Fluids

Question 1

Normal physiology

Answer 1

Total 42L water
14L ECF- 1L transcellul, 3.5L plasma, 9.5L interstit
28L ICF

Question 2

Insensible loss

Answer 2

Unaware and diffic to quantify, cant be elim-
Transdermal diffus and evap
Resp evap
Sweat?

Question 3

Sensible loss

Answer 3

Can be seen, felt and measured-
Urine
Defecation
Wounds

Question 4

Osmotic press

Answer 4

Abil of a solute to attract water.

Or press needed to reverse osmosis.

Question 5

Oncotic press

Answer 5

Press by prots to draw water into BV

Question 6

Hydrostatic press

Answer 6

Press of incomp fluid on sealed container eg BV

Question 7

Osmolality

Answer 7

Osmoles per kg of solvent

Plasma 280-305mOsmol/kg

Question 8

Osmolarity

Answer 8

Osmoles per L of solution

Question 9

Osmoles

Answer 9

Number of moles of solute that contrib to osmotic press

Question 10

tonicity

Answer 10

Effective osmolarity of solution

Same fluid can be hyper or hypotonic dep on where put it

Question 11

forces

Answer 11

Osmotic forces act across all compartments
Stalrings forces (oncot and hstat) act btw intra vasc and interstit fluid

Question 12

Veins vs arteries

Answer 12

MABP 80-100mmHg- high hstat press, high prot oncotic press.
Venous press 10mmHg- low hstat press, high oncotic
In sepsis capills leak prot so high oncot press into tiss so draws fluid out.

Question 13

Imp ion concs

Answer 13

Na- plasma 137-147, interstit 144, IC 10
K- plasma 3.5-5, interstit 4, IC 160
Gluc- plasma 3.9-6.1
Prot- plasma 10
Cl- plasma 110

Question 14

4/2/1 rule for baseline maint fluid only

Answer 14

1st 10kg- 4ml/kg/hr
2nd 10kg- 2ml/kg/hr
Subseq mass- 1ml/kg/hr
Often simplif to 1-2ml/kg/hr in adults

Question 15

Na and K reqs for adult

Answer 15

Na- 1-1.5mmol/kg/day

K- 0.7-1mmol/kg/day

Question 16

Regulation

Answer 16

ADH- opens CD aquapaorins. More rel if high Na.
High A and BNP predictor of HF.
RAAS

Question 17

NICE

Answer 17

Asses the pt
5 Rs- resus, routine maint, repl, redistrib, reass
Less fluid, less Na, more K

Question 18

Types

Answer 18

Crystalloid dissolved salt and sugar eg saline, hartmanns. Hypo, iso and hypertonic.
Colloid susp not dissolved eg gelatin, starch, alb. Draw fluid into BV. Rarely used now.
Blood products.

Question 19

Contents

Isotonic fluids 300mOsM

Answer 19

0.9% saline- 154mmol/L Na, 154 Cl
5% dextrose- 50g/L gluc
Dextrose saline- 30 Na, 30 Cl, gluc
Hartmanns- 130 Na, 109 Cl, 4K
Can get KCl 20 or 40mmol/L to saline, dextrose and dextrose saline. Given by infusion pump. Req cardiac monit if central V.
Can give 10mmol/hr K via norm V, more can burn. Big vein up to 20mmol/hr.

Question 20

Clinical assess

Answer 20

ABCDE, EWS
Reason for fluids
Hx
Diag
Dehyd- last food and fluid
Losses- diarr, vom, burns
Thirst
Postural symps
Urine output and col
Drugs eg diuretics
Weight
Pulse
Cap refill
Mucous mems
JVP
Visible oedema
Pmh- DM, CCF, CKD
UE, Cr, Hb, haematocrit
urine biochem
ECG

Question 21

Bolus

Answer 21

500ml bolus crystalloid eg hartmanns
Give fast with press bag attached
Asses resp
If inadeq give further bolus 250-500ml up to 2L total. Then seek help.
Tx cause
Fluid chall- 500ml in 10-30 mins. 20-30mk/kg/hr.

Question 22

Resus vs repl

Answer 22

Resus- ongoing fluid loss

Repl- previous loss, reqs repl

Question 23

Hypovol

Answer 23

Fluid chall- 500ml saline or hartmanns fast as poss

The reass

Question 24

Crystalloid

Answer 24

Maint and hydration

Question 25

colloid

Answer 25

``` Acute resus or repl. 250-500ml. Can worsen oedema if inflamm. Coagulopathic in trauma. Risk anaph. Expensive Crustalloid if in doubt. Main 3 are volplex gelatin, albumin, blood products. ```

Question 26

confused pt

Answer 26

Exclude hypoxia and dehyd first

Question 27

Key Qs

Answer 27

``` Pt size and weight Comorbidiy- heart, lung, renal Situation- resus vs maint Why in hosp- eg how far post op Most recent UE Underlying physiol What are they losing and how much- eg diarr, pancreatitis, open wound, perforat, obstruc cause loss electrolyte rich fluid. ```

Question 28

fluid func

Answer 28

Maint SV and hence perfus MABP= tpr x CO CO= HR x SV Low BP must be due to one of these facs eg dehyd, meds, sepsis Too much fluid over time causes overload and HF

Question 29

dextrose

Answer 29

Pure water not for resus | Good for maint just water

Question 30

hartmanns

Answer 30

Good for resus Still only 1/6 of it gets to plasma May need lot in resus phase

Question 31

sedentary av adult maint

Answer 31

2.5-3L/ day 150mmol Na per day 60mmol K per day

Question 32

Renal dis

Answer 32

Cant excrete K- hyperK

Question 33

fluids need to be isotonic

Answer 33

300 mOsM approx

Question 34

Maint regimens if start IN BAL Eg after resus UE norm, still NBM

Answer 34

Loads of saline causes acidosis Regimen 1- 1L saline 8hr, 1L 5% dextrose 8hr, 1L 5% dextrose 8hr. Regimen 2- 1L dex/saline 8hr, three times. Adjust acc to UO and UE.

Question 35

resp to surgery

Answer 35

Incr ADH as stress- reduc UO, Na reten. Incr aldoserone and cortisol- Na reten, loss K and H. Incr catecholamines Incr renin K rel by damaged tiss. So dont us give supplem K during 1st 48 hr post op.

Question 36

IV K risks

Answer 36

Renal comprom K sparing diuretics HypoK- VF HyperK- asystole

Question 37

K regimens if start IN BAL

Answer 37

Regimen 1- 1L saline 8hr 20M K, 1L 5% dextrose 8hr 20M K, 1L 5% dextrose 8hr. Regimen 2- 1L dex/saline 20M K 8hr TWICE, then 1L dex/saline 8hr. Over 20mmol/hr needs uspervis by senior and controlled pump.

Question 38

UO

Answer 38

``` Oliguria under 400ml/day Anuria under 100 Sensitive indicator hydrat status Normal 0.5ml/kg/hr Hourly monit post op. Us bit low. If unus low then small bolus top ups and monit. Also check BP, catheter, UO, drug chart. ```

Question 39

dehyd signs

Answer 39

``` Sunken eyes Reduc ocular press Reduc skin turgor Dry mucous mem Low UO Thirst Late- cap refill, tachc, low BP ```

Question 40

Equation

Answer 40

Vol (ml)/ time (mins) x giving set= drops per min

Question 41

Reasons

Answer 41

Resus- want to stay in IV space Maint- want fluids to distrib to all comparts Repl

Question 42

fluid overload

Answer 42

JVP Periph and pulm oedema Late- tachyc/p, hypoxia Monitor- UO, UE, weight.

Question 43

daily reqs

Answer 43

25ml/kg/day water 1mmol/kg/day Na 1mmol/kg/day K 50g/day glucose

Question 44

Fluid chall | Eg anyone with low UO

Answer 44

250 or 500ml hartmanns over 1hr | But account for pt facs

Question 45

ongoing losses Qs

Answer 45

``` Thrid space loss Is there diuresis Tachyp Temp Amnt of stool Are they losing electrolyte rich fluid Egs- dehyd (high urea to Cr ratio and high PCV), vom (low K, low Cl, alkalosis), diarr (low K, acidosis) ```

Question 46

Monitoring

Answer 46

Fluid bal Weight UE