So, I often listen to podcasts and i'd like to incorporate them into my blog. I was listening to a great one by Dr. Jeffrey Guy (at http://www.burndoc.net) about lactic acidosis, which was recorded nov 11,19 2001. Now since I listened while driving, I didnt take notes, so lets see.. (this is more an exercise of my own personal retention rather than a complete synopsis)
The first thing is that elevated lactic acidosis most commonly is a reflection of decreased oxygen delivery. Lactic acidosis is a biomarker, thus the lactate itself is not the causative agent. Glucose is converted to pyruvate through glycolysis. The pyruvate is then broken down in the kreb cycle, the first enzyme being pyruvate deydrogenase ( I think). BUT if there is no oxygen to support the kreb cycle, then the pyruvate is converted to lactate. It also leads to a build up of lactate. It also produces much less ATP.
Lactate is removed from the body by the liver and kidneys (and a small part by heart and skeletal muscle) The liver uses the cori cycle to convert the lactate back to glucose (by gluconeogenesis). The kidneys also metabolize the lactate, specifically in the renal cortex[1] -(my first official footnote!). It can also be excreted if there is a whole lot of lactate.
Dr. Guy also mentions that you should not automatically avoid Ringer's Lactate for fluid replacement. There is not to much lactate in it to make a difference, and the solution is actually at a basic pH (6.6). If you hang Normal saline, although there is no lactate, the large amount of chloride that is in it can cause a hyperchloremic acidosis.
There are two basic types of lactic acidosis, type A and type B. A is through the decreased oxygen delivery/ increased oxygen demand. Type B is do to other diseases, medications, or inborn metabolic error. There is also a D-lactic acidosis, which is an increase in one of the lactate isomers.
Basically if you have a patient with lactic acidosis, concentrate more on the cuasative agent rather than getting the lactate level down.
There was a whole lot more Dr. Guy talked about, so you can check it out on Itunes (ICU rounds) or the website above.
(next time ill listen twice before blogging)
1-http://www.ncbi.nlm.nih.gov/pmc/articles/PMC137458/
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