Post-resuscitation intestinal microcirculation: its relationship with sublingual microcirculation and the severity of post-resuscitation syndrome

Abstract

Objective: Post-resuscitation syndrome has been recognized as one of the major causes of the poor outcomes of cardiopulmonary resuscitation. The aims of this study were to investigate the intestinal microcirculatory changes following cardiopulmonary resuscitation and relate those changes to sublingual microcirculation and the severity of post-resuscitation syndrome as measured by myocardial function and serum inflammatory cytokine levels.

Methods: Twenty-five rats were randomized into three groups: (1) short duration of cardiac arrest (n=10): ventricular fibrillation (VF) was untreated for 4 min prior to 6 min of cardiopulmonary resuscitation (CPR); (2) long duration of cardiac arrest (n=10): VF was untreated for 8 min followed by 8 min of CPR; (3) sham control group (n=5): a sham operation was performed without VF induction and CPR. Intestinal and sublingual microcirculatory blood flow was visualized by a sidestream dark-field (SDF) imaging device at baseline and 1, 2, 4, 6, 8 h post-resuscitation. Myocardial function was measured by echocardiography and serum cytokine levels (TNF-α and IL-6) were measured by enzyme-linked immunosorbent assay (ELISA).

Results: Both intestinal and sublingual microcirculatory blood flow decreased significantly with increasing duration of cardiac arrest and resuscitation. The decreases in intestinal microcirculatory blood flow were closely correlated with the reductions of sublingual microcirculatory blood flow (perfused small vessels density: r=0.772, p<0.01; microcirculatory flow index: r=0.821, p<0.01). The decreased microcirculatory blood flow was closely correlated with weakened myocardial function and elevated inflammatory cytokine levels.

Conclusions: The severity of post-resuscitation intestinal microcirculatory dysfunction is closely correlated with that of myocardial function and inflammatory cytokine levels. The measurement of sublingual microcirculation reflects changes of intestinal microcirculation and may therefore provide a new option for post-resuscitation monitoring.

Keywords: Inflammatory response; Intestine; Microcirculation; Post-resuscitation syndrome; Sublingual.