Acid Base Disorders Flashcards
Normal anion gap
5-15 , normal approx 12
How do kidneys help when there is fixed acid in the blood?
Kidneys reabsorb more HCO3 to help turn the free H into CO2 that is formed and removed by lungs thereby maintaining pH
Acidosis vs alkalosis on O2 dissociation curve
acidosis - right shift (decreases affinity of hemoglobin -> increases O2 delivery to tissues)
alkalosis - left shift (increases affinity -> decreases O2 delivery to tissues)
What effects can acidosis and alkalosis both cause?
arrythmias
Effects of acidosis on body
decreased pulmonary blood flow arrythmias hyperkalemia (acid pulls K from cells) impairs myocardial function depresses CNS
Effects of alkalosis on body
arrythmias
tetany, seizures
decreases cerebral blood flow
causes of anion gap met acidosis
Methanol Uremia/kidney failure DKA Propylene glycol Isoniazid Lactic acidosis Ethylene glycol Salicylate OD (aspirin)
What kinds of things can cause ketoacidosis besides diabetes?
prolonged starvation or prolonged alcohol abuse (due to malnutrition)
What kinds of things can cause lactic acidosis?
low tissue perfusion, shock, excessive energy expenditure (strenuous exercise, seizures)
anything that that increases O2 demand
What acid base disturbances does salicylate overdose cause?
primary respiratory alkalosis AND primary metabolic acidosis
What causes normal AG acidosis (aka hyperchloremic metabolic acidosis)
- diarrhea (MCC)
- RTA (type 1 and type 2)
- carbonic anhydrase inhibitors (acetazolamide)
- pancreatic/small bowel fistulas
- ureterosigmoidostomy
What clinical features do you see in metabolic acidosis?
- hyperventilation/Kussmaul deep breathing to blow off CO2 for compensation
- decreased CO and tissue perfusion
Winter formula for respiratory compensation
1.5(HCO3) + 8 -> +/-2
if PCO2 falls within expected range -> acute compensated
if below expected range -> met acidosis + resp alkalosis
if higher than expecte range -> met acidosis + resp acidosis -> VERY BAD, (i.e. child with asthma is compensating by lowering pCO2 but then pCO2 becomes normal with no treatment…FUCK THIS IS BAD)
What two general events to consider in metabolic alkalosis
- event that starts met alk (loss of H via vomiting/gastric drainage, etc or increase of HCO3 concentration due to ECF contraction)
- event that maintains met alk (kidney can’t get rid of extra bicarb)
What other value to look at besides EBG and serum electrolytes in evaluating met alk?
URINE CHLORIDE!!!
(urine Cl<10) = saline sensitive
(urine Cl>20) = saline resistant