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

Other Studies

Near infrared spectroscopy as an indirect tool for assessing the microcirculation of the critically ill

Renieris P, Gerovasili V, Poulaki S, Zagorianou A, Kourtidou S, Kravari M, Bouchla A, Zervakis D, Markaki V, Nanas S. Int Care Med. 2007;33(Supp 2):S31. Abstract 0106.

Introduction: Systemic immune response syndrome (SIRS) frequently develops in critically ill patients and may lead to multiple organ dysfunction or failure even in the presence of normal or normalized global hemodynamic parameters, mainly due to tissue dysoxia and microvascular dysfunction. Near Infrared Spectroscopy (NIRS) is a validated method for the assessment of tissue oxygenation but its accordance with routine parameters has not yet been sufficiently studied. Aim: To compare NIRS parameters to routine monitoring parameters of the critically ill.

Methods: Thirty two consecutive critically ill patients (age=57±17 years, male/female=18/14, length of ICU stay=17±12 days) were enrolled. All patients were evaluated with NIRS and the occlusion technique within 24 hours of ICU admission. All patients were mechanically ventilated and 26 were sedated. Routine hemodynamic parameters (mean arterial pressure=83±15 mmHg, central venous pressure=8±3 mmHg, heart rate=85±16), full blood analysis (hemoglobin=11.3±4.4 g/dL, white blood cells=11,345±4,602 /dL) and arterial blood gases analysis were recorded. SOFA, APACHE II and SAPS III (55±13) scores were assigned on ICU entry day. Tissue Oxygen Saturation (StO₂%) was continuously monitored before, during and after 3-min occlusion of the brachial artery via pneumatic cuff inflated up to 50 mmHg above measured systolic arterial blood pressure.

Results: StO₂% (79±11) correlated with SOFA score (7.4±1.9, r=0.49, p=0.012) and SpO2 (97.7±3.1%, r=0.44, p=0.015). Reperfusion rate after release of the occlusion (StO₂%/min, 305±186) correlated with APACHE II score (15±5, r=0.47, p=0.018), ScvO2 (77.4±8.9%, r=0.45, p=0.012), PcvO2 (44±10 mmHg, r=0.27, p=0.037) and serum lactate values (1.6±1.2 ng/dL, r=0.36, p=0.044).

Conclusion: NIRS is a simple non invasive method for the assessment of peripheral tissue oxygenation that could be of value in the bed-side evaluation of the microcirculation. Our results imply that NIRS parameters correlate with severity scores as well as with invasive parameters used in everyday practice. Further studies could provide more information on its predictive or treatment-guiding value.