4-hypovolemic-shock.ppt

7/23/2019 4-hypovolemic-shock.ppt

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HYPOVOLEMIC SHOCK

University of Medicine and Pharmacy, Iasi

School of Medicine

ANESTHESIA and INTENSIVE CARE

Conf. Dr. Ioana Grigoras

MEDICINE

4th year

English Program

Suport de curs


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HYPOVOLEMIC SHOCK

DEFINITION syndrom characterized by decreased circulating blood

volume (hypovolemia), which results in reduction ofeffective tissue perfusion pressure and generalizedcellular dysfunctions.

Forms:

Hemorrhagic shock

Non-hemorrhagic hypovolemic shock


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HYPOVOLEMIC SHOCKCAUSES:

Hemorrhagic:External blood loss (wounds)

Exteriorization of internal bleeding (hematemesis, melena, epistaxis,

hemoptysis,etc.)

Internal bleeding (hemothorax, hemoperitoneum,etc. )

Traumatic shock

Non-hemorrahagic:Digestive losses (vomiting, diarrhea, nasogastric suction, billiary, digestive

fistula, etc )

Renal losses (diabetes mellitus, polyuria caused by diuretics overdose,

osmotic substances, polyuric phase of acute renal failure, etc.)

Skin losses (intense physical effort, overheated enviroment, burns, etc.)

Third space losses (peritonites, intestinal oclussion, pancreatits, ascitispleural effusions, etc.)


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PATHOPHYSIOLOGY

Primary pathophysiological event(reduction of ventr icular f i l l ing volumes and pressures)

compensatory phenomena macrocirculatory reaction

time

decompensatory phenomena microcirculatory reaction


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PATHOPHYSIOLOGYHypodynamic shock:

Macrocirculatory reaction: sympatho-adrenergic + humoral reaction (ADH, cortizol, SRAA)

o EFFECTS: centralisation of the circulation (compensatory effect)

worsening of tisular hypoperfusion (decompensatory effect)

Microcirculatory reaction: Alterations of capillary exchanges

o EFFECTS: transcapilary filling (compensatory effect)

capilary leak (decompensatory effect) Maldistribution of blood flow

o EFFECTS: preferential renal blood flow towards medular region (corticalvasoconstriction)

Abnormal peripheral oxygen extractiono EFFECTS: early - increased (compensatory effect)

late - decreased (decompensatory effect)

Rheologic changeso EFFECTS: blood viscosity, blood flow, CID

Endhotelial modificationso EFFECTS: morpho-functional modifications

proinflamatory and procoagulatory status,

altered permeability


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HYPOVOLEMIC SHOCK

CLINICAL SIGNS: Intense thirst

Tachycardia

Tachypnea

Positive orthostatic test

Small pulse wave

hTA (blood hypotension)

Agitation, anxiety , confusion, coma

Oliguria

Cold extremities Profuse sweating

Collapsed peripheral veins

Delayed return of color to the nail bed

+ H istory of hemorrhagic or non-hemorrhagic losses


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CLASSIFICATION OF HYPOVOLEMIC

SHOCKClass I Class II Class III Class IV

Blood loss- ml < 750ml 750-1500ml 1500-2000ml >2000ml

Blood loss-% 40%

Pulse rate 140/min

BP N N

Pulse wave

amplitude

N

Capillary refill N + + +

Respiratory rate 14-20/min 20-30/min 30-40/min >40/min

Urinary output >30ml/or Oliguria Oligoanuria Anuria

Mental status Mild anxiety Anxiety Confused Lethargy


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HR BP CO CVP PAOP SVR Da-vO2 SvO2

Hypovolemic

shock

Cardiogenic

shock

Septic shock N N N

DIFFERENTIAL DIAGNOSIS

WITH OTHER FORMS OF SHOCK


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ABBREVIATIONS: HR heart rate

BP arterial blood pressure CO cardiac output

CVP central venous pressure

PAOP pulmonary artery occlusion pressure

SVR systemic vascular resistance

Da-v O2 oxygen arterial-venous difference

SvO2 mixed venous blood oxygen saturation


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HYPOVOLEMIC SHOCK

TREATMENT PRINCIPLES

Initial treatment of shock states

Causative treatment STOP losses

Volume repletion

Inotropic therapy Vasomotor therapy


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TREATMENT OF HYPOVOLEMIC SHOCK

Causative treatmentSTOP losses

essential role

surgical treatment (when appropriate)

emergency surgery for ongoing hemorrhage


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volume replacement

Vascular access site Solutions for volume replacement

Rhythm of administration


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TREATMENT OF HYPOVOLEMIC SHOCK Volume replacementSITE ofVASCULAR ACCESS

Peripheral vascular access

Multiple access (2-4 veins) Large peripheral catheters

External jugular vein

Advantages: Short time of instalation

Requires basic knowledge and simple matherials

Minor complications (hematomas, cutaneous seroma, etc.)

Disadvantages: The diameter of peripheral catheter must be adapted for peripheral veins dimensions

Vascular access can be lost (restless patient, during transportation); must be changed at 24-48hours;

no catecholamines administration (except in emergency for a short time period,until a centralvenous access is available)

Central venous access

After peripheral vascular access is established and volume replacement is initiatedAdvantages:

Reliable and long lasting venous access (7-10 days)

Allows CVP measuring and guiding of treatment

Allows the administration of catecholamines and hypertonic substances

Disadvantages: Risk of complication (at instalationpneumothorax, cervical or mediastinal hematoma, cardiac

dysrhytmias; during utilizationinfection, gas embolism)


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Volume replacement - Solutions for volume

replacement

Isotonic crystalloid solutions

Hypertonic crystalloid solutions Colloid solutions

Whole blood and red blood cells Fresh-frozen plasma

Platelets


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Solutions for volume replacement

-I sotonic crystalloid solutions Normal saline (NaCl 0,9 %), Ringer solution, lactated Ringer solutions

Advantages:

easy available

cheap

reduced risks

Disadvantages: Small volume effect (out of 1000ml infused solution 250-300ml remains

intravascullarly, the rest is distributed to the interstitial space)

short duration of volume effect

risk of interstitial edema, metabolic hyperchloremic acidosis

-Hypertoniccrystall oid solutions

hypertonic saline (NaCl 7,4%)

Advantages:

Ef f icient blood volume resuscitation with small solu tion volume (water i s atractedfrom intersti tial space )

Avoidance of f luid over load and per ipheral edema

Disadvantages:

may resul t in acute pulmonary edema


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Solutions for volume replacementColloid sollutions

Dextrans: Dextran 70, Dextran 40

Gelatines: Gelofusin, Haemacel, Eufusin

Hetastarch: Haes, Voluven, Refortan Human albumin 5%, 20%

Advantages: Good volume effect

Long duration of volume effect

Disadvantages: expensive

r isk for anaphylactic reactions

inter fere with blood groups determination

can induce/ aggravate coagulation disorders


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Solution for volume replacementBlood and blood productsare not volume solutions

Only isogroup isoRh blood

Only after restauration of intravascular volume with cristalloid /colloid

solutions;

For correction of oxygen transport

In case of posthemorragic anemia (after volume replacement) orongoing hemorrhage

In case of massive blood transfusionadd fresh-frozen plasma and

platelet concentrate


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Volume replacement

RHYTHM OF ADMINISTRATION

Rhytm of administration depends on: Ongoing losses / stopped losses

Rhytm of lossesrapid (minutes, hours) or slow (days) instalation

For the patient with hypotensionnormal saline (2000 ml

in the first 15-30 minutes)

after the first 15-30 minutes - volume replacement

continues depending on the clinical and hymodinamic

parameters (BP, HR, etc..)


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Volume replacement

MONITORING THE TREATMENT EFFICIENCY

Clinical parameters normalisation of BP, HR, pulse amplitude, skin colour and

temperature, mental status, urinary output

Hemodynamic parameters

Normalization of CVP, PCPB, DC, RVS, so

Laboratory parameters

Normalization of acid-base balance, liver, renal tests, Hb i Ht, so


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Inotropic support

Only after volume replacement

Used to improve cardiac output

Dobutamine

inotropic positive support

peripheral arterial vasodilatation


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Vasopressor therapy NOT RECOMMENDED (may aggravate peripheral

hypoperfusion and metabolic acidosis)

EXCEPTIONS

Only temporary

In case of ongoing hemorrhage, which outruns thepossibilities of volume replacement

Only until surgical procedure stops the hemorrhage(emergency surgical treatment)

Noradrenaline, dopamine, adrenaline

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