Acid/Base Disorders Flashcards
What is seen in Renal Failure?
Increase in phosphate, sulfate, and organic anions
What is the most common non-anion gap?
Hyperchloremic
Is resp compensation fast or slow?
Fast, metabolic is slow
What is the 4 step algorithm for Acid Base disorders?
1) Classify Primary Disturbance
2) Compensation
3) Calculate Anion Gap
4) High AG – Calculate Potential Bicarb
What is the winter’s formula and what do you use it for?
pCO2=1.5*HCO3 + 8 +/- 2
- Use in primary metabolic acidosis
What is the formula to calculate primary metabolic alkalosis?
pCO2=0.8*changeHCO3 + 40
What is the rule for primary respiratory acidosis
Up 1 (acute) Up 3 (chronic)
What is the rule for primary respiratory alkalosis?
Down 10, Decrease 2 (acute) or 4 (chronic)
If high anion gap how do you calculate potential bicarb?
Potential HCO3=HCO3 + ^AG
What is have metabolic alkalosis that is saline/chloride Unresponsive. Ucl >20
Hyperaldosteronism
What labs to get in acid/base disorder?
Electrolyte panel
ABGs
- HCO3 from BMP and ABG should be within 2 (if not doesn’t work)
What if pCO2 is higher than expected in expected CO2 for metabolic acidosis?
Secondary respiratory acidosis
If metabolic Alkalosis present check saline responsiveness?
Saline-responsive Urine Cl
Calculate the anion gap?
Na-(Cl+HCO3)
Anion gap = unmeasured anions- unmeasured cations
- High: Decrease in HCO3, increased in unmeasured anions
What happens if there is a low albumin?
Corrected AG = (2.5-3)(changeAlbumin) - Expected AG= albumin2.5-3
Assume 4 if none is given
If high AG calculate potential Bicarb
Potential HCO3: HCO3 + (delta AG)
Calculate the Osmolar Gap?
Unmeasured plasma osmolality - calculated plasma osmolality
Gap: Measured plasma osm - calculated plasma osm
Normal: 5-10
What is MUDPILES?
AG meta acidosis M: Methanol U: Uremia D: DKA P: Propylene glycol I: Iron/INH L: Lacate E: Ethylene glycol S: Salicylates/Aceta
Is the AG isopropyl alcohol normal or abnormal?
The AG is NL
Non-AG metabolic is HARDASS?
H: Hyperalimentation A: Addison Disease R: Renal Tubular D: Diarrhea A: Acetazolamide S: Spironolactone S: Saline infusion (low aldosterone)
WHat are some other Non-Anion gap?
Ingestion: Sevelamer, toluene, cholestyramine
- Early Renal Failure
- Fistulas (pancreatic fistula, uretosigmoid fistula
- Post-hypocapnea
What is urine anion gap?
(Na + K) - (Cl): Renal NH4 excretion x (-1)
What if you have a positive UAG?
Low NH4 excretion
DDx: RTA (distal, hypoaldosteronism), early renal failure
What if you have a negative UAG?
High NH4 excretion
DDx: Vomiting, (RTA prox), ingestions, dilutional
What is type 2 RTA?
Decreased PROXIMAL reabsorption of HCO3
- Fanconi Syndrome
- Paraprotein
- Meds (acetazolamide, heavy metals, ifosfamide, NRTIs
- Renal Transplant
- Low vit D
Acidosis: Moderate
UAG: +/-
UpH: 15%
K serum: Low
What is type 1 RTA?
Distal type Defective distal H+ secretion - Autoimmune - Nephrocalcinosis - Meds (ampho, Li, ifosfamide) - Increased K: SCD, Obstruction, SLE, Renal transplant Acidosis: Severe UAG: Positive UpH: >5.3 FeHCO3:
What is type 4 RTA?
Hypoaldosteronism
Low aldo: High K: Low NH3 synthesis/delivery: Decreased urine carrying capacity
- Low renin: Diabetic nephropathy, NSAIDS, chronic interstitial nephritis, HIV
- Norm Renin, Low aldo: Primary aldo disorders, ACEI, ARBs, Hep
- Low aldo response: Meds (k-sparing diuretics, TMP-SMX, pentamidine, calcineurin inh,
- Tubulointerstitial disease (sickle cell, SLE, diabetes)
Acidosis: Mild
UAG: Positive
UpH:
What are some Saline Responsive metabolic alkalosis?
Vomiting, NGT, Prior Loop diuretics, Hypovolemia, Post-Hypercapnia
What are some Saline Resistant alkalosis?
Hyperaldosteronism (HTN, hypokalemia)
- Antacids
- Hypokalemia
- Current Loop Diuretics (exception euvolemic)
