Acute kidney injury is associated with a decrease in cortical renal perfusion during septic shock

Anatole Harrois,Samy Figueiredo,Nicolas Grillot,Jacques Duranteau

doi:10.1186/s13054-018-2067-0

Abstract

BackgroundRenal perfusion status remains poorly studied at the bedside during septic shock. We sought to measure cortical renal perfusion in patients with septic shock during their first 3 days of care using renal contrast enhanced ultrasound (CEUS).MethodsWe prospectively included 20 ICU patients with septic shock and 10 control patients (CL) without septic shock admitted to a surgical ICU. Cortical renal perfusion was evaluated with CEUS during continuous infusion of Sonovue (Milan, Italy) within the first 24 h (day 0), between 24 and 48 h (day 1) and after 72 h (day 3) of care. Each measurement consisted of three destruction replenishment sequences that were recorded for delayed analysis with dedicated software (Vuebox). Renal perfusion was quantified by measuring the mean transit time (mTT) and the perfusion index (PI), which is the ratio of renal blood volume (rBV) to mTT.ResultsCortical renal perfusion was decreased in septic shock as attested by a lower PI and a higher mTT in patients with septic shock than in patients of the CL group (p = 0.005 and p = 0.03). PI values had wider range in patients with septic shock (median (min-max) of 74 arbitrary units (a.u.) (3–736)) than in patients of the CL group 228 a.u. (67–440)). Renal perfusion improved over the first 3 days with a PI at day 3 higher than the PI at day 0 (74 (22–120) versus 160 (88–245) p = 0.02). mTT was significantly higher in patients with severe acute kidney injury (AKI) (n = 13) compared with patients with no AKI (n = 7) over time (p = 0.005). The PI was not different between patients with septic shock with severe AKI and those with no AKI (p = 0.29).ConclusionsAlthough hemodynamic macrovascular parameters were restored, the cortical renal perfusion can be decreased, normal or even increased during septic shock. We observed an average decrease in cortical renal perfusion during septic shock compared to patients without septic shock. The decrease in cortical renal perfusion was associated with severe AKI occurrence. The use of renal CEUS to guide renal perfusion resuscitation needs further investigation.

Highlights

Renal perfusion status remains poorly studied at the bedside during septic shock
Since renal function impairment may occur despite a preserved global RBF, the study of intrarenal blood flow distribution becomes an important step in understanding the pathophysiology of acute kidney injury (AKI) during septic shock
Simplified Acute Physiology Score (SAPS) Simplified Acute Physiology Score (II) and Sequential Organ Failure Assessment (SOFA) scores were significantly lower in control patients than in patients with septic shock (p = 0.001 and p = 0.003, respectively)

Summary

Introduction

Renal perfusion status remains poorly studied at the bedside during septic shock. Renal function impairment is a frequent condition during septic shock with an incidence of acute kidney injury (AKI) ranging from 55 to 73% [1,2,3]. It is independently associated with mortality [4]. Renal perfusion status remains poorly studied at the bedside during. Since renal function impairment may occur despite a preserved global RBF, the study of intrarenal blood flow distribution becomes an important step in understanding the pathophysiology of AKI during septic shock. Whether alterations of microvascular RBF are due to insufficient hemodynamic optimization or to specific microvascular injuries induced by sepsis (endothelial dysfunction, increased leukocyte adhesion, rheological abnormalities, glycocalyx alterations and functional shunting), we crucially need a tool to measure renal perfusion in daily practice [5, 9, 10]

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