Sensors for catheter pumps
Sensors for catheter pumps are disclosed herein. The catheter pump can include a catheter assembly comprising a catheter and a cannula coupled to a distal portion of the catheter. The cannula can have a proximal port for permitting the flow of blood therethrough. The catheter assembly can include a sensor to be disposed near the proximal port. A processing unit can be programmed to process a signal detected by the sensor. The processing unit can comprise a computer-readable set of rules to evaluate the signal to determine a position of the cannula relative to an aortic valve of a patient.
1. A catheter assembly comprising:
a catheter body;
a cannula coupled to a distal portion of the catheter body, the cannula having a proximal port and a distal port to enable a flow of blood through the cannula from the distal port to the proximal port;
an impeller disposed in the cannula between the proximal port and the distal port and configured to generate the flow of blood through the cannula;
a sensor assembly configured to measure a fluid property of the flow of blood through the cannula, wherein the sensor assembly comprises an elongate connector and at least one of: (a) a proximal sensor coupled with the catheter body and having a distal portion near the proximal port, and (b) a distal sensor coupled with the cannula and having a distal portion near the distal port, the catheter body configured to receive the elongate connector through a sensor lumen from outside a patient to a location near the proximal port; and
a bearing housing disposed within the cannula, the bearing housing comprising a trough sized and shaped to receive the elongate connector between the bearing housing and the cannula.
2. The catheter assembly of claim 1 , wherein the sensor assembly comprises the distal sensor.
3. The catheter assembly of claim 1 , wherein the sensor assembly comprises a pressure sensor configured to measure a pressure of the flow of blood through the cannula and generate a signal related to the pressure.
4. The catheter assembly of claim 3 , wherein the pressure sensor comprises a fiber optic sensor.
5. The catheter assembly of claim 4 , wherein the fiber optic sensor comprises an elongate optical fiber and a sensor tip coupled to a distal end of the elongate optical fiber, the catheter body configured to receive the elongate optical fiber from outside a patient to a location near the proximal port or the distal port to provide optical communication between the sensor tip and a processing unit.
6. The catheter assembly of claim 1 , wherein the sensor assembly further comprises a sensor tip at a distal end of the elongate connector.
7. The catheter assembly of claim 6 , wherein the cannula comprises a tubular portion coupled to the distal portion of the catheter body, and wherein the tubular portion is configured to receive the elongate connector along an inner wall of the tubular portion.
8. The catheter assembly of claim 1 , wherein the sensor assembly comprises the distal sensor disposed near the distal port, the distal sensor comprising an elongate connector extending from a proximal portion of the catheter assembly and a sensor tip disposed at a distal end of the elongate connector.
9. The catheter assembly of claim 8 , wherein the distal sensor is disposed on or within an outer wall of the cannula and the elongate connector extends about a circumference of the cannula.
10. The catheter assembly of claim 8 , further comprising a protective lumen coupled to a wall of the cannula, wherein the distal sensor is configured to pass through the protective lumen to position the sensor tip near the distal port.
11. The catheter assembly of claim 8 , further comprising a central lumen disposed in the cannula, the distal sensor configured to pass through the central lumen to position the sensor tip near a sensing zone formed through the central lumen.
12. The catheter assembly of claim 11 , further comprising an impeller disposed in the cannula and a tip member at a distal end of the cannula, wherein the central lumen passes between the impeller and the tip member.
13. A catheter assembly comprising:
a catheter body;
a cannula coupled to a distal portion of the catheter assembly, the cannula having a proximal port to enable a flow of blood through the cannula and exiting the proximal port;
an impeller disposed in the cannula distal the proximal port and configured to generate the flow of blood through the cannula;
a sensor assembly comprising an elongate connector and a sensor to be disposed near the proximal port, the catheter body configured to receive the elongate connector through a sensor lumen from outside a patient to a location near the proximal port;
a bearing housing disposed within the cannula, the bearing housing comprising a trough sized and shaped to receive the elongate connector between the bearing housing and the cannula; and
a processing unit programmed to process a signal generated by the sensor, the processing unit configured to execute a computer-readable set of rules to evaluate the signal to determine a position of the cannula relative to a cardiac valve of a patient during a treatment procedure.
14. The catheter assembly of claim 13 , wherein the computer-readable set of rules evaluates the signal based at least in part on a rate of change of pressure or flow rate over time.
15. The catheter assembly of claim 14 , wherein the processing unit comprises a look-up table (LUT) comprising an array of values corresponding to pressure, flow rate, rate of change of pressure, or rate of change of flow rate.
16. The catheter assembly of claim 13 , wherein the computer-readable set of rules evaluates the signal based at least in part on a recognition of a pattern in a waveform of the signal.
17. The catheter assembly of claim 13 , wherein the sensor comprises a pressure sensor, and wherein the signal is related to a pressure of a fluid flowing through the proximal port.
18. The catheter assembly of claim 17 , wherein the pressure sensor comprises a fiber optic sensor.
19. The catheter assembly of claim 18 , wherein the fiber optic sensor comprises an elongate optical fiber and a sensor tip coupled to a distal end of the elongate fiber, the catheter configured to receive the elongate optical fiber from outside a patient to a location near the proximal port to provide optical communication between the sensor tip and the processing unit.
20. The catheter assembly of claim 17 , wherein the computer-readable set of rules includes a baseline rule for determining a baseline pressure signature from the signal, wherein the baseline pressure signal indicates proper placement of the cannula relative to the cardiac valve.
21. The catheter assembly of claim 20 , wherein the baseline pressure signature indicates that the proximal port of the cannula is disposed proximal the cardiac valve.
22. The catheter assembly of claim 21 , the assembly further comprising a distal sensor near a distal port of the cannula, wherein the computer-readable set of rules includes a baseline rule for determining a distal baseline pressure signature from a distal signal received from the distal sensor, wherein the distal baseline pressure signature indicates that the distal port of the cannula is disposed distal the cardiac valve.
23. The catheter assembly of claim 22 , wherein the computer-readable set of rules includes a rule for determining whether the distal port is in close proximity to or overlying the cardiac valve.
24. The catheter assembly of claim 20 , wherein the computer-readable set of rules includes a disturbance rule for determining a disturbance pressure signature from the pressure signal, wherein the disturbance pressure signature represents improper placement of the cannula relative to the cardiac valve.
25. The catheter assembly of claim 24 , wherein the disturbance rule comprises a rule for determining a difference between a mean baseline pressure of a baseline pressure signature and a mean disturbance pressure of a disturbance pressure signature.
26. The catheter assembly of claim 24 , wherein the disturbance rule comprises a rule for determining whether the proximal port is in close proximity to or overlying the cardiac valve.