Fluid Prescribing

Question 1

5 Rs of fluid prescribing

Answer 1

• resuscitation
• replacement
• routine maintenance
• redsitribution
• reassessment

Question 2

name 2 crystalloids

Answer 2

sodium chloride 0.9% and Hartmanns solution

Question 3

what are the benefits of crystalloids

Answer 3

cheap and widely available

Question 4

what does Hartmanns contain

Answer 4

crystalloid with added electrolytes eg Potassium

Question 5

define routine maintenance

Answer 5

provide daily maintenance requirements

Question 6

define replacement

Answer 6

• Provides daily maintenance requirements and replacement of any ongoing abnormal losses

Question 7

define resuscitation

Answer 7

• Re-establishes haemodynamic stability through restoring intravascular volume

Question 8

name a colloid

Answer 8

Gelofusin

Question 9

colloids

Answer 9

should theoretically maintain onctoic pressure, however in practice they are not very good

Question 10

what are the negative sides of colloids

Answer 10

risk of anaphylaxis

expensive

Question 11

what solution is recommended for resuscitation

Answer 11

• crystalloid solution
• balanced crystalloid is good as excessive sodium chloride 0.9% can cause hypercholermic metabolic acidosis

Question 12

what is hypercholermic metabolic acidosis

Answer 12

an acidosis with a normal anion gap, caused by increased chloride and decreased bicarbonate

Question 13

when is Hartmanns solution avoided

Answer 13

in cases of eg rhabdomyolysis and AKI/CKD, when sodium chloride 0.9% is preferred due to the risk of hyperkalaemia (cells die and release phosphate and potassium ions)

Question 14

what is recommended for replacement therapy

Answer 14

balanced/crystalloid

Question 15

what is the normal daily requirement for water

Answer 15

25-30ml/kg/day

Question 16

what is the normal daily requirement for sodium, potasiuma and chloride

Answer 16

1mmol/kg/day

Question 17

what is the normal daily requirement for glucose

Answer 17

50-100g/day

Question 18

what fluids are recommended for routine maintenance

Answer 18

• 0.18% Sodium chloride/4% dextrose
• 0.45% Sodium chloride
• 5% dextrose

Question 19

what is the max fluid volume given in a day roughly

Answer 19

2.4l

Question 20

which fluids redistribute most into the PV

Answer 20

balanced/crystalloids

Question 21

when should albumin be used

Answer 21

• severe sepsis
• hepatorenal syndrome
• large volume paracentesis
• therapeutic plasma exchange

Question 22

blood as a colloid

Answer 22

it is the most physiological colloid, it increases oxygen carrying capacity

there is a risk of a type II hypersensitivity ABO reaction - overwhelming systemic inflammatory response that can occur with 1ml of blood

Question 23

PRC

Answer 23

packed RBCs - indicated when paient has lost a lot of blood or has anaemia

Question 24

FFP and cryoprecipitate

Answer 24

• FFP used when there are low clotting factors or other blood proteins
• cryoprecipitate is a concentrated subset of FFP components

Question 25

management of hyponatraemia if the patient is dry

Answer 25

0.9% saline

Question 26

management of hyponatraemia if the patient is euvolaemic

Answer 26

* consider SIADH - do a paired urine and serum osmolality and urinary electrolytes * the RAAS system is still intact, maintaining volumes

Question 27

treatment of SIADH

Answer 27

water restriction to ≤1l a day and treat underlying cause

Question 28

management of hyponatraemia if the patient is overloaded

Answer 28

water restriction consider diuretics if there is significant or symptomatic volume overload (eg ascites or pitting oedema)

Question 29

what is the goal of initial therapy in correction of hyponatraemia

Answer 29

* raise the serum sodium concentation by 4-6mg in a 24 hour period * in emergency, in a 6 hours period or less * maintain sodium constant thereafter

Question 30

what must sodium rise be restricted to in 24 hours

Answer 30

* 9mg/L * rapid correction risks osmotic **demyelination** - widespread demyelination of pontine area

Question 31

which patients are at risk of osmotic demyelination

Answer 31

* those with Sodium serum concentrations ≤105mg/L, and those with hypokalemia, alcoholism, malnutrition and liver disease

Question 32

what is severe hyponatraemia defined as

Answer 32

Na \<120 mmol/L

Question 33

what is emergency treatment

Answer 33

100ml 3% saline over 10-15 minutes

Question 34

which patients are indicated for aggressive therapy to raise sodium ASAP

Answer 34

* severe symptoms due to hyponatraemia eg seizures, obtundation * acute hyponatraemia with symptoms * hyperacute hypnatramie due to self induced water intoxication, even if there are no symptoms. serum Na may worsen spontaeously due to delayed ingestion of water * symptomatic patients with acute post op hyponatraemia or hyponatraemia associated with intracranial pathology

Question 35

what is there a risk of with acute onset hyponatraemia

Answer 35

* cerebral oedema due to osmotically driven water flow across BBB * manifest as impaired consciousness, seizures, raised ICP * potentially death due to brain herniation