Parameters related to macrocirculation, such as the mean arterial pressure,
central venous pressure, cardiac output, mixed venous saturation and central
oxygen saturation, are commonly used in the hemodynamic assessment of critically
ill patients. However, several studies have shown that there is a dissociation
between these parameters and the state of microcirculation in this group of
patients. Techniques that allow direct viewing of the microcirculation are not
completely disseminated, nor are they incorporated into the clinical management
of patients in shock. The numerous techniques developed for microcirculation
assessment include clinical assessment (e.g., peripheral perfusion index and
temperature gradient), laser Doppler flowmetry, tissue oxygen assessment
electrodes, videomicroscopy (orthogonal polarization spectral imaging,
sidestream dark field imaging or incident dark field illumination) and near
infrared spectroscopy. In the near future, the monitoring and optimization of
tissue perfusion by direct viewing and microcirculation assessment may become a
goal to be achieved in the hemodynamic resuscitation of critically ill
patients.