5- Fluid replacement and renal response

Question 1

What is osmolality

Answer 1

Number of particles of solute per Kg of solvent mOsm/g

Question 2

What is osmolarity

Answer 2

Solute per litre of solution mOsm/L

Question 3

What is tonicity

Answer 3

Effective osmotic pressure gradient of two solutions separated by semipermeable membrane

Question 4

Where does water move when hypotonic

Answer 4

Into cells = swells

Question 5

Distribution of water in Male

Answer 5

60% 
2/3 ICF
1/3 ECF
25% plasma
75% interstitial

Question 6

Why do women have less fluid

Answer 6

More fluid in muscle then in fat

55% in women 60% men

Question 7

Total body water of baby

Answer 7

75%

Question 8

Total body water of elderly

Answer 8

45%

Question 9

Main intracellular cation and anion

Answer 9

K and PO4

Question 10

Main extracellular cation and anion

Answer 10

Na and Cl-

Question 11

What happens to water in hypernatremia

Answer 11

Water drawn out of cell
Shrinks
Confusion/ seizures

Question 12

What happens to water in hyponatremia

Answer 12

Water moves into cells
Swells
Cerebral oedema
Headache/ seizures

Question 13

Where does 5% dextrose distribute

Answer 13

Glucose taken up by cell
H2O reduces osmolarity of all compartments
2/3 rd to intracellular
1/3 to interstitial
1/12 to intravascular

Question 14

Where does NaCl 0.9% go

Answer 14

Remains in ECF
3/4 interstitial
1/4 intravascular

Question 15

Where does Hartmanns go

Answer 15

Majority retained in ECF

3/4 and 1/4

Question 16

Composition of Hartmanns

Answer 16

Na, K, Ca, Lactate (metabolised into HCO3)

Question 17

Where does 4% dextrose, 0.18% saline go

Answer 17

Effectively 200ml NaCl and 800ml dextrose
200ml remains in ECF
Then 800 ml distributes 2/3, 1/4, 1/12

Question 18

Why do patients need fluid

Answer 18

NBM
GI malfunction
Fluid loss
Dehydration
Electrolyte imbalance

Question 19

How are hospitalised patients requirements different

Answer 19

Do not sweat excessively
Stress response- RAAS - Na reabsorbed = retention
ADH- pain, nausea, drugs

Question 20

NICE guidelines- maintenance

Answer 20

25-30ml/kg/day water
1mmol kg/day K,Na,Cl
50-100g/day glucose

Question 21

NICE guidelines- resus

Answer 21

500ml bolus

Up to 2L

Question 22

How do we lose Na

Answer 22

Vomiting
NG tube
Biliary drainage lost
Pancreatic drain, colostomy, ileostomy

Question 23

How do we lose K

Answer 23

Vomiting

Diarrhoea

Question 24

When does congestive cardiac failure occur

Answer 24

When heart muscle pump cannot cope with workload
Output falls
Fails to perfuse tissues

Question 25

What does hypoperfusion in CCF lead to

Answer 25

Renal hypoperfusion sensed by kidneys as hypovolemia which results in compensation and retention in NaCl and water to increase circulating volume. Edema

Question 26

How does pulmonary oedema come around

Answer 26

Increased pulmonary venous pressure = transudate from capillaries in lungs

Question 27

How do you manage pulmonary oedema

Answer 27

ACEI Diuretics Vasodilators

Question 28

Causes of fluid overload

Answer 28

``` Excess of body salt and water Retention by kidneys Reduced effective arterial volume Decreased effective circulating volume- CCF Cirrhosis- protein in plasma Hyperaldosteronism ```

Question 29

How does hypovolemia lead to shock

Answer 29

Inadequate perfusion Hypoxic state leading to anaerobic metabolism and inefficient clearance of metabolites Tired, dizzy, thirst Vasodilation occurs to maintain blood supply = acute tubular necrosis = AK

Question 30

Severe decrease in circulating volume leads to

Answer 30

Stimulation of sympathetic activity by increases HR, peripheral vasoconstriction and increased contractility of heart.

Question 31

How to kidneys react to systemic vasoconstriction

Answer 31

Prostaglandins released to maintain GFR by dilating afferent

Question 32

Acid base disturbances in hypovolemic shock

Answer 32

Na involved in co-transport of H, K, Cl as Na is retained this disturbs H distribution Initially increase in H and K secretion = met alkalosis and hypokalemia Then shift to anaerobic metabolism as a result of hypoxia = metabolic acidosis As hypovolemia worsens less urine and less H secretion = more acidosis.

Question 33

Changes seen in hypertensive renal disease

Answer 33

Arteriosclerosis of renal arteries Hyalinization of small vessels with intimal thickening- respond to myogenic feedback Can lead to reduced kidney size and chronic renal damage (hypertensive nephrosclerosis)

Question 34

Secondary hypertension 1. Impaired excretion 2. Stenosis

Answer 34

1. Renal causes Impaired Na and water excretion = increase blood volume Renin release 2. Renal artery stenosis = reduced perfusion = excessive activation of RAAS