title: Microcirculatory changes during open label magnesium sulphate infusion in patients with severe sepsis and septic shock.
abstract: BACKGROUND
  Microcirculatory alterations play a pivotal role in sepsis and persist despite correction of systemic hemodynamic parameters. Therefore it seems tempting to test specific pro-microcirculatory strategies, including vasodilators, to attenuate impaired organ perfusion. As opposed to nitric oxide donors, magnesium has both endothelium-dependent and non-endothelium-dependent vasodilatory pathways.
  
  
  METHODS
  In a single-center open label study we evaluated the effects of magnesium sulphate (MgS) infusion on the sublingual microcirculation perfusion in fluid resuscitated patients with severe sepsis and septic shock within the first 48 hours after ICU admission. Directly prior to and after 1 hour of magnesium sulphate (MgS) infusion (2 gram) systemic hemodynamic variables, sublingual SDF images and standard laboratory tests, were obtained.
  
  
  RESULTS
  Fourteen patients (12 septic shock, 2 severe sepsis) with a median APACHE II score of 20 were enrolled. No significant difference of the systemic hemodynamic variables was found between baseline and after MgS infusion. We did not observe any significant difference pre and post MgS infusion in the primary endpoint microvascular flow index (MFI) of small vessels: 2.25(1.98-2.69) vs. 2.33(1.96-2.62), p = 0.65. Other variables of microcirculatory perfusion were also unaltered. In the overall unchanged microvascular perfusion there was a non-significant trend to an inverse linear relationship between the changes of MFI and its baseline value (y = -0.7260 × + 1.629, r2 = 0.270, p = 0.057). The correlation between baseline Mg concentrations and the change in MFI pre- and post MgS infusion was non-significant (rs = -0.165, p = 0.67).
  
  
  CONCLUSIONS
  In the setting of severe sepsis and septic shock sublingual microcirculatory alterations were observed despite fulfillment of sepsis resuscitation guidelines. After infusion of a limited and fixed dose of MgS, microcirculatory perfusion did not improve over time.
  
  
  BACKGROUND
  ClinicalTrials.gov NTC01332734.
authors.affiliation: Department of Intensive Care Medicine, Medical Center Leeuwarden, Henri Dunantweg 2, Leeuwarden, 8901 BR, the Netherlands. e.boerma@chello.nl.
authors.forename: Andrius
authors.initials: A
authors.lastname: Pranskunas
authors.forename: Namkje Ar
authors.initials: NA
authors.lastname: Vellinga
authors.forename: Vidas
authors.initials: V
authors.lastname: Pilvinis
authors.forename: Matty
authors.initials: M
authors.lastname: Koopmans
authors.forename: E Christiaan
authors.initials: EC
authors.lastname: Boerma