Tissue oxygenation does not predict central venous oxygenation in emergency department patients with severe sepsis and septic shock.
OBJECTIVE
This study sought to determine whether tissue oxygenation (StO(2)) could be used as a surrogate for central venous oxygenation (ScVO(2)) in early goal-directed therapy (EGDT).


METHODS
The study enrolled a prospective convenience sample of patients aged > or =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. StO(2) and ScVO(2) 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 StO(2) and ScVO(2) (F(1,37) = 10.23, p = 0.002), StO(2) appears to systematically overestimate at lower ScVO(2) and underestimate at higher ScVO(2). 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 StO(2) and ScVO(2) was fair. The two measures trend in the same direction, but clinical use of StO(2) in lieu of ScVO(2) 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.
Napoli
Anthony M
AM
Department of Emergency Medicine, Brown University Medical School, Providence, RI, USA. anapoli@lifespan.org
Machan
Jason T
JT
Forcada
Ahteri
A
Corl
Keith
K
Gardiner
Fenwick
F
D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D002405:Catheterization, Central Venous; D015331:Cohort Studies; D016001:Confidence Intervals; D004636:Emergency Service, Hospital; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis; D012772:Shock, Septic / Q000097:blood* / Q000175:diagnosis
D010100:Oxygen