More young people are likely to die after inhaling nitrous oxide - more commonly known as laughing gas - following an "explosion" in its recreational use, researchers have warned.
Paediatricians and the public need to be more aware of the risks of inhaling the substance, also known as ''hippie crack'', with 17 deaths caused by the so-called legal high in the UK between 2006 and 2012, they said.
Dr Paul Seddon, respiratory consultant and neonatal paediatrician at the Royal Alexandra Children's Hospital in Brighton, East Sussex, said laughing gas inhaled through balloons poses a significant risk to teenagers.
He carried out the research after treating a teenager suffering from an unexplained pneumothorax (sudden sharp chest pain followed by painful breathing).
The cause of this was unknown but the patient went on to admit she had inhaled laughing gas at a festival. It is thought that many other youngsters will have suffered similar problems.
Abusing nitrous oxide can also lead to oxygen deprivation resulting in loss of blood pressure, fainting and even heart attacks.
Used laughing canisters in a festival field
His study found that 7.6% of 16-to-24-year-olds in England and Wales have admitted to having tried balloons, which he described as "widely available" in shops that sell legal highs.
"There's evidence that its use has mushroomed over the past few years," he said.
"What's little-known is that long-term use can result in all sorts of severe complications, such as causing problems to the nervous system."
While the gas can be legitimately used for pain relief in dental procedures and labour, in engines to make them perform better and in aerosol cans to prevent food going off, the canisters it comes in are also used to make whipped cream.
"Clearly the shops that sell legal highs are not selling it for use in confectionery," he added.
"It is something of a grey area, but there has certainly been an explosion in recreational use and is something that both paediatrics and the general public need to be aware of."
"Seventeen deaths in the UK were attributable to nitrous oxide between 2006-2012, a figure which we would expect to rise given the current surge in usage," the study, which is due to be presented at the Royal College of Paediatrics and Child Health's (RCPCH) annual conference this week, said.
"Pneumothorax should be considered in any teenager presenting after inhaling gaseous or volatile agents, and recreational drug use should be considered and addressed in teenagers presenting with a pneumothorax of unknown aetiology."
Although it is not illegal to be in possession the substance, it is prohibited from being sold in England and Wales to under-18s if there is a risk they will inhale it.
A Home Office campaign last year on the risks of legal highs showed that laughing gas was the second most popular drug among young adults in 2013/14 after cannabis, being more widely used than powdered cocaine and ecstasy.
Research by the Local Government Association also described as ''deeply disturbing'' the notion that many young people view nitrous oxide as safe, despite it being linked to a number of deaths.
Among those to have died was 17-year-old art student Joseph Benett, who suffered a cardiac arrest after taking the popular party drug in 2012.
Premier League and England star Raheem Sterling was recently warned about his off-the-field conduct after apparently being pictured inhaling laughing gas.