Fluid prescribing

Question 1

What are the four reasons for fluid prescribing?

Answer 1

fluid resus
routine maintenance
replacement
redistribution

Question 2

What are the principles for fluid prescribing?

Answer 2

the physiology of fluid balance in health
pathophysiological effects on fluid balance
clinical approach to assessing IV fluid needs
the properties of available IV fluids

Question 3

How much of the average body weight is comprised of water?

Answer 3

60%

Question 4

What is the extracellular volume in the body?

Answer 4

20% of body weight

~14L in adv man

Question 5

what is extracellular volume subdivided into?

Answer 5

intravascular and extravascular

Question 6

what is the volume of intravascular space?

Answer 6

4-5L

Question 7

What is the insensible loss

Answer 7

about a litre a day

Question 8

what do you have to pee in a day?

Answer 8

at least 500ml

Question 9

How do you measure the concentration of the urine?

Answer 9

check the urine osmolality

Question 10

What happens when the body cannot excrete or has too much retention of Na?

Answer 10

oedema and adverse clinical outcome

Question 11

What is normal interval of K?

Answer 11

3.5-5.3

Question 12

What should you be thinking of a patient that is fasting and malnoursied and you are giving him or her IV glucose?

Answer 12

the glucose increases insulin production in the pancreas then causing increased intra-cellular uptake of K, Mg, phosphate, and calcium. this can lead to depletion. REFEEDING SYNDROME

Question 13

Prescribing in cardiac dysfunction

Answer 13

increased senstivity to fluid and Na overload with congestive heart failure. Potential of hypokalemia from duiretics and RENIN angiotension aldosterone activation. OR hyper K if on spironloactone severe cardiac paitnet may have renal or liver impairment

Question 14

Prescribing in renal disease

Answer 14

impaired clearance or excessive losses of both fluids and e- in acute and chronic kidney disease. disordered calcium and phosphate in chronic renal failure

Question 15

prescribing in a GI ward

Answer 15

high losses of fluids and e-

patients with an ileus can sequester large volumes of lfuids

Question 16

Prescribing in liver disease

Answer 16

Very abnormal fluid and electrolyte handling with a tendency for marked sodium and water retention due to complex pathophysiological changes including hyper-aldosteronism. Moderate to severe renal impairment is seen in many patients – the hepato-renal syndrome).

Question 17

Respiratory disease

Answer 17

High respiratory fluid losses but many patients are vulnerable to fluid overload. SIADH common. Cor-pulmonale makes patients vulnerable to venous circulatory overload, sometimes with hepatic congestion and dysfunction.

Question 18

Prescribing in neurology

Answer 18

Hypothalamic or pituitary disease can severely damage fluid regulatory mechanisms. High concentration IV saline is sometime administered to try to reduce intracranial pressure.

Question 19

Prescribing in Derm

Answer 19

urns and other extensive skin inflammatory problems can lead to very high fluid/plasma loss

Question 20

endocrine

Answer 20

Problems including diabetes mellitus, Addison’s disease and SIADH can markedly alter fluid and electrolyte handling.

Question 21

first question to ask yourself?

Answer 21

Is this patient needing fluid bolus? Are they shocked? Look at their vitals 
pulse greater than 20 above baseline 
sys Bp less than 20 than normal 
cap refill greater than 2 sec
RR greater than 20 per min 
UO less than 0.3ml/ kg/hr