RES5 - Central Venous Oxygen Saturation Levels in Patients with Severe Sepsis and Septic Shock
Primary Author: Susan Pambianco
Co-Author(s): Elizabeth Bridges; Susan Woods
Institution: University of Washington Medical Center, Seattle, WA
Contact Email: sbeaty29@hotmail.com
   
Purpose: Purpose: To determine the frequency in which ScvO2 intermittent levels should be obtained to detect an alteration in tissue oxygenation when continuous fiber optic ScvO2 monitoring is unavailable.
Background/Significance: Background/Significance: Tissue oxygenation plays a key role in severe sepsis. Researchers have discovered that global tissue oxygenation levels can guide treatment and may improve patient outcomes. It is important to establish the frequency for measuring intermittent ScvO2 levels in patients with severe sepsis to assist clinicians in using ScvO2 as a guide for therapeutic interventions when continuous ScvO2 monitoring is unavailable.
Methods: Methods: A retrospective medical record review was performed on five patients with severe sepsis and septic shock who were included in an equipment evaluation at the University of Washington Medical Center. Heart Rate and ScvO2 data were gathered at five minute intervals using the ScvO2 Medical Record Review Tool for a total of 1853 data points. A frequency distribution for the variables was used to characterize the total sample. Data analyses used descriptive statistics for the continuous variable of ScvO2 and included range, mean, and standard deviation.
Results: Results: The continuously monitored ScvO2 for all five subjects ranged from 61 ± 3 to 84 ± 5%. The frequency that ScvO2 values varied more than 5% from the patient’s mean ScvO2 was between 29% and 62%. A clinically significant change in HR preceded a clinically significant change in ScvO2 for only one subject (r = 0.74). If ScvO2 were measured every hour, a clinically significant change in ScvO2 (i.e., ScvO2 that varied more than 5% of the patient’s previously obtained value) would have been missed in 10% to 32% of cases. Additionally, there was a trend of increasing missed points (up to 62%) as the time between measurements increased.
Conclusions: Conclusion: The results of this study suggest that continuous monitoring is required to reliably detect clinically significant changes in ScvO2. If intermittent measures are the only option, they should be measured hourly. Other factors to consider when deciding on intermittent versus continuous measurements include the risk of iatrogenic infection, anemia and the cost of supplies versus oximetric catheters.
   
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