Mechanisms of lactate formation in states of shock. Information from muscle microdialysis

Abstract

Muscle microdialysis technique involves the insertion of a semi-permeable membrane continuously infused with dialysis solution. At the tissue level, the solutes present in the interstitium freely diffuse into the catheter according to their concentration gradient. At a very low perfusion flow rate (0.3 μl/min), the gradient between muscular interstitium and arterialized blood concentrations indicates whether muscle produces or utilizes a specific substrate. We have demonstrated that: 1) during septic shock but also during hypokinetic and hemorrhagic shocks, muscle produces lactate through an activation of Na⁺ K⁺ ATPase pump and; 2) in severe sepsis, muscle lactate production precedes the appearance of septic shock.