Preliminary evaluation of a new continuous intra-arterial blood gas monitoring device.

Continuous intra-arterial blood gas monitoring is a new technique, possibly offering therapeutic advantages through improved monitoring in patients prone to hypoxaemia, hypercapnia and/or respiratory acidosis. Therefore, we studied the clinical applicability, reliability, precision and side effect of long-term continuous intra-arterial blood gas monitoring in patients suffering from severe acute respiratory distress syndrome. In 10 patients continuous intra-arterial blood gas monitoring based on fluorescent optodes technique was performed. At 4 h intervals, arterial blood samples for in vitro blood gas analyses were drawn, stored in ice, and analysed within 3 min. Evaluation of data retrieved from the continuous intra-arterial blood gas monitoring and in vitro blood gas analysis was based on 596 data points using 10 catheters. Average length of insertion was 281 +/- 215 h, max. lengths of stay was 750 h. Arterial blood gas data obtained in vivo were compared to the mean of in vivo and in vitro arterial blood gases. Inter-catheter bias, expressed as percent difference between continuous intra-arterial blood gas and mean in vitro blood gas analysis was 0.19 +/- 0.23% for pH. 1.1 +/- 5.2% for PaCO2 and 1.6 +/- 5.7% for PaO2. No significant gas partial pressure dependent change in precision was demonstrable. There was no significant time dependent drift in sensor precision over the study period. No negative side-effects related to IABG monitoring were observed. We conclude that long-term use of this new device is possible in patients and represents a reliable alternative to conventional in vitro arterial blood gas analysis, when continuous monitoring of blood gases and/or acid-base balance is critical.