During clinical hypothermic cardiopulmonary bypass (CPB) in 20 adult patients, the ability of the perfusionist, using an alphastat acid-base blood gas management technique, to control blood gas values has been evaluated in the Bentley 10B and Bentley 10Plus bubble oxygenators. Superior flexibility in control of the blood gas values to within a defined target range (PaO2 20 ± 3.3 kPa, PaCO2 5.3 ± 0.6 kPa) with significantly improved control of PaO2 was demonstrated in the Bentley 10Plus when compared with the Bentley 1 0B. The percentage of values when both PaCO2 and PaO2 were within the target range was higher in the Bentley 10Plus (14%) than in the Bentley 10B (11 %). The incorporation of an Integral gas proportioning valve in the Bentley 10Plus oxygenator offers a degree of independence of control of PaO 2 and PaCO2 which is unique in a bubble oxygenator. When the two oxygenator groups were compared, the rise in plasma haemoglobin was significantly less (p<0.005) in the Bentley 10Plus but no significant differences could be demonstrated between the two groups with respect to alteration in other formed blood elements (platelets or white blood cells) or in gaseous microemboli production.
ACID-BASE EQUILIBRIUM MODELING BASED ON THE BALANCE CONCEPT
