It is increasingly believed that acute microvascular alterations may be involved in the development of organ dysfunction in critically ill patients. Propofol significantly decreases vascular tone and venous return, which can induce arterial hypotension. However, little is known about the microcirculatory effects of propofol in healthy humans. We conducted a prospective, open-labelled trial in 15 patients anaesthetized by propofol for transvaginal oocyte retrieval. The sublingual microcirculatory network was studied before, during, and after propofol infusion using orthogonal polarization spectral imaging. Mean (SD) calculated propofol effect-site concentration was 6.5 (1.8) microg ml(-1). During propofol administration, systemic haemodynamic and oxygenation variables were unchanged, but total microvascular density decreased by 9.1% (P<0.05). The venular density remained unchanged, but the density of perfused capillaries was significantly reduced by 16.7% (P<0.05). Microcirculatory alterations resolved 3 h after discontinuation of the propofol infusion. Propofol infusion for anaesthesia in man reduces capillary blood flow.
