Systems and methods for controlling operation of negative pressure wound therapy apparatus
View Patent ↗Methods and apparatuses for detecting full waste canister and/or fluid flow path blockage conditions are disclosed. Also disclosed are methods and apparatuses for controlling a pump. In some embodiments, flow of fluid can be restricted in a portion of the fluid flow path. A controller can be configured to compare a difference in pressure values upstream and downstream of a fluid flow restrictor to a pressure difference threshold, and determine based on the comparison whether to activate an alarm indicating the full waste canister condition or the fluid flow path blockage condition. The controller can be additionally or alternatively configured to determine a fluid flow using a flow meter, open a selectable valve in response to a comparison of the fluid flow with a fluid flow threshold, determine fluid flow after opening the valve, and determine based on the fluid flow after opening the valve whether to activate the alarm.
1. A method of detecting a full waste canister condition and a fluid flow path blockage condition in a negative pressure wound therapy apparatus, the method comprising:
providing reduced pressure through a fluid flow path configured to be fluidically connected to a wound dressing, wherein the fluid flow path comprises a conduit and a waste canister;
determining a fluid flow rate in the fluid flow path,
detecting a presence of a blockage condition in the fluid flow path based on the determined flow rate; and
in response to detecting the presence of a blockage condition, determining whether the detected blockage condition comprises a full waste canister condition or a blocked conduit condition by opening and closing a valve positioned in the fluid flow path; and
providing an indication of a presence of the full waste canister condition or the blocked conduit condition.
2. The method of claim 1 , further comprising:
providing the indication of the presence of the full canister condition or the blocked conduit condition with at least one of a visual indication, an audio indication, or a vibration indication.
3. The method of claim 1 , wherein the valve is configured to admit ambient air into the fluid flow path.
4. A negative pressure wound therapy apparatus comprising:
a negative pressure source configured to provide negative pressure to a wound dressing through a flow path, wherein the flow path comprises a conduit and a waste canister;
a valve located in the flow path; and
a controller configured to:
determine a fluid flow rate in the flow path;
detect a presence of a blockage condition in the flow path based on the determined fluid flow rate;
in response to detecting the presence of the blockage condition, determine whether the detected blockage condition comprises a full waste canister condition or a blocked conduit condition by causing the valve to open and close; and
provide an indication of the presence of the full canister condition or the blocked conduit condition.
5. The negative pressure wound therapy apparatus of claim 4 , wherein the valve is configured to admit ambient air into the flow path.
6. The apparatus of claim 4 , wherein the indication comprises one of a visual indication, an audio indication, or a vibration indication.
7. The method of claim 1 , wherein detecting a presence of a blockage condition in the fluid flow path comprises:
comparing the determined fluid flow rate to a fluid flow rate threshold; and
detecting the presence of a blockage condition when the fluid flow rate is less than the fluid flow rate threshold.
8. The method of claim 1 , wherein detecting a presence of a blockage condition in the fluid flow path comprises:
comparing the determined fluid flow rate to a fluid flow rate threshold;
determining a pressure in the fluid flow path;
calculating a pressure difference between the determined pressure and a pressure setting;
comparing the calculated pressure difference to a threshold pressure difference; and
detecting the presence of a blockage condition when the fluid flow rate is less than the fluid flow rate threshold and the calculated pressure difference is less than the threshold pressure difference.
9. The method of claim 1 , wherein determining whether a detected blockage condition comprises a full waste canister condition or a blocked conduit condition comprises:
determining a pressure in the fluid flow path before opening the valve;
determining a pressure in the fluid flow path after opening the valve;
comparing the determined pressures; and
determining that the detected blockage condition comprises a full waste canister condition when the determined pressures are approximately equal to each other and comprises a blocked conduit condition when the determined pressures are otherwise not approximately equal to each other.
10. The method of claim 1 , further comprising:
restricting fluid flow through the fluid flow path via at least one of a fixed area flow restrictor or a variable area flow restrictor;
calculating a pressure difference between the fluid pressures upstream and downstream of the restriction;
detecting a presence of a blockage condition in the fluid flow path based partly on the calculated pressure difference; and
in response to detecting the presence of a blockage condition, determining whether a detected blockage condition comprises a full waste canister condition or a blocked conduit condition by comparing the pressure difference to a pressure difference threshold.
11. The apparatus of claim 4 , wherein the controller is further configured to detect the presence of a blockage condition in the flow path based partly on the determined flow rate by:
comparing the fluid flow rate to a fluid flow rate threshold; and
detecting the presence of a blockage condition when the fluid flow rate is less than the fluid flow rate threshold.
12. The apparatus of claim 4 , further comprising a pressure sensor configured to measure pressure in the flow path, and wherein the controller is further configured to detect the presence of a blockage condition by:
comparing the fluid flow rate to a fluid flow rate threshold;
determining a pressure in the flow path;
calculating a difference between the pressure and a pressure setting;
comparing the calculated difference to a threshold pressure difference; and
detecting the presence of a blockage condition when the fluid flow rate is less than the fluid flow rate threshold and the calculated difference is less than the threshold pressure difference.
13. The apparatus of claim 4 , further comprising a pressure sensor configured to measure pressure in the flow path, and wherein the controller is further configured to determine whether a detected blockage condition comprises a full waste canister condition or a blocked conduit condition by:
determining a pressure in the flow path before opening the valve;
determining a pressure in the flow path after opening the valve;
comparing the determined pressures; and
determining that the detected blockage condition comprises a full waste canister condition when the determined pressures are approximately equal to each other and comprises a blocked conduit condition when the determined pressures are otherwise not approximately equal to each other.