2021-11-22-noon-conf-acid-base-arroyo.md (1214B)
1 # Acid-base 2 3 JP Arroyo 4 5 H+ + HCO3- <---> H2O + CO2 ---> Vm 6 7 Minute ventilation is a key but often overlooked part of the equation, 8 need escape route for CO2. 9 10 sugar + O2 ---> ATP + CO2 + H2O <---> H+ + HCO3- ---> CO2 ---> lungs ---> the world 11 12 CO2 is a volatile acid, bc its H+ was donated. 13 14 Nonvolatile acids: H2SO4 (e.g. muscle breakdown), HCl 15 16 Kidney's roles in acid-base: 17 18 Circulating: HCO3- 24meQ/L 19 Acid production: 1 mEq H+/kg/day 20 21 Offset acid production by: 22 23 1. reabsorb HCO3- 24 2. make new HCO3- 25 3. excrete H+ 26 27 ## acid base interpretation 28 29 ABG HCO3- is trustworthy, need a concomitant BMP to assess true anion gap 30 31 1. internal consistency (ABG and BMP should be drawn close temporally, results w/in about 2mEq) 32 2. ?pH - <7.35 or >7.45 33 3. assess for primary disorder, (is the compensation appropriate)? 34 - most concerning/difficult/common in sick patients is metabolic acidosis 35 - metabolic acidosis: low HCO3- 36 - metabolic acidosis ---> increased Vm 37 - 1.5(HCO3-) + 8 +/- 2 = predicted CO2 38 4. AG (Na+ - (Cl- + HCO3-)) should be ~10 39 5. dAG + HCO3- (delta anion gap plus bicarb) 40 41 42 Practical: loaded ABG are ok, just don't directly compare the loaded ABG w the same time BMP (use one or the other as able)