Acid-Base Physiology - The Stewart Approach
Channel: Liam Skoda
Date: 2024-01-28

This video outlines the revolutionary model formulated by Canadian physiologist Peter Stewart, also known as the physicochemical approach. Despite providing an elegant, unified theory of acid base physiology through the integration of simple physical and chemical relationships, it has often been ignored by medical schools, textbooks and device manufacturers.

Slides and animations were made in Microsoft PowerPoint 365, are my own work and free for reuse (suggest using 4K version). Content developed during preparation for College of Intensive Care Medicine (CICM) primary exam. 

References and Further Reading
Book links and analyser: http://www.acidbase.org/

Literature
Stewart 1978 - Independent and dependent variables of acid-base control 
https://doi.org/10.1016/0034-5687(78)90079-8

Constable 1997 - Simplified Strong Ion Model 
https://doi.org/10.1152/jappl.1997.83.1.297

Lloyd 2004 - Strong Ion Calculator 
https://doi.org/10.1016/S1441-2772(23)01698-8

Lloyd 2006 - Quantitative Acid-Base Analysis in the ICU 
https://doi.org/10.1016/S1441-2772(23)02200-7

Scott Weingart https://emcrit.org/
https://derangedphysiology.com/main/home

Chemistry
@ProfessorDaveExplains
Textbook: https://chem.libretexts.org/

Ningaloo Reef Photo taken by Elle Gillett, Coral Bay, Western Australia 25/04/23.

00:00:00 Start
00:00:45 Independent and dependent variables
00:02:42 Water
00:03:24 Dissociation Constants
00:07:00 Strong ion difference
00:14:23 Non-Volatile Weak Acids: Atot
00:20:35 Volatile Weak Acid: pCO2
00:32:54 Acidity and Electroneutrality in Acid-Base Disturbance
00:36:19 Fluid Composition and Strong Ion Difference
00:40:55 The Stewart Equation
00:43:40 The Constable Equation
00:45:34 Case 1: 65 year old with nausea and vomiting
00:52:58 Case 2: 43 year old with coma and renal failure
00:55:31 Case 3: 71 year old with neuroendocrine tumours and cardiac failure
00:56:49 Case 4: 25 year old with life-threatening asthma
00:57:42 Case 5: 36 year old with hypotension and failing renal transplant
01:02:16 acidbase.org online analysis tool
01:03:53 Lloyd Strong Ion Calculator
01:04:39 Summary
01:05:55 References and Further Reading
01:06:58 End