Fluid resuscitation, but not inhaled nitric oxide, improves microcirculation in septic pigs.

Background: Prolonged deterioration of microvascular flow during sepsis leads to organ dysfunction. Capillary flow restoration may prevent this complication.

Objectives: The main aim of this study was to investigate the microcirculatory effects of inhaled nitric oxide (iNO) combined with intravenous hydrocortisone in a porcine model of sepsis. The 2nd aim was to evaluate the influence of hemodynamic resuscitation with noradrenaline and crystalloids on capillary flow.

Material And Methods: Eleven piglets of Polish breed underwent surgical colon perforation to develop sepsis. They were randomly allocated to one of 3 treatment groups. Group 1 received iNO and hydrocortisone, whereas group 2 did not. Both groups were resuscitated with crystalloids and noradrenaline if hypotensive. Group 3 received no treatment at all. During a 30-hour observation, we assessed the microcirculation using sidestream dark field imaging (SDF).

Results: We found no effect of iNO with hydrocortisone on the microcirculation. Fluid and vasopressor treatment led to a higher microcirculatory flow index after 20 h of observation (3 and 2.75 in groups 1 and 2 compared to 1.9 in group 3), a greater proportion of perfused vessels (94% and 87% compared to 63% in groups 1, 2 and 3, respectively) and a greater perfused vessel density (15.2 mm/mm2, 15.09 mm/mm2 and 10.1 mm/mm2 in groups 1, 2 and 3, respectively).

Conclusions: Crystalloid and vasopressor treatment postponed microvascular flow derangements, whereas iNO combined with intravenous hydrocortisone did not improve microvascular perfusion.