Sublingual and muscular microcirculatory alterations after cardiac arrest: a pilot study

Post-cardiac arrest resuscitated patients often develop a "sepsis-like" syndrome, which may be associated with organ dysfunction. Impaired microcirculatory blood flow is thought to play a key role in sepsis-induced organ failure; however, few data are available on the microcirculation after cardiac arrest. We investigated microvascular density and reactivity in the early phase following cardiac arrest.

We prospectively evaluated the sublingual microcirculation in 10 patients admitted to the intensive care unit (ICU) after cardiac arrest using a Sidestream Dark Field device. Thenar oxygen saturation (StO(2)) was also measured using a tissue spectrometer and a vaso-occlusive test was performed by rapid inflation of a pneumatic cuff around the arm to evaluate the StO(2) reperfusion rate, reflecting microvascular reactivity. In all patients, measurements were performed within the first 12h after admission (T1) and 24-48 h thereafter (T2).

There was a significant increase in functional capillary density (FCD, 7.2 ± 1.9-10.0 ± 1.4N/mm, p = 0.001), in the proportion of small perfused vessels (PSPV, 76 ± 13-92 ± 3%, p = 0.004) and in the mean microvascular flow index (MFI, 2.1 ± 0.5-2.8 ± 0.2, p = 0.003) at T2 compared to T1. FCD and PSPV were significantly correlated to body temperature, but not to cardiac output or mean arterial pressure. The StO(2) reperfusion rate did not change over the study period and showed considerable inter-individual variability.

The early post-resuscitation phase is characterised by significant abnormalities in microvascular density and flow, which return to normal within 48 h after cardiac arrest. These changes may be influenced by body temperature. Microvascular reactivity is impaired after cardiac arrest.