acid base disorders Flashcards
normal acid base homeostasis: what is normal and what is it maintained by
-pH 7.35 – 7.45
-know- 7.4 is normal
-Critical for maintaining cellular activity
-you can have disorder with a normal pH
Maintained by:
-Cellular/tissue buffering capabilities
-Pulmonary mechanisms
-Renal mechanisms
normal acid base homeostasis respiratory mechanisms
-Regulation of CO2
-Nervous system regulates respiratory rate
-independent of O2
-Hypercapnia(too much CO2 in blood)-Typically caused by hypoventilation
-Hypocapnia(too little CO2 in blood)-Typically caused by hyperventilation
-Bicarbonate is the key in the system
normal acid base homeostasis renal mechanism
-Regulates plasma bicarbonate(HCO3-)
-Reabsorption of filtered bicarb
-Formation of titratable acid
-Normally phosphate related
-Ketoacids and creatinine can contribute
-Excretion of NH4+ in urine
acid (H+) addition to the system
-Ingestion of Proteins and Fats
-Metabolic processes
-Aerobic metabolism of glucose
-Anaerobic metabolism of glucose (to lactic acid)
-Oxidative metabolism of amino acids
Metabolic Acid-Base Disorders can be defined by the plasma HCO3-:
<22 mEq/L = metabolic acidosis
>28 mEq/L = metabolic alkalosis
arterial blood gas procedure
-Identify the patient and explain the procedure
-Allen test
-Palpate the radial (or alternate) artery
-Clean the skin
-Insert the needle/syringe at a 40-60 degree angle
-Allow syringe to fill (don’t pull back) with 1cc
-Place specimen on ice and send to lab immediately
-Apply compression for 5 minutes +, then bandage
Respiratory Acid-Base Disorders can be defined by the PaCO2:
> 45 mmHg = respiratory acidosis
<35 mmHg = respiratory alkalosis
arterial blood error
-errors occur often with ABGs
-air bubble in syringe- O2 falsely high
-left too long for testing
-venous draw- less O2
mixed acid base disturbance
-When two or more primary disorders are present within one patient
-Different from a compensatory effect
-Typical case:
-Diabetic Ketoacidosis(metabolic acidosis) with Asthma exacerbation(respiratory acidosis)
metabolic acidosis: high anion gap
-Lactic Acidosis
-Ketoacidosis:
-DM
-EtOH
-Starvation
-Toxin
-Ethylene Glycol
-Methanol
-Salicylates
-Renal Failure
metabolic acidosis: non anion gap
-GI Bicarb loss
-Diarrhea
-Drugs(Ca, Mg)
-Renal cause
-RTA type 1 and 2
-Hyperkalemia
-Drugs
-Diuretics, ACE-I, ARB
-NSAIDS
-Cyclosporine
-Trimethroprim
-Pentamidine
drug induced acidosis
-Salicylates:
-aspirin OD- can also respiratory alkalosis (NOT compensatory) -> aspirin causes brain to increase respiration
-Gastric lavage
-NaBicarbonate IV = alkaline urine(pH>7.5) -> Consider acetazolamide if respiratory alkalosis
-Ethylene Gylcol (antifreeze) or Methanol:
-Thiamine and B6 supplementation
-Saline diuresis
-Ethanol IV to compete with enzymes
-Dialysis
metabolic alkalosis causes: exogenous and renal origin
Exogenous cause:
-Bicarb IV or PO
-Milk-alkali syndrome
-Gastric origin:
-Vomiting
-Gastric aspiration
-Villous adenoma
-Admin of Kayexalte + Aluminum
-Congenital
Renal origin:
-Diuretic
-Edema
-Post hypercapnia
-Recovery from acidosis
-PCN
-Mg or K deficincies
-Bartter or Gitelman
High renin levels:
-RAS
-HTN
-Renin tumor
Low renin:
-Primary aldosteronism
-Cushing Syndrome
-Licorice
-Liddle’s syndrome
metabolic alkalosis causes: high and low renin origin
High renin levels:
-RAS
-HTN
-Renin tumor
Low renin:
-Primary aldosteronism
-Cushing Syndrome
-Licorice
-Liddle’s syndrome
Exogenous cause:
-Bicarb IV or PO
-Milk-alkali syndrome
-Gastric origin:
-Vomiting
-Gastric aspiration
-Villous adenoma
-Admin of Kayexalte + Aluminum
-Congenital
Renal origin:
-Diuretic
-Edema
-Post hypercapnia
-Recovery from acidosis
-PCN
-Mg or K deficincies
-Bartter or Gitelman
respiratory acidosis causes
-Central
-Airway
-Parenchyma
-Neuromuscular
-Iatrogenic
