Acid/Base Meds Flashcards

1
Q

Respiratory Alkalosis Mnemonic

A

PAST PH

  • Panic attacks
  • Anxiety attacks
  • Salicylates
  • Tumors
  • Pulmonary embolism
  • Hypoxemia
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2
Q

Metabolic Alkalosis Mnemonic

A

LAVAlUP

  • Loop Diuretics ( Furosemide, Bumetanide, Torsemide)
  • Antacid use
  • Vomiting
  • Aldosterone increase (UP)
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3
Q

Respiratory Acidosis Mnemonic

A

AS A COW

  • Airway obstruction/Aminoglycosides/Anesthetics
  • Sedative Use
  • Acute lung disease
  • Chronic lung disease
  • opioids
  • Weakening of the respiratory muscles
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4
Q

UMetabolic Acidosis with Large anion Gap Mnemonic

A

MUD PILES

  • Methanol, metformin
  • Uremia
  • Diabetic ketoacidosis (or alcoholic ketoacidosis)
  • Paraldehyde, phenformin
  • Isoniazid, iron
  • Lactic acidosis
  • Ethylene glycol (antifreeze), ethanol
  • Salicylates
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5
Q

Metabolic Acidosis with Normal Anion Gap Mnemonic

A

USED CAR

  • Ureteral diversion
  • Saline infusion
  • Exogenous acid
  • Diarrhea
  • Carbonic anhydrase inhibitor (acetazolamide)
  • Adrenal insufficiency
  • Renal tubular acidosis
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6
Q

Treatment of Metabolic Acidosis

A

identify and tx underlying causes

  • NaHCO3- indicated when:
    • renal dysfunction→ not enough HCO3- is regenerated
    • Severe acidemia: pG <7.10
    • goal: increase HCO3- by 10mEq/L; and ph> 7.2
    • ½ of the amount is given over 3-4 hours; then remainder given over 8-24 hours
    • ****1mEq/kg/dose and monitor***
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7
Q

NaHCO3 IV

A

used to treat metabolic acidosis

  • can be used with loop diuretics to avoid too much fluid (fluid overload)
  • indicated when:
    • renal dysfunction → not enough HCO3- regenerated
    • severe acidemia: pH<7.10
    • ½ of the amount is given over 3-4 hours; then remainder given over 8-24 hours
  • one amp is 50mL (or 50mEq)
    • can give up to 3 amps + 1L D5W
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8
Q

Oral NaHCO3

A

used to tx metabolic acidosis

  • generally preferred with chronic metabolic acidosis
  • can be given as tab or powder
  • indicated when:
    • renal dysfunction → not enough HCO3- regenerated
    • severe acidemia: pH<7.10
    • ½ of the amount is given over 3-4 hours; then remainder given over 8-24 hours
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9
Q

K-citrate

A

used to tx metabolic acidosis

  • helpful when the acidosis is coupled with hypoK+
    • be cautious with renal impairment → needs to be avoided if pt has hyperK+ (can cause increased HyperK+)
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10
Q

Tx of Metabolic Alkalosis

A
  • pts rarely have symptoms due to alkalemia
    • sxs often related to volume depletion
      • muscle cramps
      • dizziness depending on position
      • HypoK+ → muscle weakness, polyuria, polydipsia
  • Tx: tx the underlying cause
    • i.e. meds, citrate containing products (K-citrate used to tx metabolic acidosis), or acetate in parenteral nutrition → causes HCO3- levels to rise
    • alkalosis caused by vomiting, NG suction, or diarrhea +/- urinary Cl- (<25mEq/L) → saline infusion
    • acetazolamide (carbonic anhydrase inhibitor) → reduces HCO3- concentration
    • ******Hemodialysis or HCl infusion for life-threatening metabolic alkalosis******
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11
Q

Tx of Respiratory Acidosis

A

represents ventilation failure or impaired control of ventilation

  • hypoxemia + hypercapnia
  • severe, acute respiratory acidosis =
    • HA, blurred vision, restlessness and anxiety, tremors, somnolence, and/or delirium
  • Tx = identify cause and tx that:
    • opiate/opioids → naloxone
    • acute bronchospasm/asthma → bronchodilators
    • assisted ventilation and mod-severe acidosis → BiPAP
    • NOTE: NaHCO3 may actually worsen acidemia due to increased CO2 generation so do NOT use this
  • Goals:
    • careful monitoring of pH
    • maintain oxygenation
    • improve alveolar ventilation
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12
Q

Tx of Respiratory Alkalosis

A

represents hyperventilation

  • sxs: irritability of central and peripheral nervous system
    • light headedness, altered consciousness, cramps, syncope
    • severe cases: HypoPhos shifts from ECF to ICF
  • tx: identify cause and tx accordingly
    • for mild-moderate severity in spontaneously breathing pts → no specific tx
    • severe alkalosis:
      • rebreathing
        • rebreathing mask, or paper bag
        • mechanical ventilation
        • high level sedation or paralysis is a good option
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13
Q

Change in Bicarbonate equations for acute respiratory acidosis vs alkalosis

A
  • Acute Respiratory Acidosis: (approx normal)
    • [change]HCO3- = 0.1 x [change]PaCO2
      • 10% of [change]PaCO2
  • Acute Respiratory Alkalosis: (approx normal)
    • [change]HCO3- = 0.2 x [change]PaCO2
      • 20% of [change]PaCO2
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14
Q

Change in Bicarbonate equations for chronic respiratory acidosis vs alkalosis

A
  • Chronic Respiratory Acidosis: (increased bicarb)
    • [change]HCO3- = 0.35x [change]PaCO2
      • 35% of [change]PaCO2
    • [change]HCO3- = 0.4 x [change]PaCO2
      • 40% of [change] PaCO2
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15
Q

Total Body Water

A
  • TBW = 60% of body weight
  • ⅓ is ECF
    • ¼ = plasma fluid
    • ¾ = interstitial fluid
  • ⅔ = ICF
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16
Q

Major Extracellular Ions

A

Na+, Cl-, HCO3-

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17
Q

Major Intracellular Ions

A

K+, Mg2+, PO42-, SO42-

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18
Q

Osmolality vs Osmolarity

A
  • osmolality = osmoles of solute per mass (kg) of solvent
  • Osmolarity = osmoles of solute per volume (L) of solvent → volume changes with temperature
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19
Q

Normal Plasma/Serum Osmolarity

A

275-290mOsmoles/L

  • 2 [Na] + [glucose]/18 + [BUN]/2.8 =osm/L
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20
Q

What do changes in plasma tonicity cause ADH to do?

A
  • Osmolarity >295 mOsm/L = max ADH release
  • osmolarity <280 mOsm/L = inhibits release of ADH
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21
Q

S/sxs of Volume Deficits

A
  • acute weight loss
  • decreased skin turgor
  • oliguria (production of small amounts of urine)
    • >100mL/day but <400mL/day
  • concentrated urine
  • tachycardia
  • prolonged cap refill
  • decreased BP
  • sensation of thirst, weakness, dizziness, muscle cramps
  • orthostatic hypotension
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22
Q

Labs associated with Volume Deficits

A
  • High Serum Osmolality
    • increased HCT, protein, electrolytes
  • Increased BUN: Scr
    • usually >20:1
  • Increased Urine Osmolality
    • yellow urine
23
Q

Causes of Volume Deficits

A
  • Lack of intake
  • GI losses: diarrhea/vomiting
  • excess sweating due to exercise/fever
  • burns
  • diabetes insipidus
  • uncontrolled DM
24
Q

Crystalloid Solutions (Therapeutic Fluids)

A
  • Normal Saline (NS), Lactated Ringer’s Solution (LR), Dextrose 5% (D5W, ½NS
25
Q

Colloidal Solutions (Therapeutic Fluids)

A
  • albumin
  • hetastarch and dextran
  • FFP (fresh frozen plasma)
26
Q

Normal Saline (0.9% NaCl)

A

isotonic

  • crystalloid solution
  • primarily used to replace ECF
    • used to maintain BP
      • osmolarity = 208 mOsm/L
        • 154mmol/L Na+ plus 154mmol/L Cl-
  • 1000 L infusion = 250 mL in the intravascular space (b/c it remains in the ECF, and ¼ → intravascular, and ¾ → interstitial space)
27
Q

Dextrose 5%

A

hypotonic → acts as “free water”

  • crystalloid solution
  • osmolarity = 250 mOsm/L
  • not used to raise BP
  • distributes via normal body water distribution (⅔ to ICF, ⅓ to ECF)
    • 1000L infusion = 333mL → ECF
      • ¼ → intravascular space = 83mLs
        • does NOT affect BP
28
Q

Lactate Ringer

A

Crystalloid solution

  • contains Na+, K+, Cl- and lactate (buffer to increase pH) →similar to blood composition
  • used to replace ECF
  • osmolarity = 274 mOsm/L
  • commonly used in:
    • acidosis
    • alkalosis
    • burn/trauma patients
29
Q

3% NS

A

3%Normal Saline

  • crystalloid solution
  • hypertonic
  • used to acutely lower intracranial pressure in TBIs
  • osmolarity = 1,025mOsm/L
30
Q

Albumin 5% or 25%

A

colloid solution used to increase plasma oncotic pressure

  • plasma volume expansion
  • 5% = for volume expansion → 1:1 expansion 25mL infusion = 25mL expansion
  • 25% = when fluid intake needs to be minimized or oncotic pressure needs to be raised → 5:1 expansion of volume
    • 25mL infusion = 125mL expansion
31
Q

Fluid Maintenance Requirements

A
  • Neonates: 1-10kg = 100ml/kg
  • Children: 10-20kg = 1L for the first 10 kg + 50mL/kg for the 2nd 10kg
  • Adults: >20 kg = 1.5L for the first 20kg + 20mL/kg for anything above 20kg Then add normal insensible losses ** (see below)
    • e.g. adult weighing 70 kg = 1.5L + 50kg(20mL/kg) = 2.5L + 1L (insensible losses)
  • Normal Insensible Losses for avg adult:
    • lungs 400mL/day
    • skin 400 mL/day
    • feces 100mL/day
    • total = ~1L /day
32
Q

General Tx strategy for severe volume depletion or hypovolemic shock

A
  • at least 1-2 L of NS as rapidly as possible (bolus)
    • restores tissue perfusion
    • fluid replacement is continued at rapid rate until clinical signs of hypovolemia improve
33
Q

General Tx Strategy for mild/moderate hypovolemia

A
  • rate of fluid admin > rate of continued fluid losses
  • *******REVIEW THIS********
  • caution in: renal failure, cardiac failure, hepatic failure, elderly
34
Q

0.45% NaCl

A

Hypotonic

  • if you infuse 1000mL:
    • 500 mL with act as NS (ECF only)
      • ¼ of 500mL → intravascular space = 125 mL
    • 500 mL will act as free water
      • ⅓ of 500mL in ICF = 166mL
        • ¼ of 166mL in intravascular space = 41.5mL
    • 125 mL + 41.5 mL = 166.5 mL
35
Q

Types of Hyponatremia

A
  • Na+ <135
  • Hypertonic hyponatremia (Osmolarity >300 mOsm/L)
  • Hypotonic Hyponatremia (i.e. dilutional→ <275 mOsm/L)
    • hypervolemic
      • gain of both water and sodium
        • water >>>>> sodium
    • euvolemic
      • gain of water (ECF volume is normal)
        • total body water >>>>normal total Na+
    • hypovolemic
      • loss of both water and sodium
        • sodium >>>>>water
36
Q

Hypertonic Hyponatremia

A

osmolarity > 300 mOsm/L

associated with severe hyperglycemia

60mg/dL of Glc >200 = 1mEq/L reduction of Na+

tx: Tx the hyperglycemia → insulin

37
Q

Hypervolemic Hyponatremia

A

Hypotonic hyponatremia (osmolarity <275 mOsm/L)

  • body gains excess Na+ and Water
    • but Water >>>>>Na+
    • Causes: HF, cirrhosis, nephrotic syndrome
  • tx: Fluid & Na+ restriction (i.e. 2 gm/day)
    • optimize the underlying disease state
    • diuretics
    • increase the intravascular oncotic pressure (albumin)
      • pulls fluid of out intracellular compartment
38
Q

Euvolemic Hyponatremia

A

aka isovolemic hyponatremia

hypotonic hyponatremia (osmolarity <275 mOsm/L)

ECF volume is normal

  • have excess water → total body water >>>>normal total Na+
    • water intoxication
  • causes: SiADH (too much ADH secreted), Polydipsia, decreased water secretion
    • carcinomas (small cell lung cancer)
    • CNS disorders → stroke, meningitis, trauma
    • medications: SSRIs, NSAIDs, antipsychotics, sulfonylureas
  • Tx:
    • Non-acute (Na >115mEq/L and asymptomatic:
      • fluid restriction, possible chronic therapy
    • Acute (Na <115 mEq/L and/or sxs):
      • 3% NaCl infusion
        • +/- diuretics to correct fluid accumulations
      • fluid restriction → 1000-1200mL/day
    • ******no more than 12 mEq/L/24 hours (0.5mEq/hour)******
      • can cause osmotic demyelination syndrome → myelin cells swell/shrink and die
39
Q

Chronic Therapy for Euvolemic Hyponatremia

A
  • in addition to fluid restriction/salt tabs
  • demeclocycline (tetracycline)
    • blocks arginine vasopressin (ADH) from binding to its receptors → less aquaporin insertion → less reabsorption of water
  • vaptans”
    • vasopressin = ADH receptor antagonist
      • conivaptan → IV formulation
      • tolvaptan → PO formulation
40
Q

Hypovolemic Hyponatremia

A

hypotonic hyponatremia (osmolarity <275 mOsm/L)

decreased ECF volume

  • decrease in both Na+ and Water
    • deficit of Na+ >>>>> deficit of water
  • Causes:
    • diuretics (thiazides), diarrhea, vomiting, NG suction
  • Treatment: NS @ 300ml/hr until improvement in symptoms
  • *****DO NOT CORRECT SODIUM LEVELS >12mEQ/L/24 HOURS******
41
Q

Types of Hypernatremia

A
  • Hypernatremia = >145 Na+
  • Hypovolemic Hypernatremia
    • loss of water >>>>> sodium
  • Isovolemic Hypernatremia
    • water loss only
  • Hypervolemic Hypernatremia
    • body has excess sodium and water
      • sodium >>>>>>water
42
Q

Hypernatremia General S/sxs and Causes

A
  • S/sxs: polyuria, polydipsia, confusion, obtundation, stupor, tremor, rigidity, coma
  • causes (free water deficit):
    • dehydration
    • incapable of obtaining water
    • fever/infx/sweating/burn pts
    • diabetes insipidus
    • hyperglyuria/osmotic diuretics
    • excessive sodium intake & cushing sx
43
Q

Hypovolemic Hypernatremia

A
  • when water loss >>>sodium loss
    • causes: diarrhea, sweating, diuretics
    • tx: d/c diuretics or laxatives
      • if symptomatic: initially 200-300ml/hr with NS (to achieve hemodynamic stability)
        • replace free water deficit: D5W, ½ NS or a combo
      • asymptomatic: D52, ½ NS, or a combo
44
Q

Isovolemic Hypernatremia

A

aka euvolemic hypernatremia

water loss only

  • causes:
    • Diabetes insipidus:
      • central DI = decreased ADH production
      • Nephrogenic DI = decreased renal response to ADH
      • drug induced DI:
        • aminoglycosides, Ampho B, cochicine, demeclocycline (used to tx chronic euvolemic hyponatremia)
  • Tx:
    • initially: D5W (replace free water)
    • chronically:
      • for central DI: desmopressin (DDVAP) b/c it is a synthetic analog to ADH → act on the V2-receptors of collecting duct → water reabsorption
      • for nephrogenic DI: NSAIDs [can cause euvolemic hyponatremia] (indomethacin, IBU, naproxen, diclofenac, ketoprofen) and thiazides
45
Q

NSAIDs and Sodium

A

NSAIDs reduce renal prostaglandins

and prostaglandins inhibit the action of ADH

so NSAID use can increase action of ADH and cause increased water reabsorption

46
Q

Desmopressin (DDVAP)

A

synthetic analogue of ADH

Act on V2-receptors at the collecting duct → reabsorption of water

used to tx central diabetes insipidus → the underlying pathophys behind isovolemic hypernatremia

47
Q

Hypervolemic Hypernatremia

A

body has excess sodium and water

sodium >>>> water

  • causes:
    • renal failure
  • Tx:
    • replace intravascular deficit if necessary (use D5W, ½ NS or a combo)
    • loop diuretics (if making urine) (increases sodium excretion)
    • hemodialysis
48
Q

Factors affecting K distribution

A
49
Q

Potassium Roles and Levels

A

Normal Serum 3.5-5 mEq/L

  • intracellular: for each 1 mEq decrease in serum K below 3.5, total body deficit = 100-400 mEq
  • Roles: maintain membrane potential
    • muscle contraction
    • nerve transmission
    • glycogen formation
    • protein synthesis
50
Q

Hypokalemia S/sxs and Causes

A
  • S/sxs: muscle weakness, decreased tendon reflex, myalgias, HTN EKG abnormalities, cardiac, arrhythmias, predisposition to digitalis toxicity
  • Causes:
    • inadequate intake
    • excessive loss: diarrhea, vomiting, NG suction
    • cellular shifting-DKA
    • refeeding syndrome
    • drugs
      • LAXATIVES, STEROIDS, AMPHO B, STEROIDS, ***LOOP DIURETICS***
51
Q

Hypokalemia Tx

A

When to tx? <3.5 mEq/L and/or pt is symptomatic

  • treatment:
    • oral: K-chloride, KPO4, K-acetate, K-citrate, k-gluconate
      • IV: if >10 mEq/L should be monitored via telemetry
    • other: diuretic induced (spironolactone- K+ sparing diuretic)
      • correct hypomagnesemia
        • ****low magnesium makes body resistant to K+ replacement, so tx mg deficiency first or concurrently*****
      • correct acid-base imbalance
52
Q

Hyperkalemia s/sxs and causes

A
  • S/sxs (Clinical Discovery):
    • >5.5mEq/L = peaking T waves, prolongation of PR
    • 7-8 mEq/L = prolonged QRS complex, Vfib
    • 8-10 mEq/L = complete heart block, asystole
  • Causes: massive tissue damage, blood stored for prolonged periods, salt substitute (KCl), Addison Disease
    • drugs:
      • K sparing diuretics (spironolactone, eplerenone), K supplements, Abx with K salts (Penicillin VK), ACE-I, ARBs, NSAIDs
53
Q

Hyperkalemia Tx

A
  • Symptomatic (urgent/emergent)
    • IV calcium to stabilize the heart membrane
    • insulin +/- glucose/dextrose to temporarily push K+ back into the cell
    • albuterol to also temporarily push K+ back into the cell
    • Sodium bicarb to be considered to tx acidosis
    • Eliminate Source: IV, total parenteral nutrition (TPN), tube feeds, oral supplements, K sparing diuretics
  • Symptomatic:
    • sodium polystyrene sulfonate (Kayexelate) → binds potassium, slower onset, but duration of 4-6 hours (constipation though…)
    • Loop diuretics (lasix)
  • Asymptomatic;
    • eliminate source
    • kayexelate (sodium polystyrene sulfonate) → binds potassium
    • loop diuretics
54
Q

Loop Diuretics

A
  • Bumetadine
  • Ethacrynic acid
  • Furosemide
  • Torsemide