Quiz 3 Flashcards
What are buffers?
acid-base pairs that can resist changes in pH either weak acids or weak bases
What do weak bases accept?
H+ ions
What do weak acids donate?
H+ ions
When there are too many H+ ions what happens?
buffers will absorb them, increasing pH
When there are low H+ ions what happens?
buffers will donate some to reduce the pH
What is the main ECF buffer?
carbonic acid (H2CO3)
What is the main ICF buffer?
sodium carbonate and proteins
(2NAHCO2), hemoglobin, albumin
What are the two buffers in the kidney?
hydrogen phosphate and ammonia
What is the main independent urinary buffer?
hydrogen phosphate
Useful for estimating the pH of a buffer solution and finding the equilibrium pH in acid-base reactions?
Henderson Hasselbalch equation
What does pH depend on?
the ratio of weak base to the weak acid
If there’s more weak acid, pH is ???
low (<7.35)
If there’s more weak base, pH is ???
high (>7.45)
What alters the pH?
ratio of base to the acid
Base is ??? related to pH?
directly
Acid is ??? related to pH?
inversely
If a acid increases, pH goes ???
down (acidiotic)
If a acid decreases, pH goes ???
up (alkalotic)
What is the pk?
6.1 (dissociation constant)
Acidemia?
blood < 7.35
Alkalemia?
blood > 7.45
What can only have one state?
blood (emia)
What can occur at the same time?
acidosis and alkalosis
In venous BMP what serves as the bicarb?
CO2
What is a bicarb?
a weak base
where is bicarb mainly produced?
kidney
How long does it take the kidneys to modify HCO3?
hrs to days
If alkalemia occurs the kidneys will ???? HCO3 to decrease pH?
dump
You cannot have ?? and ?? at the same time
respiratory acidosis and respiratory alkalosis
Anion gap is only checked in what?
metabolic acidosis
ROME?
Respiratory- Opposite
Metabolic- Equal
In metabolic acidosis how does the body compensate?
by breathing faster (pCO2 decreases)
What is anion gap?
the difference between the measured cations and measured anions
What is the normal range for anion gap?
6-12
equation for albumin anion gap?
AG= Albumin x 3
In metabolic alkalosis how does the body compensate?
by breathing slower (pCO2 should be high)
How does the lungs adjust pH levels?
by altering the PaCO2
The lungs produce a ?? response
immediate response
How does the kidneys adjust pH levels?
by altering the HCO3 or other buffers
The kidneys produce a ?? response
delayed response
What is the formula used for metabolic acidosis compensation?
winter’s formula
If actual pCO2 is less than calculated pCO2 = ?
respiratory alkalosis
If actual pCO2 is greater than calculated pCO2 = ?
respiratory acidosis
What is winter’s formula?
pCO2= (1.5 x HCO3-) + 8 (-/+2)
What causes respiratory acidosis?
primary decrease in respiration
What 3 things can cause respiratory acidosis?
lung injury, neurological or muscular disease
What is the txt for respiratory acidosis?
mechanic ventilation
Doxapram HCL- stimulate ventalation
What is the patho of respiratory acidosis?
Acute rise in CO2 causes fall in oxygen levels, dyspnea, AMS and eventually coma
Chronic respiratory acidosis can cause what?
bone loss and papilledema
What things can cause respiratory alkalosis?
fever brain disease MI mechanical ventilation anxiety pregnancy sepsis liver disease
What is the patho of respiratory alkalosis?
breathing too fast, blowing off CO2
Serum CO2 is low
Serum pH is high
Decreased cerebral blood flow
What is the most common presentation of respiratory alkalosis?
neuromuscular irritability, paresthesia, and CHEST PAIN
Wha is the txt for respiratory alkalosis?
txt underlying cause
exhalation of excess CO2
What is the txt for panic attacks?
relaxation, rebreathing
What condition is panic attacks seen in ?
respiratory alkalosis
What condition is hyperchloremic metabolic acidosis seen in?
metabolic acidosis
What is seen in non-anion gap or normal anion gap?
decrease in bicarb w/ increase in chloride
What happens to bicarb in metabolic acidosis?
it DUMPED! loss by gut or renal loss
What diseases is hyperchloremic seen in?
ARF CKD High salt intake Respiratory alkalosis txt of DKA
What are s/s of metabolic acidosis?
fatigue muscle weakness excessive thirst dry mucous membranes high bp
What symptoms is seen in metabolic acidosis with DKA?
Kussmaul’s respiration
“A CAT’S MUDPILE”
Anion gap acidosis
“FUSED CARD TIP”
Normal gap acidosis
What is seen in chronic metabolic acidosis?
osteoporosis and fractures
Txt for metabolic acidosis?
correct primary problem
IV bicarbonate (caution)
txt hyperkalemia
consult nephrology (dialysis)
A pH < ?? is an emergency in metabolic acidosis?
7.1
Txt for DKA?
fluids, insulin, judicious replacement of bicarb
Txt for salicylate overdose?
judicious bicarb txt
Txt for alcoholic MA?
thiamine w/ glucose to prevent Wernicke encep.
Txt for methanol intoxication?
fomepizole w/wo dialysis
Txt for RTA non gap MA?
large amounts of alkali replacements w/ salts, thiazides, potassium
What is metabolic alkalosis?
too much HCO3 (Tums) due to decrease in H+ concentration or increase in bicarb
What are the two classifications of metabolic alkalosis?
chloride responsive
What is chloride responsive?
acid loss w/ chloride depletion
What is chloride resistant?
excessive aldosterone- no chloride depletion
Black licorice- glycyrrhizinic acid?
metabolic alkalosis
What does black licorice do?
upgrades renal mineralocorticoid receptors
Hypokalemic metabolic alkalosis and HTN
What are the s/s of metabolic alkalosis?
muscle cramps, weakness, dysrhythmias, diminished breath sounds but adequate oxygenation
What is the txt for metabolic alkalosis- chloride responsive?
chloride and volume replacement
txt renal problems
hypokalemia
What is the txt for non-chloride responsive?
spironolactone or amiloride
oxygen ventilation w/ inspired CO2 and O2
A pH of ?? is severe alkalosis?
7.60
What is the txt of primary aldosteronism?
CAN ONLY BE TXT w/ potassium replacement
What is the txt of primary hyperaldosteronism?
surgical removal of mineralocorticoid producing tumor
ACEI or spironolactone
High anion gap?
metabolic acidosis
Hyperglycemia?
DKA w/ ketones w/ metabolic acidosis
Hypokalmeia/ hypochloremia?
metabolic alkalosis
Hyperchloremia alone?
normal anion gap acidosis
What are two things you can do in metabolic acidosis?
winter’s formula and anion gap
Normal Cl- indicates?
Hyperchloremic metabolic acidosis
Extreme metabolic acidosis is ?
a EMERGENCY! (lethargy, stupor, coma, seizures)
What is hyperkalemia associated with?
metabolic acidosis
Most abundant compartment?
Intracellular (ICF)
What compartment shouldn’t have fluid?
3rd spacing
Third spacing compartments?
Lymph Pleural Peritoneal Pericardium CSF GU GI
Net movement of molecules (STUFF) from a high concentration to a low concentration
Diffusion
Movement of a substance down a concentration gradient
Diffusion
Spontaneous movement of fluid through a selective semi-permeable membrane from a low concentration to a high concentration to equalize both sides
Osmosis
Membrane not permeable to solutes
Osmosis
Minimum amount of pressure, needed to stop osmosis across a membrane
Osmotic pressure
Keep fluid from leaking out of blood vessels
hydrostatic pressure
Pulls water into the blood vessels
oncotic pressure (proteins)
Most important protein for exerting oncotic pressure in blood vessels
Albumin
What opposes hydrostatic pressure?
oncotic pressure
What is osmolarity based on?
temperature and pressure
What is serum osmolality?
measure of the number of dissolved particles per unit of water in serum
A low serum osmolality means ?
increase of water <285
A high serum osmolality means?
decrease of water > 295
Measure of dissolved particles per unit of water in the urine
urine osmolality
Response of cells immersed in an external solution
tonicity
What is the difference between osmolality versus tonicity?
BUN
What is the calculation for Osmolality?
2NA + Glucose/18 + BUN/2.8 = 285
What is tonicity calculation?
2NA + glucose/18 without BUN/2.8
Excess fluid in the interstitial tissue is in what space?
2nd space
normal distribution of fluid in both ECF and ICF compartments is in what space?
1st space
Normal range for sodium
135-145
The most abundant ECF electrolyte?
Sodium
Normal range for potassium?
3.5-5.0
The most abudant ICF electrolyte?
Potassium
Chloride is a ICF or ECF electrolyte?
ECF
Normal range for chloride?
95-105
Normal range for Ca2+?
8.5-10.5
Causes extracellular excitation?
Sodium
Causes intracellular excitation?
Potassium
What is the first thing that is tested in hyponatremia?
serum osmolarity
What are the 3 types of hyponatremia?
Isotonic, Hypotonic, Hypertonic
Most common electrolyte abnormality is hospitalized pts?
Hyponatremia
Osmolality for isotonic?
285-295
Osmolality for hypertonic?
> 295
Osmolality for hypotonic?
<285
What is the most common hyponatremia?
Hypotonic (90%)
Pseudohyponatremia?
Isotonic Hyponatremia
What is the txt for isotonic hyponatremia?
no txt
txt high protein and cholesterol
Seen with DKA and mannitol txt?
hypertonic hyponatremia
Txt for hypertonic hyponatremia?
get rid of extra components
For txt of hypotonic hyponatremia what is needed?
patient’s volume status
What is released in hypovolemic hypotonic?
ADH/ vasopressin
Severe vomiting, diarrhea, dehydration
hypovolemic hypotonic hyponatremia
SIADH
Euvolemic hypotonic hyponatremia
What are the 3 most severe consequences of hyponatremia?
seizures, coma and death
What is the txt for euvolemic hyponatremia?
free water restriction alone
What is the txt for hypervolemic hyponatremia?
loop diuretics, dialysis if severe
What is the txt for hypovolemic hyponatremia?
normal saline 0.9% or lactated ringers (judiciously)
Neuro problem found in hypovolemic txt?
Central pontine myelinolysis (CMP)
Txt for cerebral wasting syndrome?
hypertonic saline (3%)
Txt for severe hyponatremia?
vaptans
What are 3 types of hypernatremia?
Hypovolemic, Euvolemic, Hypervolemic
In hypernatremia why isn’t serum osmolaity needed?
bc sodium determines tonicity so all are hyperosmolality > 285
What is the least likely thing to cause hypernatremia?
excessive oral intake of sodium
What cause hypernatremia to happen?
lose water and salt, then start losing more water than salt
What is the txt for hypernatremia?
correct fluid loss
replace free water and electrolytes
Cerebral edema
hypernatremia
Txt for euvolemia hypernatremia?
oral replacement or D5W
Txt for hypovolemic hypernatremia?
normal saline
Hypervolemic hypernatremia txt?
D5W and loop diuretic
What is the most common cause of K+ loss in developing countries?
GI loss from infectious diarrhea
Which electrolyte if low can cause potassium not to be reuptaked?
magnesium
What does a EKG for hypokalemia look?
BROADEN T waves, depressed ST segments, Prominent U waves, PVCs
What is the txt for hypokalemia?
Oral potassium (20-40m/d) IV potassium for severe loss <3.0
Txt for refractory hypokalemia?
magnesium
What is the most common cause of hyperkalemia?
impaired renal execretion of K+
What is hyperkalemia?
> 5.5
Fist clenching and Trousseau sign?
Hyperkalemia
Peaked T WAVES, prolonged PR interval?
hyperkalemia
Txt for chronic K+?
Partiromer (FDA approved)
What does sodium polystyrene txt cause?
colonic necrosis
What is the emergent txt for hyperkalemia?
IV calcium, insulin, bicarb, beta agonists
What percentage of america is dehydrated?
75%
What is the minimum water intake?
1600 ml/day
How much water is lost in urine?
500ml
Where is more water lost?
urine and skin
Where is most water intaked?
Food
What is sensible loss?
fluid loss that can be measured
What is insensible loss?
fluid loss that cannot be measured
Who is at the highest risk for dehydration?
infants and elderly
How is dehydration diagnosed?
concentrated urine
What is the txt for dehydration?
prevention- stay hydrated
oral fluid replacement w/ pure water
IV hydration w/ crystalloids- severe
What is hypovolemia?
state of decreased plasma (blood volume)
What is the most common fluid imbalance seen?
hypovolemia
What is given first in the txt of hypovolemia?
oxygen
What is hypervolemia?
fluid overload
What is the most common result of fluid overload?
CHF
What is the txt for hypervolemia?
furosemide
What are the most commonly used crystalloids?
NS and LR
A mixture of insoluble particles suspended throughout another substance?
Colloids
