Please see Bibliography of References for a list of abstracts, manuscripts and posters.
Lima A, Jansen T, Ince C, Bakker J. Crit Care. 2008;12(Supp 2):S23-S24. Abstract P60.
Introduction: Peripheral blood flow can be markedly impaired in septic shock. Bedside assessment of this derangement has not yet been incorporated into routine clinical practice. We hypothesize that noninvasive monitoring of peripheral perfusion with physical examination and peripheral flow index (PFI) derived from pulse oximetry signal can reflect sepsis-induced microcirculation alteration as measured by near-infrared spectroscopy (NIRS) in patients with septic shock.
Methods: NIRS (InSpectra) was used to quantify sepsis-induced circulatory alterations by calculating the increase rate of tissue oxygen saturation (slope-StO2) in a standard hyperaemia test (3min arterial occlusion followed by rapid reperfusion). The increase rate of PFI signal (slope-PFI) following the occlusion was compared to slope-StO2. We performed physical examination of extremities before arterial occlusion and abnormal peripheral perfusion was defined as an increase in capillary refill time (>4.5 sec). The measurements were registered at admission after hemodynamic stability was obtained. We performed regression analysis to study the effect of abnormal peripheral perfusion on slope-StO2 and to study the relationship between slope-PFI and slope-StO2.
Results: We prospectively studied 20 consecutive septic shock patients (age 54±15 years; 16 males and 4 females). The admission diagnoses were 10 pneumonia, 7 abdominal sepsis, 2 meningitis and 1 urosepsis. The slope-StO2 was significantly different between patients with normal peripheral perfusion (N=8; mean: 218%/min; 95% CI: 141-339) and abnormal peripheral perfusion (N=12; mean: 92%/min; 95% CI: 68-123). Regression analysis showed that the slope-StO2 is 138%/min lower in patients with abnormal than in patients with normal peripheral perfusion, controlled for the possible effect of central temperature (r2=0.42; P<0.01). We found a strong association between slope-PFI and slope-StO2 (Pearson Correlation=0.84; P<0.001). The effect of slope-StO2 on the slope-PFI was an increase in slope-StO2 of 90%/min per 1 unit/min of slope-PFI (r2=0.65; P<0.001).
Conclusions: Peripheral vascular reactivity in patients with septic shock, as measured by changes in StO2 following an ischemia-reperfusion challenge, is related to the clinical assessment with capillary refill time and PFI.