Colloid versus Crystalloid in Hypovolemic Shock Controversy

Crystalloids Fluids comprised of water and electrolytes or simple crystals Volume of distribution- intravascular,interstitial space Volume - 3 : 1 Examples Ringer’s lactate, hypertonic saline, normal saline

Colloid High molecular weight substances Volume of distribution -intravascular space Volume – 1: 1 Exert colloid osmotic pressure Costly Examples HES, Haemaccel, Albumin, Dextran

CrystalloidsColloids Intravascular vol effect-Better Interstitial vol. effectBetter- Pulmonary edemaSimilar potential Peripheral edemaCommonUncommon ReactionsAbsentCommon CostInexpensiveExpensive

Albumin 5%, 20% and 25% Half life – 16 hr Colloidal osmotic pressure - (25%) - 70 mmHg  plasma volume by ml Vol. expansion occur at expense of interstitial fluid so 25% should not be used for resuscitation Side effects – allergic reaction

Haemaccel Synthetic colloid Degraded gelatin Concentration - 3.5% Half life – 2-3 hr Dose – 20 ml/kg/day Osmotic pressure – 300 mmHg Side effects – anaphylaxis, coagulation interference (high dose)

M.wt (KD)Conc.I.V.stay (hrs) Dose (ml/kg/day) 2003% % % %6-820 Hydroxyethyl starch

Crystalloids vs Colloids Proponents of colloid fluid Resuscitation crystalloid solution dilutes plasma proteins Reduction of plasma oncotic pressure Interstitial pulmonary edema Requires smaller initial volume, generate prolonged  in circulating plasma volume Isotonic crystalloid – must be infused at least three fold greater volumes- to achieve comparable plasma expansion and hemodynamic stability

Proponents of crystalloid solution Additional cost and potential risk of colloids Removal of colloids- requires longer period than crystalloids in burn and major surgical patients Sepsis, ARDS, surgical trauma,  capillary permeability  leak  edema Coagulopathy – Dextran, HES >20 ml/kg  ionised calcium albumin Impaired cross-matching – Dextran Osmotic diuresis  LMW dextran

Crystalloid vs. Colloids in fluid resuscitation: A systematic review Peter Choi et al (1999) RCT 814 pts. No apparent difference in pulmonary edema, mortality or length of stay between isotonic crystalloid and colloid resuscitation Crystalloid resuscitation- lower mortality in trauma patients Fluid resuscitation with colloid or crystalloid - critically ill patients Schierhout G et al, 1998 Metanalysis 26 RCTs 1622 pts. Increased risk for death of 4% with colloid for resuscitation Cochrane review 30 RCTs 1419 pts. Risk for death higher in albumin treated gp. Vs. albumin + crystalloid gp.

BMJ 1998;317(7153): RCT Multicenter 42 pts. No statistically significant difference b/w crystalloid and albumin gps. w.r.t. days on mechanical ventilation, oxygenation failure, length of ICU stay and mortality rate in critically ill pts. with shock SAFE trial N Engl J Med 2004;350(22): RCT 6997 pts. No difference b/w albumin and saline w.r.t mortality rate, days of stay in ICU/ hospital/ ventilation

What to do ? According to literature: 1.Crystalloids - first preference-when available(NS,R/L) 2.Colloids –Keeping in view of adverse effects and dosage,colloids can be given with crystalloids 3.Avoid albumin as resuscitative fluid