<unk> d on a stepwise approach taught about by Dr. Weingart<unk> d on the Stewart's Strong Ion Difference
If pH >7.45 then patient's primary problem is alkalosis
If pH <7.35 the patient's primary problem is acidosis
The body never over-corrects any<unk> 
If pCO2 >45 then respiratory acidosis
If pCO2 <35 respiratory alkalosis
SID = Na - Cl
Low SID is <38 and indicates a strong ion acidosis = hyperchloremic acidosis = non-gap acidosis and causes include
Fluid administration
Any fluid that has SID of <24 can cause acidosis (e.g. NS, 1/2NS, D5W)
Renal tubular acidosis
Calculate Urine Anion Gap: (Urine Na + K – Cl); if negative, not RTA
Type I: Urine pH <5.55
Type II: Urine pH >5.55
Type IV: Hyperkalemic; from aldosterone deficiency, diabetes
Diarrhea
High SID is >38 and indicates a metabolic alkalosis and causes include:
Nasogastric suction
Diuretics
Hyperaldosteronism
Volume depletion
Fluid administration
Any fluid that has SID of <24 can cause acidosis (e.g. NS, 1/2NS, D5W)
Renal tubular acidosis
Calculate Urine Anion Gap: (Urine Na + K – Cl); if negative, not RTA
Type I: Urine pH <5.55
Type II: Urine pH >5.55
Type IV: Hyperkalemic; from aldosterone deficiency, diabetes
Diarrhea
Any fluid that has SID of <24 can cause acidosis (e.g. NS, 1/2NS, D5W)
Calculate Urine Anion Gap: (Urine Na + K – Cl); if negative, not RTA
Nasogastric suction
Diuretics
Hyperaldosteronism
Volume depletion
If >2 then the patient has hyperlactatemia
If >4 and the patient has an infection they should be considered  Severe Sepsis
Always consider the differential for a Lactic Acidosis (Lactate)
Calculate the strong ion gap (SIG) to explain the<unk>  deficit
SIG = <unk>  Deficit) + (SID – 38) + 2.5 (4.2 ‐ Albumin (g/dL)) – lactate
If SIG >2 this is a SIG metabolic acidosis = anion gap acidosis and the causes include:
Uremia
DKA
AKA
ASA
Ethylene Glycol, methanol, propylene glycol
Iron Toxicity
INH toxicity
Paraldehyde
Lactic Acidosis (from short gut/blind loop - will not show on lactate assay)
If SIG is negative (very rare) the differential includes:
Hypercalcemia
Hypermagnesemia
Hyperkalemia
Immunoglobulins
Bromide
Nitrates
Lithium
Uremia
DKA
AKA
ASA
Ethylene Glycol, methanol, propylene glycol
Iron Toxicity
INH toxicity
Paraldehyde
Lactic Acidosis (from short gut/blind loop - will not show on lactate assay)
Hypercalcemia
Hypermagnesemia
Hyperkalemia
Immunoglobulins
Bromide
Nitrates
Lithium
Indicated if have elevated SIG without explanation
Osm Gap = Measured Osmal – (2 Na + Gluc/18 + BUN/2.8 + ETOH/3.7)
Positive if osm gap >10 and differential includes:
Toxic alcohols (if Osm gap >50)
Methanol
Ethylene glycol
Mannitol
Isopropanol (isopropyl alcohol)
Propylene glycol
Lithium
Toxic alcohols (if Osm gap >50)
Methanol
Ethylene glycol
Mannitol
Isopropanol (isopropyl alcohol)
Propylene glycol
Lithium
Acid-base disorders
Metabolic acidosis
Ventilator high pressures
Metabolic alkalosis
Jet Propulsion Fuel 8 toxicity
Respiratory acidosis
Hypercapnia
Respiratory alkalosis