Choking baby Millie Thompson 'had rare complication' 3 December 2013 Last updated at 21:43 Paramedics and nursery staff could not have been expected to assess the worsening condition of a choking baby, an inquest has heard. Nine-month-old Millie Thompson died after she was given lunch at a nursery in Cheadle Hulme, Greater Manchester. An inquest at Oldham Magistrates' Court heard the main airway of her lung became blocked, leading to her death last October. An expert witness told the hearing she suffered an uncommon complication. Dr Ian Maconochie said air became trapped between the lung and chest wall as she choked at Ramillies Private Day Nursery. He said the only effective treatment was to put a needle in the chest to release the pressure. Paramedics were trained to carry out the procedure, but it would have been difficult to diagnose in a child of Millie's age and in the circumstances. A rare event Another specialist said the situation would have been "exacerbated" by air in her lungs. Robert Downes, a specialist in sudden child deaths, said it would have been "very difficult" to diagnose the developing situation "unless one had access to X-ray." Mr Downes said paramedics "receive training, but they are not doctors." The hearing was told a paramedic used a bag and mask to breathe air into her lungs after staff carried out first aid, including back slaps. He said paediatric first aid training would not cover the level of expertise needed to spot the deterioration in what was "a rare event." Pathologist Melanie Newbould said Millie had died of cardiac arrest as a result of choking. Two members of staff at the nursery gave first aid before an ambulance arrived. A police investigation took place but no criminal offences were committed, the inquest was told.