Arterial line emulator

• US 6,471,646 B1
• Filed: 07/19/2001
• Issued: 10/29/2002
• Est. Priority Date: 07/19/2001
• Status: Expired due to Fees

• Current Assignee: Medwave, Inc.
• Original Assignee: Medwave, Inc.
• Inventors: Thede, Roger C.
• Primary Examiner(s): Dolinar, Andrew M.
• Application Number:
  US09/909,148
• Time in Patent Office: 467 Days
• Field of Search: 600/301, 600/485, 600/486
• US Class Current: 600/301
• CPC Class Codes: A61B 2562/225 Connectors or couplings
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00

Abstract

An arterial line emulator interfaces a non-invasive blood pressure monitor with an invasive blood pressure monitor. The emulator receives pressure waveform signals from the non-invasive blood pressure monitor, and receives a transducer excitation voltage from the invasive blood pressure monitor. The emulator converts the pressure waveform signal from the non-invasive blood pressure monitor into an analog signal which is scaled as a function of the excitation voltage. The scaled analog pressure signal is supplied as an input to the invasive blood pressure monitor, and emulates the signal which would be received from a catheter-based blood pressure transducer.

Claims

1. A method of interfacing a non-invasive blood pressure monitor that produces digital data representing a non-invasively sensed blood pressure waveform with an invasive blood pressure monitor that provides an excitation voltage to an invasive blood pressure sensor and receives an analog pressure signal from the invasive blood pressure sensor at a pressure signal input, the method comprising:

converting the digital data to a scaled analog signal based upon the excitation voltage; and

providing the scaled analog pressure signal to the pressure signal input invasive blood pressure monitor.

2. The method of claim 1 wherein converting the digital data comprises:

receiving the digital data from the non-invasive blood pressure monitor;

sensing the excitation voltage from the invasive blood pressure monitor;

scaling the digital data based upon the excitation voltage sensed; and

converting the scaled digital data to the scaled analog pressure signal.

3. The method of claim 2 wherein converting the scaled digital data comprises:

performing a digital to analog conversion of the scaled digital data to produce a conventional signal; and

signal processing the converted signal to produce the scaled analog pressure signal.

4. The method of claim 3 wherein the signal processing includes filtering the conventional signal.

5. The method of claim 3 wherein the signal processing includes scaling the converted signal.

6. The method of claim 2 and further comprising:

sensing polarity of the excitation voltage; and

determining polarity of the scaled analog pressure signal based upon the sensed polarity of the excitation voltage.

7. A device for interfacing a non-invasive blood pressure monitor with an invasive blood pressure monitor, the device comprising:

means for receiving a blood pressure waveform signal from the non-invasive blood pressure monitor;

means for sensing an excitation voltage provided by the invasive blood pressure monitor; and

means for providing to an input of the invasive blood pressure monitor a scaled analog pressure waveform signal which is a function of the blood pressure waveform signal received from the non-invasive blood pressure monitor and the excitation voltage sensed.

8. The device of claim 7 wherein the blood pressure waveform signal is digital data.

9. The device of claim 8 wherein the means for providing comprises:

means for scaling the digital data based upon the excitation voltage sensed; and

means for converting the scaled digital data to the scaled analog pressure waveform signal.

10. The device of claim 9 wherein the means for converting comprises:

a digital-to-analog convertor for converting the scaled digital data to an analog signal; and

filter and scaling circuitry for processing the analog signal to produce the scaled analog pressure waveform signal.

11. The device of claim 7 and further comprising:

means for sensing polarity of the excitation voltage; and

means for controlling polarity of the scaled analog pressure waveform signal as a function of the sensed polarity of the excitation voltage.

12. A blood pressure monitoring system comprising:

a non-invasive blood pressure monitor that produces, at an output, a non-invasively sensed blood pressure waveform signal;

an invasive blood pressure monitor that displays blood pressure waveforms based upon an analog waveform signal received at an input from an invasive pressure sensor energized by an excitation voltage supplied by the invasive blood pressure monitor; and

an emulator connected to the output of the non-invasive blood pressure monitor and the input of the invasive blood pressure monitor for providing to the input of the invasive pressure sensor an analog signal based upon the non-invasively sensed blood pressure waveform signal and the excitation voltage which emulates the analog waveform signal produced by an invasive pressure sensor.

13. The system of claim 12 wherein the emulator comprises:

means for receiving the non-invasively sensed signal from the output non-invasive blood pressure monitor;

means for sensing an excitation voltage provided by the invasive blood pressure; and

means for providing the analog signal to the input of the invasive blood pressure monitor as a function of the non-invasively blood pressure waveform signal and the excitation voltage sensed.

14. The device of claim 13 wherein the blood pressure waveform signal is digital data.

15. The device of claim 12 wherein the means for providing comprises:

means for scaling the digital data based upon the excitation voltage sensed; and

means for converting the scaled digital data to the analog signal.

16. A method of interfacing a non-invasive blood pressure monitor with an invasive blood pressure monitor, the method comprising:

receiving a blood pressure waveform signal from the non-invasive blood pressure monitor;

sensing an excitation voltage provided by the invasive blood pressure; and

providing a scaled analog pressure waveform signal to an input of the invasive blood pressure monitor, the scaled analog pressure waveform signal being a function of the blood pressure waveform signal received from the non-invasive blood pressure monitor and the excitation voltage sensed.

17. The method of claim 16 wherein the blood pressure waveform signal is digital data.

18. A method of interfacing a non-invasive blood pressure monitor and an invasive blood pressure monitor, the method comprising:

receiving digital data representing a non-invasively sensed blood pressure waveform for the non-invasive blood pressure monitor;

sensing an excitation voltage supplied by the invasive blood pressure monitor;

producing an analog blood pressure waveform signal based upon the digital data, the analog blood pressure waveform signal having a period based upon the digital data and an amplitude based upon the digital data and an excitation voltage; and

supplying the analog blood pressure waveform signal to an input of the invasive blood pressure monitor.