Microcirculatory blood flow as a tool to select ICU patients eligible for fluid therapy

Abstract

PurposeThe aim of this study is to assess the incidence of sublingual microcirculatory flow alterations, according to a predefined arbitrary cutoff value, in patients with “clinical signs of impaired organ perfusion”. Secondary endpoints were the changes in microvascular flow index (MFI), “clinical signs of impaired organ perfusion”, and stroke volume (SV) after fluid administration, and the differences between groups.MethodsProspective, single-center, observational study in a 22-bed mixed intensive care unit (ICU). Patients ≥18 years with invasive hemodynamic monitoring and “clinical signs of impaired organ perfusion” as the principal reason for fluid administration were included. Before and after fluid challenge, systemic hemodynamics and direct in vivo observation of the sublingual microcirculation with sidestream dark-field imaging were obtained. Microvascular flow index (MFI) <2.6 was predefined as abnormal.ResultsN = 50. At baseline, MFI <2.6 was present in 66 % of the patients. In these patients, MFI increased from 2.3 (2–2.5) at baseline to 2.5 (2.1–2.8) after fluid challenge (p = 0.003). This was accompanied by a reduction in the number of “clinical signs of impaired organ perfusion” from 2 (1–2) to 1 (0–2) (p < 0.001). However, in patients with MFI >2.6 at baseline, MFI and clinical signs changed insignificantly [2.8 (2.8–2.9) versus 2.8 (2.7–3), p = 0.45, respectively, 1 (1–2) versus 1 (1–2), p < 0.32]. These changes were not restricted to patients with a rise in SV ≥10 %.ConclusionsThese data add to the understanding that noninvasive assessment of microvascular blood flow may help to identify patients eligible for fluid therapy, and to evaluate its effect.Electronic supplementary materialThe online version of this article (doi:10.1007/s00134-012-2793-8) contains supplementary material, which is available to authorized users.

Year in review in Intensive Care Medicine 2013: III. Sepsis, infections, respiratory diseases, pediatrics

“…We more or less agree that macrocirculatory endpoints might not be adequate in many cases. At least in fluid resuscitation patients the microcirculation might prove to be more important than macrocirculation [6]. Adequate microcirculatory perfusion might even permit one to have abnormal macrocirculatory parameters; however, the scientific bases for these endpoints need to be laid out [7].…”

Blood Volume Determination Through New Generation 130/0,4 Hydroxyethyl-Starch: A Propaedeutic, In-Vitro Study

“…Despite this, no clear guidelines exist concerning the choice of type, quantity and timing of fluid administrations [19][20][21].…”

Fluid resuscitation in ICU patients: quo vadis?

“…At least the Surviving Sepsis Campaign guideline has promoted continued fluid therapy in spite of a very low level of evidence [8]. Clearly, the concept of optimizing tissue perfusion by maximizing stroke volume is context dependent [9] and requires more clinical studies [10].…”