Lactic Acidosis Evaluation
CAUSES
Simple approach
- increased lactate production (including enhanced pyruvate production, reduced pyruvate conversion to CO2 & water or glucose, or preferential conversion of pyruvate to lactate)
- diminished lactate utilisation
Cohen & Woods classification
Type A – Inadequate Oxygen Delivery
- anaerobic muscular activity (sprinting, generalised convulsions)
- tissue hypoperfusion (shock, cardiac arrest, regional hypoperfusion -> mesenteric ischaemia)
- reduced tissue oxygen delivery (hypoxaemia, anaemia) or utilisation (CO poisoning)
Type B – No Evidence of Inadequate Tissue Oxygen Delivery
- B1: associated with underlying diseases
- LUKE: leukaemia, lymphoma
- TIPS: thiamine deficiency, infection, pancreatitis, short bowel syndrome
- FAILURES: hepatic, renal, diabetic failures
- B2: associated with drugs & toxins
- phenformin
- cyanide
- beta-agonists
- methanol
- adrenaline
- salicylates
- nitroprusside infusion
- ethanol intoxication in chronic alcoholics
- anti-retroviral drugs
- paracetamol
- salbutamol
- biguanides
- fructose
- sorbitol
- xylitol
- isoniazid
- congenital forms of lactic acidosis with various enzyme defects (eg pyruvate dehydrogenase deficiency)
- B3: associated with inborn errors of metabolism
MOST COMMON IN THE CRITICALLY ILL
- tissue hypoperfusion [Type A] (resulting in increased production and decreased utilisation)
- decreased utilisation due to liver disease (especially with use of lactate containing fluids in renal replacement therapy)
OTHER CAUSES IN ICU
- seizures
- beta-2-adrenergic agonists (eg. adrenaline and salbutamol)
- metformin (uncertain mechanism)
- post-cardiac surgery
- short bowel syndrome
MANAGEMENT
- correcting hypoperfusion (fluids, inotropes, vasopressors)
- correction of underlying disorder (treat seizures, shivering, glucose abnormalities, etc.)
- removal of offending drugs (including metformin, adrenaline, renal replacement fluid)
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC