A MULTIPARAMETER SENSOR FOR CONTINUOUS INTRAARTERIAL BLOOD-GAS MONITORING - A PROSPECTIVE EVALUATION

Objective: To compare measurements of arterial blood gases made by a new continuous intra-arterial blood gas monitor with measurements in a standard blood gas analyzer in patients in the general and cardiac intensive care units. Design: Criterion standard study. Setting: The cardiac surgical and the general medical intensive care units of a tertiary referral center. Patients: Thirteen consecutive patients requiring mechanical ventilation and blood gas monitoring. Interventions: All patients had a blood gas sensor placed through a 20-gauge cannula inserted into the radial artery. The duration of monitoring ranged from 9.42 to 117.45 hrs. Measurements and Main Results: A total of 158 simultaneous measurements of pH, Pco(2), and Po-2 were made from the sensor and the blood gas analyzer, and the bias and precision were calculated on all measured parameters. The overall bias +/- precision values were 0.01 +/- 0.06 for pH, 1.4 +/- 4.8 torr (0.2 +/- 0.7 kPa) for Pco(2), and 2.8 +/- 25.6 torr (0.4 +/- 3.4 kPa) for Po-2. The bias and precision for Po-2 measurements that were <150 torr (<20 kPa) were 0.45 +/- 20.7 torr (0.1 +/- 2.8 kPa). The bias and precision for values of Po-2 that were >150 torr (>20 kPa) were -8.1 +/- 28 torr (-1.1 +/- 3.8 kPa). The mean in vitro 90% response times of pH, Pco(2), and Po-2 sensors were found to be 78, 143, and 70 sees, respectively. There were no instances of any complications attributable to the sensor.