Nasal mask assembly

Abstract

A mask system is provided to fit pre-adult patients, or patients having facial features that are very small or child-like, e.g., patients having dimensions in the lower 5%-10% of the population. For example, the headgear and/or cushion are dimensioned to accommodate this range of patients.

What is claimed is: 
     
         1 . A cushion for a respiratory mask assembly to deliver breathable gas to a patient, the cushion comprising:
 a side wall structured to be attachable to a frame; and   a seal-forming portion extending away from the side wall wherein an inner edge of the seal-forming portion defines an aperture, wherein the aperture has a base portion with a length in the range of 30-32 mm, sides with a length in the range of 18-20 mm, and a top portion substantially parallel to the base portion with a length in the range of 22-24 mm.   
     
     
         2 . A cushion according to  claim 1 , wherein seal-forming portion includes a contoured notch in a nasal bridge region of the cushion having a depth in the range of 12-27 mm. 
     
     
         3 . A cushion according to  claim 1 , wherein a contact area between the seal-forming portion and the patient's face in a nasal bridge region is greater than a contact area between the seal-forming portion and lip and cheek regions of the patient. 
     
     
         4 . A cushion according to  claim 1 , wherein the seal-forming portion is a membrane. 
     
     
         5 . A cushion according to  claim 4 , wherein the cushion has a rim extending away from the side wall, and the membrane substantially surrounds the rim. 
     
     
         6 . A cushion according to  claim 5 , wherein the membrane includes a contoured portion that extends upwardly from the side wall and curves inwardly along a generally constant radius to terminate at the inner edge of the membrane. 
     
     
         7 . A cushion according to  claim 6 , wherein, in at least a portion of a nasal bridge region of the patient, the rim and the membrane are spaced away from one another to define a gap. 
     
     
         8 . A cushion as claimed in  claim 7 , wherein the rim and membrane are spaced away from one another in lip and cheek regions of the cushion to define a gap. 
     
     
         9 . A cushion according to  claim 7 , wherein an inner edge of the rim defines an aperture, the aperture of the membrane having a smaller dimension than a dimension of the aperture of the rim. 
     
     
         10 . A according to  claim 9 , wherein the aperture of the rim has a base portion with a length in the range of 35-42 mm, sides with a length in the range of 17-20 mm, and a top portion substantially parallel to the base portion with a length in the range of 29-33 mm. 
     
     
         11 . A cushion according to  claim 4 , wherein the membrane is structured to engage a patient's face such that forces applied to the patient's face are substantially evenly distributed around the entire perimeter of the cushion. 
     
     
         12 . A cushion according to  claim 1 , wherein a radius of curvature of the seal-forming portion in the nasal bridge region is in the range of 3-12 mm. 
     
     
         13 . A cushion according to  claim 1 , further comprising:
 a central portion between an edge of the side wall and the seal-forming portion, the central portion having a thickness structured to withstand buckling forces applied to the cushion when the cushion is attached to the frame.   
     
     
         14 . A cushion according to  claim 13 , wherein the thickness of the central portion is in the range of 2-10 mm. 
     
     
         15 . A cushion according to  claim 13 , wherein an end of the side wall is adapted to be inserted into a channel of a frame so as to removably attach the cushion to the frame. 
     
     
         16 . A cushion according to  claim 1 , wherein the seal-forming portion is constructed from silicone. 
     
     
         17 . A cushion according to  claim 1 , wherein the seal-forming portion is adapted to form a seal on the patient's lip region positioned below the patient's nose and above the upper lip of the patient. 
     
     
         18 . A respiratory mask assembly for delivering breathable gas to a patient, comprising:
 a frame having a front surface and a rear surface adapted in use to face the patient; and   a cushion according to  claim 1  removably attachable to the rear surface of the frame.