Fluid, Electrolyte, Acid Base Pathophysiology

Front 1

1. Approximately 60% of an adults body weight is water. True/False

Back 1

True. An infants is about 70-75%.

Females with a higher percentage of body fat, have less water than male bodies.

The elderly and obese have a lower proportion of water in their bodies.

Front 2

2. How is fluid generally distributed in the body?

Back 2

It is distributed in the intracellular compartmrnt (ICF) or fluid inside the cells, and the extracellular compartment.

Front 3

3. What are transcellular fluids?

Back 3

This fluid is present in various secretions, such as those in pericardial cavity, the pleural cavity or in the synovial cavities.

Front 4

4. What does the term edema refer to?

Back 4

Edema refers to an excessive amount of fluid in the interstitial compartment, which results in a swelling or enlargement of tissues.

Edema tends to be more severe in the dependent regions of the body, where the force of gravity is greatest.

Front 5

5. List four causes of edema.

Back 5

1. Increased capillary hydrostatic pressure.

2. Loss of plasma proteins

3.Lymphatic vessel obstruction

4. Increased capillary permeability.

Front 6

6. Give one cause of increased capillary hydrostatic pressure.

Back 6

Aside from increase blood pressure, pregnancy may result in this. The uterus compresses the pelvic veins when seasted. While standing, the pressure in the leg veins can become elevated causing edema in the feet and legs.

CHF may be another cause for obviuous reasons.

Front 7

7. briefly explain edema in loss of proteins.

Back 7

This refers more specifically to albumin which results in a decrease of plasma protein osmotic pressure.

Front 8

8. How might protein be lost resulting in edema?

Back 8

Protein can be lost in urine in renal disease. Liver disease may cause a diminished production of protein.

Patients in an undernourished state

Patients with malabsorption conditions.

Protein levels can drop in seriously burned patients.

Front 9

9. How might obstructions occur in lymphatic channels?

Back 9

This condition may develop if a tumor or infection damages a lymph node or if lymph nodes are removed, as they frequently are in cancer surgery..

Some bacterial toxins of large burn wounds

Front 10

10. How is edema related to increased capillary permeability?

Back 10

Chemical mediators such as histamine and other mediators released from cells after tissue injury can result in increased capillary permeability. There is increased fluid movement into the interstitial area.

Protein can also leak into the interstitial compartment, thus increasing the osmotic pressure.

Front 11

11. In dehydration, how might fluid loss be measured?

Back 11

It is often measured by a change in body weight. As a guide to extracellular fluid loss a mild deficit might be defined as a decrease of 2% in body weight, a moderate as 5% and severe at 8%.

Front 12

12. Why do infants have an increased need of water?

Back 12

They experience greater insensible water loss through their larger body surface area, and also have a higher meatbolic rate.

In infants a decrease in the number of wet diapers and decreased urine output is ususally an indicator.

Front 13

13. differentiate between hypotonic and hypertonic dehydration.

Back 13

Isotonic dehydration refers to a proportionate loss of fluid and electrolytes.

Hypotonic refers to a loss of more electrolytes than water.

Hypertonic refers to a loss of more fluid than electrolytes.

Front 14

14. List 5 causes of dehydration.

Back 14

1.Vomiting and diarrhea

2. Excessive sweating due to sodium loss

3. Diabetic ketoacidosis where there is a loss of electrolytes, water and glucose.

4. Inadequate water intake

5. Use of concentrated formula.

Front 15

15. List 5 effects of dehydration.

Back 15

1. Dry mucus membranes with decrased skin turgor or elasticity

2. Lowered blood pressure, weak pulse with fatigue

3. Increased hematocrit (relative). More RBCs in proportion to plasma water level.

4. Decreased mental function, confusion, headache and possible loss of consciousness.

5. Decreased urine output, with higher urine concentration and specific gravity.

Front 16

16. What does the term " third spacing" refer to?

Back 16

This refers to a situation where fluid tend to shift out of the blood and into a body cavity or tissue where it longer serves as a circulating fluid.

Examples are peritonitis and burns ( edema in the area of the wounds). As a result there is a fluid deficit in the vascular compartment (hypovolemia) and a fluid excess in the interstitial space.

Weighing the patient will not accurately determine the fluid shift change.

Front 17

17. Sodium is the primary cation the ECF. True/Fluid

Back 17

True. The diffusion od sodium occurs between the vascular and interstitial fluids. cell membrane transport of sodium is controlled by the sodium-potassium pump or active transport, resulting in higher sodium levels in ECF.

Front 18

18. Sodium makes up app. 90% of the solute in ECF. True/False

Back 18

True.

Front 19

19. List 5 causes of hyponatremia.

Back 19

1. Excessive diaphoresis, vomiting or diarhhea

2. Use of diuretic drugs combined with low salt diets

3. Hormonal imbalances due to insufficient aldosterone, adrenal insufficiency and an excess of ADH secretion

4. Early chronic renal failure

5. Excessive water intake

Front 20

20. By blood measurement, what constitutes hyponatremia?

Back 20

Hyponatremia exists when the serum sodium concentration is below 3.8 to 5 mmol per liter or 135 milliequivalents per liter.

Front 21

21. List three possible effects of hyponatremia.

Back 21

1. Impaired nerve conduction, fatigue, muscle cramps and abdominal discomfort

2. Diminished osmotic pressure in the ECF which can cause a fluid shift into cells, causing hypovolemia

3. Cerebral edema, causing confusion, headache, weakness and seizures.

Front 22

22. Hypernatremia is considered when sodium levels are above 145 mEq per liter. True/False

Back 22

True.

Front 23

23. List 5 causes of hypernatremia.

Back 23

1. Excessive sodium ingestion without adequate water intake, or excessive water loss.

2. Insufficient ADH (Diabetes insipidus)

3. Loss of thirst mechanism

4. Watery diarrhea

5. Prolonged periods of rapid respiration.

Front 24

24. Serum levels are relatively low normally. Why is this so?

Back 24

This is because potassium is an intracellular cation. Normal levels are about 3.5 to 5mEq per liter compared with the intracellular concentration that is about 160 mEq per liter.

Front 25

25. Are potassium levels influenced by the acid base balance of the body?

Back 25

Yes. Acidosis tend to shift potassium ions out of cells and into the ECFs. Alkalosis moves them into cells.

Front 26

26. In cases of acidosis, where do H+ ions tend to move?

Back 26

In acidosis, many hydrogen ions move from the blood into the interstitial fluid because of the high hydrogen ion concentration in the blood.

When H+ ions move into cells, they force K+ ions out of the cell in order to maintain electrochemical neutrality. Excess K+ ions in interstitial fluid will move into the blood resulting in hyperkalemia.

Front 27

27. What is the role of potassium in the body?

Back 27

1. Regulation of intracellular fluid volume

2. Nerve conduction

3. Muscle contraction by determining membrane potential

4. Cardiac muscle maintenance

Front 28

28. List 5 causes of hypokalemia.

Back 28

1. Excessive body fluid loss due to diarhhea

2. Diuresis due to certain drugs such as Furosemide.

3. Excessive aldosterone or glucocorticoids (Cushing's syndrome)

4. Decreased dietary intake (alcoholism, dietary or starvation)

5. Ketoacidosis treatment with insulin

Front 29

29. List 6 effects of hypokalemia.

Back 29

1. Cardiac dysrhytmias

2. Neuromuscular function. Muscle sare less responsive to stimuli.

3. Parathesias- sensations of pins and needles.

4. Decreased digestive tract motility

5. Weakened respiratory muscles

6. Renal function impairment, failure to concentrate urine, with polyuria.

Front 30

30. List 5 causes of Hyperkalemia.

Back 30

1. Renal failure

2. Aldosterone deficit

3. Use of potassium sparing drugs

4. Leakage of intracellular potassium into ECFs (crash injuries or burns)

5. Displacement of potassium from cells by prolonged or severe acidosis.

Front 31

31. How is calcium achieved?

Back 31

It is controlled by parathyroid hormone and Calcitonin. It is also influenced by Vitamin D and phophate ion levels.

Front 32

32. What is the relationship between calcium and phosphate?

Back 32

Calcium and phosphate ions in the ECF have a reciprocal relationship. If calcium is high, phosphate levels are low.

Front 33

33. What is the usual result in soft tissue if levels of both calcium and phosphate rise?

Back 33

Crystals of calcium phosphate can precipitate in soft tissue.

Front 34

34. The active form, measured or biologically of calcium is the ionized form. True/False

Back 34

True. This forms is not attached to plasma protein or bonded to other ions such as citrate. Alkalosis will decrease the number of free calcium ions, causing hypocalcemia.

Front 35

35. Briefly describe the effects of hypocalcemia.

Back 35

1. Increase the permeability and excitability of nerve membranes, resulting in spontaneous excitation of skeletal muscle.

2. Muscle twitching, and possible carpo-pedal spasm (atypical contraction of the fingers

3. Hyperactive reflexes.

4. Chvostek's sign- spasm of the lip or face when the face is tapped in front of the ear

5. Trousseau's sign,- carpo-pedal spasm when a blood pressure cuff blocks circulation to the hand,

6. Tetany

7. Possible laryngospasm

8. Weak heart contractions (affected plateau)

Front 36

36. What is the serum calcium level in hypocalcemia?

Back 36

The serum calcium level is less than 2.2 mmol per liter or below 4 mEq per liter.

Front 37

37. List 5 causes of hypercalcemia.

Back 37

1. Uncontrolled release of calcium ions, from the bones, due to some tumors, such as Bronchogenic carcinoma, may secrete too much PTH

2. Hyperparathyroidism (adenoma)

3. Immobility (decrease of bone stress)

4. Increased intake of calcium due to excessive vitamin D or too much dietary calcium

5. Milk alkali syndrome- seen with increased milk and antaacid intake which can elevate serum calcium levels.

Front 38

38. List some major effects of Hypercalcemia.

Back 38

1. Depression of neuromuscular activity, with lethargy and stupor.

2. Interference of ADH in kidneys resulting in less absorption of water and in polyuria.

Accumulation of nitrogen wastes in severe cases.

3. Cardiac contractions increase in strength with possible dysrythmias

4. Decreased bone density, with spontaneous fractures especially in weight bearing areas causing bone pain.

If intake of calcium is high, PTH levels will be low and more calcium is stored in bone.

Front 39

39. List 6 truthful statements regarding magnesium in the body.

Back 39

1. Magnesium is an intracellular ion

2. Has a normasl serum level of 0.7 to 1.1 mmol per liter

3. About 50% of total body magnesium is stored in bone

4. Serum levels are linked to both potassium and calcium levels

5. It is found in green vegetables

It is important in may enzyme reactions.

Front 40

40. Low serum magnesium levels may also occur with the use of diuretics, diabetic ketoacidosis, hyperparathyroidism and hyperaldosteronism. True/False

Back 40

True.

Front 41

41. What are some effects of low magnesium levels?

Back 41

1. neuromuscular hyperirritability

2. Tremors or chorea (involuntary repetitive movements)

3. Insomnia

4. Possible increased heart rate.

Front 42

42. Hypermagnesemia usually occurs with renal failure. True/False

Back 42

True. It may depress neuromuscular function with decreased reflexes.

Front 43

43. Briefly explain where phosphates are found in the body.

Back 43

Phosphate ions such as HPO4-- and H2PO4-- are found primarily in bone, but circulate in both the intracellulae and extracellular fluids.

The serum level is normally 0.85-1.45 mmol per liter.

Front 44

44. List 5 important functions of phosphates.

Back 44

1. Bone and tooth mineralization

2. Metabolic processes, especially those important for energy of the cell, and ATP production usage.

3. Phosphate buffer system for acid base balance, removal of hydrogen ions from the body via the kidneys

4. Integral part of cell membrane

5. Reciprocal relationship with calcium

Front 45

45. What are some effects of hypophosphatemia?

Back 45

1. Possible impaired neurologic function

2. Tremors

3. Weak reflexes

4. Paresthesias

5. Anorexia

6. Dysphagia

7. Less efficient blood cell function, less efficient clotting and possible weakened phagocytosis.

Front 46

46. High serum phosphate can often result from renal failure. True/False

Back 46

True. Dialysis patients often take phosphate binders with meals to control serum phosphate levels.

Front 47

47. Briefly explain the behavior of chloride in the body.

Back 47

Cl- is the major extracellular anion with a normal serum level of 98 to 106 mmol per liter.

Cl- tends to follow sodium ions due to their strong intraionic attraction. High sodium ions is paralleled by high Cl- ions.

Front 48

48. How is Chloride involved in acid base balance?

Back 48

Cl- and bicarbinate ions, both negatively charged, can exchange places as the blood circulates to assist in maintaining acid base balance.

As bicarbonate ions are used up in binding with metabolic acids, chloride ions diffuse out of RBCs and into the serum in order to maintain the same number of negative ions in the blood.

Should chloride ions decrease, the reverse situation can be expected.

Front 49

49. What is the effect of vomiting on chloride levels?

Back 49

Low serum chloride is usually associated with alkalosis in the early stages of vomiting when HCl is lost from the stomach.

Front 50

50. Hyperchloemia can occue with excessive intale of sodium chloride. True/False

Back 50

True.

Front 51

51. What is the normal pH range in the body?

Back 51

It is 7.35-7.45. If serum pH is below 6.8 or above 7.8, death can result.

pH below 7.35 results in a depression of the CNS, and diminishes all cell enzyme activity.

Front 52

52. Why does the body have a tendency toward acidosis?

Back 52

This is because cell metabolism is constantly producing CO2 or carbonic acid, as well as non-volatle metabolic acids such as lactic acid, ketoacids, sulfates or phosphates.

Front 53

53. List three mechanisms that can control or compensate for pH.

Back 53

1. The buffers in the blood respond to pH changes immediately.

2. The respiratory system can alter carbon dioxide levels (carbonic acid) in the body by changing the respiratory rate.

3. The kidneys can modify the excretion rate of acids and the production and absorption of bicarbonate ion.

Front 54

54. Regarding pH compensation in the body, why are the kidneys the most effective mechanism for this control?

Back 54

Technically, the lungs can change only the amount of CO2 in the body. The kidneys are slow to compensate for a pH change but are the most effective mechanism because they are capable of excreting all types of acids (volatile and non volatile) as well as adjust serum bicarbonate levels.

Front 55

55. Specifically define a buffer.

Back 55

A buffer is a combination of a weak acid and its alkaline salt.

Front 56

56. List the body's 4 buffer pairs.

Back 56

1. The sodium-bicarbonate-carbonic acid system

2. The phosphate system

3.The hemoglobin system

4. The protein system

Front 57

57. What is the bicarbonate-Carbonic acid buffer system?

Back 57

The bicarbonate buffer system is composed of carbonic acid, which arises from the combination of CO2 with water, and bicarbonate ion, which is present as sodium bicarbonate.

Front 58

58. To maintain normal serum pH, what must be the ratio of bicarbonate ion to carbonic acid?

Back 58

It should be about 20:1

As one component of the ratio changes, the other component must change proportionately to maintain the necessary 20:1 ratio

Front 59

59. What are the four basic types of acid-base imbalance?

Back 59

1. Respiratory acidosis

2. Respiratory alkalosis

3. Metabolic acidosis

4. Metabolic alkalosis

Front 60

60. What is intended by acid-base decompensation?

Back 60

If both the kidneys and the lungs cannot compensate adequately, the ratio changes and the serum pH will move or shift out of the normal range.

Front 61

61. List 2 causes of respiratory acidosis.

Back 61

1. Slow, shallow respirations

2. Respiratory congestion.

Respiratory alkalosis is the result of hyperventilation possibly from anxiety or aspirin overdose.

Front 62

62. In both respiratory acidosis and alkalosis quickly differentiate how the kidneys would react to both of these conditions.

Back 62

In respiratory acidosis, the kidneys tend to excrete more hydrogen ion and reabsorb more bicarbonate.

In the case of alkalosis, the kidneys would react in a contrary fashion. They excrete less hydrogen ion and reabsorb less bicarbonate.

Front 63

63. Respectively, give the causes of Metabolic acidosis and alkalosis.

Back 63

Metabolic acidosis-

Shock

Diabetic ketoacidosis

Renal failure

Diarrhea

Metabolic alkalosis

Vomiting (early stage)

Excessive antacid intake

Front 64

64. What are some acute and chronic causes of respiratory acidosis?

Back 64

Acute problems such as pneumonia, airway obstruction (aspiration or asthma) or chest injuries, and those taking opiate drugs, which can suppress the respiratory control center.

Chronic respiratory acidosis is common in those with COPD such as is seen in emphysema.

Front 65

65. When might decompensated metabolic acidosis be observed?

Back 65

Individuals with severe diarrhea may be so dehydrated, that the kidneys are not receiving an adequate blood supply. As a result their function is diminished causing decompensation.

Cardiac arrest or severe arrhythmias might have the same effect.

Front 66

66. Alkalosis generally does not occur as frequently as acidosis. True/False

Back 66

True. As stated, respiratory alkalosis is caused by hyperventilation. Head injuries or brain stem tumors can lead to hyperventilation.

Front 67

67. In the early stages of vomiting, there is excessive loss of HCl from the stomach. What type of acid-base imbalance might be noticed here?

Back 67

Metabolic alkalosis.

Front 68

68. What is Anion gap?

Back 68

The anion gap is the difference in the measured cations (positively charged ions) and the measured anions (negatively charged ions) in serum, plasma, or urine. The magnitude of this difference (i.e., "gap") in the serum is often calculated in medicine when attempting to identify the cause of metabolic acidosis, a lower than normal pH in the blood. If the gap is greater than normal, then high anion gap metabolic acidosis is diagnosed.

Front 69

69. Sotolol has a side effect of Torsade de pointes, that can be prevented with supplemental magnesium. True/False

Back 69

True.

Front 70

70. What is Tromethamine?

Back 70

Tromethamine (THAM) is a sodium free alkalinizing agent that acts as a hydrogen ion (proton) acceptor.

Front 71

71. Normal saline is the solution of 0.9% NaCl. True/False

Back 71

True. It has a slightly higher degree of osmolality compared to blood.

Front 72

72. A 62 year old male patient who weighs 80kg, is scheduled for a 3 hour hemicolectomy procedure. He is NPO after 2200 hours, has surgery at 0800 hrs, with a 500 ml blood loss. What are his estimated intraoperative fluid requirements?

Back 72

Fluid deficit- 1.5 ml/kg/hr X 10 hrs= 1200ml= 1200 ml total deficit: Replace 1/2 in the first half hour, 1/4 in the second hour, and 1/4 in the third hour.

Maintenance: 1.5 ml/kg/hr X 3 hours = 360ml

Third space losses: 6 ml/kg/hr X 3 hours = 1440 ml.

Blood loss: 500 X 3 = 1500 ml

Total = 1200+360=1440=1500= 4500

Front 73

73. What is the formula for mean arterial pressure?

Back 73

MAP= (2X diastolic) + systolic/3

Diastole counts two times more than systole because 2/3 of the cardiac cycle is spent in diastole.

Front 74

74. “Which patient has a better blood pressure, the patient with a blood pressure of 110/40 or the patient with a blood pressure of 90/60?

Back 74

Mean arterial pressure (MAP) is generally considered to be the organ perfusion pressure in an individual. Because MAP requires an inconvenient calculation, we’ve all been taught…misled perhaps…into focusing on systolic blood pressure (SBP) as a marker of how well-perfused a patient is, and we tend to ignore the diastolic blood pressure (DBP).It’s important to remember, however, that we spend most of our lives in diastole, not systole. As a result, our organs spend more time being perfused during diastole than systole. The MAP takes this into account: MAP = (SBP + DBP + DBP)/3. DBP is more important than SBP!So which patient is perfusing his vital organs better, the one with a BP of 110/40 or the one with a BP of 90/60? Do the MAP calculation…90/60 is better than 110/40!Pay more attention to those diastolic BPs!”

Front 75

75. If a patient's blood pressure is 83/50, what is his MAP?

Back 75

MAP = SBP + 2 (DBP) 3MAP = 83 +2 (50) 3MAP = 83 +100 3MAP = 183 3MAP = 61 mm HG

Front 76

76. What is a PaO2/FIO2 ratio?

Back 76

A PaO2/FIO2 ratio is an index to characterize the acute respiratory distress syndrome (ARDS), which involves severe hypoxemia (insufficient oxygen content in blood). PaO2 is the partial pressure of oxygen in arterial blood. It's usually measured in millimeters of mercury (mmHg or Torr) by the test called arterial blood gas (ABG) analysis. PaO2 of 75 to 100 mmHg is considered normal. FIO2 is the fraction of inspired oxygen or, simply percentage of oxygen, in a gas mixture. For example, the atmospheric air has FIO2 of 21 percent. If a patient needs mechanical ventilation, FIO2 is usually in the 30-to-40-percent range.

Front 77

77. What is an easy way to calculate loading dose of Esmolol, and drip rate?

Back 77

Divide the patient's body weight in kg by 2.

Ex: a 70kg man:

70 divided by 2 = 35mg

Multiply the loading dose by 0.1 to get the mg/kg/min drip rate

(0.1 X 35= 3.5mg