An apparatus for the delivery of 50% premixed nitrous oxide and oxygen on demand or by controlled ventilation.

A small, portable and robust apparatus for the administration of 50% premixed nitrous oxide and oxygen mixture for analgesia for hospital and emergency use is described. The equipment can deliver the mixture on demand or by intermittent positive pressure ventilation. It has important advantages over earlier devices particularly in the accident and emergency field in which it has already proved successful.