W3 Acid Base (Bill) Flashcards
Acid mnemonic
Respiratory = opposite
Metabolic = equal
Respiratory acidosis
Which electrolyte imbalance will you see?
How will the patient present?
Caused by ALVEOLAR HYPOVENTILATION
Lungs fail to expel CO2 and it accumulates in blood
CO2 reacts with H2O to form carbonic acid which dissociates into H+ and HCO3-
The increased H+ leads to a drop in PH and ACIDOSIS
Causes a lot of arterial dilation — BP drops
Low cardiac output — decreased squeeze, low peripheral resistance
These patients are “shock like” — give vasopressin, if it’s not working, the patient is acidosis, they don’t respond.
Have to correct the acidosis before the medication will work
Hyperkalemia — Why? H+ moves from Extracellular into intercellular, pushed K+ out of the cell. Causes hyperkalemia.
Muscle weakness, myoclonus.
Venous blood gas: check for pH
Arterial: CO2 and bicarb levels
What causes hypoventilation?
AIRWAY OBSTRUCTION: bronchitis, emphysema, bronchospasm
PULMONARY DISEASE (impaired gas exchange): fibrosis, PNA
RESPIRATORY DEPRESSION: anesthesia, sedatives, cerebral trauma
EXTRAPULMONARY THORACIC DISEASE: kyphosis, scoliosis, flail chest,
obesity
NEUROLOGIC DISEASE: polio
Respiratory alkalosis
Caused by?
Loss of _____ from the body
Leads to decrease of _____
Forces the kidneys to compensate and decrease _____
Caused by ALVEOLAR HYPERVENTILATION
-Excess loss of CO2 from body
-Leads to decreased formation of carbonic acid and decreased release of H+
-This increases the pH forcing the kidneys to compensate by decreasing HCO3-
Causes of increased respiratory drive: NORMAL COMPENSATORY RESPONSE:
1. ⭐️Hypoxia⭐️
a. PE
b. High altitude
c. Anemia
ABNORMAL COMPENSATORY RESPONSE
2. Anxiety
3. Salicylate Overdose
4. Brain Tumor
Some causes of respiratory alkalosis
P: panic attack A: anxiety S: salicylate overdose T: tumor P: pulmonary embolism H: hypoxia/high altitude
Respiratory alkalosis symptoms
—seizures
—low or normal BP, usually fine
—HYPOkalemia
—numbness and tingling
Metabolic acidosis
What is this?
How does the body compensate?
Caused the excess accumulation of organic acids in the body
-Increased production or ingestion
-Unable to eliminate the acid
-Excess HCO3- loss from the kidneys or GI tract
Leads to decreased HCO3- in blood (< 20 meq/L) and the pH falls < 7.35
The body hyperventilates to eliminate CO2 (compensatory)
How do you calculate the anion gap
What is high?
What is normal?
Sodium - chloride - CO2/HCO3
High is >12 mEq/L
Normal is <12
High anion gap : Excess H+
What is the mnemonic
*1. Increased Organic Acid Production:**
a. LACTIC ACIDOSIS: decreased oxygen delivery to tissues causes increased anaerobic metabolism and increased lactic acid
b. DIABETIC KETOACIDOSIS: lack of insulin causes cells to use fats as energy (instead of glucose) and the breakdown of fats produces keto acids
2. Failure of kidney to excrete organic acids:
a. Chronic Renal Failure: buildup of uric acids (uremia)
3. Ingestion:
a. Oxalic acid from ethylene glycol (anti-freeze)
b. Formic acid from methanol
c. Salicylate overdose
d. Paraldehyde (anti-epilepsy, old med)
4. Increased anaerobic metabolism and lactic acid production
a. Propylene glycol (paint)
b. Iron or Isoniazid overdose
What does MUD PILES stand for?
Metabolic acidosis and normal anion gap?
3 causes
DECREASED HCO3- OFFSET BY INCREASED OR BUILDUP OF CHLORIDE ION TO MAINTAIN THE ANION GAP Causes:
1. SEVERE DIARRHEA:
—intestinal secretions pass through GI tract prior to reabsorption
2. RENAL TUBULAR ACIDOSIS:
a. Type II: proximal convoluted tubule can’t reabsorb HCO3- and the pH decreases b. Other types of RTA: inability to excrete H+ in the urine
3. ADDISON’S DISEASE:
—don’t produce enough steroid hormones including
aldosterone.
—Aldosterone typically causes the distal collecting duct to secrete H+ ions and reabsorb Na.
When insufficient, retain H+ in blood.
a. Spironolactone: blocks aldosterone receptor
4. ACETAZOLAMIDE: decrease HCO3- reabsorption in the proximal trouble causing HCO3- wasting
5. TOTAL PARENTERAL NUTRITION: accumulation of H+ ions
6. SALINE INFUSION: IV saline has a pH of 5.5 therefore can get an accumulation of H+ ions
Normal anion gap mnemonic
HARD-ASS
Hyperalimentation
Addison’s disease
Renal tubular acidosis
Diarrhea
Acetazolamide
Spironolactone
Saline infusion
Metabolic acidosis
—headache
—decreased BP
—hyperkalemia
—warm, flushes kin,
—NVD
—changes in LOC
—kussmaul respirations
Metabolic alkalosis
Caused by:
1. Loss of excess H+ (by GI tract or kidneys) resulting in
increased HCO3- production
- Increased HCO3 Overall, the increased HCO3- increases pH and causes alkalosis
LOSS OF H+ IONS
1. From the GI tract: vomiting causes loss of stomach acid (H+ ions)
2. From the Kidneys (urine)
a. Conn’s Syndrome/Hyperaldosteronism: Aldosterone causes the sodium retention, the excretion of H+ ions into the urine, and reabsorption of HCO3-. This makes
the urine more acidic and the blood more alkaline.
INCREASED HCO3-
3. Volume contraction or contraction alkalosis: from loop diuretics
4. Ingested: antacids
Causes of metabolic alkalosis
LAVA
Loop diuretics
Antacids
Vomiting
Aldosterone increase
Know this summary of metabolic issues
Potassium in alkalosis
Potassium in acidosis
Hypokalemia
Decreased extracellular potassium causes myocardial hyperexcitability with the potential to develop reentrant arrhythmias
Can cause VT
Hypokalemia creates the illusion that the T wave is “pushed down” with resultant T wave flattening (or inverting), ST depression, and prominent U wave.
Can go into torsades
Summary of hypo and hyper kalemia
