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55 Cards in this Set
- Front
- Back
what is a process that tends to lower ECF pH?
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acidosis
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what is metabolic acidosis?
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low HCO3
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what is respiratory acidosis?
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high PaCo2
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most cases acidosis leads to what?
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acidemia (decrease in blood pH)
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what is alkalosis?
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a process that tends to increase ECF pH
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what is high HCO3?
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metabolic alkalosis
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what is low PaCO2?
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respiratory alkalosis
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in most cases alkalosis leads to what?
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alkalemia (increase in blood pH)
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what are characteristics of metabolic acidosis?
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-reduced arterial pH (acidemia)
-reduced plasma (HCO3) |
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what is response to metabolic acidosis?
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compensatory hyperventilation and decreased PaCO2
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what are some causes of metabolic acidosis?
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-inability to excrete dietary H+ load
(renal failure, hypoaldesteronism) |
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what are some causes of increased H+ load or HCO3 loss?
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-lactic acidosis
-ketoacidosis -diarrhea |
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what is due to severe tissue hypoperfusion assoc w/ shock or cardiopulmonary arrest; seizures?
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lactic acidosis
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what is cause of HCO3 loss from intestine?
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diarrhea
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what are pulmonary symptoms of metabolic acidosis?
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-marked increase in minute ventilation-compensatory
-dyspnea, hyperpnea |
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what are cardiac symptoms of metabolic acidosis?
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-reduction in ventricular contractility
-potentially fatal ventricular dysrhythmias |
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what are neurologic symptoms of metabolic acidosis?
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symptoms range from lethargy to coma
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what is most important buffer response to acidemia?
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-extracellular buffering- HCO3 is most important buffer
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what are some other buffers for metabolic acidosis?
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-intracellular and bone buffering
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what is most important respiratory compensation for metabolic acidosis?
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-stimulation of peripheral and central chemoreceptors-increase in alveolar ventilation
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the increase in ventilation does what to try and compensate for metabolic acidosis?
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-decrease CO2 and allows CO2/HCO3 system to shift to the left
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on avg PaCO2 will fall how much for every 1.0meq/L in the plasma HCO3?
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1.2 mmHg
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PaCO2= ?
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(HCO3 x 1.5) + 8
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last two digits of the pH=?
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HCO3 + 15
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PaCO2 substantially different from predicted suggests what?
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a mixed acid-base disturbance
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what is renal compensation responsible for?
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-ultimately responsible for excreting excess H+ in order to correct ECF pH; requires several days
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what is principal compensatory response from renal system?
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increased tubular cell NH3 production and excretion of H+ as NH4--can exceed 250meq per day
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what are characteristics of respiratory acidosis?
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-reduced arterial pH (acidemia)
-elevation in PaCO2 (hypercapnia) -variable increase in plasma HCO3 |
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becaue the CO2 stimulus to ventilation is so strong hypercapnia and resp acidosis are almost always due to what?
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a reduction in effective alveolar ventilation
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what are neurologic symptoms of acute hypercapnia?
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-HA
-blurred vision -restlessness -anxiety -tremors -delirium -somnolence |
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what are cardiovascular symptoms of acute hypercapnia?
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-dysrhythmias
-peripheral vasodilation |
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is the CO2/HCO3 buffer a good buffer in the acute rsponse to resp acidosis?
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not an effective buffer in this situation
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what are some important intracellular buffers?
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Hgb and other protein important in buffering H+
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on avg there will be how much of rise in plasma HCO3 for every 10mmHG rise in PaCo2?
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1 meq/L
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persistent elevation of PaCO2 stimulates renal H+ secretion resulting in what?
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addition of HCO3 to the ECF
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after several days of acidosis a new steady-state is reached in which there is how many meq/L increase in plasma HCO3 for every how many mmHg rise in PaCo2?
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4 meq/L for every 10mmHg rise in PaCO2
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the extent of the increase in plasma HCO3 in chronic respiratory acidosis is determined by what?
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the extent to which renal H+ secretion increases
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what are characteristics of metabolic alkalosis?
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-elevation in arterial pH (alkalemia)
-increase in plasma HCO3 -compensatory hypoventilation resulting in a rise in PaCO2 |
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a rise in plasma HCO3 ususally results from what?
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H+ loss from the GI tract or in teh urine
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what are symptoms of metabolic alkalosis?
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-muscle cramps
-postural hypotension -hypokalemia (muscle weakness) |
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development of alkalemai is sensed by what?
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the peripheral chemoreceptors, resulting in a decline in ventilation and an appropriate increase in PaCO2
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an avg PaCO2 increases how much for every 1.0 meq/L increase in plasma HCO3?
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0.6 mmHg
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usually metabolic alkalosis is self limiting b/c why?
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kidneys excrete increase HCO3
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perpetuation of metabolic alkalosis requires what?
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some impairment in renal HCO3 excretion due to increased tubular HCO3
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what are some characteristics of respiratory alkalosis?
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-elevated arterial pH (alkalemia)
-elevated PaCO2 (hypocapnia) -variable reduction in plasma HCO3 |
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what are neurologic symptoms of resp. alkalosis?
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-light-headedness
-altered consciousness -syncope (related to increased membrane excitability and impaired cerebral function) |
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there is a reduction in cerebral blood flow by how much w/ resp alkalosis?
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35-40%
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what are cardiac symptoms of resp alkalosis?
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dysrhythmias
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what is another symptoms of resp alkalosis?
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hypokalemia
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what is an acute response to respiratory alkalosis?
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H+ move frm cells into the ECF, combine w/ HCO3 and cause an appropriate fall in plasma HCO3
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w/ resp alkalosis an avg plasma HCO3 is reduced by how much for each 10mmHg decrease in PaCO2?
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2 meq/L
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what is a chronic response to persistent hypocapnia in resp alkalosis?
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-compensatory decrease in renal H+ secretion
-increased urinary excretion of HCO3 and decreased NH4 excretion (lower plasma HCO3) |
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when a steady state in resp alkalosis is reached how much is the plasma HCO3 reduced?
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by 5meq/L for each 10 mmHg decrease in PaCO2
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causes of metabolic acidosis- MUDPILES?
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M=methanol
U=Uremia D=Diabetic ketoacidosis P=paraldehyde, propylene glycol I=infection, iron;ionized (INH) L=Lactic acidosis E= Ethylene Glycol r ethanol ing. S= salicylates |
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causes metabolic acidosis w/ nml anion gap= HARD UP?
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H=hyperalimentation (w/ TPN)
A=acetazolamine R=RTA (renal tubule acidosis) D=Diarrhea U=ureterosigmoidostomy P=pancreatic fistula |