title: A clinical evaluation of the gas transfer characteristics and gaseous microemboli production of two bubble oxygenators.
abstract: The gaseous microemboli (GME) production and gas transfer characteristics of two series of bubble oxygenators (Harvey H-1500 and Bentley BOS-10) were evaluated during clinical perfusion in 33 adult patients during open heart surgery for acquired valvular and ischaemic heart disease. For each oxygenator series, patients were divided into two groups, depending upon the method of measurement (intermittent or continuous) of the arterial PO2(PaO2). Using the data available, the perfusionist altered the gas:blood flow ratio in an attempt to maintain the PaO2 within the normal range. In the first group (I = intermittent), where PaO2 data were available only intermittently, the PaO2 values were well above normal, and large numbers of GME were detected in the arterial blood. In the second group (C = continuous), where the PaO2 data were available continuously, there was significantly better control of the PaO2 (P less than 0.001 and P less than 0.01 for the H-1500 and BOS-10, respectively) and significantly fewer GME (P less than 0.01 and P less than 0.05 for the H-1500 and BOS-10, respectively). The Bentley BOS-10 oxygenator used a lower gas:blood flow ratio to achieve physiological levels (range 9 to 13 kPa at 37 degrees C) of PaO2 than did the Harvey H-1500 oxygenator, but there was no difference in the number of GME detected. The lower gas:blood flow ratios for the BOS-10 oxygenators in group C resulted in significantly higher PaCO2 values well outside the physiological range (4 to 6 kPa at 37 degrees C) during the rewarming phase (mean PaCO2 = 7.6 +/- 0.8 kPa) of cardiopulmonary bypass than did the H-1500 oxygenator (mean PaCO2 = 6.3 +/- 0.7 kPa). Mean values for the PaCO2 for both oxygenators during other phases of bypass (cooling and hypothermia) were within the physiological range. If the CO2 retention was corrected by increasing the gas:blood flow ratio the PaO2 values and GME counts became elevated.
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000097:blood; D002315:Cardiopulmonary Bypass; D004618:Embolism, Air / Q000209:etiology*; D005069:Evaluation Studies as Topic; D006801:Humans; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010106:Oxygenators / Q000009:adverse effects; D010313:Partial Pressure
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen