Microcirculatory alterations in the critically ill.

Disturbed regional oxygenation is believed to contribute to organ dysfunction, organ failure, and death. Recent techniques such as orthogonal polarization spectral/sidestream darkfield imaging and near infrared spectroscopy have provided insight into the microcirculatory alterations present in critically ill patients. Using these techniques, persistent microcirculatory alterations have been shown to be associated with a worse prognosis, notably in patients with septic shock, irrespective of systemic hemodynamic variables. Data on the effects of therapeutic interventions on the microcirculation are also being gathered and may help in developing strategies that can influence regional oxygenation and cellular metabolism, and thereby prevent or reverse organ failure. Whether monitoring the microcirculation can be used to guide therapy remains unclear and requires further study, and this is an exciting field of ongoing research.