title: Clinical evaluation of a multiparameter intra-arterial blood-gas sensor.
abstract: OBJECTIVE
  To evaluate the in vivo performance of a continuous, intra-arterial, multiparameter blood-gas sensor containing a thermocouple, miniaturized polarographic oxygen electrode, as well as fiberoptic pH and pCO2 sensors.
  
  
  METHODS
  Prospective, multicenter study comparing pH, PaCO2, and PaO2 measurements from the intraarterial sensor with those obtained from a conventional, laboratory blood-gas monitor.
  
  
  METHODS
  Intensive care units in three academic medical centers.
  
  
  METHODS
  Adult ICU patients (n = 26) with a clinical need for a radial artery catheter and frequent monitoring of arterial blood gases for > or = 3 days.
  
  
  METHODS
  All patients had the multiparameter intra-arterial sensor placed through a 20-gauge catheter into the radial artery. Every 4 h, or more frequently if clinically indicated, a blood-gas sample was withdrawn from the radial artery catheter and sent to the laboratory for analysis using a conventional laboratory blood-gas analyzer. Immediately prior to withdrawal of the arterial blood, values for pH, PaCO2, and PaO2 from the multiparameter intra-arterial sensor were recorded.
  
  
  RESULTS
  The multiparameter sensor was placed into 26 patients. In 7 of the patients, premature discontinuation of monitoring was necessary because of dampening of the pressure tracing, difficulty in withdrawing blood from the arterial catheter, or bending of the extra-arterial fiberoptic channel owing to the cable being inadequately secured (mean monitoring time in these 7 patients: 40.6 +/- 25.7 h). In the other 19 patients, monitoring was continued until no longer clinically indicated. In these patients, a total of 341 data sets was collected, with the average length of monitoring being 69.9 +/- 37.9 h (range 22.0 to 57.9 h). Comparison of the sensor values with those from the blood-gas analyzer showed bias and precision values of 0.006 and 0.026 for arterial pH - 1.19% and 12.54% for PaO2, and 1.28 mmHg and 2.48 mmHg for PaCO2, respectively. No complications were associated with the intra-arterial sensor.
  
  
  CONCLUSIONS
  Clinical performance of this intra-arterial, multiparameter blood-gas sensor demonstrated stability, consistency, and accuracy comparable to laboratory blood-gas analyzers. The present multiparameter, intravascular blood-gas sensor, when inserted in the radial artery, can provide stable and accurate monitoring of pH, PaCO2, and PaO2 over clinically relevant periods of as long as 6 days in the critical care setting.
authors.affiliation: Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: E
authors.initials: E
authors.lastname: Abraham
authors.forename: T J
authors.initials: TJ
authors.lastname: Gallagher
authors.forename: S
authors.initials: S
authors.lastname: Fink
mesh_terms: D000328:Adult; D015982:Bias; D001784:Blood Gas Analysis / Q000009:adverse effects / Q000295:instrumentation*; D002138:Calibration; D002406:Catheterization, Peripheral; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D008839:Microelectrodes; D008991:Monitoring, Physiologic / Q000295:instrumentation; D011446:Prospective Studies; D017534:Radial Artery; D015203:Reproducibility of Results; D013997:Time Factors