# US 12,005,176 B2 · Method for recovering residual blood from an extracorporeal circulation circuit and equipment for collecting and recovering residual blood in the extracorporeal circulation circuit

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- Number: US 12,005,176 B2
- Document ID: US12005176B2
- Status: Granted
- Kind: B2
- Application number: 16/753,655
- Filed: 2018-09-12
- Published: 2020-11-12
- Granted: 2024-06-11
- Earliest claimed: 2017-10-06
- Assignees: Zammi Instrumental Ltda
- Applicants: Zammi Instrumental Ltda
- Inventors: Luiz Henrique Vargas Fonseca
- Web page: https://patentgrep.com/patent/US12005176B2

## CPC

- A61M 1/3646: {Expelling the residual body fluid after use, e.g. back to the body}
- A61M 1/34: Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
- A61M 1/3403: {Regulation parameters}
- A61M 1/3601: {Extra-corporeal circuits in which the blood fluid passes more than once through the treatment unit}
- A61M 1/341: {by measuring the filtrate rate or volume}
- A61M 1/3666: {Cardiac or cardiopulmonary bypass, e.g. heart-lung machines}
- A61M 2205/3331: Pressure; Flow
- A61M 2230/207: hematocrit
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}

## Abstract

The processes and equipment for collecting and recovering residual blood from cardiopulmonary bypass provide increased efficiency in hemoconcentrators and hemodialysers. Residual blood collection and recovery equipment for extracorporeal circulation circuits include a flow-limiting valve disposed at an exit of a hemofilter, which automatically regulates a resistance in a line as a function of an inlet pressure. The valves of the residual blood collection and recovery equipment also include an opening that is proportional to a flow and a hematocrit. The systems and methods for blood recovery can be used after surgery or for hemodialysis, in addition to other applications.

## Claims

### Claim 1

A residual blood collection and recovery system for an extracorporeal circulation circuit, comprising:
a hemofilter provided with hollow fibers, an inlet end, and an outlet end;
a pump connected upstream of the hemofilter;
an inlet flow sensor connected upstream of the pump;
an inlet pressure sensor connected to the inlet end of the hemofilter;
a flow-limiting valve disposed in the outlet end of the hemofilter,
wherein the flow limiting valve comprises a flexible membrane molded in a sphincter format,
wherein the flexible membrane is assembled inside a hermetically sealed rigid casing such that the flexible membrane divides an inner pathway of the flow limiting valve and is provided between a compartment filled with compressed air and a blood flow compartment,
wherein the flow limiting valve is configured to transition from a closed position to an open position when a pressure of the blood flow leaving the hemofilter corresponds to an opening pressure of the flow limiting valve,
wherein the flow-limiting valve mechanically and automatically regulates a resistance in a line as a function of the flow-limiting valve inlet pressure,
wherein an automatic regulation includes a mechanical opening and closing of the membrane of the flow-limiting valve and wherein the automatic regulation is proportional to a flow in the line and a hematocrit;
an actuator in fluid communication with the compartment filled with compressed air of the flow limiting valve;
an outlet pressure sensor arranged in the hermetically sealed rigid casing of the flow limiting valve;
an outlet flow sensor connected downstream of the flow limiting valve; and
a computer processing unit (CPU) interconnected with the pump, the inlet flow sensor, the outlet flow sensor, the inlet pressure sensor, the outlet pressure sensor, and the actuator,
wherein the CPU is configured to:
drive the actuator for controlling the opening pressure of the flow limiting valve,
continuously calculate a transmembrane pressure and a filtration efficiency, and
maintain a transmembrane pressure at a magnitude lower than a maximum transmembrane pressure supported by the hemofilter hollow fibers.

### Claim 2 (depends on 1)

The system, according to claim 1, further comprising:
a piston installed in a casing of the flow-limiting valve to adjust an opening pressure of the membrane thereof at a beginning of an extracorporeal circulation process.

### Claim 3 (depends on 2)

The system according to claim 2,
wherein a pressure sensor embedded in the inlet end of the hemofilter measures the filter inlet pressure, together with the outlet pressure sensor, to allow the CPU to calculate the transmembrane pressure during the extracorporeal circulation process.

### Claim 4 (depends on 1)

The system, according to claim 1, further comprising a pump, disposed upstream of the hemofilter equipped with a flexible and impermeable membrane installed inside a hermetically sealed rigid casing having cartwheel valves at the inlet and outlet, a pumping being provided through an outer driver that cyclically injects and sucks air or liquid into the compartment formed between said membrane and said outer pump casing, through a side connector.

### Claim 5 (depends on 2)

The system, according to claim 2, further comprising a pump, disposed upstream of the hemofilter equipped with a flexible and impermeable membrane installed inside a hermetically sealed rigid casing having cartwheel valves at the inlet and outlet, a pumping being provided through an outer driver that cyclically injects and sucks air or liquid into the compartment formed between said membrane and said outer pump casing, through a side connector.

### Claim 6 (depends on 1)

The system according to claim 1,
wherein a pressure sensor embedded in the inlet end of the hemofilter measures the filter inlet pressure, together with the outlet pressure sensor, to allow the CPU to calculate the transmembrane pressure during the extracorporeal circulation process.