EVALUATION OF AN ON-DEMAND, EX-VIVO BEDSIDE BLOOD-GAS MONITOR ON PULMONARY-ARTERY BLOOD-GAS DETERMINATIONS

Critically ill patients often have cardiopulmonary perturbations that require rapid and frequent assessment for optimal care, including card iac output determinations, measurement of cardiac filling pressures, a nd arterial and mixed venous blood gas determinations. We evaluated th e performance of a rapid, on-demand bedside blood gas monitor to deter mine arterial and mixed venous blood gas values. The blood gas monitor uses fluorescent optode technology to directly measure PO2, PCO2, and pH. This measurement is accomplished by aspirating blood from the art ery or vein into a sampling chamber where it interfaces with the fluor escent optode. After approximately 90 s of equilibration, the blood ga s values are reported. Since the blood is drawn into the sampling cham ber, it can be returned to the patient, thus eliminating the need for phlebotomy. We studied 15 critically ill patients requiring systemic a nd pulmonary arterial catheterization. Conventional blood gas analysis was performed simultaneously. The results obtained from the blood gas monitor were compared with those obtained via traditional blood gas a nalysis using Bland-Altman plots and examination of bias and precision . The results were well within the expected clinical variance. During the study period, there was no interference with patient care or adver se events related to the use of the monitoring system. In conclusion, the blood gas monitor can provide rapid, accurate determinations of ar terial and mixed venous blood gases allowing optimal therapeutic inter ventions in critically ill patients.