Browsing by Subject "central venous oxygen saturation"

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    End expiratory oxygen concentrations to predict central venous oxygen saturation: an observational pilot study
    (2006-09) Jones, Alan E; Kuehne, Karl; Steuerwald, Michael; Kline, Jeffrey A.
    Background A non-invasive surrogate measurement for central venous oxygen saturation (ScVO2) would be useful in the ED for assessing therapeutic interventions in critically ill patients. We hypothesized that either linear or nonlinear mathematical manipulation of the partial pressure of oxygen in breath at end expiration (EtO2) would accurately predict ScVO2. Methods Prospective observational study of a convenience sample of hemodialysis patients age > 17 years with existing upper extremity central venous catheters were enrolled. Using a portable respiratory device, we collected both tidal breathing and end expiratory oxygen and carbon dioxide concentrations, volume and flow on each patient. Simultaneous ScVO2 measurements were obtained via blood samples collected from the hemodialysis catheter. Two models were used to predict ScVO2: 1) Best-fit multivariate linear regression equation incorporating all respiratory variables; 2) MathCAD to model the decay curve of EtO2 versus expiratory volume using the least squares method to estimate the pO2 that would occur at <20% of total lung capacity. Results From 21 patients, the correlation between EtO2 and measured ScVO2 yielded R2 = 0.11. The best fit multivariate equation included EtCO2 and EtO2 and when solved for ScVO2, the equation yielded a mean absolute difference from the measured ScVO2 of 8 ± 6% (range -18 to +17%). The predicted ScVO2 value was within 10% of the actual value for 57% of the patients. Modeling of the EtO2 curve did not accurately predict ScVO2 at any lung volume. Conclusion We found no significant correlation between EtO2 and ScVO2. A linear equation incorporating EtCO2 and EtO2 had at best modest predictive accuracy for ScVO2.
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    Prognostic Value and Agreement of Achieving Lactate Clearance or Central Venous Oxygen Saturation Goals During Early Sepsis Resuscitation
    (2012-03) Puskarich, Michael A; Trzeciak, Stephen; Shapiro, Nathan I; Arnold, Ryan C; Heffner, Alan C; Kline, Jeffrey A.; Jones, Alan E
    Objectives:  Lactate clearance (LC) and central venous oxygen saturation (ScvO2) have been proposed as goals of early sepsis resuscitation. The authors sought to determine the agreement and prognostic value of achieving ScvO2 or LC goals in septic shock patients undergoing emergency department (ED)-based early resuscitation. Methods:  This was a preplanned analysis of a multicenter ED randomized controlled trial of early sepsis resuscitation targeting three variables: central venous pressure, mean arterial pressure, and either ScvO2 or LC. Inclusion criteria included suspected infection, two or more systemic inflammation criteria, and either systolic blood pressure of <90 mm Hg after intravenous fluid bolus or lactate level of >4 mmol/L. Both ScvO2 and LC were measured simultaneously. The ScvO2 goal was defined as ≥70%. Lactate was measured at enrollment and every 2 hours until the goal was reached or up to 6 hours. LC goal was defined as a decrease of ≥10% from initial measurement. The primary outcome was in-hospital mortality. Results:  A total of 203 subjects were included, with an overall mortality of 19.7%. Achievement of the ScvO2 goal only was associated with a mortality rate of 41% (9/22), while achievement of the LC goal only was associated with a mortality rate of 8% (2/25; proportion difference = 33%; 95% confidence interval [CI] = 9% to 55%). No agreement was found between goal achievement (κ = –0.02), and exact test for matched pairs demonstrated no significant difference between discordant pairs (p = 0.78). Conclusions:  No agreement was found between LC and ScvO2 goal achievement in early sepsis resuscitation. Achievement of a ScvO2≥ 70% without LC ≥ 10% was more strongly associated with mortality than achievement of LC ≥ 10% with failure to achieve ScvO2≥ 70%.