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 in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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