Infusion system and method of use which prevents over-saturation of an analog-to-digital converter

• US 10,596,316 B2
• Filed: 07/13/2017
• Issued: 03/24/2020
• Est. Priority Date: 05/29/2013
• Status: Active Grant

• Current Assignee: ICU Medical Incorporated
• Original Assignee: ICU Medical Incorporated
• Inventors: Dumas, III, John Hicks, Kotnik, Paul T., Sur, Kunal, Belkin, Anatoly S., Ruchti, Timothy L.
• Primary Examiner(s): Do, An H
• Application Number:
  US15/648,975
• Publication Number:
  US 20180028749A1
• Time in Patent Office: 985 Days
• Field of Search: 702 57, 702 66, 702 75, 73 1903, 73 191, 604 67, 604151, 604500
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3327 Measuring
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/702 automatically during use
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/02433 Gases in liquids, e.g. bubbles, foams
• CPC Class Codes: G01N 29/02 Analysing fluids using acoustic emission techniques G01N29/14 ; constructional or flow details for analysing fluids G01N29/222; optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: H03M 1/129 Means for adapting the input signal to the range the converter can handle, e.g. limiting, pre-scaling H03M1/18 takes precedence; Out-of-range indication

Abstract

To detect air in a fluid delivery line of an infusion system, infusion fluid is pumped through a fluid delivery line adjacent to at least one sensor. A signal is transmitted and received using the at least one sensor into and from the fluid delivery line. The at least one sensor is operated, using at least one processor, at a modified frequency which is different than a resonant frequency of the at least one sensor to reduce an amplitude of an output of the signal transmitted from the at least one sensor to a level which is lower than a saturation level of the analog-to-digital converter to avoid over-saturating the analog-to-digital converter. The signal received by the at least one sensor is converted from analog to digital using an analog-to-digital converter. The at least one processor determines whether air is in the fluid delivery line based on the converted digital signal.

Claims

1. An infusion system configured to improve detection of air in a fluid delivery line, the infusion system comprising:

a sensor configured to detect a first signal transmitted in a fluid delivery line;

an analog-to-digital converter electronically connected to the sensor, the analog-to-digital converter configured to convert the detected signal from analog to digital;

a hardware processor connected with the analog-to-digital converter, the hardware processor configured to;

determine that the detected first signal is saturated;

change an operating frequency of the sensor based on the determination of saturation;

transmit a second signal at the changed operating frequency; and

determine air in the fluid delivery line based on the transmitted second signal.

2. The infusion system of claim 1, wherein the changed operating frequency is different than a resonant frequency of the sensor.

3. The infusion system of claim 1, wherein the one or more hardware processors are further configured to determine the resonant frequency of the sensor.

4. The infusion system of claim 1, wherein the one or more hardware processors are further configured to determine a minimum level for received signals.

5. The infusion system of claim 4, wherein the one or more hardware processors are further configured to change the operating frequency to exceed the minimum level for received signals.

6. The infusion system of claim 1, wherein the changed operating frequency is within ±

50% of the resonant frequency.

7. An method of improving detection of air in a fluid delivery line, the method comprising:

detecting a first signal transmitted in a fluid delivery line;

converting the detected signal from analog to digital;

determining that the detected first signal is saturated;

changing an operating frequency of the sensor based on the determination of saturation;

transmitting a second signal at the changed operating frequency; and

determining air in the fluid delivery line based on the transmitted second signal.

8. The method of claim 7, wherein the changed operating frequency is different than a resonant frequency of the sensor.

9. The method of claim 7, further comprising the resonant frequency of the sensor.

10. The method of claim 7, further comprising determining a minimum level for received signals.

11. The method of claim 10, further comprising changing the operating frequency to exceed the minimum level for received signals.

12. The method of claim 7, wherein the changed operating frequency is within ±

50% of the resonant frequency.

13. An infusion system configured to improve detection of air in a fluid delivery line, the infusion system comprising one or more hardware processors configured to:

receive a first digital signal corresponding to a first signal detected by a sensor, wherein the first signal is responsive to a transmitted signal in a fluid delivery line;

determine that the first digital signal is saturated;

change an operating frequency of the sensor based on the determination of saturation;

transmit a second signal at the changed operating frequency; and

determine air in the fluid delivery line based on the transmitted second signal.

14. The infusion system of claim 13, wherein the changed operating frequency is different than a resonant frequency of the sensor.

15. The infusion system of claim 13, wherein the one or more hardware processors are further configured to determine the resonant frequency of the sensor.

16. The infusion system of claim 13, wherein the one or more hardware processors are further configured to determine a minimum level for received signals.

17. The infusion system of claim 16, wherein the one or more hardware processors are further configured to change the operating frequency to exceed the minimum level for received signals.

18. The infusion system of claim 13, wherein the changed operating frequency is within ±

50% of the resonant frequency.