Fluid balance and therapy in critically ill

Dr Anand.M.TiwariF.N.B critical care medicine

Intensivist

Revision of the known facts

What is the water content of human body?

Male female

50 to 60% of body weight

Higher in neonates and children

Lower in elderly

Lower in women

40% is intracellular.

20% extracellular

15% is interstitial 5% is intravascular

28 L

14L

3.5 L

Diffusion Facilitated diffusion Active transport Osmosis Osmolality Calculation 2na+glu/18+ bun/2.8 Freezing point

depression method

Hypotonic (cell swells) 200mosm/litre

Hypertonic cell shrink –360 mosm/l

Isotonic nochange 280mosm/l

IntracellularInterstitial

Intravascular

2/3 1/3

3/4 1/4

IntracellularInterstitial

Intravascular

2/3 1/3

3/4 1/4

ECF osmolality = ICF osmolality

K, ATPCreatinine PO4phospholipids

Na, ClHCO3

Intravascular

Interstitial

3/4 1/4

Capillary membrane

Plasma proteins

IntracellularInterstitial

Intravascular

2/3 1/3

3/4 1/4

Na

K

Plasma Na 153

IC K 150

Intracellular Interstitial

Intravascular

2/3 1/3

3/4 1/4

Intracellular

Interstitial Intravascular

2/3 1/3

3/4 1/4

IntracellularInterstitial

Intravascular

2/3 1/3

666ml 250ml 84ml

IntracellularInterstitial

Intravascular

2/3 1/3

750ml 250ml

IntracellularInterstitial

Intravascular2/3 1/3

1000ml

IntracellularInterstitial

Intravascular2/3 1/3

1000ml

Intake and output must be balanced.Intake---N fluid ingested—2100 +from metabolism(200)=2300mloutput—urine-1400+feces(100) -sweat-100 - insensible loses—skin-350+lungs350ml

Subject to variation environmental condition and disease states

Weight Water requirement 0-10 kg 4mL/kg/hr10-20 kg 40mL/hr +2ml/kg/hr for each kg>10kg>20kg 60ml/hr +1ml/kg/hr for each

kg>20kg

for 60kg man this = 100ml/hr or 2400 ml/24 hrsfor normal people!!

Solutions Volumes Na+ K+ Ca2+ Mg2+ Cl- HCO3- Dextrose mOsm/L

ECF 142 4 5 103 27 280-310

Lactated Ringer’s

130 4 3 109 28 273

0.9% NaCl 154 154 308

0.45% NaCl 77 77 154

D5W 50 250

D5/0.45% NaCl 77 77 50 406

3% NaCl 513 513 1026

6% Hetastarch

500 154 154 310

5% Albumin 250,500

130-160

<2.5 130-160 330

25% Albumin 20,50,100

130-160

<2.5 130-160 330

Crystalloidsrelatively large volume for resus

Ideal for repleshing third space loss

Less fear of allergic reaction

Used as diluent for ionotropic adminstration

Colloids Lesser volume

better expander more duration

Allergic reaction seen as well interfearance with blood crossmatch

R.L hartmen “solution, balanced salt solution

Isotonic -isobaric- iso-osmolar- crystalloid solution.

Concentrations of ions—Na-131mEq/l calcium-2mEq/l

bicarbonate-29mEQ/L AS LACTATE

K+ 5MeQ/L, CL- 110mEq/lPh-6.5,osmolarity-279

mosm/L

Normal saline Isotonic isobaric 0.9% w/vsolution

Na+/cl- =154mEq/l Ph-5.0 0smolarity -308mosm/L

--common maintainence fluid till other are made available

---in treatment of diabetic ketoacidosis—2 litres

--upper intestinal obstruction and hypochloremia

RL-Solutions provides electrolytes with lactate.

Lactate is rapidly metabolized in liver to bicarbonate helps in correction of acidosis

Mild to moderate hypovolemia due to any cause

As a maintainence fluid Preloading before spinal

anaesthesia Risk—Lactic acidosis hyperkalemia

NS-Only fluid compatible with blood.

Flushing of dialysis set with saline Surgeons use for –washing crush injuries peritoneal lavageunder water seal bottle

Can be used as diluent for medication

NS-RISK-Hyperchloraemic metabolic acidosis more likely with renal insufficiency

FULFILLS INDICATIONS OF BOTH 5% DEX AND .9% SALINE

Useful particularly in pediatric patient Safely be used as maintainence fluid. Avoid for surgical procedures as dex best

media for bacterial growth Can be used along with blood

It provides calories –each gm of glucose 4 kcal.

--used to correct water deficit --used to correct hypoglycemia --used as carrier for giving drugs

dopamine, aminophylline,noradrenaline,insulin,SNP

Higher concentration is irritant to vien. Avoid extravasation Water intoxication,odema states Should not be given along with blood

transfusion Avoid in known hyperglycemic as

maintainence fluid

Hemaccel 3.5% poly gelatin Na 145/cl 145 k-5.1, ca++-6.25mEq/l

Mol wt 30,000 pH 7.3 Half life 4-6hr Use in mod to severe shock. Priming solution

Citrated blood should not be mixed. Produces histamine release/anaphylactic Dose should not increase 1000ml in 24 hrs. Careful in digitalized patient Avoid in hepatic renal and CCF However unlike other colloids does not

cause agglutination and Rolex formation

6% SOLUTION mol wt-2,00,000da Dose 20ml/kg in 24 h These are hyperoncotic and cause

intravascular volume expansion Duration 12-24 hrs The incidence of anphylactoid reaction is

low

IT interferes PL Aggregation and coagulation.

Thermo osmalarity-308mosm/l Ability to with draw fluid from interstital

space in to intravascular compartment It should be cautiously used in presence of

renal failure

Dextran 40/ rheomacrodex --IT decreases viscosity of blood. --it improves micro circulation. --plasma half life 6-12hrs --dose 20 cc/kg/24hrs --it does not interfere with blood gp and

crossmatch

Accumulation and tissue storage

Effects on renal function

Coagulopathy and bleeding risk

Increase in amylase levels

Anaphylactic potentials

Cost factors

New generation colloids-0.4 Molar substitution==degradation factor

hydroxyl ethyl group No risk of accumulation even with dosages

increased from 20ml/kg---50ml/kg No effects on renal and coagulopathy Quest for the new colloid--

Balanced colloid solution like volulyte will end the debate

HES therapy was associatedwith higher

HES therapy was associated with higher rates of acute renal failure and renal-replacement therapy than wasRinger’s lactate.

N Engl J Med 2008;358:125-39.Copyright © 2008 Massachusetts Medical Society

What is the first sign of shock? a. Tachycardia b. hypotension c. narrow pulse pressure d. low urine output

parameter

class1 clqss2 class3 class4

%blood vol/cns

<15%

anxious

15-30%

agitated

30-40%

confuse

>40%

lethargic

Pulse rate

<100 >100 >120 >140

Supine b.p

n n decrease decreas

Urine output

>30ml/hr .20-30ml 5-15ml <5ml

Fluid resuscitation in uncontrolled bleeding is deleterious

Delayed resuscitation is valid in trauma systems with short response times (<20 minutes to hospital from injury)

Attempts to control bleed should be given greater importance

Fluids (pre-op) 2.4 L 0.4 L (p<0.001)Survival 62% 70% (p=0.04)ARDS/ renal failure 30% 23% (p=0.08)Sepsis/ infectionHospital days 14+24 11+19 (p=0.006)

N Engl J Med 1994; 331:1105-1109.

598 patients; penetrating torso injuryField systolic BP <90 mm Hg (58+35)

309 289

Immediate fluids Delayed until induction

Trauma

Haemorrhage

Coagulation Hypotension

Fluid Resuscitation

Haemorrhage Haemorrhage

Fluid Resuscitation

Raises BP

Dilutesfactors

Restores volume +o2 carrying capacity Indicated in severe hemorrhagic shock eg

pelvic trauma ,variceal bleed Pre-operative measure Blood products for replenishing

coagulation/factors eg FFP, PL Conc,

Pyrexial reaction,allergy Transmission of disease-syphilis ,viral

hepatitis,HIV,malaria Hemolytic reactions Citrate intoxication Hyperkalemia ,hypothermia Volume overload TRIM,TRALI

PERIPHERIAL INTRACATH 16G Same gauze central line Hagen poiseuille equation rate @{radius}

4th power inversely proportional to length :;; infusion through central catheter will be

as much as 75% less than infusion rate through peripheral cathter of equal diameter

Fluid resuscitation may consist of natural or artificial colloids or crystalloids

No evidenced-based support for one type of fluid over another

•Crystalloids have a much larger volume of distribution compared to colloids•Crystalloid resuscitation requires more fluid to achieve the same endpoints as colloid•Crystalloids result in more edema

Choi PTL. Crit Care Med 1999;27:200-210.

Cook D. Ann Intern Med 2001;135:205-208.

Schierhout G. BMJ 1998;316:961-964.

Fluid Therapy: Choice of FluidFluid Therapy: Choice of Fluid

Grade C

Dellinger, et. al. Crit Care Med 2004, 32: 858-873.

Fluid challenge in patients with suspected hypovolemia may be given

500 - 1000 mL of crystalloids over 30 mins300 - 500 mL of colloids over 30 minsRepeat based on response and toleranceInput is typically greater than output due to venodilation and capillary leakMost patients require continuing aggressive fluid resuscitation during the first 24 hours of management

Fluid Therapy: Fluid ChallengeFluid Therapy: Fluid Challenge

Grade E

Dellinger, et. al. Crit Care Med 2004, 32: 858-873.

Central venous pressure (CVP) 8–12 mmHg

– Mean arterial pressure (MAP) 65 mmHg – Urine output 0.5 ml/kg h1 – Central venous (superior vena cava) or

mixed venous oxygen saturation 70%.

Rationale. Early goal-directed therapy (EGDT)

IntracellularInterstitial

Intravascular

2/3 1/3

3/4 1/4

Na

Blood Pressure—not a sensitive marker until blood loss >30%

NIBP-spuriously low measurement in patient with hypovolemia (vasoconstrictor response)

Direct IAP better ? Cardiac filling pressures CVP—limitation—Indirect measure

Change in CVP measured before and 5 mins after bolus of fluid◦0-3 mmHg: underfilled◦3-5 mmHg: adequately filled◦5-7 mmHg: overfilled

1 a wave is due to atrial contraction

2.c wave due to buldging of tricuspid valve in rt atrium

3 x descent depicts atrial relaxation

4 v due to rise in atrial pressure before the tricuspid valve opens

5 y decent is due to atrial emptying as blood enters ventricles

Watch out forSystolic pressure variation