AUTOMATED BLOOD ANALYSIS SYSTEM

• US 3,838,682 A
• Filed: 12/29/1972
• Issued: 10/01/1974
• Est. Priority Date: 12/29/1972
• Status: Expired due to Term

• Current Assignee: Justin S. Clark, Lloyd George Veasy
• Original Assignee: Justin S. Clark, Lloyd George Veasy
• Inventors: Clark, Justin S., Veasy, Lloyd George
• Primary Examiner(s): Medbery, Aldrich F.
• Application Number:
  US05/319,561
• Time in Patent Office: 641 Days
• Field of Search: 128/2L,2G,2R,214B,214E,214F 356/39-42
• US Class Current: 600/325
• CPC Class Codes: G01N 35/00594 Quality control, including calibration or testing of components of the analyser
• CPC Class Codes: G01N 35/00693 Calibration

Abstract

A system for automatically withdrawing blood from a patient and testing various parameters of the blood, such as oxygen saturation, hemoglobin, gas content (PO2, PCO2) and pH, includes a withdrawal unit which automatically withdraws a measured volume of blood, and returns all of it to the patient except a small measured quantity which is provided to an analysis unit that measures the gas content and pH. The withdrawal unit includes provision for continuously monitoring patients'"'"''"'"' blood pressure, irrigation from a standard I. V. source between blood withdrawals, or a constant low flush of saline, alternatively, as well as detection of any air in the blood, which results in shutting down the system and activating an air alarm. The withdrawal unit also has provision for automatically withdrawing a small sample of blood, measuring oxygen content, and returning all blood to the patient, all on a programmed basis. The analysis unit includes two-point gas and pH calibration and includes use of calibration fluid for washout. In each complete use cycle, blood from the withdrawal unit is washed into the analysis unit and blood in the analysis unit is moved and washed out using saline, water and calibration fluids. The withdrawal unit may be used alone to acquire blood samples, and the analysis unit may be fed by more than one withdrawal unit or by manually-acquired blood specimens.

Claims

1. An automated blood unit comprising:

first and second fluid valves, each having a normal position and an operated position;

a first fluid path means adapted to be connected to an indwelling blood catheter for interconnecting said catheter with a first port of said first fluid valve;

a second fluid path means connected to said first fluid path means and to a first port of said second fluid valve;

a third fluid path means interconnecting a second port of said second fluid valve with a second port of said first fluid valve;

a reversible pump;

means for interconnecting said pump with a third port of said first fluid valve;

said first fluid valve comprising first fluid communicating means, when in its normal position, connecting said first fluid path means with said pump, and also comprising second fluid communicating means when in its operated position, connecting said third fluid path means with said pump via the interconnecting means, and said second fluid valve comprising first fluid communicating means, when in its operated position, connecting said second fluid path means with said third fluid path means, so that, with a catheter connected (a), in response to said pump initiating a draw cycle with said first fluid valve in its normal position, fluid is drawn by force of said pump along a pathway comprising said first fluid path means, said first fluid communicating means of the first fluid valve and said interconnecting means thereby drawing blood from said catheter into said first fluid path means, and (b) in response to said pump initiating a draw cycle with said first and second fluid Valves in their operated positions, fluid is drawn along another pathway comprising said second fluid path means, the first fluid communicating means of the second fluid valve and the third fluid path means thereby drawing blood from said catheter into said second and third fluid path means, and so that, in response to said pump initiating a push cycle following said blood withdrawal into either of said pathways, blood is returned to said catheter along said pathways.

2. The automated blood unit according to claim 1 additionally comprising:

an intravenous irrigation solution source connected to a third port of said second valve, said third port being connected by second fluid communicating means to said second fluid path means when said second valve is in its normal position, a fourth port of said second fluid valve and third fluid communicating means connecting said fourth port to said third fluid path means at the second port of the second valve when said second valve is in its normal position, said fourth port adapted to discharge to waste fluid passing from the third fluid path means and said third communicating means, said first fluid path being adapted to be filled with saline solution, so that blood is withdrawn from said catheter into said first fluid path means due to negative saline pressure caused by the pump and thereafter returned to said catheter from said first fluid path means in response to positive fluid pressure created by the pump against the saline and thence against the blood when said fluid valves are in their normal positions, and blood is withdrawn from said catheter through the first fluid path means into said second fluid path means due to negative saline pressure caused by the pump and thereafter returned to said catheter from said second fluid path means along said first fluid path means in response to positive fluid pressure of said intravenous solution when said pump is operated with said valves in their operated positions.

3. The automated blood unit according to claim 1 wherein said first fluid path means includes an oximeter disposed between the junction of said second fluid path means with said first fluid path means and the point of connection of said catheter to said first fluid path means and wherein the oximeter comprises means for taking oximeter readings by pump drawing a small sample of blood along the first fluid path means through the oximeter and then pump displacing at least a portion of the blood sample back along the first fluid path means into the patient.

4. The automated blood unit according to claim 1 additionally comprising:

a selectively disengagable connection means for connecting said second fluid path means with said first fluid path means, said connection means being adapted for connection to a second indwelling catheter in lieu of the first fluid path means.

5. The automated blood unit according to claim 1 additionally comprising:

a low pressure constant flow saline source connected by fourth fluid path means to a fourth port of said first valve, said first valve comprising a third fluid communicating means which, when the first valve is in its normal position, connects said saline source with said third fluid path means, said first fluid valve also comprising fourth fluid communicating means which, when said first valve is in its operated position, connects said saline source with said first fluid path means, the second fluid valve comprising an additional port being connected by additional fluid communicating means to said third fluid path means, when said second valve is in its normal position, said fourth port adapted to discharge fluid passing therethrough to waste, so that said first fluid valve (a) connects said first fluid path means with said pump via said first fluid communicating means of the first valve and the interconnecting means and connects said saline source with waste via said third fluid communicating means of the first fluid valve, the third fluid path means, the additiOnal fluid communicating means and the additional port of the second fluid valve, when said first and second valves are in their normal positions, and (b) connects said saline source to said first fluid path means via said fourth fluid communicating means, to act as a blood clot preventing flush for a catheter connected to said first fluid path means, when said first valve is in its operated position, said pump being simultaneously in communication with said second catheter via the interconnecting means, the second fluid communicating means of the first valve, the third fluid path means, the first fluid communicating means of the second valve and the second fluid path means, said second valve being in its operated position.

6. The automated blood unit according to claim 5 including a blood pressure transducer in fluid communication with one of said pathways.

7. A blood testing system comprising:

a catheter to be introduced through the skin into the cardiovascular system of a patient using a sharp instrument;

a blood withdrawal unit connected to the catheter, the blood withdrawal unit comprising a closed fluid storage system comprising fluid pathway means comprising flexible tubing, the pathway having a uniform small bore throughout, which pathway means are initially filled with biologically inert fluid, blood flow means including two directional power means imposing positive and negative pressures upon the inert fluid within the pathway means for withdrawing blood, under negative pressure, through the catheter into and expelling all of the withdrawn blood from the withdrawal unit under positive pressure, said blood flow means comprising means for causing at least a substantial portion of the withdrawn blood to be returned through the pathway means and the catheter into the cardiovascular system under negative pressure caused by said power means, whereby upon withdrawal of blood through the catheter into the uniform bore pathway means of the withdrawal unit said blood flow means causes little if any turbulent flow resulting in an essentially two dimensional blood/fluid interface comprising a negligible amount of fluid with little or no mixing of blood and fluid and, thereafter, causing return of substantially all blood along the pathway means and into the cardiovascular system through the catheter and infusion into the cardiovascular system of very little inert fluid under positive pressure caused by the power means.

8. An automated blood testing system comprising:

a catheter to be placed in the cardiovascular system of a patient through venipuncture;

a blood withdrawal unit comprising fluid passageway means in fluid communication with the catheter, biologically inert fluid in said passageway means, at least one test station disposed at a site intermediate the passageway means, and two way hydraulic pressure control means for removing blood juxtaposed the inert fluid through the catheter and along a path comprising said passageway means to said test station under hydraulic pressure at the same time withdrawing said inert fluid along the same path thereby creating a movable interface between the blood and fluid;

said withdrawal unit further comprising means at said test station site for testing said blood disposed in said passageway means at said station and means creating hydraulic pressure which acts upon said inert fluid to jointly displace the inert fluid and blood in a reverse direction along said path and thereby return essentially all of said removed blood to the patient'"'"''"'"'s cardiovascular system through the catheter, said two way control means having means terminating the return of blood to the cardiovascular system when the blood/fluid interface is juxtaposed the catheter.

9. An automated blood testing system comprising:

a plurality of sterile blood withdrawal units each withdrawal unit adapted to be coupled to a patient via a catheter placed through the skin into a vessel by a sharp instrument and each withdrawal unit Defining an independent blood flow path therethrough;

a single non-sterile blood analysis unit comprising one-way blood ingress means which receives blood from any selected one of said withdrawal units at any specified point in time, passageway means connected to the one-way blood ingress means, a plurality of blood testing sites disposed at various locations along the passageway means, each blood testing site comprising means for evaluating blood, means for displacing blood received at the one-way blood ingress means along the passageway means to each testing site, and blood egress means for expelling blood from the analysis unit to waste;

each withdrawal unit comprising means for removing blood from a patient through the associated catheter and flow path of the associated withdrawal unit to the one-way blood ingress means of the analysis unit and for returning blood to the patient which, following withdrawal, is disposed within the flow path of said withdrawal unit between the catheter and the one-way blood ingress means of the analysis unit.

10. An automated blood testing system comprising:

a sterile blood withdrawal unit adapted to be coupled to a patient via a catheter placed through the skin into a vessel by a sharp instrument, the withdrawal unit defining a blood flow path therethrough;

a non-sterile blood analyzer comprising a one-way blood ingress interface in one-way communication with the blood flow path to receive blood from the withdrawal unit, the one-way blood ingress interface comprising means preventing blood flow from the analyzer back to the withdrawal unit, and passageway means connected to the one-way blood ingress interface, at least one blood testing site disposed at a location along the passageway means, the blood testing site comprising means for evaluating blood, means for displacing blood received from the withdrawal unit at the one-way blood ingress interface along the passageway means to the testing site, blood egress means for expelling blood from the analyzer to waste;

the withdrawal unit comprising means for removing blood from the patient through the catheter and flow path of the withdrawal unit to the one-way blood ingress interface of the analyzer and for returning to the patient residual blood disposed within the flow path of the withdrawal unit between the catheter and the one-way blood ingress interface.

11. The system of claim 10 wherein the blood flow preventing means of the one-way blood ingress interface comprise a blood effluent tube comprising part of the withdrawal unit and a blood collection chamber comprising part of the analyzer, the blood collecting chamber being physically separated from the effluent tube and into which blood from the effluent tube is discharged.

12. In a blood monitoring system:

a catheter to be introduced into a patient by a needle;

a blood withdrawal/intravenous infusion apparatus having means operating in a withdrawal mode and means operating in an infusion mode comprising;

blood withdrawal passageway means in fluid communication with the catheter, at least one blood monitoring site along the passageway means comprising means for evaluating blood, power means for withdrawing blood through the catheter and passageway means to the monitoring site when the withdrawal operating means are caused to function, control means for shifting the unit between said two modes;

infusion means comprising a source of infusion fluid a first flow path comprising part of said passageway means including the blood monitoring site spanning between the source of infusion fluid and the catheter, a second flow path spanning between the source and a waste station, and pressure-creating means to drive the fluid along (a) the first flow path when the control means have set the infusion operating means to function and (b) the second flow path when the control means have set the withdrawal operating means to function.