Microcirculation and Macrocirculation in Cardiac Surgical Patients

Abstract

Background. The aim of our study was to investigate the relationship between microcirculatory alterations after open cardiac surgery, macrohemodynamics, and global indices of organ perfusion. Methods. Patients' microcirculation was assessed with near-infrared spectroscopy (NIRS) and the vascular occlusion technique (VOT). Results. 23 patients undergoing open cardiac surgery (11 male/12 female, median age 68 (range 28–82) years, EuroSCORE 6 (1–12)) were enrolled in the study. For pooled data, CI correlated with the tissue oxygen consumption rate as well as the reperfusion rate (r = 0.56, P < 0.001 and r = 0.58, P < 0.001, resp.). In addition, both total oxygen delivery (DO2, mL/min per m2) and total oxygen consumption (VO2, mL/min per m2) also correlated with the tissue oxygen consumption rate and the reperfusion rate. The tissue oxygen saturation of the thenar postoperatively correlated with the peak lactate levels during the six hour monitoring period (r = 0.50, P < 0.05). The tissue oxygen consumption rate (%/min) and the reperfusion rate (%/min), as derived from the VOT, were higher in survivors compared to nonsurvivors for pooled data [23 (4–54) versus 20 (8–38) P < 0.05] and [424 (27–1215) versus 197 (57–632) P < 0.01], respectively. Conclusion. Microcirculatory alterations after open cardiac surgery are related to macrohemodynamics and global indices of organ perfusion.

Tissue near infra red spectroscopy change is not correlated with patients' outcome in elective cardiac surgery

“…Several studies focused on microcirculatory alterations during cardiac surgery using orthogonal polarization spectral (OPS) or side‐stream dark‐field imaging techniques, gastric tonometry and calculation of the venous‐arterial CO 2 gap . NIRS is a validated tool to explore tissue oxygenation in cardiac surgery and has been evaluated in a few studies . We confirm that the ‘dynamic’ recovery slope of StO 2 transiently dropped just after CPB and returned to baseline value early in postoperative period.…”

“…By contrast, the ‘static’ StO 2 value, albeit decreased 2–6 h post‐CPB, stayed in the normal range i.e. above 75%, as underlined by other authors . This threshold has been determined in trauma patients as a predictor of organ dysfunction occurrence .…”

“…In cardiac surgery, few studies have correlated microcirculatory alterations and outcomes. A study showed that parameters derived from VOT were associated with survival, but their statistical analysis included pooled data from different time points, thus compromising the interpretation of their results . The statistics used here (i.e.…”

“…Reactive hyperaemia can be assessed with NIRS technology by interrogation of the recovery slope. Few studies have been carried out using NIRS parameters in cardiac surgery, and none of them examined both the baseline StO 2 and recovery slope during and after surgery.…”

The effect of hydroxyethyl starch 6% 130/0.4 compared with gelatin on microvascular reactivity

“…Subsequent reperfusion favours opening of previously closed capillaries (recruitment) and increases blood flow in previously patent capillaries. The capability of the microcirculation to recruit the microvascular network can be used as a surrogate for microvascular integrity .…”