title: Pulsatile flow decreases gaseous micro-bubble filtering properties of oxygenators without integrated arterial filters during cardiopulmonary bypass.
abstract: OBJECTIVE
  Cardiopulmonary bypass (CPB) has a risk of embolic injury with an important role of gaseous micro-bubbles (GMBs), coming from CPB-circuit. Pulsatile perfusion (PP) can provide specific conditions for supplementary GMB-activity with respect to non-pulsatile (NP). We aimed to test GMB-filtering properties of three modern oxygenators under pulsatile and non-pulsatile conditions.
  
  
  METHODS
  Seventy-eight patients undergoing on-pump myocardial revascularization were randomized prospectively into three equal groups according to the oxygenator model used during CPB. Terumo Capiox-FX25, Sorin Synthesis or Maquet Quadrox-i-Adult membrane oxygenators were tested. Each group was divided equally to undergo PP or NP. GMBs were counted by means of a GAMPT-BCC200 bubble-counter with two probes placed at preoxygenator and arterial post-filter positions. Results were evaluated in terms of GMB-volume, GMB-number, amount of large over-ranged GMBs, a series of filtering indices and major neurological outcomes.
  
  
  RESULTS
  PP decreased GMB-filtering properties of the tested oxygenators. Those with integrated filters (CAPIOX-FX25 and SYNTHESIS) did not show significant differences between perfusion groups, while QUADROX-i oxygenator with external arterial filter showed significantly higher GMB-volume (P < 0.001), GMB-number (P < 0.001) and amount of over-ranged bubbles (P < 0.001) detected in arterial line during PP. Despite the differences in filtering capacity of all circuits with both types of perfusion, no important differences in clinical outcomes and major neurological events were observed.
  
  
  CONCLUSIONS
  Pulsatile flow decreases gaseous micro-bubble filtering properties of oxygenators without integrated arterial filters during CPB. PP requires specially designed circuit components to avoid the risk of additional GMB delivery.
authors.affiliation: Division of Cardiac Surgery, University of Verona Medical School, Verona, Italy.
authors.forename: Aldo D
authors.initials: AD
authors.lastname: Milano
authors.forename: Mikhail
authors.initials: M
authors.lastname: Dodonov
authors.forename: Francesco
authors.initials: F
authors.lastname: Onorati
authors.forename: Tiziano
authors.initials: T
authors.lastname: Menon
authors.forename: Leonardo
authors.initials: L
authors.lastname: Gottin
authors.forename: Giovanni
authors.initials: G
authors.lastname: Malerba
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mazzucco
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Faggian
mesh_terms: D000368:Aged; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D001026:Coronary Artery Bypass; D004618:Embolism, Air / Q000209:etiology / Q000517:prevention & control*; D004867:Equipment Design; D015199:Extracorporeal Membrane Oxygenation / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D011446:Prospective Studies; D011673:Pulsatile Flow; D016896:Treatment Outcome
keywords: Air embolism; Cardiopulmonary bypass; Pulsatile perfusion