Week 10 - fluids and acid-base balance

Question 1

What are the two main fluid compartments?

Answer 1

Intracellular (ICF) and Extracellular (ECF)

Question 2

Extracellular is further divided into:

Answer 2

• Intravascular (within blood vessels)
• Interstitial (surrounding the cell. e.g. lymph)
• Transcellular (cerebrospinal, synovial, pleural, sweat, digestive secretions)

Question 3

Movement of fluid through cellular & capillary walls depends on:

Answer 3

• Hydrostatic pressure (pressure exerted on walls of blood vessels eg. BP)
• Osmotic pressure (exerted by the protein in plasma)

Question 4

The direction of fluid movement depends on the differences of these pressures?

Answer 4

• Passive (osmosis, diffusion, filtration)

* Active (Active Transport)

Question 5

Osmosis is:

Answer 5

The movement of a low solute concentration to an area of high solute concentration in an attempt to reach equilibrium.

Question 6

Tonicity is:

Answer 6

The ability of solutes to influence an osmotic gradient.

Question 7

A Hypertonic solution is

Answer 7

a solution that contains a higher concentration of solutes than say, blood. So an IV solution that is hypertonic has more solutes to solvent (water) than the blood does. e.g. 3% NaCl (hypertonic saline). Used in critical situations to treat hyponatraemia which may be due to drinking too much water! (so drink more alcohol I say)

Question 8

A Hypotonic solution

Answer 8

a solution that contains a lower concentration of solutes than say, blood. e.g. 0.45% NaCl (half-strength saline). Used to treat hypertonic dehydration.

Question 9

And isotonic?

Answer 9

The same as blood - equilibrium - yay! e.g. 0.9% NaCl (normal saline). Works to expand extracellular fluid volume, used in hypovolaemic states.

Question 10

General rule for normal urine output for all body types

Answer 10

1 mL/kg/hour

Question 11

Fluid in third spaces is when:

Answer 11

Fluid is not lost from the body but remains unavailable for use.
Evidence of a third-space shift is a decrease in urine output despite adequate intake. Also increased HR, decreased BP, decreased central venous pressure, oedema, increased body weight.

Question 12

Homeostatic mechanisms _ fluid balance

Answer 12

• Kidneys • Heart/blood vessels • Lungs • Pituitary/hypothalamus function • Adrenal function • Baroreceptors • Thirst

Question 13

The elderly have reduced homeostatic mechanisms due to:

Answer 13

• Cardiac/respiratory/renal function
• Less muscle mass
• Decreased response to sympathetic/para-sympathetic nervous systems
• Thirst stimulation
• Diff. meds can affect responses and mask symptoms

Question 14

Hypovolaemia

Answer 14

May be either a volume or a distribution of water or electrolyte issue.

Question 15

Objective signs of hypovolaemia:

Answer 15

• skin/mucous membranes/weight loss
• Vital signs - especially postural BP drop
• U & E
- disproportionate urea - creatinine levels
- sodium decreased if adrenal, potassium decreased if GI, renal
• FBC - haematocrit increased

Question 16

Nursing management of hypovolaemia:

Answer 16

• oral & IV fluids (1st isotonic then hypotonic)
• fluid balance - input & output
• daily weights
• vital signs
• monitor skin & mucous membranes
• Urine specific gravity (1.010 - 1.025 depending on who you talk to)
• Mental function

Question 17

Hypervolaemia

Answer 17

Abnormal retention of fluid & electrolytes in equal proportion.

Question 18

Three processes maintain the acid-base balance

Answer 18

• Buffers • Lungs • Kidneys

Question 19

Buffers:

Answer 19

Bind or release H+

Question 20

A patient’s lab results show a slight decrease in potassium (K+). The physician has declined to treat with drug therapy but has suggested increasing K+ through diet. Which of the following would be a good source of K+?

a. Bananas
b. Carrots
c. Asparagus
d. Apples
e. Red wine

Answer 20

a. Bananas

Question 21

While admitting a new patient to our medical-surgical unit, you note that the patient is oliguric. You notify the medical officer who orders a fluid challenge of 100 to 200 mL of normal saline solution over 15 minutes. What do you know this intervention will do?

a. Help provide an effective treatment for hypertension induced oliguria
b. Help distinguish reduced renal blood flow from decreased renal function
c. Very little
d. Help evaluate pituitary gland function
e. Help distinguish hyponatraema from hypernatraemia

Answer 21

b. Help distinguish reduced renal blood flow from decreased renal function

Question 22

The nursing instructor is discussing renal failure with her senior nursing class. The instructor states: “A patient in renal failure partially loses the ability to regulate changes in pH.” What is the cause of this partial inability?

a. The kidneys produce carbonic acid to act in the buffering process.
b. The kidneys combine carbonic acid and bicarbonate to maintain a stable pH.
c. The kidneys buffer acids through electrolyte changes.
d. The kidneys regulate and reabsorb carbonic acid to change and maintain pH.
e. The kidneys regenerate and reabsorb bicarbonate to maintain a stable pH.

Answer 22

e. The kidneys regenerate and reabsorb bicarbonate to maintain a stable pH.

Question 23

A nurse in the medical ICU has orders to infuse a hypertonic solution into her patient with low BP. This solution will increase the number of dissolved particles in the patient’s blood, creating pressure for fluids in the tissues to shift into the capillaries and increase the blood volume. Which term or terms is/are associated with this process?

a. Hydrostatic pressure b. Rhubarb
c. Osmosis and osmolality d. Active transport
e. Diffusion

Answer 23

c. Osmosis and osmolality

Question 24

You are an emergency-room nurse caring for a trauma patient. Your patient has the following arterial blood gas results: pH 7.26, PaCO2 28, HCO3, 11 mmil/L. How would you interpret these results?

a. Respiratory alkalosis
b. Metabolic acidosis with a compensatory respiratory alkalosis
c. Metabolic alkalosis with a compensatory alkalosis
d. Metabolic acidosis with no compensation
e. Respiratory acidosis with no compensation.

Answer 24

b. Metabolic acidosis with a compensatory respiratory alkalosis

Question 25

A pt with anxiety presents to the emergency room. The triage nurse notes upon assessment that the pt is hyperventilating. The triage nurse is aware that hyperventilation is the most common cause of which acid-base imbalance?

a. None of the above
b. Respiratory alkalosis
c. Respiratory acidosis
d. CNS disturbances
e. Increased PaCO2

Answer 25

b. Respiratory alkalosis

Question 26

You are working on a burn unit. One of your patients is exhibiting signs and symptoms of third spacing, which occurs when fluid moves out of the intravascular space but not into the intracellular space. Based upon this fluid shift, what would you expect the patient to demonstrate?

a. Bradycardia b. Hypovalaemia
c. Decreased oxygen saturations
d. Hypervolaema e. Hypertension

Answer 26

b. Hypovalaemia

Question 27

You are caring for a pt admitted with a diagnosis of renal failure. When you review your pt’s lab reports, you note that the pt’s magnesium levels are high. What would be important for you to assess?

a. Increased Serum magnesium
b. Cool, clammy skin c. Tachycardia
d. Diminished deep tendon reflexes
e. Visual acuity

Answer 27

d. Diminished deep tendon reflexes

Question 28

Hyponatraemia refers to a serum sodium level that is

Answer 28

< 135 mmol/L (cell swells)

Question 29

Hypernatraemia refers toa serum sodium level that is

Answer 29

> 145 mmol/L (cell shrinks)

Question 30

Hypertension is a product of

a reminder of levels as well

Answer 30

• Cardiac output • Peripheral resistance
Grade 1 (mild) Systolic 140-159 Diastolic 90-99
Grade 2 (mod) Systolic 160-179 Diastolic 100-109
Grade 3 (severe) >180 Diastolic >110

Question 31

Signs of a haemolytic reaction

Answer 31

Restlessness, anxiety, flushing, chest/lumbar pain, tachypnoea, tachycardia, nausea, shock, blood in urine, chills & fever.

Question 32

Acute haemolytic reaction

Answer 32

Reaction is immediate with low BP, haemoglobinuria, bronchospasm & vascular collapse may result. Blood & urine specimens are obtained for evidence of haemolysis.
Treatment: Stop treatment, O2 10L. MET? Full assessment, vitals, check IV site for phlebitis.