It is well known that extracorporeal surfaces have the ability to bind such drugs as fentanyl, nitroglycerine and propofol. Adsorption of the injectable anesthetic agent Diprivan (propofol) onto uncoated and heparin-coated extracorporeal surfaces during cardiopulmonary bypass (CPB) has been previously investigated; however, propofol adsorption onto synthetic-coated extracorporeal surfaces has not been published previously. The focus of this investigation was on the interaction of propofol and the synthetic biomimetic coating from the Sorin Group called Mimesys (phosphorylcholine (PC)). A randomized series of six in vitro experiments were done with propofol using both PC-coated circuits without arterial filters and those with arterial filters. The circuits were identical in all experiments and priming remained the same, with 750 mls of normal saline and 1250 mls of fresh bovine blood (hematocrit 41.0 +/- 1.0%). After circulation and collection of baseline samples, the first (low) dose of 4 mg (4000 mcg) of Diprivan 1% was added to the perfusate, followed by the second (high) dose of 40 mg (40,000 mcg) and the final challenge (extreme dose) of 356 mg (356,000 mcg) of Diprivan. Drug assay was done by an independent laboratory, using the standardized method of High Performance Liquid Chromatography (HPLC). Measurements of total propofol were done at baseline, 20 minutes, 40 minutes and 60 minutes after each injection. Oxygenator performance was also measured prior to the addition of propofol and repeated after exposure to 4 mg, 40mg and 356 mg propofol for 60 min, 120 min and 180 minutes of circulation. Results indicate that phosphorylcholine coating does not prevent the adsorption of propofol during extracorporeal circulation and the oxygenator's gas exchange ability is not affected by prolonged exposure to an extreme dose of the medication during high flow extracorporeal circulation.

During a previously published study on gaseous micro-emboli (GMEs) and perfusionist interventions, it was noted that emboli could be detected after the arterial filter when blood/air challenges entered the membrane oxygenator’s integral cardiotomy. The findings indicated that further study into the oxygenator’s integral cardiotomy reservoir was warranted. This is the first know published report that connects the vent return to GME activity after the arterial filter. To study the air handling ability of the membranes integral cardiotomy, an in vitro study was conducted on five hard shell coated membrane oxygenators (Terumo Capiox SX25, X coated; Sorin Synthesis, phosphorylcholine coated; Gish Vision, GBS coated; Medtronic Affinity NT, trillium coated; Maquet Quadrox, bioline coated). The oxygenators were matched with their own manufacturer’s coated arterial filters (Medtronic 351T Arterial Filter, Sorin Synthesis Integrated Arterial Filter, Terumo CXAF200X Arterial Filter, Gish GAF40GBS-2 Arterial Filter, and Maquet Quart HBF140 Arterial Filter). There were three arms to the study, and three separate oxygenator/filter combinations were used in each arm. The first arm consisted of a pump flow of 4.0 L/min with only the filter purge blood entering the integral cardiotomy. In the second arm, 500 mL/min of simulated vent blood was added to the filter purge blood entering the integral cardiotomy. During the final arm, 200 mL/min of air was added to the vent blood as it entered the integral cardiotomy, to more closely simulate vent return during cardiopulmonary bypass. All GME activity in the oxygenator/filter combinations was examined using the Hatteland CMD20 Microemboli Counter. Placement of the Hatteland probes was 4 in after the hard shell reservoir outlet (PRO) and 12 in after the arterial filter (PAF). When vent blood flow was turned on, there was a significant increase in the PRO microemboli activity detected in all reservoirs. In the PAF position, three of the oxygenator/filter combinations were able to remove 98–99% of the GME, one removed 84.3%, and another removed only 55.5% of the GMEs coming out of the oxygenator’s reservoir. All oxygenators were found to have a dramatic increase in reservoir GME activity when the vent was turned on. Depending on the oxygenator/filter combination, vent return into the oxygenator’s integral cardiotomy resulted in the presence of significant amounts of GMEs after the arterial filter.