title: Use of tissue microdialysis to investigate hyperlactataemia following paediatric cardiac surgery.
abstract: We investigated tissue lactate, pyruvate and lactate:pyruvate (LP) ratio post cardiac surgery and the relationship of cardiac index and oxygen delivery to late onset hyperlactataemia in ICU. It involved a prospective study of 10 children, mean age 4.9 (0.4) years, post-Fontan operation admitted with normo-lactataemia. Tissue lactate, pyruvate and LP ratio were monitored postoperatively every 30 min for 12 h via subcutaneous microdialysis in the abdominal wall. Cardiac index was measured by PiCCO at 0, 4, 8 and 12 h. Blood and subcutaneous tissue lactate were strongly correlated (r=0.87; P=0.001). Mean (S.D.) blood lactate rose from 2.23 (0.49) to 3.73 (1.16) mmol l(-1) in the first 5 h after ICU admission (P=0.008), only one child remaining normal. Microdialysis revealed lactate rising from 3.8 (0.83) to 5.3 (1.6) (P=0.011), with a parallel pyruvate rise. LP ratio remained below 20, indicating no tissue oxygen debt. Cardiac index increased from 2.83 (0.63) to 3.77 (1.34) l min(-1) m(-2) over the same period (P=0.05), with a corresponding increase in oxygen delivery from 4556 (1094) to 6076 (2322) ml min(-1) (P=0.04). Tissue microdialysis provides near-continuous measurement of tissue lactate and pyruvate, post cardiac surgery. Blood lactate rise post-Fontan is mirrored by tissue lactate and pyruvate concentrations, and not associated with a low or falling cardiac index or with tissue oxygen debt.
authors: Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Steelhouse Lane, Birmingham, B4 6NH, UK.
authors: Riad B M
authors: RB
authors: Hosein
authors: Kevin P
authors: KP
authors: Morris
authors: William J
authors: WJ
authors: Brawn
authors: David J
authors: DJ
authors: Barron
mesh_terms: D034861:Abdominal Wall; D000140:Acidosis, Lactic / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D015415:Biomarkers / Q000378:metabolism; D002675:Child, Preschool; D004837:Epinephrine / Q000097:blood; D005240:Feasibility Studies; D018729:Fontan Procedure / Q000009:adverse effects*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D019344:Lactic Acid / Q000097:blood / Q000378:metabolism*; D017551:Microdialysis; D009638:Norepinephrine / Q000097:blood; D010101:Oxygen Consumption; D011446:Prospective Studies; D019289:Pyruvic Acid / Q000097:blood / Q000378:metabolism*; D012107:Research Design; D040521:Subcutaneous Tissue / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation; D016276:Ventricular Function
chemical_list: D015415:Biomarkers; D019344:Lactic Acid; D019289:Pyruvic Acid; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine