HYPOVOLEMIC SHOCK

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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 of effective tissue perfusion pressure
  and generalized cellular dysfunctions.
• Forms
• Hemorrhagic shock
• Non-hemorrhagic hypovolemic shock

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HYPOVOLEMIC SHOCK

• CAUSES
• 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, ascitis pleural
  effusions, etc.)

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PATHOPHYSIOLOGY

• Primary pathophysiological event
• (reduction of ventricular filling volumes and
  pressures)
• compensatory phenomena
  macrocirculatory reaction
• time
• decompensatory phenomena
  microcirculatory reaction

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PATHOPHYSIOLOGY

• Hypodynamic shock
• Macrocirculatory reaction
• sympatho-adrenergic humoral reaction (ADH,
  cortizol, SRAA)
• EFFECTS centralisation of the circulation
  (compensatory effect)
• worsening of tisular
  hypoperfusion (decompensatory effect)
• Microcirculatory reaction
• Alterations of capillary exchanges
• EFFECTS transcapilary filling (compensatory
  effect)
• capilary leak
  (decompensatory effect)
• Maldistribution of blood flow
• EFFECTS preferential renal blood flow towards
  medular region (cortical vasoconstriction)
• Abnormal peripheral oxygen extraction
• EFFECTS early - increased (compensatory effect)
• late - decreased (decompensatory
  effect)
• Rheologic changes
• EFFECTS ? blood viscosity, ? blood flow, CID
• Endhotelial modifications
• EFFECTS morpho-functional modifications
• proinflamatory and
  procoagulatory status,

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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
• History of hemorrhagic or non-hemorrhagic
  losses

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CLASSIFICATION OF HYPOVOLEMIC SHOCK
Class I Class II Class III Class IV
Blood loss- ml lt 750ml 750-1500ml 1500-2000ml gt2000ml
Blood loss- lt15 15-30 30-40 gt40
Pulse rate lt100/min lt 100/min 120-140/min gt140/min
BP N N ?? ???
Pulse wave amplitude N ? ?? ???
Capillary refill N
Respiratory rate 14-20/min 20-30/min 30-40/min gt40/min
Urinary output gt30ml/ora Oliguria Oligoanuria Anuria
Mental status Mild anxiety Anxiety Confused Lethargy
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DIFFERENTIAL DIAGNOSIS WITH OTHER FORMS OF
SHOCK
HR BP CO CVP PAOP SVR Da-vO2 SvO2
Hypovolemic shock ? ? ? ? ? ? ? ?
Cardiogenic shock ? ?? ? ? ? ? ? ?
Septic shock ? ? ? N ? N N ? ? ?
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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 treatment STOP losses
• essential role
• surgical treatment (when appropriate)
• emergency surgery for ongoing hemorrhage

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TREATMENT OF HYPOVOLEMIC SHOCK

• volume replacement
• Vascular access site
• Solutions for volume replacement
• Rhythm of administration

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TREATMENT OF HYPOVOLEMIC SHOCK

• Volume replacement SITE of VASCULAR 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 24-48
  hours
• no catecholamines administration (except in
  emergency for a short time period,until a central
  venous access is available)
• Central venous access
• After peripheral vascular access is established
  and volume replacement is initiated
• Advantages
• Reliable and long lasting venous access (7-10
  days)
• Allows CVP measuring and guiding of treatment
• Allows the administration of catecholamines and
  hypertonic substances

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TREATMENT OF HYPOVOLEMIC SHOCK

• 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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TREATMENT OF HYPOVOLEMIC SHOCK

• Solutions for volume replacement
• -Isotonic 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
• -Hypertonic crystalloid solutions
• hypertonic saline (NaCl 7,4)
• Advantages
• Efficient blood volume resuscitation with small
  solution volume (water is atracted from
  interstitial space )
• Avoidance of fluid overload and peripheral edema
  
• Disadvantages
• may result in acute pulmonary edema

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TREATMENT OF HYPOVOLEMIC SHOCK

• Solutions for volume replacement
• Colloid 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
• risk for anaphylactic reactions
• interfere with blood groups determination
• can induce/ aggravate coagulation disorders

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TREATMENT OF HYPOVOLEMIC SHOCK

• Solution for volume replacement
• Blood and blood products are 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) or ongoing hemorrhage
• In case of massive blood transfusion add
  fresh-frozen plasma and platelet concentrate

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TREATMENT OF HYPOVOLEMIC SHOCK

• Volume replacement
• RHYTHM OF ADMINISTRATION
• Rhytm of administration depends on
• Ongoing losses / stopped losses
• Rhytm of losses rapid (minutes, hours) or slow
  (days) instalation
• For the patient with hypotension normal 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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TREATMENT OF HYPOVOLEMIC SHOCK

• 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 si Ht, so

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TREATMENT OF HYPOVOLEMIC SHOCK

• Inotropic support
• Only after volume replacement
• Used to improve cardiac output
• Dobutamine
• inotropic positive support
• peripheral arterial vasodilatation

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TREATMENT OF HYPOVOLEMIC SHOCK

• Vasopressor therapy
• NOT RECOMMENDED (may aggravate peripheral
  hypoperfusion and metabolic acidosis)
• EXCEPTIONS
• Only temporary
• In case of ongoing hemorrhage, which outruns the
  possibilities of volume replacement
• Only until surgical procedure stops the
  hemorrhage (emergency surgical treatment)
• Noradrenaline, dopamine, adrenaline