The inflammatory cytokine response after autotransfusion of shed mediastinal blood

The inflammatory response in patients undergoing cardiac surgery with cardiopulmonary bypass is well known and increased levels of inflammatory cytokines have been shown. High levels of cytokines have been reported in blood drained from the surgical field. The present study aimed to elucidate whether autotransfusion of shed mediastinal blood in itself causes increased cytokine levels in coronary artery bypass graft (CABG) patients.

A prospective, randomized controlled study was performed in 23 patients having elective uncomplicated CABG. Autotransfusion of shed mediastinal blood was done every hour for 18 h in group I. In group II, the shed mediastinal blood was accumulated for 4 h in the cardiotomy reservoir and then autotransfused every hour for the next 14 h. Plasma levels of tumour necrosis factor-alpha (TNFalpha) and interleukin (IL)-1alpha, IL-1beta, IL-6 were measured. In vitro study of cytokine production was performed with or without stimulation (phytohaemagglutinin (PHA) and Escherichia coli (E. coli) lipopolysaccharide (LPS)).

We found high levels of IL-6 in the shed mediastinal blood. However, autotransfusion of shed mediastinal blood did not lead to increased level of cytokines (TNFalpha, IL-1alpha, IL-1beta and IL-6) in plasma in group I nor in group II. In vitro study showed activation of the leucocytes in the shed mediastinal blood with a significantly increased production of TNFalpha and IL-6 both in the stimulated and non-stimulated samples.

Shed mediastinal blood contains high levels of IL-6. However, autotransfusion of shed mediastinal does not cause measurable elevations in plasma levels of IL-6. In vitro study shows that autotransfusion activates leucocytes, which may enhance production of inflammatory cytokines.