Impact of vasopressin analogues on the gut mucosal microcirculation.

Given the controversial experimental and clinical data reported in the literature, up to now it is rather difficult to draw a definitive conclusion on the effects of V1 agonists on splanchnic haemodynamics. Nevertheless, it must be underscored that most of the experimental studies assessing the effects of low dose V1 agonist infusion in hyperdynamic models did not demonstrate any detrimental effect on splanchnic haemodynamics both at macro- and microcirculatory levels. Interestingly, all the reported studies focused on macro- and microcirculatory haemodynamics, while only some also addressed the local oxygenation and metabolism. In clinical studies in patients with septic shock, data are accumulating regarding the absence of clinically relevant side effects in the splanchnic region when vasopressin is used, but conversely little is known about the safety of terlipressin, mainly because of the small number of patients studied. Thus, the absence of clinically harmful effect does not exclude covert splanchnic ischaemia, which may counterbalance the beneficial systemic effects.