Breathing assistance apparatus

A pressure regulating device for use with a breathing assistance and/or resuscitation apparatus, said apparatus being capable of supplying gases to an infant or neonate requiring breathing assistance and/or resuscitation, said pressure regulating device comprising:

• a housing comprising:
• an inlet adapted to be in fluid communication or integrated with said breathing assistance and/or resuscitation apparatus;
• a main outlet adapted to in use be in fluid communication with the infant or neonate;
• an external venting outlet configured to be occluded and un-occluded to vary a pressure at said main outlet between a peak inspiratory pressure (PIP) with said external venting outlet occluded and a peak end expiratory pressure (PEEP) with said external venting outlet un-occluded such that a portion of said gases flows through said external venting outlet to vent externally;
• and
• an internal venting aperture extending through a wall and having a perimeter;
• said housing defining a first flow path between said inlet and said main outlet and a second flow path between said inlet and said external venting outlet, said internal venting aperture positioned in said second flow path between said inlet and said external venting outlet such that gases in said second flow path flow from said inlet through said wall within the perimeter of the internal venting aperture to said external venting outlet, and
• an umbrella valve disposed within said housing in said second flow path between said external venting outlet and said internal venting aperture, a flap of said umbrella valve having a periphery positioned against said internal venting aperture, so that when a pressure of gases in said first flow path is below a predetermined level, said umbrella valve at least partially blocks said internal venting aperture, said gases thereby flowing from said inlet to said main outlet, and wherein when said pressure of said gases is above said predetermined level, said umbrella valve opens to allow a portion of said gases to flow from said inlet through said internal venting aperture and said external venting outlet,
• said flap having a cross-sectional shape such that a central portion of said flap is thinner in cross-sectional width than said periphery.