Two early Danish respirators designed for prolonged artificial ventilation.

Two Danish respirators are described. The first one was made by August Krogh in 1931 and was based on the principles of the Drinker tank respirator. The original feature was a motor driven by water from an ordinary water tap. It was never widely used, most likely due to practical problems connected with nursing care, etc. The polio epidemic in Copenhagen in 1952 initiated the era of the IPPV-methods and gave rise to the construction of a great number of new respirators. Among the first of these was the Claus Bang respirator. Although it contained many modern features, it proved technically unreliable and was only used for 3-5 years.