In Vitro Evaluation of the Air Separation Ability of Four Cardiovascular Manufacturer Extracorporeal Circuit Designs

Microemboli are implicated in neurological injury; therefore, the extracorporeal circuit (ECC) should not generate microbubbles or transmit introduced air. The venous reservoir is the first component in the ECC designed to remove introduced air. The purpose of this study was to investigate the relative safety of two kinds of adult venous reservoirs—the closed soft-shell venous reservoir (SSVR [Medtronic CBMVR 1600]) and the open hard-shell venous reservoir (HSVR [Affinity NT CVR])—in terms of microbubble generation and introduced air transmission. A recirculating in-vitro circuit was used to compare the two reservoirs with the SSVR further assessed in a fully closed or partially open state. Microbubbles were counted using a Hatteland CMD10 Doppler in the outflow of the reservoirs before (microbubble generation) and after infusing 20 mL/min of air into the venous line (microbubble transmission) while altering pump flow rates (3 L/min; 5 L/min) and reservoir prime (200 mL; 700 mL). Negligible bubble generation was noted in the SSVRs at both flow rates and either reservoir volume. However, microbubble generation was significant in the HSVR at the higher flow rate of 5 L/min and lower reservoir volume of 200 mL. When infusing air, a flow of 3 L/min was associated with insignificant to small increases in microbubble transmission for all reservoirs. Conversely, infusing air while flowing at 5 L/min was associated with significantly more microbubble transmission for all reservoirs at both low and high reservoir volumes. The SSVR is as safe as the HSVR in microbubble handling as the generation and transmission of microbubbles by the SSVR is not more than the HSVR over a range of prime volumes and flow rates. As both reservoirs transmitted microbubbles at higher pump flow rates regardless of reservoir volumes, it is important to eliminate venous air entrainment during cardiopulmonary bypass.

Section: Discussionmentioning

confidence: 99%

Microbubble Generation and Transmission of Medtronic’s Affinity Hardshell Venous Reservoir and Collapsible Venous Reservoir Bag: An In-Vitro Comparison

Potger,

McMillan,

Ambrose

2011

“…The pilot ALF project of Cruz et al and the method used herein are modeled after the air-handling tests found in the US Food and Drug Administration guidance document (http://www.fda.gov/cdrh/ode/guidance/1622). The first use of the newly FDA-qualified EDAC™ device to measure and record GME activity in an extracorporeal circuit (ECC) in vitro test circuit was published by Dickinson et al (9). Jones et al ( 4) used a very early prototype of the EDAC and showed numerous GME passing ALFs from several manufacturers.…”

Section: Introductionmentioning

confidence: 99%

Arterial Line Filters Ranked for Gaseous Micro-Emboli Separation Performance: An In Vitro Study

Riley¹

2008

Self Cite

Arterial line filters (ALFs) are arguably the most important component in the cardiopulmonary bypass circuit to protect the patient from gaseous macro-and micro-emboli (GME) originating in the perfusion circuit. The GME separating ability of 10 ALFs was ranked according to seven performance criteria. Ten ALFs rated between 20 and 43 μm were evaluated for flow resistance, the count, size, and volume of GME passed after a 10-mL room air bolus, and the ability to separate a high-count, 10-to 200-μm flowing distribution of GME. The Luna Innovations EDAC™ emboli detector was used to size, count, and sort GME. Three test trials were conducted for 3 each of the 10 filters. Performance criteria were correlated by regression analysis, statistically compared using analysis of variance, or ranked using non-parametric tests. Significance was set at 0.05. Weighting all seven test parameters equally, the most effective ALFs were the Cobe 21 and Gish 25-μm filters. The Pall LG-6 ranked more efficient than the Medtronic 20 and Dideco 27-μm filters. The Cobe 43, Terumo 40, Medtronic 38, Terumo 37, and Gish 40-μm filters were less effective as a group compared with the other filters. For the 10 filters, blood flow resistance was not correlated to rated pore size. Generally, the smaller the pore rating, the higher the GME separation ability rank, except for the leuko-reduction filter, which performed more effectively than other large pore filters.

“…Taylor and colleagues (6) identified emboli associated with perfusionists' techniques, includ-ing drug administration and blood sampling. Subsequent investigators have undertaken in vitro studies to quantify the air-handling characteristics of a variety of perfusion technologies (7)(8)(9). Groom and colleagues (10), although not able to discriminate between non-and gaseous microemboli, documented reduction of emboli subsequent to changes in CPB technique and devices.…”

mentioning

confidence: 99%

Embolic Activity During In Vivo Cardiopulmonary Bypass

DeFoe,

Dame,

Farrell

et al. 2014

Neurologic injury after cardiac surgery is principally associated with emboli. Although much work has focused on surgical sources of emboli, less attention has been focused on emboli associated with the heart–lung machine. We tested whether emboli are associated with discrete processes during cardiopulmonary bypass (CPB). One hundred patients undergoing cardiothoracic surgery were enrolled between April 2008 and May 2011 at a single medical center. During each surgical procedure, emboli were counted in three CPB locations: the venous side (Channel 1), before the arterial line filter (Channel 2), and after the arterial line filter (Channel 3). We used prespecified event markers to identify perfusionist interventions. Identical circuits were used on all patients. Of the 100 patients enrolled, 62 underwent isolated coronary artery bypass grafting (CABG), 17 underwent isolated valve operations, and 21 underwent CABG plus valve. Median counts across Channels 1, 2, and 3 were 69,853, 3,017, and 1,251, respectively. The greatest contributor to emboli in Channels 1, 2, and 3, respectively, were achieving the calculated CPB flow, opening of the electronic arterial line clamp, and introducing a hemofilter. The circuit technology was efficient in reducing total emboli counts from Channels 1–2 irrespective of the size of the emboli. Nearly 71% of all emboli 30–100 mm in size were removed from the circuit between Channels 2 and 3. No significant association was found between emboli counts and S100B release. Emboli occur frequently during CPB and are predominantly associated with the initiation of bypass, operation of the electronic arterial line clamp, and the initiation of a hemofilter. Continued work to reduce the occurrence of emboli is warranted.