Newcastle.

Following the publication of their article in British Medical Journal the doctors have called on the Government to replace all anaesthesia machines which do not have the anti-hypoxia safeguard mechanism.

"Almost 30 per cent of the machines in our survey do not have an anti-hypoxia device. We have no reason to believe it is not the case for the places we didn't survey," said Dr Meek, who estimates that each new machine will cost around £20,000.

"We know patients can be harmed by the use of these machines and set out to find the national situation. It is in everybody's interests that this is addressed and in patients' interests more than anybody else's."

Dr Meek said the £60m needed to replace around 3,000 machines "would be money spent mitigating against a real risk."

Checks by The Northern Echo found that most NHS trusts in the region have modernised its anaesthetic machines, although some are still using older equipment.

Trusts in South Tees, North Tees and Hartlepool and North Durham have anti-hypoxia devices fitted to all machines.

But South Durham NHS Trust, which includes Darlington Memorial Hospital and Bishop Auckland General Hospital, has 11 machines which lack anti-hypoxia devices. Replacement machines are on order.

A spokesman for the Friarage Hospital in Northallerton said eight of their machines do not have anti-hypoxia devices but special precautions are taken and they are due to be replaced by the end of the year.