Please see Bibliography of References for a list of abstracts, manuscripts and posters.
Creteur J, Neves AP, Ospina G, Oliveira T, De Backer D, Vincent JL. Crit Care Med. 2008;36(12, Abstract Supplement):A158. Abstract 621.
Introduction: Despite adequate resuscitation, microvascular alterations may persist in severe sepsis. Near-infrared spectroscopy (NIRS) has been proposed as a tool to quantify microvascular dysfunction in patients with sepsis. By inducing a vaso-occlusive test (VOT), several NIRS-derived variables can be measured to assess microvascular function.
Hypothesis: The persistence of alterations in these NIRS-derived variables following resuscitation is associated with a worse outcome in patients with severe sepsis.
Methods: Thenar muscle oxygen saturation (StO2) was measured by a tissue spectrometer (InSpectraTM 325, HTI, MN) in patients with early severe sepsis. A VOT (upper limb ischemia induced by inflation of a pneumatic cuff around the upper arm) was performed every hour during the first 6 hrs of resuscitation. The following variables were recorded: “steadystate” StO2, slope of the decrease in StO2 during the occlusion (desc sl; %/min), and slope of the increase in StO2 following the ischemic period (asc sl; %/sec). Central venous oxygen saturation (ScvO2) was also measured every hour. Variables are expressed as mean±SD or median(25th;75th percentiles).
Results: Thirty-three patients were included (APACHE II 23±7, mortality 42%). ScvO2 was similar in survivors (S) and non-survivors at 6 hrs (72±6 vs 71±8%, p=NS). The time course of StO2 was similar in S and NS, from 82(74;92)% and 80(62;87)%, respectively, at baseline to 88(75;93)% and 84(67;88)%, respectively, at 6 hrs. At baseline, the desc sl were less steep in NS (-20(-12;-25)%/min) than in S (-35(-26;-60)%/min) (p<0.05), and remained less at 6 hrs (-19(-13;- 28) vs -40(-29;-56) %/min, respectively; p<0.05). Asc sl were similar at baseline in S and NS (2.6(2.1;3.5) vs 1.5(0.7;2.9) %/sec, respectively), but increased over time in S (3.6(3.3;4.3)%/sec at 6 hrs, p<0.05) but not in NS (1.9(1.5;2.8)%/sec at 6 hrs).
Conclusions: Despite seemingly adequate resuscitation, persistence of alterations in NIRS-derived variables is associated with a worse outcome in patients with severe sepsis.