The effects of continuous blood gas monitoring during cardiopulmonary bypass: a prospective, randomized study--Part I.

The use of continuous in-line blood gas management (CILBGM) is steeped in controversy concerning its potential utility and impact on patient outcomes. The purpose of this study was to determine whether the use of CILBGM results in improved quality of patient care. Fifty-nine patients were enrolled in a Institutional Review Board-approved, prospective, randomized study. An in-line blood gas monitor (CDI 500) was placed into the arterial and venous lines for all patients. Blood gas monitoring in the control group was managed by intermittent sampling (every 20-30 min), while the treatment group was managed with continuous monitoring. There were no differences between groups in preoperative, surgical, anesthetic, or perfusion variables. The accuracy of the in-line monitor was comparable to laboratory analysis for arterial blood gas parameters (N = 160; pH bias = 0.00; PaCO2 bias = -1.1 mmHg; and PaO2 bias = 0.7 mmHg). There was less deviation from target values (pH = 7.40, PaCO2 = 40 mmHg, PaO2 = 150-200 mmHg) when in-line monitoring was used versus intermittent sampling (N = 784; pH deviation = 0.05 +/- 0.03 vs. 0.03 +/- 0.01, p < 0.0001; PaCO2 deviation = 4.0 +/- 2.9 mmHg vs. 2.0 +/- 0.9 mmHg, p < 0.0001; and PaO2 deviation = 22.7 +/- 16.9 mmHg vs. 11.7 +/- 8.3 mmHg, p < 0.0001). In conclusion, the results of part I of this study demonstrate that the use of CILBGM results in more accurate blood gas management during CPB.