Please see Bibliography of References for a list of abstracts, manuscripts and posters.

Sepsis

Tissue oxygenation does not predict central venous oxygenation in emergency department patients with severe sepsis and septic shock

Napoli AM, Machan JT, Forcada A, Corl K, Gardiner F. Acad Emerg Med. 2010;17(4):349-352.

Objectives: This study sought to determine whether tissue oxygenation (StO₂) could be used as a surrogate for central venous oxygenation (ScVO₂) in early goal-directed therapy (EGDT).

Methods: The study enrolled a prospective convenience sample of patients aged ≥18 years with sepsis and systolic blood pressure <90 mm Hg after 2 L of normal saline or lactate >4 mmol, who received a continuous central venous oximetry catheter. StO₂ and ScVO₂ were measured at 15-minute intervals.  Data were analyzed using a random coefficients model, correlations, and Bland-Altman plots.

Results: There were 284 measurements in 40 patients. While a statistically significant relationship existed between StO₂ and ScVO₂ (F(1,37) = 10.23, p = 0.002), StO₂ appears to systematically overestimate at lower ScVO₂ and underestimate at higher ScVO₂. This was reflected in the fixed effect slope of 0.49 (95% confidence interval [CI] = 0.266 to 0.720) and intercept of 34 (95% CI = 14.681 to 50.830), which were significantly different from 1 and 0, respectively. The initial point correlation (r = 0.5) was fair, but there was poor overall agreement (bias = 4.3, limits of agreement = -20.8 to 29.4).

Conclusions: Correlation between StO₂ and ScVO₂ was fair. The two measures trend in the same direction, but clinical use of StO₂ in lieu of ScVO₂ is unsubstantiated due to large and systematic biases. However, these biases may reflect real physiologic states. Further research may investigate if these measures could be used in concert as prognostic indicators.