RESUMEN
OBJECTIVE: Our objective was to investigate the accuracy of a new intravascular blood gas sensor, the Paratrend 7 (P7) (Biomedical Sensors Ltd, Pfizer Hospital Products Group, High Wycombe, England) in a porcine model. METHODS: A total of 12 sensors were inserted into 10 animals under total intravenous anesthesia. Changes in blood gas chemistry were produced over a wide range by manipulating the inspired oxygen and carbon dioxide concentrations and by adjustments in minute ventilation. Blood gas samples (BGA) were taken and analyzed during periods of stability; the results obtained were compared with the readings from the intravascular sensor. RESULTS: A total of 292 blood gas samples were taken and analyzed for pHa, PaCO2, and Po2; the results were compared with the readings from the intravascular sensor. Correlation coefficients of r = 0.98 for PCO2 and r = 0.99 for PO2 were obtained. Analysis of bias and precision as mean +/- SD of the difference (P7 - BGA) gave the following results: pH bias = -0.03, precision = +/- 0.04; PCO2 bias = 0.65 mm Hg, precision = +/- 3.1 mm Hg; and PO2 bias = -6.50 mm Hg, precision = +/- 0.6 mm Hg. No problems with clot formation on the sensor were seen, and the sensors did not appear to show the "wall effect" seen with other systems. CONCLUSIONS: The results obtained were well within the requirements for a clinically useful blood gas monitoring system.