Abstract: A method and apparatus provide more efficient eucapnic voluntary hyperventilation (EVH) testing by using a low pressure demand valve that has low resistance during rapid breathing and by monitoring air flow to the subject from a pressurized tank using measurements of change in the tank's pressure. A second stage Scuba regulator is modified to provide a demand valve that has low resistance during rapid breathing.

Abstract: An improved bow and/or stern seal is provided for a surface effect vehicle herein the vehicle has a pair of spaced apart side hulls which are joined by a wet deck, and the bow and stern seals extend between the side hulls so that an air cushion can be formed between the side walls and the bow and stern seals. The improved seal includes a portion of the deck having an opening for providing an air inlet to the air cushion. An elongated pneumatic bag is mounted along its length to the bottom of the wet deck, is sealed at its ends and is positioned to receive air from the deck opening along its forward side. Provision is made for a passageway between the side hulls for directing air around the forward side of the bag.