Chest
Clinical Investigations in Critical CareVariability of Arterial Blood Gas Values Over Time in Stable Medical ICU Patients
Section snippets
Patient Selection
The study group consisted of 28 clinically stable patients from the medical ICU at the Long Beach VA Medical Center. The study was approved by the Institution's Human Subjects Committee and informed consent was obtained from each patient the start of each study. The study patients had an arterial catheter placed by the primary team and were judged to be clinically stable. They are representative of typical patients from our medical ICU (Table 1). The patients were not consecutive since
Results
During the monitoring period, the patients were clinically stable as shown by the minimal percentage changes (±SD) in pulse, mean arterial blood pressure, and respiratory rate which were −1.6 (±5.3) percent, 5.0 (±9.6) percent, and −1.0 (±11) percent, respectively. Inspection of the 84 individual PO2, Pco2, and pH plots vs time revealed no consistent upward or downward trends in any patient.
The comparisons of the CDI blood gas monitor values with the Instrumentation Laboratories 1306 blood gas
Discussion
Our results provide additional information regarding the degree of spontaneous variability that can be expected from blood gas and pH measurements obtained from typical medical ICU patients, ventilated and oxygenated under a wide range of conditions. We performed multiple measurements, using an accurate monitoring system, with frequent calibration checks to validate our data.
One might question whether this monitor is accurate enough to examine the issue of spontaneous variability. For PO2, the
REFERENCES (18)
- et al.
Variability of arterial blood gas values in stable patients in the ICU
Chest
(1983) Indications for blood gas analysis
Ann Intern Med
(1986)- et al.
ABGs and arterial lines: the relationship to unnecessarily drawn arterial blood gas samples
J Trauma Traumarauma
(1990) - et al.
Variability of blood gases, pulse oximeter saturation, and end-tidal carbon dioxide pressure in stable, mechanically ventilated trauma patients
J Clin Monit
(1992) - et al.
Clinical performance of an arterial blood gas monitor
Crit Care Med
(1993) - et al.
Development of a patient dedicated, on-demand, blood gas monitor
Am J Respir Crit Care Med
(1994) - et al.
Optical fluorescence and its application to an intravascular blood gas monitoring system
IEEE Trans Biomed Eng
(1986) - et al.
Performance of an in-vivo, continuous blood gas monitor with disposable probe
Clin Chem
(1987) - et al.
Performance characteristics and interanalyzer variability of PO2 measurements using tonometered human blood
Am Rev Respir Dis
(1993)
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Presented at the 58th Annual Scientific Assembly, American College of Chest Physicians, Chicago, October 25-29, 1992.
Manuscript revision accepted November 29.