Journal of cardiothoracic and vascular anesthesia
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J. Cardiothorac. Vasc. Anesth. · Dec 1992
Continuous intra-arterial oximetry, pulse oximetry, and co-oximetry during cardiac surgery.
This study evaluated arterial catheter oximetry versus pulse oximetry in eight patients (ASA III-IV) who underwent cardiac surgery. Co-oximeter saturation values served as the standard. Arterial oxygen saturation was determined simultaneously with these three methods at 162 prospectively defined points of measurement before, during, and after cardiopulmonary bypass (CPB). ⋯ The standard deviations of the individual differences between readings of catheter or pulse oximetry and readings of co-oximetry (= precision) were +/- 0.5% to +/- 1.0% for catheter oximetry and +/- 1.0% to +/- 1.2% for pulse oximetry. In summary, catheter oximetry was superior to pulse oximetry with regard to obtaining readings and to reliability of the obtained readings. Invasiveness and high costs influence the decision as to whether to use catheter oximetry, but if reliable and precise measurements of saturation are important at any time during surgery, pulse oximetry is an insufficient method and co-oximetry is a time-consuming method of analysis, whereas catheter oximetry is quick, reliable, and precise.
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J. Cardiothorac. Vasc. Anesth. · Dec 1992
Should the gas outlet port on membrane oxygenators be routinely scavenged during cardiopulmonary bypass?
Elimination of a volatile anesthetic agent administered prior to the start of bypass through the oxygenator has not been previously described. The purpose of this study was to determine the contamination risk from enflurane used before but not during cardiopulmonary bypass. Enflurane concentration was measured from the gas outlet port of a membrane oxygenator using infrared gas analysis in 11 cardiac surgical patients. ⋯ In one patient with a final end-tidal enflurane of 1.1%, a contaminant level of 2 ppm could be measured at 95 cm from the oxygenator gas outlet port. This demonstrates that there is a potential risk of contamination from volatile anesthetics used immediately prior to extracorporeal circulation. Minimizing this risk may necessitate routine scavenging of the oxygenator, or simply avoiding increased concentrations of inhalation anesthesia before initiating cardiopulmonary bypass.