Performance of an on-demand blood gas monitor in surgical intensive care unit (SICU) patients

Introduction: Frequent in vitro arterial blood gas (ABG) analysis, often performed during periods of prolonged mechanical ventilation, necessitates blood removal causing iatrogenic-induced anemia, increases exposure to blood borne pathogens, and leads to delays in therapeutic decisions. Continuous intra-arterial ABG monitors utilizing fiberoptic sensors have been evaluated but have shown limited success. Recent technology with external fluorescent, optode-based ABG systems have eliminated the need for intravascular catheters. A new system (VIA -1-01 ABG monitor, VIA Medical Corp., San Diego, CA), utilizing external ion selective (pH), Severinghaus (PCO2), and Clark (PO2) electrodes has been introduced and is now evaluated in this study comparing its accuracy relative to a standard ABG monitor. Methods: Following institutional approval, 20 patients requiring prolonged mechanical ventilation in our SICU and who were determined to need multiple ABG sampling were studied. The VIA-1-01 system was attached either preoperatively or in the SICU by way of a specialized adapter that did not interrupt arterial waveform analysis. Each monitor underwent standard calibration in accordance with the manufacturer's procedure. ABG samples were ordered by the patient's physician and simultaneously paired with VIA in-line samples. Non-iced samples were transported immediately to a central ABG station in the SICU and were analyzed by a CIBA Corning ABG monitor (Chiron Diagnostics, serial #'s 03347 and #01225). Results: The table compares the performance of the ABG monitors in terms of bias and precision. Conclusions: We conclude that the VIA-1-01 ABG monitor performs with a high degree of accuracy and may lead to more timely ABG results, diminished blood loss and less occupational exposure to blood.