Crystalloids (ASAN002/7) Flashcards

1
Q

What are Crystalloids? (1)

A

Water–based solutions that contain small particles (ions & molecules).

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2
Q

What are the common constituents of Crystalloids? (3)

A
  • Electrolytes
  • Glucose or Dextrose
  • Buffers
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3
Q

What are common Electrolytes found in Crystalloids? (5)

A
  • Sodium
  • Potassium
  • Calcium
  • Magnesium
  • Chloride
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4
Q

What is the main purpose of Electrolytes in Crystalloids? (2)

A
  • to replace or maintain plasma levels
  • to correct electrolyte imbalances
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5
Q

What is the purpose of Glucose or Dextrose in Crystalloids? (1)

A

To provide energy to the patient

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6
Q

What is the purpose of Buffers in Crystalloids? (1)

A

To correct or maintain the normal acid–base balance of plasma.

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7
Q

What are the main characteristics of Crystalloids? (2)

A
  • The small particles readily pass through membranes and into all body compartments.
  • The fluid is rapidly redistributed through the body.
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8
Q

Do Crystalloids stay in the intravascular space?

A

No

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9
Q

What % of crystalloid fluids given will leave the intravascular space within 30 mins of administration?

A

75%

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10
Q

IMAGE – Crystalloids passing through membrane

A
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11
Q

What types of Tonicity can Crystalloid solutions be? (3)

A
  • Isotonic
  • Hypotonic
  • Hypertonic
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12
Q

What are the two types of fluids that Crystalloids are divided into? (2)

A
  • Replacement fluids
  • Maintenance fluids
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13
Q

What is the aim of Replacement fluids? (2)

A

Replace patient deficits of water & electrolytes.

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14
Q

What are Replacement fluids used to correct? (2)

A
  • Dehydration
  • Hypovolaemia
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15
Q

What are the main characteristics of Replacement fluids? (3)

A
  • Similar composition to plasma
  • Isotonic
  • Can be given rapidly in large volumes without causing electrolyte shifts.
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16
Q

What are the two most common Replacement fluids? (2)

A
  • Hartmann’s (Lactated Ringers Solution)
  • 0.9% NaCl (Normal saline)
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17
Q

What is the other name for Hartmann’s? (2)

A

Lactated Ringers Solution or LRS

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18
Q

What are the main characteristics of Hartmann’s? (6)

A
  • Crystalloid solution
  • Isotonic
  • Similar concentration of electrolytes as extracellular fluid
  • High concentrations of Sodium & Chloride
  • Small amounts of Potassium & Calcium
  • Lactate as a buffer
19
Q

Why must a patient’s liver function be adequate if administering Hartmann’s? (1)

A

Has a negative ion that requires hepatic metabolism

20
Q

What is 0.9% NaCl commonly called?

A

Normal Saline

21
Q

What are the main characteristics of 0.9% NaCl? (4)

A
  • Isotonic
  • High concentrations of Sodium & Chloride
  • No Potassium
  • Can be used with other fluids / medications
22
Q

Why would a type of fluid be classed as a Maintenance Fluid? (1)

A

When used to ‘maintain’ fluid balance.

23
Q

Why are Maintenence fluids used? (2)

A

To meet patient’s ongoing sensible & insensible fluid losses

24
Q

When is it appropriate to use Maintenance fluids? (1)

A

Once hydration has been restored.

25
Q

How do we determine Maintenance fluid requirements? (2)

A

Insensible fluid losses
+
Sensible fluid losses

26
Q

What are the main characteristics of Maintenance fluids? (3)

A
  • Hypotonic
  • Lower Sodium & Chloride content
  • Lower osmolality
27
Q

What electrolyte often needs to be added to maintenance fluids to maintain it? (1)

A

Potassium

28
Q

What are two common Maintenance fluids? (2)

A
  • 0.45% NaCl + 2.5% Dextrose
  • Plasmalyte 56
29
Q

What is the main characteristic of Hypertonic Crystalloids? (1)

A

High osmolality

30
Q

What are Hypertonic Crystalloids often used for? (1)

A

Rapid volume expansion

31
Q

What is the main benefit to using Hypertonic Crystalloids? (1)

A

Small amts can be used to increase the intravascular space, which will increase circulating volume.

32
Q

How does Hypertonic Saline cause a sudden rapid rise in circulating blood volume? (1)

A

Causes fluid to move from extravasulcar space into intravascular space.

33
Q

When is it beneficial to use Hypertonic Saline? (2)

A

In early tx of hypovolaemic & haemorrhagic shock.

34
Q

When should Hypertonic Saline be used with caution & why? (2)

A
  • When used in severely dehydrated patients
  • It will worsen dehydration.
35
Q

What type of fluids are recommend to be adminsted with Hypertonic Saline? (1)

A

Replacement Crystalloids

36
Q

What is the benefit of administering Replacement Crystalloids and Hypertonic Saline together? (2)

A

Prolongs desired effect
(↑ circulating volume)

37
Q

What are the major beneficial haemodynamic effects of Hypertonic Saline? (5)

A
  • ↑ myocardial contractility
  • ↑ cardiac output
  • ↓ peripheral vasucular resistance
  • Precapillary vasodilation
  • Minimises risk of cerebral oedema – esp. with head trauma.
38
Q

Why is it beneficial to administer Hypertonic Saline to a patient with head trauma? (1)

A

Minimises risk of cerebral oedema

39
Q

How does giving large amounts of replacement fluids affect Intracranial Pressure? (2)

A
  • During hypovolaemic shock it ↓ below normal due to systemic hypotention.
  • If large amts of replacement fluids are given = ↑ IC pressure above normal, which may ↑ cerebral oedema & interfere with cerebral blood flow.
40
Q

How does Hypertonic Saline protect the brain from Increased Intracranial Pressure? (1)

A

By helping to keep fluid in intravascular space rather than crossing into brain.

41
Q

What are the main characteristics of Mannitol? (3)

A
  • Hypertonic crystalloid
  • Osmotic diuretic
  • It is a high molecular–weight sugar.
42
Q

How does an Osmotic diuretic work? (2)

A

Acts in kidneys to remove excess body water from blood & convert to urine.

43
Q

What is Mannitol mainly used for?

A
  • Prevent & treat oliguria (low urine output) associated with kidney failure
  • Reduce ↑ pressure in brain (cerebral oedema) & intraocular pressure in eyes
  • Promotes excreation of substances, i.e. aspirin & barbiturates in overdoses.