CRITICAL CARE Effect of site of lactate infusion on regional lactate exchange in pigs

Key points † This study addresses the uptake of lactate after central venous or portal infusion in pigs. † Lactate metabolism is important for understanding the haemodynamics and regional blood flow of sepsis. † Lactate infused into the portal vein is removed mainly by the liver, whereas central venous infusion results in less uptake by the liver. Background. The rate of extra-hepatic lactate production and the route of influx of lactate to the liver may influence both hepatic and extra-hepatic lactate exchange. We assessed the dose–response of hepatic and extra-hepatic lactate exchange during portal and central venous lactate infusion. Methods. Eighteen pigs randomly received either portal (n1⁄45) or central venous (n1⁄47) lactate infusion or saline (n1⁄46). Sodium lactate was infused at 33, 66, 99, and 133 mmol kg min for 20 min each. Systemic and regional abdominal blood flows and plasma lactate were measured at 20 min intervals until 1 h post-infusion, and regional lactate exchange was calculated (area under lactate uptake–time curve).