Self-testing for negative pressure wound therapy devices

A negative pressure wound therapy device comprising:

• a negative pressure source configured to be connected, via a fluid flow path, to a wound covered by a wound dressing and provide negative pressure to a wound;
• a valve positioned in the fluid flow path and configured to, in an open state, permit supply of negative pressure from the negative pressure source upstream of the valve and, in a closed state, block supply of negative pressure from the negative pressure source upstream of the valve;
• a flow restrictor positioned in the fluid flow path;
• a pressure sensor configured to measure pressure in the fluid flow path;
• and
• a control circuitry configured to:
• in a normal operational mode in which negative pressure is being applied to the wound dressing, cause the valve to be in the open state;
• and
• in a test mode in which performance of the device is being verified, perform at least one of a leak test or a flow test, wherein the test mode is not performed when negative pressure is being applied to the wound dressing, and wherein:
• the leak test comprises the control circuitry being configured to:
• cause the valve to be closed, cause the negative pressure source to operate at a first intensity level, cause the negative pressure source to pause operation for a duration of time, and indicate presence of a leak in the fluid flow path in response to determining that a change in the negative pressure measured by the pressure sensor subsequent to expiration of the duration of time satisfies a threshold indicative of a leak;
• and
• the flow test comprises the control circuitry being configured to:
• cause the valve to be opened, cause the negative pressure source to operate at a second intensity level, and indicate insufficient flow in response to determining that a pressure difference across the flow restrictor measured by the pressure sensor satisfies a pressure difference threshold indicative of insufficient flow.

A method of operating a negative pressure wound therapy device comprising:

• by a control circuitry of the negative pressure wound therapy device:
• at a first time, operating in a normal operational mode by causing:
• a valve positioned in a fluid flow path to be opened to permit supply of negative pressure from a negative pressure source to a wound covered by a wound dressing;
• and
• causing the negative pressure source to apply negative pressure to the wound dressing covering the wound;
• and
• at a second time, initiating a test mode configured to verify performance of the negative pressure wound therapy device, the test mode comprising performing at least one of a leak test, a flow test, or an excessive pressure test, wherein the test mode is not performed when negative pressure is being applied to the wound dressing, and wherein:
• the leak test comprises:
• causing the valve of the negative pressure wound therapy device to be closed to block supply of negative pressure from the negative pressure source upstream of the valve, causing the negative pressure source to operate at a first intensity level, causing the negative pressure source to pause operation for a duration of time, and indicating presence of a leak in the fluid flow path in response to determining that a change in the negative pressure subsequent to expiration of the duration of time satisfies a threshold indicative of a leak;
• the flow test comprises:
• causing the valve to be opened, causing the negative pressure source to operate at a second intensity level, and indicating insufficient flow in response to determining that a pressure differential across a flow restrictor positioned in the fluid flow path satisfies a pressure differential threshold indicative of insufficient flow;
• and
• the excessive pressure test comprises:
• causing the valve to be closed, causing the negative pressure source to operate at a third intensity level, and indicating fault in a system configured to protect against unsafe negative pressure in the fluid flow path in response to determining that pressure in the fluid flow path satisfies a threshold indicative of unsafe negative pressure and the system configured to protect against unsafe negative pressure has not been activated.