An indicator configured to be attached to a wound dressing includes first and second parts. The wound dressing is configured to collapse in response to an applied negative pressure. The first and second indicator parts are configured to move relative to one another as the wound dressing is collapsed. The movement of the first and second indicator parts is configured to allow a user to easily visualize the compression of the wound dressing and monitor the application of the negative pressure to the wound dressing. A marker is provided along a top surface of the first part and a window is formed on the second part. The changes in the portion of the marker that is visible in the window as the first part is slid into or under the second part are configured to provide for easier detection of the collapse of the wound dressing by the user.

A digitally controlled aspirator is provided with a processor that allows the user to select operating conditions including one or more default settings. The processor further includes sensors for sensing operational and environmental conditions and adjusts the operation of the aspirator to reflect the sensed conditions.

Described herein are devices, systems, and methods for generating a variable liquid vacuum with an accompanying stable gas flow rate. In particular, when a suction device suctions a liquid and gas mixture it is advantageous to provide a variable vacuum or vacuum to apply to the liquid component while the flow rate of the gas stays constant or essentially constant.

Systems and methods for controlling and/or calibrating a pump system for use in negative pressure wound therapy are described herein. In some embodiments, a method for controlling a pump system includes calculating an amplitude and an offset for a drive signal based at least in part on previously calculated parameters and a negative pressure setting, generating the drive signal, and applying the drive signal to a pump system. The pump system can be fludicially connected to a wound dressing positioned over a wound.

An image coding method includes: performing context arithmetic coding to consecutively code (i) first information indicating whether or not to perform sample adaptive offset (SAO) processing for a first region of an image and (ii) second information indicating whether or not to use, in the SAO processing for the first region, information on SAO processing for a region other than the first region, the context arithmetic coding being arithmetic coding using a variable probability, the SAO processing being offset processing on a pixel value; and performing bypass arithmetic coding to code other information which is information on the SAO processing for the first region and different from the first information or the second information, after the first information and the second information are coded, the bypass arithmetic coding being arithmetic coding using a fixed probability.

A dressing for treating a tissue site with negative pressure may include a first layer configured to deform under a first predetermined negative pressure, and a second layer. The second layer may include an indicator configured to remain visible or hidden until the first layer deforms.

A chest drainage system including a collection device configured to receive fluid from the pleural cavity of a patient. A sensor is included to detect a pressure differential in the fluid. A display is configured to display a trend in occurrences of changes in pressure of the fluid over time in predetermined time increments based on a number of detections of pressure differentials that exceed a predetermined pressure differential during each of the predetermined time increments. The trend is correlative to the percentage of time that the patient is deemed to have an air leak in the pleural cavity in the predetermined time increments. The trend is derived from a ratio of the quantity of respiratory cycles of the patient for which the predetermined pressure differential is detected (QRC.sub.leak) in the predetermined time increments to the total quantity of respiratory cycles of the patient in respective predetermined time increments (QRC.sub.total).

Method for introducing and maintaining a level of negative pressure in a body cavity of at least 80 mmHg using a tube having an elongate distal portion and a proximal portion having first and second arms, each arm having a lumen in flow communication with one another and with the body cavity via apertures at or near the distal end of the tube, wherein the first arm or tubular extension therefrom is adaptable to receive suction from a suction source. An indicator, arranged in relation to the second arm, signals when a specific negative pressure has been exceeded in the tube, or a valve, arranged in relation to the second arm, admits ambient air into the lumen of the second arm when suction is applied to the tube and differential air pressure between the air in the lumens of the tube and ambient air exceeds a specified amount.

Systems and methods for delivery of fluid to a wound therapy dressing. In exemplary embodiments, a pressure sensor measures the pressure at the wound therapy dressing and restricts fluid flow to the wound therapy dressing when a predetermined pressure is achieve.

Systems and methods are presented for providing reduced pressure to and monitoring pressure at a plurality of tissue sites using a plurality of pressure management devices. The pressure management devices are associated with a plurality of sensing conduits that fluidly couple the pressure management devices and the plurality of tissue sites. Other systems, methods, and devices are disclosed.