Related Experiment Video
Updated: Jul 6, 2026
Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue
Published on: June 21, 2018
Use of tissue microdialysis to investigate hyperlactataemia following paediatric cardiac surgery
Riad B M Hosein1, Kevin P Morris, William J Brawn
1Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Steelhouse Lane, Birmingham, B4 6NH, UK.
Insights
Post-cardiac surgery in children, blood lactate levels rise but do not indicate tissue oxygen debt. Tissue microdialysis effectively monitors lactate and pyruvate, showing no correlation with low cardiac index.
Area of Science:
- Biomedical Engineering
- Critical Care Medicine
- Pediatric Cardiology
Background:
- Post-cardiac surgery, particularly after the Fontan operation, children may develop hyperlactataemia.
- Monitoring tissue metabolism is crucial for understanding and managing post-operative complications.
Purpose of the Study:
- To investigate tissue lactate and pyruvate levels and the lactate:pyruvate ratio post-cardiac surgery in children.
- To explore the relationship between cardiac index, oxygen delivery, and late-onset hyperlactataemia in the intensive care unit (ICU).
Main Methods:
- A prospective study of 10 children post-Fontan operation with normo-lactataemia.
- Subcutaneous microdialysis of the abdominal wall for near-continuous monitoring of tissue lactate and pyruvate every 30 minutes for 12 hours.
- Cardiac index (CI) measurement using PiCCO at set intervals (0, 4, 8, 12 hours).
Main Results:
- Strong correlation found between blood and subcutaneous tissue lactate (r=0.87; P=0.001).
- Both blood and tissue lactate and pyruvate levels increased post-operatively, with blood lactate rising significantly within 5 hours of ICU admission (P=0.008).
- Despite rising lactate, the lactate:pyruvate ratio remained below 20, indicating no significant tissue oxygen debt. Cardiac index and oxygen delivery increased post-operatively (P=0.05 and P=0.04, respectively).
Conclusions:
- Tissue microdialysis is a valuable tool for near-continuous monitoring of tissue metabolites post-cardiac surgery.
- Post-Fontan operation, elevated blood lactate in children is mirrored by tissue lactate and pyruvate changes but is not associated with impaired cardiac function or tissue oxygen debt.
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.
