Pro: the superiority of the membrane oxygenator

Blood-Air Interface during Cardiopulmonary Bypass

The aim of this study was to compare the systemic blood activation with open and closed perfusion management during cardiopulmonary bypass. In 30 patients undergoing coronary artery bypass grafting, we prospectively studied systemic blood activation, blood loss and the need for donor blood. In 15 patients we used an open venous reservoir consisting of a hard shell venous reservoir with an integrated cardiotomy filter. In another 15 patients we used a totally closed venous reservoir consisting of a collapsible venous reservoir, no coronary suction, modified vent and cell saver. Venous blood samples were collected pre, post and 24 hours postoperatively. Sex, age and perfusion times were identical in both groups. There were no statistically significant differences in concentrations of FXIIa and C3a, amount of blood loss and need for donor blood. Interleukin-6 and Elastase levels showed trends toward a lesser inflammatory reaction in closed venous reservoir patients. Modification of perfusion management with optimized air management does not seem to be an effective strategy in reducing the inflammatory response and influencing the coagulation system in this small cohort.

A survey of cardiopulmonary bypass perfusion practices in Australia in 1992

Twenty-four cardiopulmonary bypass (CPB) perfusion units around Australia were surveyed to determine the characteristics of CPB perfusion as practised in Australia in 1992. Twenty completed survey forms were received. Findings were compared with those of a similar study performed by one of the authors for the year 1986. The field of CPB perfusion continues to expand both in terms of numbers of cases and increasing technological complexity. The major technological changes evident are the now clear dominance of membrane over bubble oxygenators and the proliferation of inline SvO2 monitoring devices. The greatest change in practice has been to the virtually universal use of cardioplegia. There remains considerable variation in the composition of the cardioplegia solutions used in the responding units. A range of minimum perfusion pressures for CPB is noted, whereas most units employ similar minimum perfusion flows. Methods of central nervous system and renal protection are mainly hypothermia and diuretics, respectively, with a scattering of other techniques. Staffing of CPB perfusion units is essentially unchanged since 1986 and at least five units had no medical perfusionist appointed in 1992.

Low-dose aprotinin infusion is not clinically useful to reduce bleeding and transfusion of homologous blood products in high-risk cardiac surgical patients

A high-dose regimen of aprotinin 5-6 million KIU is effective in reducing bleeding and the need for homologous blood products (HBP) associated with cardiopulmonary bypass (CPB). These high doses aim at achieving plasmin and plasma kallikrein concentrations which in vitro are inhibitory but, theoretically, smaller doses could suffice in vivo. Also, aprotinin is an expensive drug, so efficiency requires using the smallest effective dose. Therefore, the efficacy of prophylactic aprotinin 1 million KIU (the maximal dose approved currently) was evaluated in a patient population at high risk of bleeding and of being transfused. Forty-one patients undergoing reoperation or a complex surgical procedure were included in a prospective, randomized, placebo-controlled, double-blind study. Before skin incision, a bolus of 200,000 KIU aprotinin was administered in 20 min, followed by an infusion of 100,000 KIU.hr-1 over eight hours. Control patients received an equal volume of saline. Dryness of the operative field, chest drainage, transfusion of HBP, haemoglobin concentrations, and coagulation variables (including bleeding time) were compared. There were no differences between aprotinin and placebo-treated patients for all clinical and laboratory variables. The apparent ineffectiveness of aprotinin may be explained by the use of an insufficient dose, by a different protocol of administration (e.g., no bolus in CPB prime), or by the inability of aprotinin to decrease bleeding and transfusions any further. Also, the number of patients studied does not exclude the possibility of a Type II error.(ABSTRACT TRUNCATED AT 250 WORDS)