Non-invasive ventilation masks (also referred to as ventilation masks) are commonly used in medical treatment to provide breathable gases to a patient. For example, ventilation masks can be used in the treatment of respiratory conditions and sleep disorders (e.g. obstructive sleep apnea) by delivering a flow of breathable gas for, or to assist patient respiration. These ventilation masks typically receive a gas supply line which delivers gas into a chamber formed by the walls of the ventilation mask. The ventilation mask also has a face contacting portion so that the chamber covers the nose and mouth of the patient. The ventilation mask can be secured to the patient's head by straps. The straps can be adjusted to pull the ventilation mask against the face with sufficient force to achieve an airtight seal between the ventilation mask and the patient's face. Because of the sealing effect that is created, gases can be provided at a positive pressure within the ventilation mask for consumption by the patient. Since the ventilation mask is placed on the patient's face with sufficient force to achieve a seal, this can result in excessive pressure on the patient's face.
The pressure may also be excessive because the ventilation mask is improperly or poorly fitted to the patient's face, which can cause various facial wounds. For example, poorly fitting ventilation masks can decrease perfusion, which is the process of nutritive delivery of arterial blood to a capillary bed in biological tissue. Poorly fitting ventilation masks can also cause nasal and facial necrosis, which is the accidental death of cells and living tissue. Furthermore, the ventilation masks may irritate a user's nose bridge, which typically is an area of thin skin, where even slight pressure can cause a blood flow constriction, and, thus, skin breakdown, ulcers, sores, bruising or discomfort. Not only does the patient receive facial wounds, the patient may also experience discomfort due to excessive pressure on the nasal bones, cheekbones and paranasal sinuses.
Also, in addition to the problems caused by poorly fitting ventilation masks, facial wounds and discomfort can also occur if the pressure settings are high on the machine which provides the ventilation to the ventilation mask. Sometimes patients are so dependent on receiving ventilation from a ventilation mask that the patients cannot take breaks from wearing the ventilation mask. In these situations, the facial wounds can be quite severe, particularly when the patient must receive ventilation for a long period of time.
Ventilation mask technology has improved over the years. For example, the U.S. Patent Application Publication No. 2007/0163594 to Ho et al. discloses a cushion for use with a patient interface apparatus that generally conforms to the interface apparatus on one side thereof and on the other side thereof, where contact is made with the patient's face, a chamber having a dampening medium therein for reducing the pressure of the ventilation mask on the patient's face. The chamber is equipped with an orifice that allows the passage of the dampening medium into or out of the chamber in order to adjust the compressive contact with the patient's face.
Additionally, the U.S. Patent Application Publication No. 2007/0125384 to Zollinger et al. discloses a nasal interface ventilation mask for an infant. The apparatus is generally triangular shaped and includes a ventilation mask body and a base. The ventilation mask body forms a cavity for placement over a patient's nose. The portion of the ventilation mask that contacts the face includes a bellows segment characterized by an increased flexibility to thereby lessen the pressure applied by the ventilation mask.
Also, the U.S. Patent Application Publication No. 2007/0125385 to Ho et al. discloses a full face respiratory ventilation mask with an integrated nasal interface. The apparatus provides a patient interface that includes a face plate and a seal member coupled to the face plate. The seal member contacts the user's face to provide a seal interface with the user. The seal member includes an oral cushion portion and a nasal interface portion. The oral cushion portion provides a seal interface with the user over a sealing area that at least partially surrounds the user's mouth. The nasal interface portion is integral with the oral cushion and contacts at least a portion of the user's nose below the bridge of the nose. The apparatus is shown in use in FIG. 27 wherein it can be seen that the top of the apparatus has inserts which protrude into the patient's nostrils while the remainder of the ventilation mask surrounds the patient's mouth. The seal member is typically filled with silicone.
The U.S. Patent Application Publication No. 2007/0107735 to Kwok et al. discloses an apparatus designed to contact a patient's face between the base of the nose and top lip and extend upwardly therefrom to completely encircle the patient's nose. The apparatus is shown in use in FIG. 7. The ventilation mask is designed to seal to the patient's face and to restrict movement between the ventilation mask and the face to maintain the seal via the application of pressure.
Furthermore, the U.S. Patent Application Publication No. 2006/0076019 to Ho et al. discloses a user interface having a pivotable coupling. The apparatus is shown in use in FIG. 7. The patient interface includes a cushion, a shell, and a coupling that are connected together. The cushion has a cavity and the shell has an opening that is connected to the coupling which in turn is connected to a gas delivery conduit. The apparatus extends from the portion of the face between the lower portion of the nose and the lip upwardly to a contact point with the user's forehead. The design of the apparatus allows pivotable couplings to be used and provides for two flex points, one at the user's forehead and another at the user's nose for preventing tangling between the coupling and items connected thereto. The cushion appears to be relatively conventional in design and it is stated that it can be made from a variety of suitable materials such as silicon or foam.
Finally, the U.S. Pat. No. 5,909,732 issued to Diesel et al. discloses a ventilation mask insert designed to provide conformal support for the reflective seal of an oxygen ventilation mask. The insert consists of a formed foam rim which conforms to the contour of the reflective seal and is held in place beneath the reflective seal by a supporting formed framework which conforms to the contours of the interior surface of the ventilation mask face piece. Previously, the unsupported reflective silicon rubber seal was not supported which had the potential for leaks. The insert appears to be primarily designed for use by pilots, life support technicians or those in professions which may require the use of a gas ventilation mask. The cushioned edge is provided by a foam material and fits over the bridge of the user's nose and extends to the chin.
While ventilation mask technology has improved over the years, patients continue to acquire facial wounds and suffer discomfort from the use of ventilation masks.