Automatic catheter recognition and associated methods, systems and circuits
Disclosed is a medical device for pumping fluid through a conduit, the pump including: one or more sensors to detect a parameter associated with the fluid; a circuit to (a) receive from the sensor a first signal indicative of one or more characteristics associated with the fluid; and (b) to determine if an occlusion is indicated based on a signal analysis of the first signal.
1. A medical device for delivering fluid to a patient, said device comprising:
a pump including a pumping mechanism designed to pump fluid through a conduit;
a pressure sensor positioned to sense pressure within the conduit and to generate signals in response thereto; and
a controller communicatively coupled to said sensor and said pump, said controller comprising processing circuitry configured to dynamically modify and update velocity or cycles of said pumping mechanism, during operation of said pumping mechanism, based on said signals from said pressure sensor, so as to maintain a desired flow rate within the conduit,
wherein said controller is configured to:
(i) analyze said signals to determine if the pressure within the conduit is indicative of a backpressure within the conduit passing above a backpressure-threshold;
(ii) in response to determining in step (i) that the backpressure within the conduit is above the backpressure-threshold, determine the presence of a catheter having an internal diameter that is narrower than the internal diameter of the conduit coupled to the conduit downstream of the pump, and adjust the velocity or cycles of the pumping mechanism based on the backpressure within the conduit being above the backpressure-threshold;
(iii) in response to determining in step (i) that the backpressure within the conduit is not above the backpressure-threshold, determine the non-presence of a catheter having an internal diameter that is narrower than the internal diameter of the conduit coupled to the conduit downstream of the pump;
(iv) in response to determining the non-presence of a catheter based on the analyzing of said signals, continue operation of the pump, and when said signals indicate that pressure sensed by said pressure sensor is over an occlusion-threshold, issue an alarm indicative of an occlusion within the conduit; and
(v) in response to determining the presence of a catheter having an internal diameter that is narrower than the internal diameter of the conduit based on the backpressure within the conduit being above the backpressure-threshold, increase a value of the occlusion-threshold.
2. The device of claim 1 , wherein said controller is configured to update velocity or cycles of said pumping mechanism, during operation of said pumping mechanism, based on periodic signals from said pressure sensor, sampled by said pressure sensor after a defined number of cycles, a defined number of cam rotations or a defined length of time.
3. The device of claim 1 , wherein, in response to determining the presence of a catheter, said controller is further configured to determine a catheter flow group characterization of a catheter coupled to the conduit downstream of the pump, based on the signals from said pressure sensor.
4. The device according to claim 3 , further comprising a hysteresis operator configured to prevent transition between catheter flow group characterization determinations due to noise.
5. The apparatus according to claim 4 , wherein the hysteresis operator is configured to prevent transition between catheter flow group characterization determinations by, in response to determining a catheter flow group characterization of the catheter, changing a backpressure-threshold corresponding to the catheter flow group characterization so as to inhibit the controller from transitioning to a different catheter flow group characterization determination due to noise.
6. A method for operating a medical device for delivering fluid to a patient, said method comprising:
using a pressure sensor to sense pressure within a fluid conduit delivering fluid to the patient and generate signals in response thereto; and
using a controller:
(i) analyzing said signals to determine if the pressure within the conduit is indicative of a backpressure within the conduit passing above a backpressure-threshold;
(ii) in response to determining in step (i) that the backpressure within the conduit is above the backpressure-threshold, determining the presence of a catheter having an internal diameter that is narrower than the internal diameter of the conduit coupled to the conduit downstream of the pump, and adjusting the velocity or cycles of the pumping mechanism based on the backpressure within the conduit being above the backpressure-threshold;
(iii) in response to determining in step (i) that the backpressure within the conduit is not above the backpressure-threshold, determining the non-presence of a catheter having an internal diameter that is narrower than the internal diameter of the conduit coupled to the conduit downstream of the pump;
(iv) dynamically modifying and updating velocity or cycles of a pumping mechanism of a pump causing the fluid to flow through the conduit, during operation of said pump, based on said signals from said pressure sensor, so as to maintain a desired flow rate within the conduit;
(v) in response to determining the non-presence of a catheter based on the analyzing of said signals, continuing to operate the pump, and when said signals indicate that pressure sensed by said pressure sensor is over an occlusion-threshold issuing an alarm indicative of an occlusion within the conduit; and
(vi) in response to determining the presence of a catheter having an internal diameter that is narrower than the internal diameter of the conduit based on the backpressure within the conduit being above the backpressure-threshold, increasing a value of the occlusion-threshold.
7. The method of claim 6 , wherein further comprising updating velocity or cycles of said pumping mechanism, during operation of said pumping mechanism, based on periodic signals from said pressure sensor, sampled by said pressure sensor after a defined number of cycles, a defined number of cam rotations or a defined length of time.
8. The method of claim 6 , further comprising, in response to determining the presence of a catheter, determining a catheter flow group characterization of a catheter coupled to the conduit downstream of the pump based on the signals from said pressure sensor.
9. The method of claim 8 , further comprising applying a hysteresis operation to prevent transition between catheter flow group characterization determinations due to noise.
10. The method according to claim 9 , wherein applying the hysteresis operation comprises, in response to determining a catheter flow group characterization of the catheter, changing a backpressure-threshold corresponding to the catheter flow group characterization so as to inhibit the controller from transitioning to a different catheter flow group characterization determination due to noise.