Disposable blood pump

A hemocompatible flexible diaphragm and flexible wall pumping chamber positioned in a rigid body and actuated by alternating positive and negative fluid pulses. An inlet valve and an outlet valve are integrally molded in the pumping chamber. The diaphragm and pumping chamber are preferably molded of an elastomer. The pump is atraumatic, inexpensive and the pumping chamber and diaphragm are disposable.

BACKGROUND OF THE INVENTION 
It has been reported that approximately 360,000 open heart procedures were 
performed in 1983 and approximately 25 percent used a disposable membrane 
oxygenator. As open heart procedures become more complex, entailing higher 
risks, it is anticipated that membrane oxygenators will be utilized more 
often. The present invention is directed to an inexpensive, atraumatic, 
hemocompatible, pulsatile diaphragm pump that can be used for 
cardiopulmonary bypass and replace the conventional blood roller pump 
which after a time period causes blood trauma. The present pump, because 
of its qualities, is useful for use with membrane oxygenators. Present 
blood pumps are extremely expensive, use clinical heart valves which cost 
as much as $2,500 per valve, and still are thrombogenic. The present blood 
pump uses simple leaf valves that are integral in a pumping chamber and 
molded as part of the chambers to provide an inexpensive, disposable 
atraumatic pump which can be used for heart surgery, post operative 
support and other uses. 
SUMMARY 
The present invention is directed to a disposable blood pump and includes a 
rigid housing having a cavity therein and having first and second parts 
which are joined together with coupling means. A flexible hemocompatible 
diaphragm is positioned in the cavity and has an outer edge supported 
between the first and second housing parts. A flexible wall hemocompatible 
pumping chamber is positioned in the cavity having one end adjacent the 
diaphragm. The flexible chamber includes an integral inlet leaf valve and 
an integral outlet leaf valve with the inlet valve being in communication 
with a blood inlet port in the housing and the outlet valve being in 
communication with a blood outlet port in the housing. The valves are 
operable between open and close positions by alternating actuation of the 
diaphragm. 
Still a further object of the present invention is the provision of a 
disposable blood pump including a rigid housing having a cavity therein 
and having first and second parts. The first part has a first supporting 
shoulder and the second part has a second and a third supporting shoulder. 
The first part includes a port for receiving actuating fluid and the 
second part includes a blood inlet port and a blood outlet port. Coupling 
means are connected between the first and second parts for joining the two 
parts with the first and second shoulders adjacent each other and coupling 
means are connected to the second part for joining the second part to an 
oxygenator. A flexible hemocompatible diaphragm is positioned in the 
cavity and the diaphragm includes an outer edge supported between the 
first and second supporting shoulders. A flexible wall hemocompatible 
pumping chamber having first and second ends is positioned in the cavity 
with the first end supported between the first and second supporting 
shoulders and the second end engaging the third shoulder. The chamber 
includes an integral inlet leaf valve and an integral outlet leaf valve, 
the inlet valve being in communication with the blood inlet port and the 
outlet valve being in communication with the blood outlet port and the 
valves being operable between open and close positions by alternating 
actuation of the diaphragm. 
Still a further object of the present invention is wherein the second part 
of the body includes an inward projection for engaging the exterior of the 
chamber adjacent the outlet valve for supporting the outlet valve. 
Still a further object of the present invention is the provision wherein 
the flexible diaphragm and chamber are of an elastomer material and molded 
to shape. 
Other and further objects, features and advantages will be apparent from 
the following description of a presently preferred embodiment of the 
invention, given for the purpose of disclosure and taken in conjunction 
with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawing, the reference numeral 10 generally indicates 
the disposable blood pump of the present invention which is useful in 
cardiac surgery such as cardiopulmonary bypass operations and which is 
particularly useful for connection to a membrane oxygenator 12. However, 
the pump 10 is useful in other applications such as a post operative 
support device. 
The pump 10 includes a rigid housing 14 which may be any suitable material 
such as a rigid plastic or metal having a cavity 16 therein and includes a 
first part 18 and a second part 20. The first part 18 includes a first 
supporting shoulder 22 and the second part 20 includes a second supporting 
shoulder 24 and a third supporting shoulder 26. The first part 18 includes 
a port 28, preferably in the end, having suitable connecting means 30 for 
receiving an actuating fluid line 32 for receiving pneumatic or mechanical 
hydraulic created alternating actuating pulses. The second part 20 of the 
housing 14 includes a blood inlet port 34, preferably in a side, and a 
blood outlet port 36 at one end. Suitable coupling means such as a 
threaded nut 38 connects the first part 18 to the second part 20 of the 
body 14 and a connecting means such as a nut 40 is provided for connecting 
the second part 20 of the body 14 to any suitable blood handling or 
treating equipment such as a conventional membrane oxygenator. 
A flexible hemocompatible diaphragm 42 is positioned in the cavity 16 of 
the body 14 having one side exposed to the port 28 and having an outer 
edge 44 which is supported between the first and second shoulders 22 and 
24 of the parts 18 and 20 of the body 14. A flexible wall hemocompatible 
pumping chamber 46 is provided in the cavity 16 of the body 14 having a 
first end 48 and a second end 50. The first end 48 is positioned adjacent 
the diaphragm edge 44 and between the shoulders 22 and 24 of the parts 18 
and 20 of the body 14 and the second end engages the third shoulder 26 for 
support between the body part 14 and the oxygenator 12. The edge 44 of the 
diaphragm and the ends 48 and 50 of the pumping chamber 46 are securely 
held in place by the units 38 and 40 for avoiding crevices which collect 
blood. The first end 48 is positioned adjacent the diaphragm 42 whereby 
pressure pulses generated by the diaphragm 42 will be transmitted to the 
interior 52 of the flexible wall chamber 46. The diaphragm provides a 
pulsatile actuation of the pump 10 which is less traumatic to blood as 
compared with the conventional roller pumps. The flexible wall chamber 46 
includes an integral inlet leaf valve 54 and seat 56 and an integral 
outlet leaf valve 58 and a seat 60. The inlet valve 54 is in communication 
with the blood inlet port 34 and the outlet valve 58 is in communication 
with the outlet port 36. Both the diaphragm 42 and the flexible wall 
chamber 46 are molded members made of any suitable hemocompatible 
elastomer such as silicone rubber or urethane thereby providing a pumping 
action which is atraumatic to the blood supply. In addition, the diaphragm 
42 and flexible wall chamber 46 with the integral valves 54 and 58 may be 
inexpensively made, and will thus allow the use of a pump for various 
applications including cardiac surgery which has not been available in the 
past because of the expense. The body 14 includes an inward projection 60 
for engaging the exterior of the flexible chamber 46 adjacent and around 
the outlet valve 58 for securely supporting the outlet valve 58. 
In one use, the pump 10 is generally connected, as noted, to an oxygenator 
12 and the inlet port 34 is connected to the atrium of the patient and the 
actuating port 28 is connected to the line 32 leading to a pneumatic, 
hydraulic or mechanically actuated alternating pulse. When a negative 
pressure is applied to the actuating port 28, the parts are as shown in 
solid outline with the diaphragm 42 being drawn toward the actuating port 
28, the inlet valve 54 being opened drawing blood into the interior 52 of 
the flexible wall chamber 46 while closing the outlet valve 58. And when 
the alternating positive pressure is applied in the port 28, the diaphragm 
42 moves away from the port 28, closing the inlet valve 54, opening the 
outlet valve 58, and pumping blood from the interior 52 of the flexible 
wall chamber 46 out the outlet 36 to the oxygenator 12 and back to the 
patient, all as shown in dotted outline. 
The pump 10 provides an inexpensive, disposable atraumatic pump which can 
be used in cardiac surgery, post operative support or other uses. After 
use, the diaphragm 42 and flexible wall chamber 46 may be discarded and 
replaced with new elements 42 and 46 for reuse, all at a minor expense 
compared to the expensive and still thrombogenic devices presently being 
used and will allow heart surgery to be performed in many cases not now 
available because of the expense. 
The present invention, therefore, is well adapted to carry out the objects 
and attain the ends and advantages mentioned as well as others inherent 
therein. While a presently preferred embodiment of the invention has been 
given for the purpose of disclosure, numerous changes in the details of 
construction and arrangement of parts will be readily apparent to those 
skilled in the art and which are encompassed within the spirit of the 
invention and the scope of the appended claims.