2 ERS Practical Handbook Noninvasive Ventilation Introduction In fairness, similar ideas were flourishing elsewhere, in Europe, but it was not until the 1920s that an iron lung with a motorised pump was developed by Drinker in 1928 in the USA and demonstrated in London in 1931. This concept then entered the medical mainstream, disseminated by a brisk correspondence in the Lancet. That was fortuitous, as the coming scourge was epidemics of poliomyelitis, which had begun in the First World War and swept across Europe and the USA in the 1930s–1950s. Polio paralyses the respiratory muscles as well as limbs muscles, resulting in respiratory failure. Iron lungs were pressed into action, including the intimidating multitier versions in figure 2. There is no doubt that iron lungs saved thousands of lives but they were big, cumbersome and expensive (the original Drinker ventilator cost $1500 – equivalent to the cost of a US new-build house at the time), and so were not going to be a practical way forward in respiratory care. In their observations on the use of negative-pressure respirators in polio, Plum and Wolff (1951) found that the tank ventilator was safest for managing respira- tory insufficiency and that in the acute phase of polio, the cuirass was too ineffi- cient. Upper airway obstruction provoked by the negative pressure was a common problem. Practical limitations were compounded by the huge outbreak of polio in Denmark in 1952, which was associated with a very high prevalence of cases with bulbar weakness. Not only was an insufficient number of iron lungs available but these were also inadequate in caring for patients with bulbar problems – mortality rose to 90% and the only solution open to Ibsen (1954) and the Danish anaesthetic and medical teams was invasive positive-pressure ventilation via a tracheostomy Figure 1. Drawing of a negative pressure device for children by Alexander Graham Bell. Image: US Library of Congress, Washington, DC, USA.