Download Hypovoluemic shock

APPROACH TO PATIENT IN
HYPOVOLUEMIC SHOCK AND
FLUID RESUSCITATION
Dr.Kashif Javed
PGT,MU1,HFH
Criteria for accessing pt’s in
shock
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SBP<90mm of HG(postural hypotesion)
Pulse>100/mins
Capillary refill time>2sec
Cold calm extremities
Gut ischemia may cause nausea &
vomiting(decreased motility due
tohypoperfusion leads bilious green colored
aspirate in N/G)
• Late features include low motor
tune,confusion & even coma.
Investigations
• Check Hb, U&E, LFT and, in haemorrhage
and burns, group and cross-match.
• Coagulation screen.
• Blood gases (arterial or venous) may show a
metabolic acidaemia from poor perfusion;
lactate levels particularly reflect
hypoperfusion.
• Monitor urine output, which may require a
catheter.
• Ultrasound can be useful for
differentiating hypovolaemic from
cardiogenic shock; the vena cava
can be assessed for adequate filling
and echocardiogram can show any
pump failure.
• Central venous pressure (CVP)
monitoring may be useful where
there is evidence of shock.
Staging
clinical staging
relating to loss of blood volume
Class 1: 10-15% blood loss;
physiological compensation and no
clinical changes appear.
Class 2: 15-30% blood loss; postural
hypotension, generalised
vasoconstriction and reduction in
urine output to 20-30 ml/hour.
Class 3: 30-40% blood loss;
hypotension, tachycardia over 120,
tachypnoea, urine output under 20
ml/hour and the patient is confused.
Class 4: 40% blood loss; marked
hypotension, tachycardia and
tachypnoea. No urine output and the
patient is comatose.
Physiologically:
Three stages of hypovoluemic shock
Compensated shock:
Baroreceptor reflexes result in
increase in myocardial contractility,
tachycardia and vasoconstriction.
They maintain cardiac output and B.P
and lead to the release of
vasopressin, aldosterone and renin
Progressive or uncompensated shock:
occurs with myocardial depression,
failure of vasomotor reflexes and
failure of the microcirculation, with
increase in capillary permeability,
sludging and thrombosis, resulting
in cellular dysfunction and lactic
acidosis.
Irreversible shock: failure of vital
organs with inability to recover.
Shires Shock Study
Results
• Na+ leaked into cells
• K+ leaked out of
cells
• Albumin leaked into
interstitial space
• Water followed Na+
• Translocated fluid 3
times the shed blood
• Measured
composition of
transloc. fluid
Shires Shock Study
Conclusions
• Translocated Fluid composition is LR
• Inadequate O2 delivery shuts down Na+/K+
pumps, making cells leaky
– Gave Shed Blood plus 3 times volume of LR
• Mortality decreased from 80 to 30%
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Treatment of Hypovolumic
Shock
Large bore access
– 2 upper extremity IVs
– 16 gauge or larger
• Bolus therapy
– 20 cc/kg
– Adults- 2 liters
• Monitor Effect
• Repeat if necessary
• After 2nd bolus: need blood txn
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10cc/kg:
• 2 large bore, upper extremity
lines and:
– Volume
– Volume
– Volume
When in doubt, try a little more
volume
Management
General measures
• Oxygen should be given.
• Venous access must be secured
early. It is more difficult to achieve
once further circulatory collapse
occurr.
• A CVP line may be required. CVP is
far more sensitive to the balance
between loss and replacement than
pulse or BP ,in the elderly, it can
prevent over-transfusion and
pulmonary oedema.
– In burns, a high CVP may
be required to maintain
adequate output of urine.
• Resuscitation
Usually started with crystalloid, such as
normal saline or Hartmann's solution, although
some prefer colloids from the outset.
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2 liters crystalloid for adults( 500 ml in 15
mins than reaccess & give 1 to 1.5 liters in
next 1 hour).
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Or 20 cc/kg crystalloid immediately.
• Reaccess pt’s if shock persist seek expert
advice or repeat the bolus.
If vital signs are normal give
maintenance fluid
• 25-30ml/kg/day
• 1mmol/kg/day sodium,potassiu,chloride.
• 50-100g/day glucose
Reaccess and monitor pt’s
• Stop i/v fluids when no longer needed.
• N/G fluids or enteral feeding is preffered
when maintenance needed more than 3 days
Resuscitation Fluids
Isotonic Crystalloid Solution
• Normal saline and lactated Ringer’s( hypooncotic because of there lack of protein).
• Most of the fluid given will shift into the
extravascular space instead
ofintravascular or interstitial space.
• It is physiologic basis for the 3:1 ratio for
isotonic crystalloid volume replacement.
• Therefore for every 1 ml of blood loss 3ml is
needed to replace intravascular volume
using crystalloids.
However
• Infusing large volumes causes neutrophil
activation.
• LR also increases cytokine release and may
increase lactic acidosis in large amounts.
• NS exacerbate I/C potassium depletion
causes hypochloremic acidosis.
Colloid Resuscitation
• Colloids have larger molecular
weight particles with plasma oncotic
pressures similar to normal plasma
proteins.
• It would be thought colloids would
be more effective at restoring
circulating blood volume compared
to crystalloid solutions.
• But still there is no clear basis for the
choice of these agents over
crystalloids for resuscitation.
Hypertonic Resuscitation Fluids
• Hypertonic saline proposed as a potential
crystalloid solution alternative to isotonic
due to the limited tissue edema.
• Rapidly expand intravascular volume and
enhance tissue perfusion.
Benefit in trauma patients:
• Limiting cerebral edema,
• Lowering intracranial pressure,
• Limit pulmonary I/S fluid shift,
• Improving cerebral perfusion.
HYPERTONIC SALINE WITH
DEXTRAN (HSD)
7.5%saline with 6% dextran-70
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Less volume and weight to carry
May reduce mortality
Limits secondary brain injury
Less activation of inflammatory cells
Being used in dengue shock
syndrome treatment protocol
Blood Transfusion
There are no clear parameters for
transfusions.
• It is generally accepted that a patient in
shock not responding to 2-3 liters of
crystalloids will need a blood
transfusion.
• Per American Society of
Anesthesiologists patients with an H/H of
10/30 will very rarely need a transfusion.
• However an H/H of 6/18 will almost always
need a transfusion.
• Remember blood is the ideal resuscitation
agent.
• Modern ideas include avoiding excessive
crystalloid fluid resuscitation by allowing
permissive hypotension and early use of
blood and massive transfusion protocols
with damage control surgery to combat the
lethal triad of hypothermia, coagulopathy
and acidosis.
Alternatives to Transfusion
Blood Substitutes:
– Immediately available, storage easier, no need
for compatibility testing, disease free
– Polymerized, Stroma-free Hemoglobin
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50 gm in 500 ml
No adverse effects up to 6 units
Slight increase in Bilirubin
Studies small, more needed
Oxygen-Carrying Resuscitation
Fluid
• Currently not being used in present
day resuscitation.
• Studies underway for use during
resuscitation efforts.
• The thought behind the idea is to
have products able to carry O2 when
loss of RBC’s occur.
• Two classes of agents, hemoglobinbased O2 carriers and fluorocarbonbased O2 carriers.
End Points of Resuscitation
• Restoration of normal vital signs
• Adequate Urine output
– 0.5 - 1.0 cc/kg/hr
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Tissue Oxygenation measurement
Adequate Cardiac Index
Normalization of Oxygen delivery DO2I
Normal Serum Lactate levels
Pharmacological
• Traditional teaching is that vasopressors
have no part to play, as they will only
increase tissue ischaemia. They may have a
place if there is failure to respond to volume
replacement; however, the evidence is
inconclusive.
• If there is pain, analgesia must be given by
the IV route, as any other route will be
ineffective. Pain increases metabolic rate
and so aggravates tissue ischaemia
• Vasodilator therapy is for the
intensive care specialist. It is used
more for septic shock. If
hypovolaemia is the problem, volume
should be replaced.
Surgical
If bleeding continues, surgery may be
needed to stem the flow.
TAKE HOME MESSAGE
• Even slight dehydration has a marked adverse
effect on fitness.
• Where the loss is simply salt and water, oral
replacement will be adequate in the early
stages.
• Lactated Ringers is still the standard
• Giving more fluid is better than less, maybe
• New techniques:
– Hypertonic Saline• okay in Head Injury
• Less immunosuppression
• Helpful in the sickest patients
– Better Indicators are Endpoints of Resuscitation
THANK YOU