IV Fluid Management

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

Keep up with the fluids

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)

Structure of Talk• Human water content + distribution• Fluid requirements• Fluid state assessment• Available fluids• Replacement (incl acute hypotensive patient)• Maintenance• Special situations

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

Fluid State AssessmentSeverity Clin Pulse BP JVP

(not CVP)

Severe SOB++. Drowsy

Tachyc++ ? V high

Mod SOB+ Tachyc+ ? High

Hypervolaemia Mild N Tachyc N NEuvolaemia N N N

Hypovolaemia Mild N Tachyc N N

Mod 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

Contents Available FluidsNa+ 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

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

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 paediatrician Alexis Hartmann for treating

acidosis

Colloid

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

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

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

‘Normal’ Saline – 0.9% Not ‘normal’ at all Not physiological, so no role as a maintenance• fluid - if given alone

Na+ 154 mmol/L (135-145) Cl- 154 mmol/L (100-120) 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

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)

IV Fluids - Complications Affect Na

0.9% NaCl 0.9% 5% Dext

Affect K Hartmanns, Blood

Acid/base 0.9% NaCl

Any Fluid overload (incl pulmonary oedema), esp blood

Special Situations

1. Post-op. Give if need only. Rem: K is intracellular2. CCF. Not >2L/day3. CLF (esp if unsure fluid state). 5% Dext only4. CRF/AKI (esp if unsure fluid state). V variabel needs 5. Sepsis. ‘Third space’. Eg warm hands, tachyc, low

BP. Hartmanns. May need inotrope6. Alcohol. Give Pabrinex before any 5% Dext7. Cerebral haemorrhage. 0.9% Saline. No Dext

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 them3. 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 errors4. Patient is hypervolaemic, hypovolaemic or euvolaemic. Decide, or ask.5. Overall requirements = replace + maintain

1. Replace plasma with physio fluids (noting K)2. Replace blood with blood3. Maintain with NaCl/Dext

6. All drugs have side-effects. IV fluids cause/worsen biochem disturbance (eg Na or K ↑ or ↓, 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 loss9. 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