Effects of early hemodynamic resuscitation on left ventricular performance and microcirculatory function during endotoxic shock

Abstract

BackgroundMicrocirculation and macrohemodynamics are severely compromised during septic shock. However, the relationship between these two compartments needs to be further investigated. We hypothesized that early resuscitation restores left ventricular (LV) performance and microcirculatory function but fails to prevent metabolic disorders. We studied the effects of an early resuscitation protocol (ERP) on LV pressure/volume loops-derived parameters, sublingual microcirculation, and metabolic alterations during endotoxic shock.MethodsTwenty-five pigs were randomized into three groups: LPS group: Escherichia coli lipopolysaccharide (LPS); ERP group: LPS + ERP based on volume expansion, dobutamine, and noradrenaline infusion; Sham group. LV pressure/volume-derived parameters, systemic hemodynamics, sublingual microcirculation, and metabolic profile were assessed at baseline and after completing the resuscitation protocol.ResultsLPS significantly decreased LV end-diastolic volume, myocardial contractility, stroke work, and cardiac index (CI). Early resuscitation preserved preload, and myocardial contractility, increased CI and heart rate (p < .05). LPS severely diminished sublingual microvascular flow index (MFI), perfused vascular density (PVD), and the proportion of perfused vessels (PPV), while increased the heterogeneity flow index (HFI) (p < .05). Despite MFI was relatively preserved, MVD, PVD, and HFI were significantly impaired after resuscitation (p < .05). The macro- and microcirculatory changes were associated with increased lactic acidosis and mixed venous O2 saturation when compared to baseline values (p < .05). The scatter plot between mean arterial pressure (MAP) and MFI showed a biphasic relationship, suggesting that the values were within the limits of microvascular autoregulation when MAP was above 71 ± 6 mm Hg (R2 = 0.63).ConclusionsEarly hemodynamic resuscitation was effective to restore macrohemodynamia and myocardial contractility. Despite MAP and MFI were relatively preserved, the persistent microvascular dysfunction could explain metabolic disorders. The relationship between micro- and systemic hemodynamia and their impact on cellular function and metabolism needs to be further studied during endotoxic shock.Electronic supplementary materialThe online version of this article (doi:10.1186/s40635-015-0049-y) contains supplementary material, which is available to authorized users.

Effects of volume resuscitation on the microcirculation in animal models of lipopolysaccharide sepsis: a systematic review

“…peak flow was defined as the highest flow signal obtained post-pneumatic occlusion of blood flow to the legs. Duration of the flow signal was also recorded]a) 0.9% sodium chloride group 5 mL/kg/hb) 8.4% hypertonic sodium bicarbonate 5 mL/kg/hc) 11.2% hypertonic sodium lactate 5 mL/kg/hHypertonic sodium lactate solution improves microvascular reactivity with a negative fluid balanceInvestigate effects of hypertonic sodium lactate compared to sodium chloride on the microcirculation in endotoxic shockLopez et al [51]2015Pig–Sidestream dark-field videomicroscopy:Microcirculation was assessed by the following measurements obtained from the average of 12 quadrants (i.e. three videos of sublingual mucosa, four quadrants each);(a) Microvascular density, MVD [i.e.…”

“…The featured 11 studies involved both small rodent models, included two hamster studies ( n  = 58) [61, 62], and two rat studies ( n  = 57) [52, 63], and large mammal models, which included three pig ( n  = 64) [51, 64, 65], two dog ( n  = 28) [66, 67] and two sheep studies ( n  = 27) [15, 68]. In each instance, sepsis was induced by intravascular LPS infusion post induction of appropriate anaesthesia.…”

“…Laser Doppler flowmetry and/or videomicroscopic sidestream dark-field (SDF) imaging were largely used for microcirculatory assessments in the larger mammalian models [15, 51, 65, 67]. One study utilized indirect quantification of oxygen extraction to assess microcirculatory function [66].…”

“…Six studies reported improved blood flow in the microcirculation and reduced extravasation of plasma following fluid resuscitation [61–64, 66, 67]. One study reported improvement of microvascular blood flow and oxygenation with overall negative fluid balance in sepsis [65], whilst three studies documented persistent microcirculatory dysfunction with volume resuscitation [15, 51, 52]. One study exhibited improved sublingual and serosal intestinal microcirculation, but persistent dysfunction in the intestinal mucosal villi within the same sepsis model resuscitated with hydroxyethyl starch (HES) [68].…”

“…A comparison of crystalloid and colloid in cecal ligation and puncture-induced sepsis in rodents concluded that crystalloid infusion produced better microcirculatory function as well as mortality benefit [48], with growing interest in comparison of fluid types [49, 50] and early versus late resuscitation in experimental animal models [51, 52]. Clinically, there is still controversy on the choice of resuscitation fluids.…”