Fluids and Electrolytes

Question 1

How many litres of water = 1 kg?

Answer 1

1 L = 1 kg

Question 2

Where is 2/3 of the body’s water held: ICF or ECF?

Answer 2

ICF

Question 3

What is the primary cation in ICF and ECF?

Answer 3

ICF = potassium

ECF = sodium

Question 4

Define diffusion and facilitated diffusion

Answer 4

• Diffusion – molecules move from high to low concentration until equal, needs permeable membrane to diffusing substance, no external energy (passive)
• Facilitated diffusion – uses a protein carrier, large molecules that can’t pass on their own, high to low concentration, no external energy (passive)
  o i.e., if a patient has meningitis, we have to pair the antibiotic with a protein to surpass the blood-brain barrier

Question 5

Define active transport and osmosis

Answer 5

• Active transport – requires energy, moves against concentration gradient
  o Sodium and potassium are essential and use active transport
  o They can move against or with gradients
• Osmosis – water moves through a semi-permeable membrane, low solute to high solute, no energy, stops when concentrations are equal OR when hydrostatic pressure builds and is sufficient to oppose any further movement of water (i.e., IV administration)

Question 6

Define hydrostatic pressure and oncotic pressure

Answer 6

• Hydrostatic pressure – force within a fluid compartment (i.e., blood pressure) – can be referred to as a pushing pressure
  o Major force that pushes water out of the vascular system at the capillary level
• Oncotic pressure – osmotic pressure exerted by colloids (proteins) in a solution (can be referred to as a pulling pressure)

Question 7

How can we increase hydrostatic pressure?

Answer 7

Increase hydrostatic pressure through an increase of fluid, such as IV

Question 8

Do alcoholics have high or low oncotic pressure?

Answer 8

Low due malnutrition

Question 9

Will malnutrition result in low or high oncotic pressure?

Answer 9

Malnutrition may result in low oncotic pressure – can quickly get protein into the IF through a transfusion of albumin

Question 10

Define hypotonic and hypertonic

Answer 10

• Hypotonic - Solutions in which the solutes are less concentrated than they are in the cell (i.e., water would move into the cell)
• Hypertonic - Solutes are more concentrated in the ECF than inside the cells (i.e., water would move out of the cell to dilute the ECF)

Question 11

Describe the difference between first, second, and third spacing

Answer 11

First spacing – normal/regular

Second spacing – abnormal accumulation of interstitial fluid (edema)

Third spacing – fluids accumulating in an area we cannot easily exchange (i.e., ascites – usually need to perform paracentesis)

Question 12

How do the hypothalamus and pituitary regulate water balance?

Answer 12

Hypothalamus – balances intake, excretion, and known as the control centre; stimulates the ADH receptors if there is a need for drinking

Pituitary (posterior) – releases ADH, which induces water reabsorption in the renal distal and collecting tubules

Question 13

How does the adrenal gland regulate water balance?

Answer 13

Releases glucocorticoids (i.e., cortisol, increase glucose level in the blood, which drives us to drink water) or mineral corticoids (aldosterone – causes sodium retention, which congruently retains water while dumping potassium)

Question 14

How does aldosterone effect water balance?

Answer 14

Promotes sodium retention and thereby water retention, and dumping of potassium

Question 15

How does cortisol affect water balance?

Answer 15

suppresses the urge to drink and urinate

Question 16

How does atrial natriuretic factor (ANF) effect water balance?

Answer 16

ANF will be released when the atria expand due to increased fluid volume - this results in vasodilation and increased excretion from the kidneys, which decreases blood volume

Question 17

How much water does the GI tract absorb on a daily basis?

Answer 17

2-3 L per day

Question 18

What is the primary portion of the body for water balancing?

Answer 18

The GI tract

Question 19

Define insensible water loss and how much is lost per day to this

Answer 19

Loss of fluid from lungs and skin

900mL of fluid lost per day – fever and hyperventilation could increase fluid loss

Question 20

List four older adult concerns with water balance

Answer 20

Decreased kidney functions, decreased hormone and hormone functions, dermal regulation (cannot adjust as quickly to heat and cooling – sudden changes to temperature are not well adapted), decreased sense of thirst

Question 21

What cardiac medication may lead to hyperkalemia?

Answer 21

ACE inhibitors

Question 22

Leg cramping, peaked T waves, and atrial fibrillation (cardiac depolarization) are all symptoms of

Answer 22

hyperkalemia

Question 23

Flattened t-waves and heart dysrhythmias are symptoms of

Answer 23

hypokalemia

Question 24

impaired memory, confusion, disorientation, fatigue, muscle weakness, constipation, cardiac dysrhythmias are symptoms of

Answer 24

hypercalcemia

Question 25

neuromuscular irritability, tetany are symptoms of

Answer 25

hyperphosphatemia

Question 26

What is tetany and what are two signs that indicate it?

Answer 26

Prolonged/continuous muscle contraction due to hypocalcemia

Trousseau’s and Chvostek’s sign – carpal spasms and contraction of face muscles in response to a tap over the facial nerve

Question 27

What electrolyte imbalance presents very similarly to hypocalcemia?

Answer 27

hypomagnesemia

Question 28

edema (due to reduced oncotic pressure), slow healing, anorexia, fatigue, and anemia are symptoms of

Answer 28

low protein

Question 29

How is an ABG collected?

Answer 29

Blood taken from the artery instead of the vein

Question 30

How will oxygen-rich versus oxygen depleted blood look?

Answer 30

Oxygen rich blood will be bright red, whereas oxygen depleted blood will be a burgundy colour

Question 31

What is the normal pH range?

Answer 31

7.35 to 7.45

Question 32

What three systems regulate acid-base balance?

Answer 32

Buffers, respiratory system, and renal system

Question 33

How do buffers reduce/manage acid-base balance?

Answer 33

Strong acids get converted to weaker acids if blood is too acidic or bind acids to neutralize their effect

Question 34

How does the respiratory system effect acid-base balance?

Answer 34

Excretes CO2 and water through either increased or decreased rate of respiration

o If increased amounts of CO2 and H+ are present, the respiratory system stimulates an increased rate and depth of breathing

o If low levels of CO2 and H+ are present, the respiratory system stimulates a decrease in respirations

Question 35

How does the renal system effect acid-base balance?

Answer 35

The renal system either reabsorbs or conserves hydrogen

secretion of small amounts of free hydrogen into renal tubule, combination of H+ with ammonia to form ammonium, and excretion of weak acids

Question 36

Provide an example of isotonic, hypotonic, and hypertonic solutions

Answer 36

Isotonic - 0.9% NaCl, ringer’s lactate, D5W

Hypotonic - 0.45% NaCl

Hypertonic - 3% NaCl

Question 37

What is our primary concern with patients on hypertonic solutions?

Answer 37

Must be cautious of the patient’s kidney and heart function because they can go into fluid overload quickly