Acid/Base Meds Flashcards
1
Q
Respiratory Alkalosis Mnemonic
A
PAST PH
- Panic attacks
- Anxiety attacks
- Salicylates
- Tumors
- Pulmonary embolism
- Hypoxemia
2
Q
Metabolic Alkalosis Mnemonic
A
LAVAlUP
- Loop Diuretics ( Furosemide, Bumetanide, Torsemide)
- Antacid use
- Vomiting
- Aldosterone increase (UP)
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
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
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
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***
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
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
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+)
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
- sxs often related to volume depletion
-
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******
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
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
- rebreathing
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
- [change]HCO3- = 0.1 x [change]PaCO2
- Acute Respiratory Alkalosis: (approx normal)
- [change]HCO3- = 0.2 x [change]PaCO2
- 20% of [change]PaCO2
- [change]HCO3- = 0.2 x [change]PaCO2
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
- [change]HCO3- = 0.35x [change]PaCO2
15
Q
Total Body Water
A
- TBW = 60% of body weight
- ⅓ is ECF
- ¼ = plasma fluid
- ¾ = interstitial fluid
- ⅔ = ICF
16
Q
Major Extracellular Ions
A
Na+, Cl-, HCO3-
17
Q
Major Intracellular Ions
A
K+, Mg2+, PO42-, SO42-
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
19
Q
Normal Plasma/Serum Osmolarity
A
275-290mOsmoles/L
- 2 [Na] + [glucose]/18 + [BUN]/2.8 =osm/L
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
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
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
Colloidal Solutions (Therapeutic Fluids)
* albumin
* hetastarch and dextran
* FFP (fresh frozen plasma)
26
Normal Saline (0.9% NaCl)
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
Dextrose 5%
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
Lactate Ringer
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
3% NS
3%Normal Saline
* crystalloid solution
* **hypertonic**
* used to acutely lower **intracranial pressure** in TBIs
* osmolarity = 1,025mOsm/L
30
Albumin 5% or 25%
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
Fluid Maintenance Requirements
* 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
General Tx strategy for severe volume depletion or hypovolemic shock
* 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
General Tx Strategy for mild/moderate hypovolemia
* rate of fluid admin \> rate of continued fluid losses
* \*\*\*\*\*\*\*REVIEW THIS\*\*\*\*\*\*\*\*
* **caution in: renal failure, cardiac failure, hepatic failure, elderly**
34
0.45% NaCl
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
Types of Hyponatremia
* 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
Hypertonic Hyponatremia
osmolarity \> **300 mOsm/L**
associated with **severe hyperglycemia**
60mg/dL of Glc \>200 = 1mEq/L reduction of Na+
tx: **Tx the hyperglycemia** → insulin
37
Hypervolemic Hyponatremia
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
Euvolemic Hyponatremia
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
Chronic Therapy for Euvolemic Hyponatremia
* 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
Hypovolemic Hyponatremia
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
Types of Hypernatremia
* *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
Hypernatremia General S/sxs and Causes
* 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
Hypovolemic Hypernatremia
* 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
Isovolemic Hypernatremia
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
NSAIDs and Sodium
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
Desmopressin (DDVAP)
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
Hypervolemic Hypernatremia
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
Factors affecting K distribution
49
Potassium Roles and Levels
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
Hypokalemia S/sxs and Causes
* 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
Hypokalemia Tx
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
Hyperkalemia s/sxs and causes
* 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
Hyperkalemia Tx
* _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
Loop Diuretics
* Bumetadine
* Ethacrynic acid
* Furosemide
* Torsemide
