acid base balance Flashcards

Terms Definitions
Normal Blood pH
Respiratory Acidosis

Inadequate ventilation creates excess CO2 levels
pH < 7.35
PaCO2 > 45
Normal PaO2
80 to 100
Normal valuses for pO2
80-100 mmHg
Normal SaO2 Range
95% to 100%
represents the metabolic component of the body's acid-base balance
Which is primarily involved in transporting excess cholesterol to the liver for disposal?
Respiratory alkalosis is almost always a result of _________?
What kind of relationship exists between arterial carbon dioxide levels (PaCO2) and Blood pH?
Hypotonic Solutions
1/2 NS(0.45% NaCl)Na 69.3mEqCl 69.3mEqpH 5.0
Potassium-Sparing Diuretics Indications amiloride
Treatment of heart failure
deficiency of magnesium in the blood plasma
a condition that occurs with increases in blood bicarbonate or decreases in blood carbonic acid; blood pH above 7.45 (low hydrogen ion concentration)
Hypoventilation creates _, which can lead to _

Co2 retention
Respiratory Acidosis
pH indicates the number of
Hydrogen Ions H+
A diagnostic test that assesses the effectiveness of breathing and overall acid-base balance from a sample of arterial blood
Increased levels of carbonic acid lead ________ in pH
Metabolic Alkalosis
pH is up HCO3 is up
Compensatory Mechanisms
Respiratory Acidosis Renal Absorption of HCO3-
Respiratory Alkalosis Glomerular Filtration of HCO3-
Metabolic Acidosis Hyperventilation
Metabolic Alkalosis Hypoventilation
osmotic pressure
the pressure exerted by a solution necessary to prevent osmosis into that solution when it is separated from the pure solvent by a semipermeable membrane
acid - base disturbances are compensated by either the __ or __
lungs or kidneys
S/S of Metabolic Alkalosis
RR depression, lethargy, confusion, seizure, coma, nausea, vomiting,
muscle weakness/twitching/cramps/tetany
in what condition do cells release H+ into the blood and K+ move into cells from blood serum causing low K+ levels
Respiratory Alkalosis
1. Deep, rapid breathing
2. CNS stimulation - resulting in confusion, syncope, seizures
3. Hypokalemia
4. Muscle twitching and weakness
5. Tingling of extremities
What is the body’s primary buffer system?
Bicarbonate buffer
Causes of Respiratory Alkalosis
Conditions causing overstimulation of the respiratory status
- Fever, hyperventilation, hypoxia, hysteria, pain
Diuretic Drugs
Drugs that accelerate the rate of urine formation Result: removal of sodium and water
vascular access device
VAD, devices such as a needle, cannula, or catheter that allow direct access to the circulatory system
What is alkaline?
- basic- a solution with a predominance of hydroxide (OH-) ions
provides a more complete picture of body's ability to buffer
Base Excess (BE)
How do we check to see if ventilation is keeping pH in check?
Carbonic Anhydrase Inhibitors (CAIs) Mechanism of Action
Inhibition of carbonic anhydrase reduces H+ ion concentration in renal tubulesAs a result, there is increased excretion of bicarbonate, sodium, water, and potassiumResorption of water is decreased and urine volume increased
Which buffer system has a minor role in blood, but plays a bigger role intracellularly?
Phosphate buffer system
What transporters are likely to be active if a cell becomes acidic?
*Na+/H+ antiporter (extrudes H+)*K+/H+ ATPase (extrudes H+)
Compensatory Mechanisms of Respiratory alkalosis
*Respirations decrease or even cease until CO2 levels rise enough to stimulate increase in respirations.
*Kidneys slow absorption of HCO3 and increase release of hydrogen ions causing alkaline urine
How can respiratory mechanisms compensate for a metabolic alkalosis? Why is this not a great mechanism?
Hypoventilation increases PCO2 in the blood which increases [H+] and lowers pH. This is limited by the O2 demands of the body.
A gas that combines with water to form carbonic acid
carbon dioxide
Loop Diuretics Indications
Edema associated with HF or hepatic or renal diseaseControl of HTNIncrease renal excretion of Ca in patients with hypercalcemiaCertain cases of HF resulting from diastolic dysfunction
How is CO2 transported across the membrane?
It moves freely by diffusion.
How is CO2 transported across the membrane?
It moves freely by diffusion.
Hydrogen ions decrease or bicarbonate ions increase
High pH above 7.45 = Alkalosis
metabolic acidosis is cause by what?
decreased level of HCO3 in arterial blood
2nd step to blood gas interpretation
look at respiratory component to see if the imbalance is due to a respiratory reason
Metabolic Acidosis pH < 7.35, HCO3 < 22, K > 5.5, PaCO2 N
Increased noncarbonic acids or decreased bicarbonate Diabetic ketoacidosisDiarrheaRenal failureShockSalicylate (acetylsalicylic acid) overdoseSepsis
What is the role of HDLs in the transport of lipids?
transport cholesterol from the peripheral tissues to the liver to be excreted in bile
Metabolic Alkalosis pH>7.45, PaCO2 N, HCO3>26, K+<3.5
Excess loss of acid Loss of gastric secretions,Vomiting,Gastric suctioning Overuse of antacids or increased intake of bicarbonate K+ wasting diuretics H+ is excreted to balance K+ loss
What happens to the keto acid produced by deamination?
It is converted to pyruvate acid, acetyl coa or enter the CAC
What is the formula for figuring anion gap?
Sodium – (chloride + bicarbonate) = anion gap
what is the normal value and range for blood Pco2?
40mm Hg with a range of 35-45mm Hg
What is the fate of the amino group stripped from an amino acid during deamination?
the amino group picks up H+ ions to become NH4 (ammonium) which is then converted to urea and excreted in urine
10-30mg/dl (1.8-7.1mmo/L)
Base = ______pH
Normal valuses for pH
bicarbonate is basic(alkaline)Binds with free H= to decrease concentration
Respiratory component of blood gases
Hypercalcemia Manifestations
Decreased memory Confusion Disorientation Fatigue Constipation
electrolyte solutions that move freely between the intravascular compartment and interstitial spaces
BE, aka _, is
&#13;&#10;Base Excess&#13;&#10;a number that indicates an excess/deficiency in the total amount of HCO3 available to buffer acids&#13;&#10;
Metabolic imbalances affet the base ____________.
Fewer hydrogen ions = _____pH
higher pH
mannitol (Osmitrol)
Increases glomerular filtration and renal plasma flow—helps to prevent kidney damage during acute renal failureReduces excessive intraocular pressure
deficiency of chloride in the blood plasma
the presence of abnormally high levels of calcium in the blood
S/S of Respiratory Alkalosis
Ligh-headedness, paresthesias, blurred vision, dysrhythmias, diaphoresis, xerostomia, spasms
Measures the pressure exerted by CO2 dissolved in the blood
Moves in the opposite direction as pH
High serum potassium caused by Massive intake Impaired renal excretion Shift from ICF to ECFCommon in massive cell destructionBurn, crush injury, or tumor lysis
a number of tests are done to determine an acid/base imbalance one in which is an
a substance that dissolves in water to give a solution that conducts an electric current
Which has the highest triglyceride content?
Chylomicrons (95% triglycerides)
Interventions for Respiratory acidosis
Improve respiratory function, correct acidosis, assess for iatrogenic complications of interventions
Interpret the ABG: ph 7.35, pCo2 50, HCO3 30, pO2 60
PaCO2 Imbalance
Occurs when the origin or primary system causing imbalance is respiratory, or it is compensating for a metabolic problem
Takes hours or days to make pH changes
Respiratory Alkalosis
A decrease in H+ ion concentration resulting in accumulation of base
αco2 represents what?
solubility coeficient of CO2 in blood (0.03 mEq/l/mm Hg
Name some conditions that might result in a respiratory acidosis.
*pulmonary fibrosis*obstructive lung disease*neural and neuromuscular disorders affecting regulation of ventilation
Interpret the ABG: ph 7.25, pCo2 54, HCO3 24, pO2 84
Respiratory acidosis
Are volatile acids buffered by intracellular or extracellular processes? What about fixed acids?
*volatile acids - intracellularly
*fixed acids - both
What is the normal range for anion gap?
8-14 mEq/L
Respiratory problem = respiratory imbalance
COPD Pneumonia Pulmonary embolus Respiratory failure
what is respiratory acidosis?
increased level of CO2 in arterial blood
How can respiratory mechanisms compensate for a metabolic alkalosis? Why is this not a great mechanism?
Hypoventilation increases PCO2 in the blood which increases [H+] and lowers pH. This is limited by the O2 demands of the body.
other causes of Metabolic acidosis
excessive ingestion of acid (aspirin, ferrous sulfate), Renal diseases( kidneys lose ability to secrete acids), abnormal loses of alkali (acute vomiting, loss of pancreatic, biliary and lower intestinal fluids
Respiratory Alkalosis Nursing Care
1. Evaluate need for sedation
2. Use rebreathing mask to increase CO2 levels
3. Remain with client to decrease anxiety
Give two examples of paraprotein enemia states.
Multiple myeloma and Waldenstrom’s Macroglobulinemia
pH, PaCO2, and bicarbonate level
An ABG involves several seperate test results, only three of which relate to acid-base balances:
what are some possible reasons for metabolic acidosis? (handout from class)
Diabetic ketoacidosis, shock, kidney failure
Correction of Acid base balance
When the problem in the system primarily affected is corrected, thereby returning the pH to a more normal level
What ABG results indicate metabolic acidosis?
PH and Bicarbonate levels are decreased
what is the henderson-hasselbach equation?
pH = pK + log [HCO3]/(aco2) x (Pco2)
How do metabolic systems compensate for a respiratory acidosis? How is PCO2 affected?
There is increased renal excretion of H+ and secretion of HCO3- into the blood. PCO2 remains constant and at an abnormally high level.
if ration of H-H equationis less than 20...
then pH is less than 7.4
What creates metabolic acidosis? Alkalosis?
Acidosis is due to the addition of a fixed acid to the blood or removal of a base. Alkalosis is due to the addition of a fixed base to the blood or the loss of an acid.
HCO3-/H2CO3 has a pKa of 6.1, while the pH of blood is 7.4. How can this still be a good buffer?
*it is abundant*the effective pKa is greater than 6.1 because this is an open system and excess HCO3- can be breathed off
a decrease in pH is regulated by the kidneys by
increase secretion of H+ and increase in reabsorption of HCO3
How does the bicarbonate buffer system respond to an acid or base?
- if a strong acid is added, the H+ will combine with HCO3- to form a weak acid- if a strong base is added, then more of the carbonic acid dissociates freeing H+ that can combine with a hydroxide (OH-) to form water
What is the ideal blood pH and what is the range of normal blood pH?
7.40 with a range of 7.35 - 7.45 (blood slightly alkaline)
44. Is the acid-base disturbance respiratory or metabolic if the problem involves CO2?
54. What acid-base disturbance is caused by hyperventilation?
respiratory alkalosis
41. If the ratio ([HCO3-]/[dissolved CO2]) is equal to 20, what will the pH be?
7.4 (normal)
57. What acid-base disturbance is caused by diuretics or overdose on alkaline drugs (like Tums)?
metabloic alkalosis
59. Would duodenal vomiting cause metabolic acidosis or alkalosis?
metabolic acidosis
43. If the ratio ([HCO3-]/[dissolved CO2]) is greater than 20, will you have an acidic or alkaline pH?
alkaline (> 7.4)
48. What acid-base disturbance is due to increased CO2 in arteriole blood (high PCO2)?
respiratory acidosis
30. Which organ that regulates pH is powerful but takes days to correct problem?
51. What acid-base disturbance is due to increased HCO3- in arteriole blood (high HCO3-)?
metabolic alkalosis
49. What acid-base disturbance is due to decreased CO2 in arteriole blood (low PCO2)?
respiratory alkalosis
9. What blunts (dampens) changes in pH in the body (tries to keep pH from changing)?
53. What acid-base disturbance would someone have if they overdosed on barbituates?
respiratory acidosis (barbituates decrease respiratory rate - increases CO2 left in body)
52. What acid-base disturbance is caused by hypoventilation (poor gas exchange in lungs, pulmonary diseases- bronchitis, fibrotic lung disease)?
respiratory acidosis (hypoventilation increases CO2)
31. After buffer systems fail to maintain pH, what is the first response?
lungs (respiratory compensation)
6. What is the range of the pH scale?
25. Is H2CO3 very stable, or does it dissociate quickly?
dissociates quickly
16. What type of buffering system has a minor role in the blood and a much bigger role intracellularly?
phosphate buffer system
28. What will take over when the buffer systems get overwhelmed and cannot control the problem?
the lungs and kidneys
Can you describe the major intacellular fluid chemical buffers? Extracellular fluid buffers?
ICF buffers include Na2HPO4 (sodium monohydrogen phosphate) and protiens.
ECF is bicarbonate ion HCO3-
46. If you increase PCO2 above normal range, would you have acidosis or alkalosis?
acidosis (making denominator larger decreases pH)
what contributed to the acidity of a solution
the concentration of protons present
26. What happens in the carbon dioxide/bicarbonate buffer system when pH gets too low?
excess H+ combines with HCO3- which will lead to an increase in CO2 (shift to left)
13. What are the three types of buffering systems?
protein buffer system / phosphate buffer system / carbon dioxide-bicarbonate buffer system
what is a strong acid? strong base? whats the difference between the stong and weak acids and bases
strong acids- completely dissociate in solution(donate protons) creating a proton and anion HCl
strong base- dissociates into an anion that can bind up a protien "removing" it from solution NAOH
can you describe the pH scale
the lower the pH number he higher protons which means higher acidity. the higher number the less the protons which makes them less acidic and more alkaline. each number represents a ten fold increase or decrease in protons
67. How do the kidneys compensate for respiratory alkalosis?
decrease secretion of H+ and decrease reabsorption of HCO3-
27. What happens in the carbon dioxide/bicarbonate buffer system when pH gets too high?
CO2 in body will combine with water which will lead to the breakdown of H2CO3 to release more H+ (shift to right)
22. In the phosphate buffer system, what will happen if pH starts to get too high (not enough H+)?
H3PO4 will break down to release more H+ (shift to right)
34. What will the lungs do to compensate for an increase in pH?
decrease ventilation (keep CO2, so + H2O, equation shifts to right, get more H+)
35. What will the kidneys do to compensate for acidosis (low pH)?
increase secretion of H+ / increase reabsorption of HCO3- (want to keep HCO3- so will combine with H+ to remove H+ from blood)
36. What will the kidneys do to compensate for alkalosis (high pH)?
decrease secretion of H+ / decrease reabsorption of HCO3- (want to keep H+ in blood)
can you explain the 3 different regulatory systems for pH balance of blood
Renal- the kidney can release HCO3- in the blood to buffer pH
Respiratory- breathing rate can increase or decrease to expel or retain more or less CO2 and thus alter proton #in the blood
Chemical buffers- these are molecules such as various salts or protiens that are naturally available in the body fluids that act as buffers
63. How do the lungs compensate for metabolic acidosis?
increase ventilation to get rid of CO2 so the equation will shift to left (decrease H+)
24. What is the equation for the carbon dioxide/bicarbonate buffer system?
CO2 + H2O H2CO3 H+ + HCO3-
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