A plane's oxygen masks are essential to passengers' safety during an emergency descent. However, one detail about these masks ...

Meanwhile, many confessed they were actually relieved to learn there was a purpose behind the oxygen masks. “Thought you were going to say it was just to make you think you were safe and they weren’t ...

UCLH critical care consultant Prof Mervyn Singer said: "These devices are a halfway house between a simple oxygen mask and invasive mechanical ventilation which requires patients to be sedated.