Esmolol may efficiently reduce heart rate (HR) and decrease mortality during septic shock. An improvement of microcirculation dissociated from its macrocirculatory effect is suspected to play a role. The present study investigates the effect of esmolol on gut and sublingual microcirculation in a resuscitated piglet model of septic shock.
Fourteen piglets, anesthetized and mechanically ventilated, received a suspension of live Pseudomonas aeruginosa. They were randomly assigned to two groups: esmolol (E) group received an infusion of esmolol, started at 7.5 μg.kg(-1).min(-1), and progressively increased to achieve a HR below 90 beats · min(-1). Control (C) group received an infusion of Ringer's lactate solution. HR, mean arterial pressure (MAP), cardiac index (CI), stroke index (SI), systemic vascular resistance (SVR), arterio-venous blood gas and lactate were recorded. Oxygen consumption (VO2), delivery (DO2) and peripheral extraction (O2ER) were computed. Following an ileostomy, a laser Doppler probe was applied on ileal mucosa to monitor gut microcirculation and laser Doppler flow (GMLDF). Videomicroscopy was also used on ileal mucosa and sublingual areas to evaluate mean flow index (MFI), heterogeneity, ratio of perfused villi (PV) and proportion of perfused vessels (PPV). Resuscitation maneuvers were performed following a defined algorithm.
Bacterial infusion induced a significant alteration of the gut microcirculation with an increase in HR. Esmolol produced a significant time.group effect with a decrease in HR (p < 0.004) and an increase in SVR (p < 0.004). Time.group effect was not significant for CI and MAP, but there was a clear trend toward a decrease in CI and MAP in the E group. Time.group effect was not significant for SI, O2ER, DO2, VO2, GMLDF, and lactate. A significant time.group effect of ileal microcirculation was found with a lower ileal villi perfusion (p < 0.025) in the C group and a trend toward a better MFI in the E group. No difference between both groups was found regarding microcirculatory parameters in the sublingual area.
Esmolol provided a maintenance of microcirculation, during sepsis despite its negative effects on macrocirculation. Some parameters even showed a trend toward an improvement of the microcirculation in the gut area in the esmolol group.