fluid and electrolyte objectives

Question 1

define mEq

Answer 1

the amount of substance it takes to comine with 1 mol H ions
or
amount of an ion needed to cancel out the electrical charge of an oppositely charge monovalent ion

Question 2

define mOsm

Answer 2

the measure of the number of osmotically active ions or particles in a solution

Question 3

define mmol

Answer 3

standard unit used when describing the amount of a substance.
the molecular weight of a substance in milligrams

Question 4

what is osmolality?

osmolarity?

Answer 4

osmolality = number of osmoles per kg of water
osmolarity = number of osmoles per liter of solution

Question 5

what is the formula for calculating plasma osmolality?

Answer 5

na + (glucose/18) + (BUN/2.8)

in mOsm/kg

Question 6

what is the formula for calculating mEq?

Answer 6

(mg x valence)/ atomic weight

Question 7

describe the distribution of total body water in a normal person?
how many compartments?
how much in each compartment?

Answer 7

2 compartments: ECF and ICF
1/3 of TBW in ECF
2/3 of TBW in ICF
ECF = 75% ISF and 25% IVF

Question 8

what amount of total body weight is used to find total body water?

Answer 8

60%

Question 9

what are the major electrolytes in the ECF and their normal levels

Answer 9

Na = 140 mEq/L
K = 3.5-5 mEq/L

Question 10

What is the major cation in the ICF and there normal levels

Answer 10

K = 140 mEq/L
Na = 12 mEq/L

Question 11

what levels are considered:

1. hypotonic
2. isotonic
3. hypertonic

Answer 11

1. hypotonic = less than 280 mOsm/L
2. isotonic = 280-300 mOsm/L
3. hypertonic = more than 300 mOsm/L

Question 12

what does ADH do to water and electrolyte balance?

Answer 12

ADH increases reabsorption of water in response to hypovolemia and hyperosmolarity
Secondarily it increases response to STOP AIM (Stress, trauma, operation, pulmonary insufficiency, Anesthetic, incection, multi-organ failure)

Question 13

what does Angiotensin II do to water and electrolyte balance?

Answer 13

Angiotensin II causes kidneys to retain both salt and water by:

1. acting directly on kidneys to cause salt and water reabsorption
2. causes the adrenal glands to secrete aldosterone

Question 14

what does aldosterone do to water and electrolyte balance?

Answer 14

aldosterone stimulates Na K ATPase pump on interstitium side of collecting tubules and increases the sodium permeability on the luminal side

Question 15

what do catecholamines do to electrolyte balance, and circulation in general?
what 3 factors are involved?

Answer 15

released via sympathetic system as vasoconstrictors
Increase Na reabsorption by:
1. direct stimulation of proximal and loop Na transport
2. increased arteriolar resistance
3. activate RAA system

Question 16

what effect does atrial natriuretic peptide have

Answer 16

counterbalance RAA system. produced in response to ADH, catecholamines and endothelin as a vasodialator (increase volume)

Question 17

what are some physical signs of water imbalance?

THIRD D

Answer 17

1. recent weight loss
2. diminished skin turgor
3. intraocular tension
4. dry mouth
5. tachycardia
6. hypotension

Question 18

what is associated with ECF volume excess (DIE)

Answer 18

1. increase capillary hydrostatic pressure in ECF
2. decreases plasma oncotic pressure
3. edema

Question 19

what are some signs of ECF expansion?

Answer 19

dyspnea
eyes puffy
weakness