Cardiotomy reservoir

• US 4,662,906 A
• Filed: 11/04/1985
• Issued: 05/05/1987
• Est. Priority Date: 04/12/1984
• Status: Expired due to Term

• Current Assignee: Pall Corporation (Danaher Corporation)
• Original Assignee: Pall Corporation (Danaher Corporation)
• Inventors: Rosenberg, David J., Matkovich, Vlado I.
• Primary Examiner(s): Hart, Charles
• Application Number:
  US06/794,559
• Time in Patent Office: 547 Days
• Field of Search: 55/159, 55/178, 55/185-187, 55/204, 55/318, 128/DIG. 3, 210/321.4, 210/436, 210/472, 210/512.1, 210/927, 604/4, 604/5, 604/122, 604/126
• US Class Current: 96/6
• CPC Class Codes: A61M 1/325 Surfactant coating; Improving wettability
• CPC Class Codes: A61M 1/3627 Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
• CPC Class Codes: A61M 1/3643 Priming, rinsing before or after use
• CPC Class Codes: A61M 2205/7536 allowing gas passage, but preventing liquid passage, e.g. liquophobic, hydrophobic, water-repellent membranes
• CPC Class Codes: A61M 2206/16 Rotating swirling helical flow, e.g. by tangential inflows
• CPC Class Codes: Y10S 128/03 Heart-lung

Abstract

A cardiotomy reservoir for separating air from blood including a housing having top, bottom and side walls and defining upper and lower cylindrical chambers. A defoaming element comprising an annulus of sponge material is disposed in the upper end of said lower chamber and extends around the periphery of the housing. The upper chamber includes a channel for directing blood to the sponge annulus whereby the blood flows through the latter to the lower chamber, the sponge annulus including an antifoaming agent for causing air bubbles in the blood to coalesce and form larger air bubbles as the blood flows through the sponge annulus. A passage is disposed between the sponge annulus and the upper chamber whereby large air bubbles exit the sponge annulus and move through the passage to the upper chamber where air but not blood is vented automatically to the atmosphere through a hydrophobic membrane.

Claims

1. A cardiotomy reservoir comprising, in combination, a housing having top, bottom and side walls and defining upper and lower cylindrical chambers, a defoaming element comprising an annulus of sponge material disposed in the upper end of said lower chamber and extending along the periphery of said housing, means in said upper chamber for directing blood tangentially of the side wall so that the blood flows in a generally circular path and then out of said chamber through said sponge annulus, said circular flow producing a centrifugal action which causes the blood to flow at the outer periphery of the upper chamber while air entrained in the blood separates and moves inwardly, automatic venting means in said upper chamber to permit air but not blood to escape from the housing, said sponge annulus including means for causing air bubbles remaining in the blood to coalesce and form larger air bubbles as the blood flows through said sponge annulus, means forming a passage between said sponge annulus and said upper chamber whereby said large air bubbles exit the sponge annulus and move through said passage to said upper chamber to be vented automatically to atmosphere.

2. A cardiotomy reservoir as defined in claim 1 in which said means for forming said passage is a cylindrical support element radially spaced from the axis of said upper chamber and said sponge annulus is disposed between the support element and the side wall of said housing.

3. A cardiotomy reservoir as defined in claim 2 in which said support element is perforated whereby blood and said larger air bubbles flow out of said sponge annulus through the perforations in the support element and into said passage.

4. A cardiotomy reservoir as defined in claim 3 in which said means for causing the air in the blood to coalesce is a compound of silicone and silica with the silicone capturing smaller air bubbles in said sponge annulus and said silica causing the film between adjacent bubbles to break and form larger bubbles.

5. A cardiotomy reservoir comprising, in combination, a housing having top, bottom and side walls and defining upper and lower cyclindrical chambers, a defoaming element comprising an annulus of sponge material disposed in the upper end of said lower chamber and extending around the periphery of said housing, means in said upper chamber for directing blood to said sponge annulus wherein the blood flows through the latter to said lower chamber, said sponge annulus including a compound of silica and silicone for causing air bubbles in the blood to coalesce and form larger air bubbles as the blood flows through said sponge annulus, means forming a passage between said sponge annulus and said upper chamber including a cylindrical support element radially spaced from the axis of said upper chamber, said sponge annulus being disposed between the support element and the side wall of the housing, said support element being perforated whereby blood and said larger air bubbles flow out of said sponge annulus through the perforations in the support element and into said passage, said larger air bubbles moving through said passage to said upper chamber, and means permitting air but not blood in said upper chamber to be vented automatically to atmosphere, said cardiotomy reservoir further comprising a cylindrical filter element disposed in said lower chamber and having a hollow interior, an outlet formed in said bottom wall and communicating with the interior of said filter element, the outer surface of said filter element being spaced from said side wall of said housing to define an annular space surrounding the filter element, and means for closing the top of said filter element whereby blood from said upper chamber enters said annular space and flows through the filter element from the outside to the interior and out through said outlet.

6. A cardiotomy reservoir as defined in claim 5 in which said cylindrical support element encircles said filter element.

7. The cardiotomy reservoir of claim 6 wherein the means for directing blood to said sponge annulus includes an annular baffle disposed in said upper chamber concentrically of said side wall to define an annular channel overlying said sponge annulus and an inlet communicating with said channel through said side wall and disposed to direct blood tangentially of the side wall whereby the blood flows in a generally circular path in the channel and then out of the upper chamber through the sponge annulus.

8. Apparatus for separating air from blood, said apparatus comprising a housing defining a first cylindrical chamber having top and bottom walls and a cylindrical side wall, said bottom wall having an annular opening extending around the periphery of said chamber and adapted to communicate with a defoaming element, an annular baffle disposed in said chamber concentrically with said side wall to define an annular channel overlying said defoaming element, an inlet communicating with said channel through said side wall and disposed to direct blood into the channel tangentially of the side wall whereby the blood flows in a generally circular path in the channel and then out of said chamber through said defoaming element, said circular flow producing a centrifugal action which causes the blood to flow at the outer periphery of said channel while air entrained in the blood separates and moves inwardly, said baffle having an opening to permit the air to enter the center portion of the chamber inside the baffle, venting means in the center portion of said top wall to permit air in the center portion of said chamber to escape from the housing, a hydrophobic membrane in said top wall covering said venting means and extending substantially over said center portion of said chamber to permit the flow of air out through said venting means, said housing defining a second cylindrical chamber coaxial with and disposed beneath said first chamber, said second chamber comprising a reservoir for the collection and storage of blood, a cylindrical filter element disposed in the lower portion of said second chamber coaxially therewith and having a hollow interior, an outlet formed in said housing and communicating with the interior of said filter element, the outer surface of said filter element being spaced from the outside of said second chamber to define an annular space, said defoaming element comprising an annulus of sponge material extending around the periphery of the upper end portion of said second chamber whereby blood flows from the annular channel of said first chamber through the sponge annulus to said second chamber and hence to said filter element, said sponge annulus including means for causing air bubbles in the blood to coalesce and form larger air bubbles as the blood flows through said sponge annulus, and a support element holding said sponge annulus radially spaced outwardly from the axis of said housing to define a passage whereby said larger gas bubbles exit said sponge annulus and move through said passage to said center portion of said first chamber where they are vented through said membrane.

9. Apparatus as defined in claim 8 in which said support element is perforated whereby blood and said larger bubbles flow out of said sponge annulus through the perforations in the support element and into said passage.