Alveolar dead space of a subject is determined by measuring an end tidal partial pressure of carbon dioxide during a sequence of normal breaths of the subject and, during a sequence of deep breaths by the subject, delivering a first volume of a first gas to the subject over a first portion of each inspiration by the subject. The first volume is less than or equal to an expected alveolar volume of the subject when the subject is breathing normally. A second volume of a second gas is delivered to the subject over a second portion of each inspiration. The second gas includes a neutral gas. An end tidal partial pressure of carbon dioxide is measured during the sequence of deep breaths. The alveolar dead space is computed using the end tidal partial pressures of carbon dioxide measured during the sequence of normal breaths and the sequence of deep breaths.

A customizable mask including a conforming seal is configured to utilize the physical process of granular jamming to enable it to adapt to a wide range of facial geometries. The mask may include a frame having a perimeter and a conduit connection, a conforming seal positioned along the perimeter of the frame. The conforming seal may include a sealing surface and a connecting surface, the connecting surface configured to mate with the perimeter of the frame, and the sealing surface configured to conform to a users' face. The conforming seal may further include an outer casing, granular material contained within the outer casing, and a vacuum connection. The mask may also include a similarly configured conforming frame. Further disclosed are methods of forming such masks.

The invention relates to a non-heated humidification device comprising a wick; a chamber for holding water in contact with the wick; and a gas inlet to the chamber, wherein the chamber and wick are configured to humidify gas passing through or over the wick at ambient conditions. The device may be modular and attachable to a flow generator. The device may comprise dual gas circuits and a control system for controlling the gas flow through the gas circuits in order to control the humidity of the gas output.

A patient interface includes a plenum chamber, a seal-forming structure, and a positioning and stabilising structure to provide a force to hold the seal-forming structure in a therapeutically effective position on a patient's head. The positioning and stabilizing structure includes a superior strap portion, an inferior strap portion, and a posterior connecting strap portion connected to or formed integrally with the superior strap portion and the inferior strap portion. The posterior connecting strap portion is constructed from a mesh material that is different than the material used to construct the superior strap portion and the inferior strap portion. The posterior connecting strap portion has a greater stretch capability than the superior strap portion and a lesser stretch capability than the inferior strap portion. The stretch capabilities allow the positioning and stabilizing structure to be removable from the patient's head when the loop engages the connection portion.

A neck strap, a crown strap assembly and a headgear for a breathing mask. The neck strap for a headgear includes a one-piece main body adapted to engage a patient's neck, first and second lower connection portions adapted to connect to first and second lower mask connection straps, and first and second upper connection portions adapted to connect to respective first and second lateral crown straps.

A resuscitation management system for a manual resuscitator may include a radio frequency identification (RFID) tag that may be configured to be mounted on a first side of a bag of the manual resuscitator. The RFID tag may be configured to transmit information indicative of the presence of the RFID tag. The system may further include an RFID reader that may be configured to be mounted on an opposite second side of the bag. The RFID reader may be configured to generate an output signal corresponding to the presence of the RFID tag responsive to receiving the information transmitted by the RFID tag. The RFID reader may be configured to receive the information transmitted by the RFID tag responsive to the RFID tag being at a distance from the RFID reader smaller than a predetermined threshold.

A valve for a bypass conduit is comprised of a rigid inner frame having an arm with a tab at one end and a hinge at an opposite end. A flexible outer seal is positioned over the inner frame, the flexible outer seal defining a peripheral edge to substantially house the tab and arm of the inner frame. The valve is pivotable from a first position to a second position on the bypass conduit.

A system for preventing cross-contamination in single-limb ventilators is described. In one embodiment, the system includes an airflow generator connected in-line to a humidifier, a first check valve and a patient interface by a gas flow circuit. A controller is electrically coupled to the airflow generator, and a cartridge is connected to the gas flow circuit between a first point downstream of the humidifier and a second point upstream of the patient interface. The cartridge includes a bacteria filter and the first check valve. A method for preventing cross-contamination in single-limb ventilators and a method for providing gaseous flow through a single-limb ventilator are also described.

An interface for positive pressure therapy includes a mask assembly and a headgear assembly. The mask assembly comprises a mask seal that is adapted to underlie the nose. The mask seal extends up the lateral sides of the nose. The mask seal has a primary seal below the nose and a secondary seal alongside the nose.

Systems and methods for determining a touch input are provided. The systems and methods generally include measuring the peak voltage at an electrode over a measurement period and determining a touch input based on the peak voltage. The systems and methods can conserve computing resources by deferring digital signal processing until after a peak electrode capacitance has been sampled. The systems and methods are suitable for capacitive sensors using self-capacitance and capacitive sensors using mutual capacitance. The systems and methods are also suitable for capacitive buttons, track pads, and touch screens, among other implementations.