Observational Study of Sublingual Microcirculatory Blood Flow Characteristics in Patients Undergoing Transthoracic Esophagectomy

Microcirculatory alterations occur in critically ill patients and those undergoing major surgeries. The severity of perioperative microvascular alterations appear to be related to the severity of organ dysfunction after surgery. Non-cardiac thoracic surgeries comprise a subgroup of high risk surgical procedures which have the potential to significantly affect and impair microcirculatory function but this patient population has not been well studied. Esophagectomy surgery in particular produces a profound systemic inflammatory response which correlates with a number of adverse outcomes. It is likely, though unproven, that microcirculatory derangements may underly these phenomena. Though the study of microcirculatory dysfunction in thoracic surgery is in its infancy, the body of available evidence at this point supports the following hypotheses; that microcirculatory derangements and dysfunction 1) occur during major surgeries including transthoracic esophagectomy 2) may be related to SIRS, 3) may predict adverse outcomes, and 4) may be amenable to modification via specific therapies. We propose a prospective observational study to determine the effects of transthoracic esophagectomy on microcirculatory function. Two hundred patients meeting inclusion criteria undergoing planned transthoracic esophagectomy via thoracotomy incision will be prospectively enrolled at The University of Virginia. Patients will be followed for 28 days or until discharge from the ICU. Evaluation of the sublingual, gastric serosal and mucosal tissues will be performed using sidestream dark field (SDF) imaging using the CytoCam® by Braedius Medical BV (Huizen, The Netherlands). Scoring of the microcirculation will include an index of vascular density (perfused vessel density), an assessment of capillary perfusion (proportion of perfused vessels and microcirculatory flow index) and a heterogeneity index. Note: the CytoCam® will only take a series of images as consistent with a microscope of exposed tissue. Also, the FDA Office of Device Evaluations (ODE) General Surgery Devices Branch One - Light Based/laser (GSDB1) has deemed this device to be exempt from 510(K) approval. http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPCD/classification.cfm?ID=5021 Data from patient's medical charts before and after surgery (30 days post) will be used for elucidation of specific complications. We will use the cardiovascular and respiratory components of the SOFA score as independent measures of organ dysfunction. Acute kidney injury will be defined by the AKIN criteria as an increase of at least 50% above baseline serum creatinine and will be graded from stage 1 to 3.