Application of Micropore Filter Technology: Exploring the Blood Flow Path in Arterial-Line Filters and Its Effect on Bubble Trapping Functions.
Conventional arterial-line filters commonly use a large volume circular shaped housing, a wetted micropore screen, and a purge port to trap, separate, and remove gas bubbles from extracorporeal blood flow. Focusing on the bubble trapping function, this work attempts to explore how the filter housing shape and its resulting blood flow path affect the clinical application of arterial-line filters in terms of gross air handling. A video camera was used in a wet-lab setting to record observations made during gross air-bolus injections in three different radially designed filters using a 30-70% glycerol-saline mixture flowing at 4.5 L/min. Two of the filters both had inlet ports attached near the filter-housing top with bottom oriented outlet ports at the bottom, whereas the third filter had its inlet and outlet ports both located at the bottom of the filter housing. The two filters with top-in bottom-out fluid paths were shown to direct the incoming flow downward as it passed through the filter, placing the forces of buoyancy and viscous drag in opposition to each other. This contrasted with the third filter's bottom-in bottom-out fluid path, which was shown to direct the incoming flow upward so that the forces of buoyancy and viscous drag work together. The direction of the blood flow path through a filter may be important to the application of arterial-line filter technology as it helps determine how the forces of buoyancy and flow are aligned with one another.
Assessment of three methods for removing massive air in a cardiopulmonary bypass circuit: simulation-based multi-discipline training in West China Hospital
Background and Objective: A multi-discipline cardiac and cardiopulmonary bypass (CPB) team simulation scenario was established to compare three different de-airing approaches dealing with massive air embolism in CPB, so as to formulate a standardized procedure to handle this adverse acute event more proficiently and ensure clinical safety. Method: A simulation-based clinical CPB massive air embolism scenario was developed by a cardiac and CPB team. Study Objects: Five licensed perfusionists and five CPB trainees were matched randomly into five pairs. Each pair would simulate the three different de-airing approaches separately as followed: (1) Conventional Method: arterial line filter (ALF) de-airing purge line and oxygenator self-recirculation bypass were used to de-air; (2) Arterial-Venous Loop (A-V Loop) Method: surgeons reconnected the arterial and venous lines to de-air by restoring the original priming A-V loop configuration; (3) Isolation of the ALF Method: this ensures de-bubbling of the CPB circuit, but bypasses the ALF function. Assessment Criteria: (1) Times to recovery (duration of the circulation suspension); (2) Subjective evaluation of skill and non-skill performances. Results: As to times to recovery, the Conventional Method group took 290.6 s ± 36.2, the A-V Loop Method group took 196.8 s ± 52.0 and the Isolation of ALF group took 99.4 s ± 15.1. The statistical difference is significant among the three groups (p<0.01). The subjective evaluation of training performance indicates that this simulation-based training is effective in assessing both skill and non-skill abilities. Conclusion: CPB simulation-based training was effective in comparing de-airing strategies and can instruct perfusion practices how to optimize techniques. For well-trained, multi-discipline cardiac teams, the A-V Loop Method is highly efficient and reliable in managing CPB massive air embolism. For cardiac teams that do not have this sophisticated training, the Isolation of ALF Method should be their alternative option.
Clinical evaluation of the Terumo Capiox FX05 hollow fiber oxygenator with integrated arterial line filter.
Perfusion techniques and equipment in pediatric open heart surgery have continued to focus on decreasing prime volumes and lowering surface areas of the cardiopulmonary bypass circuit. While this has improved drastically over the last 20 years, greater demand is being placed on the perfusionist to reduce the deleterious effects of bypass without compromising safety or efficiency. Specifically, manufacturers of disposable perfusion equipment have focused on providing pediatric perfusionists with oxygenators that provide the smallest prime and surface area possible while attempting to maximize performance. Recently,Terumo Cardiovascular has introduced the Capiox FX05, a neonatal hollow fiber oxygenator that includes an integrated arterial line filter. The FX05 provides a blood flow range of 0.1-1.5 L/min and a low priming volume of 43 mL. Additionally, it is coated with X Coating, a biocompatible, hydrophilic polymer surface coating that reduces platelet adhesion and protein denaturation. The purpose of this study was to test the FX05 for gas transfer, blood path resistance, and blood handling characteristics in a standardized clinical setting. Heat exchange coefficients were also calculated during the cooling and warming period. Other data analyzed includes bypass circuit prime volumes and initial patient hematocrit along with the total operative homologous blood donor exposures. In summary, the FX05 offers good gas exchange capabilities and a low pressure drop during normal cardiopulmonary bypass parameters along with the safety of an integrated arterial line filter. Furthermore, the FX05 with integrated filter allows a reduction in overall bypass prime volume and surface area while promoting the reduction of homologous blood transfusions, optimizing hemostasis.