Ablation catheters and systems include catheter tips with a positioning element to ablate a target tissue that damages substantial cellular component in the target tissue while avoiding significant damage to the extra cellular matrix.

Ablation catheters and systems include catheter tips with a positioning element to ablate a target tissue that damages substantial cellular component in the target tissue while avoiding significant damage to the extra cellular matrix.

Systems and methods suitable for extracorporeal lung support are provided that expose blood, across a semipermeable membrane, to a dialysis liquid. The dialysis liquid features a buffering agent and has a high buffering capacity for H.sup.+ ions. Carbon dioxide, bicarbonate and hydrogen cations are transported across a semipermeable membrane into the dialysis liquid. The dialysis fluid may be recycled and repeatedly used, and its pH may be adjusted, and other fluids added to it. Certain substances may be removed from the blood, and the amount of these substances removed from the blood may be substantially automatically or substantially continuously monitored or quantified. The systems and methods are suitable for treating or preventing respiratory acidosis, metabolic acidosis, and diseases featuring lung malfunction, kidney malfunction, or liver malfunction.

An apparatus to maintain an environment over an anterior surface of a patient eye can include an enclosure sized and shaped to be seated about the patient eye to form a cavity within the enclosure. The enclosure can be configured to contain a fluid other than ambient air in contact with the patient eye. The apparatus can include a fluid regulator in communication with the enclosure, where the fluid regulator can be configured to regulate the composition of the fluid contained within the enclosure.

An apparatus to maintain an environment over an anterior surface of a patient eye can include an enclosure sized and shaped to be seated about the patient eye to form a cavity within the enclosure. The enclosure can be configured to contain a fluid other than ambient air in contact with the patient eye. The apparatus can include a fluid regulator in communication with the enclosure, where the fluid regulator can be configured to regulate the composition of the fluid contained within the enclosure.

A shroud for a mask system includes a retaining portion structured to retain a frame, a pair of upper headgear connectors each including an elongated arm and a slot at the free end of the arm adapted to receive a headgear strap, and a pair of lower headgear connectors each adapted to attach to a headgear strap. The retaining portion, the upper headgear connectors, and the lower headgear connectors are integrally formed as a one piece structure.

A shroud for a mask system includes a retaining portion structured to retain a frame, a pair of upper headgear connectors each including an elongated arm and a slot at the free end of the arm adapted to receive a headgear strap, and a pair of lower headgear connectors each adapted to attach to a headgear strap. The retaining portion, the upper headgear connectors, and the lower headgear connectors are integrally formed as a one piece structure.

A face mask for extended wear by a user including a customized, contoured facial mask portion constructed and configured to cover and matingly contact a corresponding contoured surface area of a human face, preferably formed by 3D printing methods and materials. The face mask includes strap attachments and at least one strap for securing the customized, contoured facial mask portion to the face.

A vent structure may include a vent housing comprising an inlet, an outlet, at least one exhaust gas orifice, and a membrane having a first end and a second end spaced apart, the membrane having a moveable portion between the first end and the second end. The moveable portion may be spaced radially from a membrane-facing surface inside of the vent housing to form an exhaust gas flow passage therebetween to allow exhaust gas to flow from the pressurised volume through the exhaust gas flow passage to atmosphere via the exhaust gas orifice. The moveable portion may be elastically deformable and configured to move radially relative to the membrane-facing surface in response to pressure differences between an interior side of the membrane and an exterior side of the membrane to change a cross-sectional area of the exhaust gas flow passage and regulate the vent flow of gas.

A vent structure may include a vent housing comprising an inlet, an outlet, at least one exhaust gas orifice, and a membrane having a first end and a second end spaced apart, the membrane having a moveable portion between the first end and the second end. The moveable portion may be spaced radially from a membrane-facing surface inside of the vent housing to form an exhaust gas flow passage therebetween to allow exhaust gas to flow from the pressurised volume through the exhaust gas flow passage to atmosphere via the exhaust gas orifice. The moveable portion may be elastically deformable and configured to move radially relative to the membrane-facing surface in response to pressure differences between an interior side of the membrane and an exterior side of the membrane to change a cross-sectional area of the exhaust gas flow passage and regulate the vent flow of gas.