title: The effect of arterial filtration on reduction of gaseous microemboli in the middle cerebral artery during cardiopulmonary bypass.
abstract: Noninvasive in vivo detection of gaseous microemboli in the middle cerebral artery, by transcranial Doppler ultrasound, was used to determine the effect of filtration in the arterial catheter using 25- and 40-microns filters and bubble oxygenators in patients undergoing cardiopulmonary bypass surgery. Eighteen patients undergoing coronary artery bypass surgery were studied using a closed cardiac (unvented heart) model. Group 1 patients (no filters) had the highest incidence of gaseous microemboli, as indicated by the ultrasound microemboli index, at both high and low oxygen flow rates. Group 2 patients (40-microns filters) had a significantly lower microemboli index, particularly at low oxygen flow rates (t = 4.9, p less than 0.001). The 25-microns group patients had the lowest values of all. No microemboli were detected at low oxygen flow rates, and microemboli were detected in only 0.1% of the samples at high oxygen flow rates. Additionally, observations on vented hearts in 3 patients undergoing cardiac valve surgery indicate that the origin of gaseous microemboli may be air trapped inside the heart.
authors.affiliation: Department of Radiological Sciences, Guy's Hospital, London, England.
authors.forename: T S
authors.initials: TS
authors.lastname: Padayachee
authors.forename: S
authors.initials: S
authors.lastname: Parsons
authors.forename: R
authors.initials: R
authors.lastname: Theobold
authors.forename: R G
authors.initials: RG
authors.lastname: Gosling
authors.forename: P B
authors.initials: PB
authors.lastname: Deverall
mesh_terms: D002315:Cardiopulmonary Bypass; D002536:Cerebral Arteries / Q000473:pathology; D004618:Embolism, Air / Q000175:diagnosis / Q000517:prevention & control*; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000175:diagnosis / Q000517:prevention & control*; D007430:Intraoperative Care / Q000379:methods; D007431:Intraoperative Complications / Q000517:prevention & control; D008875:Middle Aged; D010106:Oxygenators; D014463:Ultrasonography