Post on 15-Apr-2017
Contents General Description
History
Fluids and Human Body
Uses of IV Fluids
Goals of IV Fluids
Assessment of Fluid volume status
Specific Description
Concept of Osmosis
Osmolarity
Tonicity
Body Fluid compartments
Impact of IV Fluid on Fluid
Compartments
Something About Colloids
Crystalloid
Categories of colloid & Crystalloid
Down sides
Rule of 4:2:1
Drip Rate
Pre, intra & post Operative Maintenance
Complications
Take home message
HISTORY
The first record available that shows an understanding of
the need for fluid in injured patients was apparently from
Ambroise Paré (1510-1590), who urged the use of clysters
(enemas to administer fluid into the rectum) to prevent
“noxious vapors from mounting to the brain.”
The term shock appears to have been first used in 1743 in
a translation of the French treatise of Henri Francois Le
Dran regarding battlefield wounds.
In 1830, Herman provided one of the first clear
descriptions of intravenous (IV) fluid therapy. In response
to a cholera epidemic, he attempted to rehydrate patients
by injecting 6 ounces of water into the vein
0.9% normal saline originated during the cholera pandemic
that afflicted Europe in 1831, but an examination of the
composition of the fluids used by physicians of that era
found no resemblance to normal saline. The origin of the
concept of normal saline remains unclear
Sydney Ringer found three ingredients essential were potassium, calcium, and bicarbonate. Ringer’s solution soon became ubiquitous in physiologic laboratory experiments.
In 1932, attempting to develop an alkalinizing solution to administer to his acidotic patients, Hartmann modified Ringer’s solution by adding sodium lactate. The result was lactated Ringer’s (LR), or Hartmann’s solution.
By world war II, shock was recognized as the single most common cause of treatable morbidity and mortality. Out of necessity, efforts to make blood transfusions available heightened and led to the institution of blood banking for transfusions.
It maintains the shape and integrity of all cells in the body
It maintains blood pressure/ volume
A transport medium for ;
Delivery of nutrients and oxygen to the tissues
Removal of waste products from the body
A medium for all the biochemical reactions necessary for life
Approximately 60% of the body is water!
Resuscitation
Rehydration / Replacement
Maintenance
Special purpose
To maintain adequate oxygen delivery to the tissues
To maintain normal electrolytes concentration
To maintain normoglycemia
Look at the patient:
- Pulse
- Blood pressure
- Capillary refill
- Skin turgor
- Mucous membranes
- Peripheral circulation
“If the eyes are the windows to the soul,
then the kidneys are the windows to the
body”
Sandra Ouellette.
The principle of osmosis and tonicity.
The different fluid compartment of the body
Predict the effect that specific types of IV fluids
will have on the volume within different body fluid
compartments.
The Spontaneous movement of water across a
semipermeable membrane from a region of low
solute concentration to one of high solute
concentration , which tends to equalize the
solute concentrations on either side of the
membrane.
OSMOLALITY
Measure of a fluid’s capability to create osmotic pressure
is called osmolality or osmotic (osmolar) concentration of
a solution. In simple words, it is the concentration of
osmotically active substance in the solution. Osmolality is
expressed as the number of particles (osmoles) per
kilogram of solution (osmoles/kg H2O).
OSMOLARITY
Osmolarity is another term to express the osmotic
concentration. It is the number of particles (osmoles) per
liter of solution (osmoles/L).
The hydrostatic pressure necessary to counteract the process
of osmosis
The total number of solute particles per volume of solution
The difference in the osmolarity of two solutios on either side
of a semipermeable membrane.
Extracellular Fluid
(1/3 TBW)
Capillary Membrane
Tonicity #Osmolarity
Osmilarity is dependent upon all particles of solute
Tonicity is dependent just upon those particles when exert an
osmotic force (i.e. those which cannot permeate through cell
membrane
Example: Urea creates osmolarity but does not contribute to
tonicity since it freely moves through the cell membrane
IV Fluid containing osmotic pressure due to presence of large
molecules is called colloid
Osmotic pressure due to such molecules is sometimes
referred to as oncotic pressure
If Oncotic pressure in an infused fluid exceeds that in the
plasma, it can pull water from interstitial space into the
intravascular space.
List the categories of IV fluids , and several examples of each (e.g.
NS, D5W, LR,albumin, hydroxyethyl starch, etc….)
Constitunts of common IV Fluids
Primary Indication, contraindications aside effects of common IV
fluids.
Relatively high tendency
to stay intravacualr
Examples: Albumin
Fresh frozen Plasma
Dextran
Hydroxyethyl starch
Electrolyte-Free Water
Examples: D5W, D10W
Blood
Examples: Packed RBCs
FLUID Na+
mEq/L
Cl
mEq/L-
K+
mEq/L
Ca2+
mEq/L
Glucose
g/L
Buffer Osmolarity
mOsm/L
Tonocity Typical
Indication
Normal
Plasma
140 100 4 2.4 0.85 HCO3-
24mEq/L
290 N/A N/A
0.9%
Saline
(a.k.a NS)
154 154 0 0 0 0 308 Isotonic Resuscitation
0.45%
saline
(a.k.a)1/2
NS
77 77 0 0 0 0 154 Hypotenic Maintenance
3% Saline 513 513 0 0 0 0 1026 Hypertoni
c
Severe
Hyponatremia
D51/2
NS+
20mEqKC
L
77 97 20 0 50 0 446 Hypertoni
c--
Hypotonic
Maintanance
D5W 0 0 0 0 50 0 252 Hypotonic Hypernatremia
Hypoglycemia
Lactated
Ringer’s
(LR)
13 109 4 3 0 Lactate
28mEq/L
273 Isotonic Resuscitation
Large volume s of NS can lead to a normal anion gap
metabolic acidosis
LR is relatively contraindicated in:
Hyperkalemia (due to presence of K+) usually a
minimal concern
Concurrent blood transfusion ( due to binding of
Ca+ with citrate in blood products)
Colloids can be divided in to natural (e.g. albumin, FFP) and
synthetic (e.g. Dextran , hydroxyethyl starch, gelatins )
Volume expansion due to colloid is determined by its molecular
wight and concentration.
Colloid fluids can be either saline based solutions or balanced
solutions
Colloids are typically only used for resuscitation in severe
hypovolemia
Exception include use of albumin in cirrhotic patients and renal
failure
FLUID Avg
Molecular
Weight(kD)
Osmotic
Pressure(m
mHg)
Initial
Volume
expamsion
Duration of
Volume
expansion
4-5%
Albumin
69 20-30 70-100% 12-24 hrs
20-25% 69 70-100 300-500% 12-24 hrs
10% Dextran
40
40 20-60 100-200% 1-2 hrs
6%
Hydroxyethyl
Starch
(Hespan)
450 25-30 100-200% 8-36 hrs
To about the rule of maintenance fluid and rate of IV drip
0-10 kgs 4ml/kg/hr
10-20 kgs 2ml/kg/hr
>20 kgs 1 ml/kg/hr
For Example :
1. 1.5 kg pt
so
1.5kg x 4= 20ml/hr
2.15kg
so
10 x 4 = 40ml/hr
5 x 2 = 10 ml/hr
50ml/ hr
3. 25kgs
10 x 4 = 40ml/hr
10 x 2 =20 ml/hr
5 x 1 = 5 ml/hr
65ml/hr
In adult > 20 kgs
Simply add age with 40
For example:
A 25 kgs pt
then 40 + 25 = 65ml/kg/hr
A certain amount of liquid, a time period, and a drop factor (gtts/mL)
x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min) Volume (mL)
Time in min
Formula:
Example: Calculate the IV flow rate for 1200 mL of NS to be infused in 6 hours. The infusion set is calibrated for a drop factor of 15 gtts/mL.
Time (min) x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)
Convert 6 hours to minutes.
min ← hr ( x by 60 ) 6 hr x 60 = 360 min
1200 mL
360 min x 15 gtts/mL = 50 gtts/min
Volume (mL)
Example: Calculate the IV flow rate for 200 mL of 0.9% NaCl IV over 120 minutes. Infusion set has drop factor of 20 gtts/mL.
Time (min) x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)
200 mL
120 min x 20 gtts/mL = 33 gtts/min
Volume (mL)
Pre-operative fluid therapy
IV Fluid Calculation
4 mL/kg for first 10 kg
2 mL/kg for next 10 kg
1 mL/kg for every kg over 20 kg
E.g. for 45-kg patient:
10 kg × 4 mL / kg = 40 mL
10 kg × 2mL / kg = 20 mL
25 kg ×1mL / kg = 25mL
Maintenance rate = 85mL/hr, 2000 ml/day
Alternative approach is to replace the calculated daily
water losses in urine, stool, and insensible loss with a
hypotonic saline solution.
An appropriate choice of 5% dextrose in 0.45% sodium
chloride at 100 ml/h as initial therapy, with potassium
added for patients with normal renal function.
Volume deficits should be considered in patients who
have obvious GI losses, such as through emesis or
diarrhea, as well as in patients with poor oral intake
secondary to their disease.
Intra-operative fluid therapy
With the induction of anesthesia, compensatory
mechanisms are lost, and hypotension will
develop if volume deficits are not appropriately
corrected.
In addition to measured blood loss, major open
abdominal surgeries are associated with
continued extracellular losses in the form of
bowel wall edema, peritoneal fluid, and the
wound edema during surgery.
Large soft tissue wounds, complex fractures with
associated soft tissue injury, and burns are all
associated with additional third-space losses that must
be considered in the operating room. These functional
losses have been referred to as parasitic losses,
sequestration, or third-space edema, because the lost
volume no longer participates in the normal functions of
the ECF.
Replacement of ECF during surgery often requires 500
to 1000 ml/h of a balanced salt solution to support
homeostasis.
Post-operative fluid therapy
Postoperative fluid therapy should be based on the
patient’s current estimated volume status and
projected ongoing fluid losses.
Any deficits from either preoperative or intraoperative
losses, third-space losses should be included in fluid
replacement strategies.
The adequacy of resuscitation should be guided by
the restoration of acceptable values for vital signs and
urine output.
If uncertainty exists, particularly in patients with renal
or cardiac dysfunction, a central venous catheter may
be inserted to help guide fluid therapy.
In the initial postoperative period, an isotonic solution
should be administered.
After the initial 24 to 48 hours, fluids can be changed to
5% dextrose in 0.45% saline in patients unable to
tolerate enteral nutrition.
If normal renal function and adequate urine output are
present, potassium may be added to the IV fluids.
Daily fluid orders should begin with assessment of the
patient’s volume status and assessment of electrolyte
abnormalities. All measured losses, including losses
through vomiting, nasogastric suctioning, drains, and
urine output, as well as insensible losses, are replaced
with the appropriate parenteral solutions.
Infiltration
Extravasation
Infection
Thrombophlebitis
Severed catheter
Fluid overload
Air embolism
Fluid is like “prescription” so give it with caution.
Children are more vulnerable for rapid fluid loss.
Maintenance calculation by “4-2-1” rule or Holliday Segar’s formula.
Vigilant Monitoring of WEIGHT, URINE OUTPUT, SERUM SODIUM CONCENTRATION while giving fluid is must.
As far as possible try to give maintenance fluid requirement orally.
0.45% DNS + 20 mEq/l KCl is ideal fluid in most of the children requiring maintenance therapy.
Replacement of fluids should be prompt & appropriate.