Fluid Therapy In Cardiac Surgery Patients

Done by Dr. Ayman Raweh August 26, 2009

Goal of Fluid Resuscitation to restore tissue perfusion  cellular oxygenation 

maintain end organ function

The body of a healthy 70 kg male contains

about 42 liters of water, which is distributed into the following: Extracellular Fluid Intracellular Fluid

Extracellular Fluid (1/3 of Total Body Water) Volume Interstitial fluid 11.2 liters Plasma 2.8 liters Total 14.0 liters

% of body weight (16%) (4%) (20%)

Intracellular Fluid (2/3 of Total Body Water) Volume Red Cells 2.2 liters Intracellular Fluid 25.8 liters Total 28.0 liters

% of body weight (3%) (37%) (40%)

Intravascular volume (plasma + red cells) is about 5 liters, with a hematocrit of 44%

Types of Resuscitation Fluid Crystalloid solutions Colloid solutions

Types of Crystalloid Solutions Hypotonic 5% Dextrose  ½ Normal Saline 

Isotonic Ringer’s Lactate  Normal Saline 

Hypertonic 3% Normal Saline  6% Normal Saline  7.5% Normal Saline 

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Types of Crystalloid Solutions Hypotonic 5% Dextrose  ½ Normal Saline 

Isotonic Ringer’s Lactate  Normal Saline 

Hypertonic 3% Normal Saline  6% Normal Saline  7.5% Normal Saline 

Dextrose Solution 5% Hypotonic solution consists of 5g Dextrose in every 100 mL water does not contain any electrolytes distributes rapidly and evenly throughout the

entire body fluid compartments

Dextrose Solution 5% (continued) One liter of intravenous dextrose solution

expands intravascular compartment by only 70 ml and the interstitial fluid by 260 mL

has no use in fluid resuscitation to expand the

intravascular volume

Dextrose Solution 5% (continued) More concentrated dextrose solutions (10%,

20%, and 50%) are available 

their use is limited to management of diabetic patients or patients with hypoglycaemia



These solutions are irritant to veins.

Types of Crystalloid Solutions Hypotonic 5% Dextrose  ½ Normal Saline 

Isotonic Ringer’s Lactate  Normal Saline 

Hypertonic 3% Normal Saline  6% Normal Saline  7.5% Normal Saline 

Ringer’s Lactate and Sodium Chloride 0.9% (‘normal saline’) Isotonic solutions rapidly redistribute within the extracellular space

(intravascular space and interstitium) One liter of intravenous normal saline or Ringer’s lactate expands the intravascular volume by 220 mL after equilibration. Redistribution is complete within 30-60 minutes

Ringer’s Lactate and Sodium Chloride 0.9% (continued)

a four-fold amount of fluids is needed in

comparison to whole blood or colloid plasma substitution in order to achieve the same intravasal volume effect

Ringer’s Lactate and Sodium Chloride 0.9% (continued)

a risk of interstitial fluid overload 

may lead to a decrease in arteriolar PaO2 in case of increasing extravasal lung water

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Colloid Solutions sufficiently large molecules that normally do

not cross capillary membranes in significant numbers exert an oncotic pressure remains intravascular for about 6-25 hours

unless an altered permeability condition is present

Colloid Solutions (continued) good resuscitation fluids because all the

volume administered stays in the circulation

One liter of intravenous hydroxyethyl starch,

for example, expands the intravascular volume by 1200-1300 mL after 30-60 minutes

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Human Serum Albumin Natural protein Stays within the intravascular space unless the

capillary permeability is abnormal cause anaphylaxis in rare circumstances. 5% solution – isooncotic, 10% and 25% solutions

– hyperoncotic

Human Serum Albumin (continued) Expands volume 5x its own volume in 30

minutes (when 25% Albumin Solution is used for example) 65 times more expensive than crystalloids

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Gelatin Solutions Bovine collagen is the basis for gelatin solutions up to 50% leaves intravasal space within 1-2 hours completely metabolized and can be eliminated by

the kidneys

do not impact kidney function 

suitable for use in patients suffering from impaired kidney function

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Hetastarch (HES= hydroxyethyl starch)  A synthetic highly branched glucose polymer  Cheaper alternative to Albumin  Available as 6% and 10% solution in normal saline solution  Excreted in the urine (smaller particles), metabolised by blood amylase, then

excreted into the bile and faeces (medium sized molecules), or undergoes phagocytosis by the reticulo-endothelial system (RES) (larger molecules).

 Dose: limit the amount to 20 ml/kg/day  13 times more expensive than crystalloids

Hetastarch (HES= hydroxyethyl starch) (continued) Excretion 

Excreted in the urine (smaller particles)



metabolised by blood amylase, then excreted into the bile and faeces (medium sized molecules)



undergoes phagocytosis by the reticulo-endothelial system (RES) (larger molecules)

Hetastarch (HES= hydroxyethyl starch) (continued) Impact on blood coagulation 

There are reports that HES caused  significant

prolongation of prothrombin time and prolonged thromboplastin time

 reduced

the levels of fibrinogen, factor VIII, factor C, and factor V



but the changes remained within the normal range

Hetastarch (HES= hydroxyethyl starch) (continued) Impact on blood coagulation 

In another report, patients who received large doses of HES (about 1L) for trauma and surgery  had

 up

a prolonged partial thromboplastin time

to a 50% decrease in factor VIII and factor C

Hetastarch (HES= hydroxyethyl starch) (continued) Impact on blood coagulation 

HES seems to cause changes in fibrin clot formation and fibrinogenolysis



This characteristic may be related to the incorporation of the HES molecules into the clot, with subsequent prevention of solid clot formation.

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Pentastarch (Pentaspan) Lower MW analogue of hydroxyethyl starch (HES) 10% solution in 500 ml normal saline solution vials eliminated from the circulation at a faster rate than

HES because of its smaller molecular weight

is mostly excreted in the urine, so it should be avoided

\ in patients with renal disease complicated by oliguria or anuria unless it is related to hypovolemia

Types of Colloid Solutions Protein Solutions Human Serum Albumin (5%, 25%)  Gelatin Solutions 

Non-Protein Solutions 

Starches  6%

hetastarch (HES= hydroxyethyl starch)  10% pentastarch 

Dextrans  dextran-40

in normal saline  dextran-70 in 5% dextrose in water

Dextrans  High MW polysaccharide  Dextran 40 - MW 40,000  Dextran 70 - MW 70,000  10% solution in NS or D5W  Excretion is through the urine, faeces and reticulo-endothelial system

(RES) (according to molecular size)

 Dose: limit to 20 Dose: limit to 20 ml/kg/day  occasional anaphylaxis

Dextrans (continued) Impact on Coagulation 

causes defects in platelet interaction and an antifibrinolytic effects



seems to be incorporated into the polymerising fibrin clot so that it alters clot structure and enhances fibrinogenolysis

Crystalloids Vs. Colloids still a matter of debate and needs to be

determined Colloids and crystalloids have the same (SAFE Study, 2004) mortality rate  ICU or hospital days  days of mechanical ventilation  days of renal-replacement therapy 

Colloids are much more expensive than

crystalloids

Crystalloids Vs. Colloids (continued)  Crystalloids can cause interstitial and lung edema  more crystalloids are needed compared to colloids  Colloids have a dose-related coagulopathy (greatest with

hetastarch), and occasional anaphylaxis

 starch molecules may adversely affect renal function by

causing tubular injury

 Non-protein colloids can also interfere with antigen

detection during cross matching of blood products

Simulation of Fluid Management http://pie.med.utoronto.ca/CA/CA_content/CA_

fluidManagement.html