IV Fluid Management

Dr Andrew Stein, Consultant NephrologistCaroline Letchford, Practice Development Nurse, UHCW

Background Humans are 60% water 70kg man (43L water / 70kg = 61%): Intracellular (28L) Extracellular

Interstitial (10L) Intravascular (5L = 9 Pints)

Frail elderly = Hyponatraemic and ‘dry’ with SOA, on a LOOP diuretic (Na↓, K↓), and ACE/ARB/SPIRONO (K↑), .. ie ‘charged dry kidneys’, waiting AKI (UTI, gastro, drugs)

Normal maintenance requirements- Depends on weight. For 70 kg man

Amount/kg/time Amount/day Ideal

H20 in 1.5 ml/kg/h 2.5L

Na+ in 1-2 mmol/kg/24h 100 mmol (70-140)

K- in 0.5 mmol/kg/24h 50 mmol (35-70)

UO out >0.5 ml/kg/h Approx 0.8L Input = 2.5L

Output = 2.5L =

Urine = 1.5L (5 x 300 ml)Sweat = 0.5LLungs + faeces = 0.5L

Contents Available Fluids

Na+ Cl- K+ HCO3- Gluc Notes

Normal pl 135-145 100-120 3.5-5.0 22-26 3.5-7.8

0.9% NaCL 154 154 0 0 0 Not ‘normal’. pH 5.5

Hartmanns 131 111 5 29 (lactate) 0 PhysiologicalpH 6.5

5% Dext 0 0 0 0 50g (170 cals)

Water

Dext-Saline 4%/0.18%

30 30 0 0 40g

Gelofusin 154 120 0 0 0 Colloid

Fluid State AssessmentSeverity Clin Pulse BP JVP

(not CVP)Severe SOB++.

DrowsyTachyc++ ? V high

Mod SOB+ Tachyc+ ? High

Hypervolaemia Mild N Tachyc N NEuvolaemia N N N

Hypovolaemia Mild N Tachyc N NMod Drowsy Tachyc+ Low (<100

systolic)Not seen

Severe Unconscious Tachyc++ V low <80) Not seen

Tachycardia = Acute ProblemBradycardia = (Prob) Problem

Patient = (centrally) ‘wet’, ‘dry’ or ‘middle’, not 2/3 or 3/3) ..you have to decide

Hartmann’s Solution

‘Physiological’: Na+ 131 (135-145 Cl- 111 (100-120) K+ 5 (3.5-5.0) HCO3- 29 (22-26) as lactate

Good as a plasma replacement fluid, esp post-op Good for sepsis Complications 1930s. American pediatrician Alexis Hartmann for treating

acidosis

‘Normal’ Saline – 0.9% Not ‘normal’ at all Not physiological, so no role as a maintenance

fluid - if given alone Hypernatraemic (Na+ 154 mmol/L) Hyperchloraemic (Cl- 154 mmol/L) Acidotic (pH 5.5)

Complications 1831. William Brooke ‘Shaughnessy, E’burgh. Just qualified. Indian Blue

Cholera pandemic 1882-83. Hartog Jacob Hamburger. Dutch physiologist coined term

‘normal’

5% Dextrose

Is water Given instead of pure water (maintenance) No role as a replacement fluid (plasma or blood), as not

physiological If can drink, give water orally (or by NG if cannot) Not sugar and not a food Complications

Dextrose Saline – 4%/0.18%

Na+ 30 mmol/L Cl- 30 mmol/L Good maintenance fluid No role as a replacement fluid as not

physiological

Colloid

Eg gelofusin, albumin Given to keep fluid in intravascular space Not inert (like crystalloids) Complications Not recommended by NICE

Where Do IV Fluids Go?

Given IV, so initially into intravascular space Then distributed across all fluid departments So .. NB: can get premade crystalloids with K in (eg

20 or 40 mmol/L)

Blood Packed cells (300 ml) vs whole blood (450-500 ml) Replacement (Emergency, ie bleeding)

Do not wait for blood. Give anything eg 0.9% Saline Whole blood (stat) O negative if necessary

Maintenance – packed cells, 2h Does ‘maintenance blood transfusion’ exist

Consider FRUS ‘cover’ (NB: normal dose, if creat >200, give 80 mg)

Check K+ if necessary

Principles - Choosing IV Fluid

1. Overall requirements = replacement then maintenance fluids

2. Give what they lack, at rate they need (prop to loss and weight)

• Plasma• Na, K• Blood

Replacement Fluids

Hartmanns Occ N Saline, 2N Saline, Dext-saline

(Colloids) 50% Dext if hypoglycaemic Blood

Acutely Hypotensive Patient

Needs IV fluids (usually). Rarely FRUS! Anything (physiological, not, colloid, blood) 250-500 ml/15 min then re-assess More (much) if bleeding (or might be) If little/no response (feels better, BP, UO), call

reg, ICU (? more fluids ?inotropes)

Maintenance Fluids Dextrose-saline Alternating “1 salty and 2 sweet, with a leetle but of K in”

(0.9% Saline/5% Dext (+ K 20 mmol/L)) This gives: 3L H2O, 154 mmol Na+, 60 mmol K+ Vs Hartmanns: 3L H2O, 393 Na+, 15 K+ Vs requirements: 2.5L H2O, 100 Na+, 50 K+

3L a day Too much for 70 kg man, esp if drinking Far too much for 40kg old lady Too little for 120 kg man

Special Situations

Post-op. Give if need only. K is intracellular CCF. Not >2L/day CLF (esp if unsure fluid state). 5% Dext only CRF/AKI (esp if unsure fluid state) Sepsis. ‘Third space’. Eg warm hands, tachyc, low

BP. Hartmanns. May need inotrope Alcohol. Give Pabrinex before any 5% Dext Cerebral haemorrhage. 0.9% Saline. No Dext

IV Fluids - Complications Affect Na

0.9% NaCl 0.9% - ↑ 5% Dext - ↓

Affect K Hartmanns, Blood – ↑

Acid/base 0.9% NaCl - acidosis

Any Fluid overload (incl pulmonary oedema), esp blood

IV Fluids - Ten Commandments1. Humans = 60% water. Know where it is (compartments). Think about ‘Third Space’

2. IV fluids are a drug. Only give if patient needs them

3. Assess fluid state before prescribing. 1. Examination (esp JVP, not SOA), 2. Obs (incl UO) and 3. U+E. Ask the patient! Clinical mainly. Beware CVP errors

4. Patient is hypervolaemic, hypovolaemic or euvolaemic. Decide, or ask.

5. Overall requirements = replace + maintain1. Replace plasma with physio fluids (noting K)

2. Replace blood with blood

3. Maintain with NaCl/Dext

6. All drugs have side-effects. IV fluids cause/worsen biochem disturbance (eg Na or K up, or acidosis) or cause pulmonary oedema

7. If BP (or UO) not up after replacement .. ?inotropes (call reg)

8. Young patients will not drop BP until >30% blood/fluid loss

9. Do not copy previous fluids. Go and see, assess patient, then prescribe/stop

10. If in doubt .. do ABGs and ask

Thankyou

http://www.oscestop.com/Adult%20IV%20Fluids.pdf caroline.letchford@uhcw.nhs.uk andrew.stein@uhcw.nhs.uk