Fluids and Electrolytes

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Fluids and Electrolytes
2011-05-21 22:50:17
DPAP2012 Fluids Electrolytes

Fluids and Electrolytes cards made by previous students
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  1. total body water accounts for __% or more of body weight
  2. water is contained primarily in
    skeletal muscle
  3. interstitial water accounts for __% of extracellular water
  4. intravascular water or plasma water, constitutes __% of extracellular water volume or 4-7% of body weight
  5. in the intracellular compartment __ is the dominant cation
  6. in the interstitial and intravascular compartments __ is the dominant cation
  7. electrical neutrality is maintained by a balanced amount of
    chloride and bicarb ions
  8. to maintain electrical neutrality, the negative charge on plasma albumin requires an increase in
    plasma cations, mostly sodium
  9. the redistribution of ions across the semipermeable membrane is called the
    Donnan effect
  10. refers to the number of particles dissolved in a solution
  11. is calculated by considering only the concentration of impermeable solutes in solution
  12. ___ is an enzyme released by the juxtaglomerular cells of the afferent arteriole in response to a decrease in arterial blood pressure, hypovolemia, hyponatremia, and increased beta-adrenergic activity
  13. Renin converts angiotensinogen to angiotensin I which is then converted to angiotensin II in the pulmonary circulation by
    Angiotensin-converting enzyme (ACE)
  14. Angiotensin releases ___ from the renal cortex
  15. Aldosterone acts on the distal tubules and collecting ducts to
    increase sodium reabsorption and potassium excretion
  16. angiotensin increases
    cardiac output and peripheral resistance
  17. normally and adult ingests __L of water per day
  18. ___ mL/day is the minimal volume required to allow solute excretion
  19. chronic volume depletion is manifested by
    • oliguria,
    • loss of skin turgor,
    • orthostatic hypotension,
    • low urine sodium concentration,
    • BUN/creatinine ratio that exceeds 15:1.
  20. Acute volume losses are manifested by
    • hypotension,
    • tachycardia,
    • tachypnea
  21. normal dietary salt intake is __g/day
  22. hypernatremia is defined as a serum sodium concentration that exceeds __ mEq/L
  23. hypernatremia is always accompanied by
  24. any net gain in sodium will increase the
    extracellular fluid and trigger transmembrane water shifts leading to cellular dehydration
  25. hypernatremia may be due to
    • excessive salt intake,
    • excessive water loss,
    • reduced salt excretion,
    • reduced water intake
  26. ordinarily the hyperosmolar state of hypernatremia will drive thirst and
    ADH release
  27. in surgical patients, hypernatremia may result from the administration of __ which lead to free water depletion
    loop diuretics
  28. neurologic symptoms of hypernatremia
    • malaise,
    • lethargy,
    • vomiting,
    • general seizures,
    • coma
  29. rapid sodium increases will lead to
    cerebral dehydration
  30. therapy for hypernatremia is directed first at
    restoring volume with isotonic saline solution
  31. once intravascular volume is restored in hypernatremia, it is further corrected by administration of
    free water in the form of D5W
  32. hyponatremia is defined as a serum sodium concentration that is less than __mEq/L
  33. hyponatremia may be caused by
    • excessive water intake,
    • impaired renal water excretion,
    • loss of renal diluting capacity
  34. symptoms of hyponatremia are
    mostly neurologic and are due to cellular swelling
  35. cellular swelling in hyponatremia is induced by
    extracellular fluid hypo-osmolality
  36. in hyponatremia cerebral swelling causes
    • lethargy,
    • confusion,
    • vomiting,
    • seizures,
    • coma
  37. patients in this group often have edema
    hypervolemic hyponatremia
  38. causes include renal failure, CHF, COPD, severe liver disease
    hypervolemic hyponatremia
  39. the most common cause of normovolemic hyponatremia is
    the syndrome of inappropriate secretion of ADH (SIADH)
  40. SIADH is seen in patients with
    central nervous system pathology such as stroke or injury, and in pulmonary conditions including tuberculosis and cancer
  41. patients with hypovolemic hyponatremia have
    renal or extrarenal losses of sodium that exceed water losses
  42. in hypervolemic hyponatremic patients the treatment includes
    volume restriction and loop diuretics
  43. patients with SIADH usually respond to
    fluid restriction
  44. in hypovolemic hyponatremic patients treatment includes
    salt and water replacement
  45. in asymptomatic patients, hyponatremia should be treated
  46. with symptomatic hyponatremia, current recommendations are to increase the serum sodium concentration no faster than __mEq/L/hr
  47. in patients with stupor, coma, or other severe neurologic symptoms from hyponatremia __ is used
    hypertonic (3% NaCl) solution
  48. most of the bodies potassium is found in
    skeletal muscle
  49. the normal plasma potassium concentration is __ mEq/L
  50. the usually dietary intake of potassium is __ mEq/kg
  51. hyperkalemia is defined as a serum potassium concentration greater than __ mEq/L
  52. hyperkalemia can result from
    • renal or adrenal insufficiency,
    • metabolic acidosis,
    • iatrogenic causes
  53. the most common cause of metabolic alkalosis in surgical patients is
    nasogastric losses or vomiting
  54. the peritoneal surfaces represent __% fo body surface area
  55. during laparotomy, the expected evaporative fluid loss from exposed peritoneum is __ mL/kg/hr
  56. hyperphosphatemia may result from
    rhabdomyolysis due to muscle ischemia or crush injury
  57. the stress response to surgery results in the release of
    glucagon, aldosterone, cortisol, and antidiuretic hormone
  58. hyperkalemia occurs with __ due to transcellular exchange of K+ and H+
    metabolic acidosis
  59. extrarenal causes of hyperkalemia
    intravascular hemolysis, rhabdomyolysis, seizures, and sever GI bleed
  60. iatrogenic causes of hyperkalemia
  61. the earliest EKG abnormality of hyperkalemia is
    peaking of T waves
  62. as plasma potassium increases
    PR intervals become prolonged, and the RR interval increases
  63. further increases in K+ concentration are associated with
    loss of P waves and widening of QRS
  64. the final effect of hyperkalemia on the heart is
    complete heart block, v-tach, then asystole
  65. extracardiac symptoms of hyperkalemia
    paresthesias, flaccid paralysis, ileus
  66. to reverse cardiac toxicity in hyperkalemia __ should be administered
    calcium gluconate
  67. in hyperkalemia the response to calcium salt therapy occurs in
    1-5 minutes and lasts 30 minutes
  68. in hyperkalemia concurrent treatment with __ moves K+ into cells
    insulin or sodium bicarbonate
  69. potassium can be removed by treatment with the cation-exchange resin
    Kayexalate (50-100 g as enema) or 40g orally with sorbitol
  70. the most effective method of removing potassium is
  71. when using ___ to treat hyperkalemia, the onset of action is slow, and the effects last 4-6 hours
  72. hypokalemia is defined as a serum potassium concentration that is less than __mEq/L
  73. hypokalemia is a common problem in surgical patients and is usually caused by
    GI losses from vomiting, diarrhea, or fistula, and the use of diuretics
  74. ___ often coexists with hypokalemia
    metabolic alkalosis
  75. metabolic acidosis decreases
    renal potassium conservation
  76. EKG may show ___ in hypokalemia
    t-wave flattening/inversion, diminished QRS voltage, and U waves
  77. in patients taking digoxin __ can provoke life threatening arrhythmias
  78. potassium should be given __ unless the hypokalemia is severe (<2.5 mEq/L)
  79. the serum ionized calcium concentration is maintained within a narrow range of ___ mg/dL
  80. a reduction in serum calcium stimulates a release of
    parathyroid hormone
  81. parathyroid hormone increases
    calcium reabsorption from bone
  82. PTH enhances
    calcium reabsorption from the distal convoluted tubule
  83. PTH stimulates
    formation of the active metabolite of vitamin D that increases gut absorption of elemental calcium
  84. hypercalcemia is defined as ionized calcium concentration that exceeds __ mg/dL
  85. although hypercalcemia is most frequently associated with hyperparathyroidism in surgical patients, it is also commonly associated with
  86. other causes of enhanced bone reabsorption
    Paget's disease, pheochromocytoma, hyperthyroidism, and use of thiazide diuretics
  87. cardiovascular manifestations of hypercalcemia include
    arrhythmias and a shortened QT interval
  88. GI effects of hypercalcemia
    anorexia, constipation, pancreatitis, and hyperacidity
  89. the most common renal defect associated with hypercalcemia is
  90. if hyperparathyroidism is the cause of hypercalcemia the best treatment is
  91. initial supportive therapy for hypercalcemia includes
    saline diuresis and furosemide
  92. __ reduces bone reabsorption and has an immediate effect
  93. ___ are highly effective inhibitors of osteoclast activity but have a delayed onset of 2-3 days
  94. hypocalcemia is defined as an ionized calcium concentration of less than __ mg/dL
  95. hypocalcemia is seen in
    • parathyroid or thyroid surgery,
    • severe pancreatitis,
    • magnesium deficiency,
    • after massive blood transfusion
  96. neuromuscular findings in hypocalcemia include
    • paresthesias,
    • muscular spasms,
    • seizures,
    • tetany,
    • weakness
  97. cardiovascular symptoms of hypocalcemia include
    heart block, arrhythmias, bradycardia, and refractory hypotension
  98. EKG findings with hypocalcemia
    prolongation of the QT interval and T-wave inversion
  99. in patients with symptomatic or severe hypocalcemia ___ is indicated
    IV calcium therapy
  100. fixed acids
    citric, pyruvic, sulfuric, phosphoric, acetoacetic
  101. ___ are the main buffers in the body
    bicarbonate and hemoglobin
  102. in body fluids CO2 combines with water to form
    carbonic anhydrase
  103. kidneys can compensate for the buffer lost during CO2 excretion by the lungs with
    bicarbonate reabsorption and ammonia production
  104. metabolic acidosis is present when pH is less than 7.35 and plasma bicarbonate is less than __ mEq/L
  105. in spontaneously breathing patients the increase in hydrogen ion concentration should stimulate __ thereby decreasing PCO2
    compensatory increase in ventilatory rate
  106. the presence or absence of an ___ helps to categorized metabolic acidoses
    anion gap
  107. the anion gap is calculated as the difference between the concentrations of
    the major extracellular cation sodium and the major anions chloride plus bicarbonate
  108. the causes of anion gap acidosis can be remembered by the mnemonic
    Dr. Maples
  109. Dr. Maples stands for
    • Diabetic Ketoacidosis,
    • Renal failure,
    • methanol,
    • alcohol,
    • paraldehyde,
    • lactic acidosis,
    • ethylene glycol,
    • salicylates
  110. in trauma patients metabolic acidosis must be assumed to be due to
    blood loss (hypoperfusion and tissue hypoxia)
  111. non-anion gap metabolic acidosis is characterized by loss of
    buffer base
  112. common causes of non-anion gap metabolic acidosis
    • GI tract loss,
    • renal tubular acidosis,
    • Addison's disease,
    • total parenteral nutrition,
    • use of carbonic anhydrase inhibitors
  113. therapy with ___ is reserved for those in severe metabolic acidosis (<7.2), and in those with life threatening ventricular arrhythmias, hemodynamic instability, inadequate compensatory response
    sodium bicarbonate
  114. explained by the inability of the kidney to excrete excess bicarbonate or to retain hydrogen ion
    metabolic alkalosis
  115. metabolic alkalosis is usually accompanied by
    respiratory compensation
  116. respiratory acidosis is present when the pH is low and the PCO2 is
  117. respiratory acidosis is due to
    ineffective alveolar ventilation
  118. treatment of respiratory acidosis may require
    intubation and mechanical ventilation
  119. respiratory alkalosis is present when the pH is high and the PCO2 is
  120. caused by alveolar hyperventilation
    respiratory alkalosis
  121. in the surgical patient respiratory alkalosis may be caused by
    hypoxia, central nervous system lesion, pain, hepatic encephalopathy, and mechanical ventilation
  122. in acute respiratory alkalosis renal compensation is
  123. in chronic respiratory alkalosis renal compensation is by
    a decrease in hydrogen ion excretion
  124. most patients with respiratory alkalosis are
  125. hyperventilation is particularly dangerous in patients with subarachnoid hemorrhage because it exacerbates
  126. Water constitutes __% of total body weight in humans
  127. Total body water is inversely proportional to the amount of __
    body fat
  128. __ are the major cations of the intracellular space
    potassium and magnesium
  129. __ are the major anions of the intracellular space
    phosphate and protein
  130. __ are the major anions of the extracellular space
    chloride and bicarbonate
  131. __ is the major cation of the extracellular space
  132. __ determines the movement of fluid across the cell membrane
    osmotic gradient
  133. Except for transient changes, the intracellular and extracellular fluid compartments are in __
    osmotic equilibrium
  134. The transfer of fluid between the vascular and interstitial compartments occurs across the capillary wall and is governed by the balance between ___
    hydrostatic pressure gradients and plasma oncotic pressure gradients
  135. Hemodynamic alterations to a perceived volume reduction
    tachycardia, vasoconstriction, venoconstriction
  136. __ promotes salt and water retention in the kidneys
  137. __ is released from the atrial myocytes in response to atrial stretch associated with volume expansion
    atrial natriuretic peptide
  138. __ increases GFR and inhibits sodium reabsorption in the collecting ducts
    atrial natriuretic peptide
  139. __% of total body blood is in the atrial compartment
  140. True volume depletion
    decrease in effective circulating volume and extracellular fluid volume
  141. When volume depletion occurs from renal losses the urine is inappropriately __
    dilute and sometimes rich in salt
  142. Mild volume depletion may be associated with __
    orthostatic dizziness and tachycardia
  143. Patients with severe volume depletion may exhibit __
    • vasoconstriction,
    • hypotension,
    • mental obtundation,
    • cool extremities,
    • negligible urine output
  144. vasoconstrictor hormones released in response to hypovolemia
    catecholamine, angiotensin II
  145. if doubt exists about the state of hydration, measurement of the pulmonary __ permits assessment of the intravascular volume status
    capillary wedge pressure
  146. nearly all of the volume of solution containing __ are retained in the extrarenal space
    0.9% sodium chloride and colloid
  147. __ are the preferred parenteral solutions for the treatment of hypovolemia
    0.9% sodium chloride and colloid
  148. only 1/3 of infused __ remains in the extracellular compartment
    5% glucose in water (D5W)
  149. __ occurs when salt and water intake exceeds renal and extrarenal losses
    volume expansion
  150. sever hypoalbuminemia associated with liver disease, nephrotic syndrome, or severe malnutrition may lead to __
  151. the mainstay in treating volume excess is ___
    dietary sodium restriction in combination with diuretics
  152. Diuretics enhance
    natriuresis by inhibiting the reabsorption of sodium and water
  153. most patients with nephrotic syndrome have increased effective circulating volume resulting from
    primary renal sodium retention
  154. ___ inhibit sodium, chloride and potassium cotransporter of the thick ascending loop of Henle
    loop diuretics (furosemide, bumetanide)
  155. loop diuretics __ calcium excretion
  156. thiazide diuretics __ calcium excretion
  157. __inhibit the sodium and chloride cotransporter of the distal tubule
    thiazide diuretics
  158. __ are useful in managing hypercalcemia
    thiazide diuretics
  159. __ are useful in managing calcium stone formation
    loop diuretics
  160. potassium sparing diuretics
    • spironolactone (aldosterone agonist),
    • amiloride (sodium channel blocker)
  161. decreases sodium reabsorption in the cortical collecting duct
    • spironolactone (aldosterone agonist),
    • amiloride (sodium channel blocker)
  162. because __ is the major cation in ght ECF, disorders of osmolality are generally reflected by and abnormal __ concentration
  163. __ causes renal water conservation by increasing water permeability and water reabsorption in the collecting ducts
  164. baroreceptors in the venous and arterial circulation stimulate __ release through neuronal pathways when the EDF volume is reduced by about 10%
  165. Hyperglycemia and the use of mannitol may result in __ because of a water shift from the intracellular to extracellular space
  166. most hyponatremic disorders are associated with
  167. failure to suppress ADH secretion in response to hypotonicity
  168. in most instances hypernatremia is caused by __ rather than by sodium gain
    excess water loss
  169. __ is a powerful stimulus for thirst
    hypertonicity of the plasma
  170. patients unable to sense thirst or with a lack of available water may develop
  171. a disorder in which the collecting tubule is impermeable to water
    diabetes insipidus
  172. hypernatremia that is associated with hypovolemia implies __ in addition to the water deficit
    a sodium deficit
  173. hypernatremia that is associated with hypovolemia requires __
    isotonic saline infusion
  174. administration of fluids that are __ relative to the urine corrects hypernatremia
  175. the ascending limb of the loop of Henle is __ to water
  176. the ascending limb of the loop of Henle is __ to NaCl
  177. the descending limb of the loop of Henle is __ to water
  178. if the blood is hypo-osmolar then ADH will be turned __
  179. if the blood is hyperosmolar then ADH will be turned __
  180. if the blood is hypo-osmolar and ADH is turned on this is called __
  181. function of ADH
    increases water retention and results in a more concentrated urine, increases blood volume, decreases serum osmolality
  182. __ is a powerful vasoconstrictor and increases cardiac output
    angiotensin II
  183. __ initiates the active transport of Na from the distal tubules and collecting ducts into the bloodstream. this promotes the reabsorption of water
  184. major stimulus for angiotensin II
    low ECV, beta-adrenergics (via renin release)
  185. major site of action of angiotensin II
    proximal convoluted tubule
  186. major stimulation of aldosterone
    angiotensin II, hyperkalemia
  187. major site of action of aldosterone
    cortical distal nephron
  188. major stimulus for atrial natriuretic factor
    vascular volume expansion
  189. major site of action for atrial natriuretic factor
    GFR, medullary CD
  190. __% of body water is in the ICF
  191. __% of body water is in the ECF
  192. __% of ECF is intravascular
  193. __% of ECF is interstitial
  194. effective circulating volume is the same as
    intravascular volume
  195. hyperosmolar is the same thing as
    less water
  196. hypo-osmolar is the same thing as
    more water
  197. effective plasma osmolality is calculated by
    2Na + glucose/18
  198. normal saline is given for
    intravascular fluid volume resuscitation
  199. D5W is given for
  200. __ is a true vascular volume expander
    packed red blood cells
  201. if the serum is hyperosmotic the urine should be __
  202. if the serum is hypoosmotic the urine should be __
  203. if the kidneys are unable to to concentrate urine this is called
    diabetes insipidus
  204. in SIADH if the serum osmolality is low the urine osmolality will be
  205. in DI or low ADH if the serum osmolality is high then the urine osmolality will be
  206. if the patient is hyponatremic, hypovolemic treat with
    normal saline
  207. if the patient is hyponatremic and euvolemic treat with
    H2O restriction, hypertonic Na
  208. if the patient is hyponatremic and hypervolemic treat with
    H2O and Na restriction
  209. when a patient is in DKA you give them __ until the anion gap normalizes then you give them insulin
  210. in hyponatremia always correct sodium to __
  211. in hyponatremia correct the sodium at __ mEq/L/hr
  212. if you correct hyponatremia too fast you can cause
    demyelination of neurons in the Pons
  213. hypernatremia and hypovolemia treat with
    hypotonic saline
  214. hypernatremia and euvolemia treat with
    water replacement
  215. hypernatremia and hypervolemia treat with
    water and diuretics
  216. don't use __ when treating diabetes insipidus
    loop diuretics
  217. major complication of rapid correction of chronic hypernatremia is __
    cerebral edema
  218. safe initial correction of hypernatremia is at the rate of __mEq/L/hr
  219. hypernatremia with severe hypovolemia treat with
    0.9% saline
  220. with a patient that is hypernatremic bring the Na to