Medical standards for the use of 'Scubadoo' - a discussion paper

'Scubadoo' is a novel recreational diving device which operates at a fixed depth of three metres' sea water (msw). The diver is free to move in an air-filled dome replenished by continuous air flow from a scuba tank which is an integral part of the device. Calculations show that the equilibrium concentration of carbon dioxide and oxygen in the dome depend on the volumetric air flow from the compressed air cylinder. Experiments carried out with an air flow of 20 L/min gave gas mixtures consistent with the calculations. This provides the basis of safe design for the air supply to the dome. The medical issues that may arise in the use of the Scubadoo device are discussed. Most of the medical issues which apply to scuba diving are minimised here because of the rigid three msw depth limit. Pulmonary barotrauma and also bronchospasm for asthmatics are theoretically possible but are considered to be low risk conditions in the context of the use of the device. Epilepsy and other conditions likely to cause sudden loss of consciousness are the only contraindications to use of the device. It is concluded that Scubadoo should not be subjected to the same medical restrictions as scuba diving.