Crystalloids

1
Crystalloids

• Types
• Saline e.g. 0.9 saline, Hartmanns solution
  0.18 saline in 4 glucose.
• Glucose e.g. 5 glucose, 10 glucose, 20
  glucose.
• Postassium chloride
• Sodium bicarbonate e.g. 1.26, 8.4.
• Uses
• Crystlloid fluids are used to provide the daily
  requirements of watr and electrolytes. They
  should be given to critically ill patients as a
  continuous background infusion to supplement
  fluids given during feeding or to carry drugs
• Higher concentration glucose infusions are used
  to prevent hypoglycaemia.
• Potassium chloride is used to supplement
  crystalloid fluids.
• Correction of metabolic acidosis (sodium
  bacarbonate)
• Routes
• IV

2
Notes

• Plasma volume should be maintained or replaced
  with colloid solutions since crystalloids are
  rapidly lost from the plasma. It should be noted
  that plasma substitutes are carried in 0.9
  saline. So that the majority of critcally ill
  patients only require 0.9 saline infusions for
  excess loss.
• Sodium content of 0.9 saline is equivalent to
  that of extra cellular fluid. A daily requirement
  of 70-80mmol sodium is normal although there may
  be excess loss in sweat and from the
  gastrointestinal tract.
• Hartmanns solution has no practical advantage
  over 0.9 saline for fluid maintenance. It may,
  however, be useful if large volumes of
  crystalloid are exchanged (e.g. during continuous
  haemofiltration) to maintain acid balance.

3

• 5 glucose is used to supply intravenous water
  requirements, the 50g/L glucose being present to
  ensure an isotonic solution. Normal requirement
  is 1.5-2.0L/day. Water loss in excess of
  electrolytes is uncommon but occurs in excess
  sweating, fever, hyperthyroidism diabetes
  insipidus and hypercalcaemia.
• Potassium chlorid must be given slowly since
  rapid injection may cause fatal arrhythmias. No
  more than 40mmol/h may be given although 20mmol/h
  is more usual. Frequency of infusions are
  predicted by plasma potassium measurements.

4
Ion content of crystalloids (mmol/L)

• Na K HCO3 C1 Ca2
• 0.9 saline 150 150
• Hartmanns 131 5 29 111 2
• 0.18 saline in 30 30
• 4 glucose
• Ion content of gastrointestinal fluids (mmol/L)
• H Na K HCO3 C1
• Gastric 40-60 20-80 5-20 150 100-150
• Biliary 120-140 5-15 30-50 80-120
• Pancreatic 120-140 5-15 70-110 40-80
• Small bowel 120-140 5-15 20-40 90-130
• Large bowel 100-120 5-15 20-40 90-130

5
Sodium Bicarbonate

• Type
• Isotonic sodium bicarbonate 1.26
• Hypertonic sodium bicarbonate (1mmol/ml) 8.4
• Uses
• Correction of metabolic acidosis
• Alkalinisation of urine
• Routes
• IV

6
Notes

• Sodium bacarbonate may be given as an isotonic
  (1.26) solution to correct acidosis associated
  with renal failure or to induce a forced alkaline
  diuresis. The hypertonic (8.4) solution is
  rearely required in intensive care practice to
  raise the pH to gt7.0 in the serve metabolic
  fusion or necrosis is present
• Administration may be indicated as either
  specific therapy (e.g. alkaline diuresis for
  salicylate overdose), or if the patient is
  symptomatic (usually dyspnoeic) in the absence to
  tissue hypoperfusion (e.g. renal failure).
• The PaCO2 may rise in minute volume is not
  increased. Bicarbonate anot cross the cell
  membrane without dissociation so the increase in
  PaCO2 may result in intracellular acidosis and
  depression of myocardial cell function.

7

• Convincing human evidence that bicarbonate
  improves myocardial contractility or increases
  responsiveness to circulating catecholamines in
  severe acidosis is lacking though anecdotal
  success has been reported. Acidosis relating to
  myocardial depression is related to intracellular
  changes which are not accurately reflected by
  arterial blood chemistry.
• Excessive administration may cause
  hyperosmolality, hypernatraemia hypokalaemia and
  sodium overload.
• Bicarbonate may decrease tissue oxygen
  availability by a left shift of the
  oxyhaemoglobin dissociation curve.
• Soidum bacarbonate does have a place in the
  management of acid retention or alkali loss, e.g.
  chronic renal failure, renal tubular acidosis,
  fistulae, diarrhoea, Fluid and potassium deficit
  should be corrected first.

8
Ion content of sodium bacarbonate (mmol/L)

• Na K HCO3 C1 Ca2
• 1.26 sodium 150 150
• Bacarbonate
• 8.4 sodium 1000 1000
• bacarbonate

9
Colloids

• Types
• Albumin e.g. 4.5-5, 20-25 human albumin
  solution
• Dextran e.g. 6 Dextran 70
• Gelatin e.g. 3.5 polygeline (Haemaccel), 4
  succinylated gelatin (Gelofusion)
• Hydroxyethyl starch e.g. 6 hetastarch
  (Elo-HAES, Hespan), 6 10 pentastarch
  (Pentaspain, HAES-steril)
• Uses
• Used for maintenance of plasma volume and acute
  replacement of plasma volume deficit.
• Short term volume expansion (gelatin, dextran)
• Medium term volume expansion (albumin,
  pentastarch)
• Long term volume expansion (hetastarch)
• Routes
• IV
• Side effects
• Dilution coagulopathy
• Anaphylaxis
• Interference with blood cross matching (Dextran
  70)

10
Notes

• Smaller volumes of colloid are required for
  resuscitation with less contribution to oedema.
  Maintenance of plasma colloid osmotic pressure
  (COP) is a useful effect not seen with
  crystalloids but they contain no clotting factors
  or other plasma enzyme systems.
• Albumin is the main provider of COP in the Plasma
  and has a number of other functions. However,
  there is no evidence that maintenance of plasma
  albumin levels, as opposed to maintenance of
  plasma COP with artificial plasma substitutes, is
  advantageous.

11

• Albumin 20-25 and Pentaspan 10 are
  hyperonocotic and used to provide colloid where
  salt restriction is necessary. This use is
  rearely necessary in intensive care where it has
  been shown that plasma volume expansion is
  related to the weight of colloid infused rather
  than the concentration.
• Artificial colloids used with ultrafiltration or
  diuresis are just as effective in oedema states.
• Polygeline is a 3.5 solution and contains
  calcium (6.25 mmol/L) The calcium contents
  prevents the use of the same administration set
  for blood transfusion.
• Succinylated gelatin is a 4.5 solution with a
  larger molecular weight range than polygeline
  giving a slightl longer effect. This and the lack
  of calcium in solution make this more useful
  solution than polygeline for short term plasma
  volume expansion.

12

• In patients with capillary leak there is
  onsiderable leak of albumin and smaller molecular
  weight colloids to the interstitum.
• In these caes it is probably better to use larger
  molecular weight colloids such as hydroxyethyl
  starch.
• Hetastarch is usually a 6 solution with a high
  degree of protection from metabolism.
• The molecular weight ranges vary but molecular
  sizes are large enough to ensure a prolonged
  effect.
• These are the most useful colloids in capillary
  leak.
• Pentastarch has a lower degree of protection from
  metabolism and therefore a shorter effect.

13

• Unique features of albumin
• Transport of various molecules
• Free radical scavenging
• Binding of toxins
• Inhibition of platelet aggregation
• Relative persistence of colloid effect
• Albumin
• Dextran 70
• Gelofusin
• Haemaccel
• Hespan
• Pentaspan
• Elo-HAES
• HAES-Steril
• Presistence is dependent on molecular size and
  protection from metabolism.
• All artificial colloids are polydisperse (i.e.
  there is a range of molecular sizes).