Dr Jeffrey Apfelbaum, told a conference that in the future relatively complex surgery will be available with only an extremely short stay in hospital thanks to advances in anaesthetics.

Patients will be able to have a pacemaker replaced or their breasts enlarged without having to spend hours in a recovery room afterwards.

Dr Apfelbaum, vice-chairman of anaesthetics and critical care medicine at Chicago University, was addressing the annual meeting of the American Society of Anesthesiologists on Sunday.

He said new anaesthetic agents and improved surgical techniques enabled many patients to wake up and recover from anaesthesia in a fraction of the time of traditional medications.

In and out

The fast recovery times mean patients can leave hospital "within minutes" of having surgery, Dr Apfelbaum said.

A specialist in anaesthesia works with the surgery team

His team conducted a study of five community hospitals.

They found that up to 40% of patients who underwent surgery with recently-developed short-acting anaesthetics were able to leave hospital almost immediately after operation.

Patients recovering from general anaesthetic would normally stay in hospital for medical staff to monitor their progress and administer pain killers if needed.

Fast recovery

Dr Apfelbaum said: "Office-based (day) surgery began with minor procedures such as the removal of moles but is quickly progressing to major procedures, including gall bladder removals, breast augmentation surgery and pacemaker placements."

Short-acting general anaesthetic techniques allow patients to regain consciousness and alertness faster than ever before, he said.

Combined with nonsteroidal, anti-inflammatory analgesics to relieve pain after surgery, the technique improves patient comfort by replacing or reducing the need for narcotics, he said.

They can impede recovery because they cause drowsiness, nausea and other adverse side-effects.

Care improvements

Professor Leo Strunin, president of the Royal College of Anaesthetists, said that advances in anaesthesia did mean that people had to spend less time in hospital.

Professor Leo Strunin: "Side-effects"

"We're looking at new drugs that may shorten the recovery time, which is important because when the patient goes home we want to be sure the drugs have worn off," he said.

But despite constant improvements, no drug was without side-effects, he said.

"There is no drug so far that is instantly effective, does what you want and then wears off and has no side-effects."

However, the improvements in anaesthesia will greatly increase the number of precedures that can be performed as day surgery cases, Dr Apfelbaum said.

Seventy per cent of surgical procedures in the US already take place on a day surgery basis.

Dr Apfelbaum believes patient demand will fuel further advances.