Sublingual microcirculatory changes during high-volume hemofiltration in hyperdynamic septic shock patients

Abstract

Introduction: Previous studies have suggested that high volume hemofiltration (HVHF) may contribute to revert hypotension in severe hyperdynamic septic shock patients. However, arterial pressure stabilization occurs due to an increase in systemic vascular resistance, which could eventually compromise microcirculatory blood flow and perfusion. The goal of this study was to determine if HVHF deteriorates sublingual microcirculation in severe hyperdynamic septic shock patients.

Methods: This was a prospective, non-randomized study at a 16-bed, medical-surgical intensive care unit of a university hospital. We included 12 severe hyperdynamic septic shock patients (norepinephrine requirements > 0.3 μg/kg/min and cardiac index > 3.0 L/min/m2) who underwent a 12-hour HVHF as a rescue therapy according to a predefined algorithm. Sublingual microcirculation (Microscan for NTSC, Microvision Medical), systemic hemodynamics and perfusion parameters were assessed at baseline, at 12 hours of HVHF, and 6 hours after stopping HVHF.

Results: Microcirculatory flow index increased after 12 hours of HVHF and this increase persisted 6 hours after stopping HVHF. A similar trend was observed for the proportion of perfused microvessels. The increase in microcirculatory blood flow was inversely correlated with baseline levels. There was no significant change in microvascular density or heterogeneity during or after HVHF. Mean arterial pressure and systemic vascular resistance increased while lactate levels decreased after the 12-hour HVHF.

Conclusions: The use of HVHF as a rescue therapy in patients with severe hyperdynamic septic shock does not deteriorate sublingual microcirculatory blood flow despite the increase in systemic vascular resistance.

Figure 1

Effects of high-volume hemofiltration (HVHF) on sublingual microvascular density. The graphs present the individual evolution of total vascular density (upper graph) and perfused vascular density (lower graph) of small vessels (< 20 μm) at baseline, at the end of the 12-hour period of HVHF, and 6 hours after stopping HVHF. There was no significant change. Density is expressed as the number of vessels divided by the total length of the gridline in millimeters.

Figure 2

Effects of high-volume hemofiltration (HVHF) on sublingual microvascular flow. The graphs present the individual evolution of flow assessed by the percentage of perfused vessels (upper graph) and by the microvascular flow index (lower graph) of small vessels (< 20 μm) at baseline, at the end of the 12-hour period of HVHF, and 6 hours after stopping HVHF. *P < 0.05 compared with baseline.

Figure 3

Relationship between baseline sublingual microcirculatory parameters and their change during the 12-hour high-volume hemofiltration (HVHF). The upper graph shows a significant correlation between baseline values of perfused vascular density (PVD) and their variation during the 12-hour HVHF. The lower graph shows a similar correlation between the baseline values of the percentage of perfused vessels (PPV) and their variation during the 12-hour HVHF. Both PVD and PPV were calculated for small vessels (< 20 μm). Density is expressed as the number of vessels divided by the total length of the gridline in millimeters.