The Many Faces Of Shock

The Many Faces of ShockThe Many Faces of Shock

Søren Boysen, DVM, DACVECCSøren Boysen, DVM, DACVECCUniversity of Montreal University of Montreal

Saint Hyacinthe, Quebec, CanadaSaint Hyacinthe, Quebec, Canada

Université de Montréal

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ShockShock

What is the definition of shock?What is the definition of shock?

ShockShock

What is the definition of shock?What is the definition of shock? Inadequate oxygen delivery to the tissues to meet Inadequate oxygen delivery to the tissues to meet

tissue demandtissue demand

ShockShock

What is the definition of shock?What is the definition of shock? Inadequate oxygen deliveryInadequate oxygen delivery to the tissues to meet to the tissues to meet

tissue demandtissue demand What causes inadequate oxygen delivery to the What causes inadequate oxygen delivery to the

tissues?tissues?

ShockShock

What factors influence oxygen delivery (DOWhat factors influence oxygen delivery (DO22))

Oxygen Delivery (DOOxygen Delivery (DO22))

Influenced by two important factorsInfluenced by two important factors Cardiac outputCardiac output

Oxygen Delivery (DOOxygen Delivery (DO22))

Influenced by two important factorsInfluenced by two important factors Cardiac outputCardiac output Arterial oxygen contentArterial oxygen content



O2

O2

O2

O2

O2

O2

DODO22 = CO x CaO = CO x CaO22

DODO22 = = COCO x CaO x CaO22

What factors influence cardiac output?What factors influence cardiac output?


Stroke volumeHeart rate x


Stroke volume - Preload - Aferload - Contractility

Heart rate x

DODO22 = CO x = CO x CaOCaO22What factors influence arterial oxygen What factors influence arterial oxygen content?content?

DODO22 = CO x = CO x CaOCaO22

CaO2 = (Hgb × 1.34 × SaO2) + (PaO2 × .003)Hematocrit Hemoblobin saturation Arterial oxygen pressure

General Therapy for ShockGeneral Therapy for Shock

Increase cardiac output Increase cardiac output (CO)(CO) Heart rate: Correct arrhythmias Heart rate: Correct arrhythmias Preload: Fluid therapy (except heart disease)Preload: Fluid therapy (except heart disease) Afterload: Nitropursside, ACE inhibitors Afterload: Nitropursside, ACE inhibitors Contractility: Positive ionotropesContractility: Positive ionotropes

Increase the arterial oxygen content Increase the arterial oxygen content (CaO(CaO22)) Blood transfusion: when indicatedBlood transfusion: when indicated Increased inspired oxygen contentIncreased inspired oxygen content

Correct refractory (vasodilatory) hypotensionCorrect refractory (vasodilatory) hypotension



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Delivery of blood to the tissuesDelivery of blood to the tissues

Vascular diseases (volume, tone) Vascular diseases (volume, tone)

Oxygenation of bloodOxygenation of blood

Severe pulmonary diseaseSevere pulmonary disease

Problems with hemoglobin (anemia, MetHgb)Problems with hemoglobin (anemia, MetHgb)

Cardiac disease (arythmia, contractility)Cardiac disease (arythmia, contractility)

Oxygen uptake/use by cellsOxygen uptake/use by cellsMitochondrial dysfunctionMitochondrial dysfunction (sepsis, cyanosis)(sepsis, cyanosis)

Inadequate Oxygen DeliveryInadequate Oxygen Delivery

Classifications of ShockClassifications of Shock

The causeThe cause HypovolemiaHypovolemia HemorrhagicHemorrhagic TraumaticTraumatic CardiogenicCardiogenic SepticSeptic AnaphylacticAnaphylactic ObstructiveObstructive AnemicAnemic HypoxemicHypoxemic


The physiologic stateThe physiologic state Compensated (normal BP)Compensated (normal BP) Uncompensated (low BP)Uncompensated (low BP) Terminal (about to die)Terminal (about to die)


Cardiac outputCardiac output HyperdynamicHyperdynamic HypodynamicHypodynamic

ZolaZola

5 year old m/n Husky5 year old m/n Husky 40 kg40 kg Hit by carHit by car

ZolaZola

Physical examinationPhysical examination T 98.6 P 168 bpm R 38 BPMT 98.6 P 168 bpm R 38 BPM MM: Pale CRT: > 2 secondsMM: Pale CRT: > 2 seconds Weak peripheral pulses Weak peripheral pulses

ZolaZola

Physical examinationPhysical examination T 98.6 P 168 bpm R 38 BPMT 98.6 P 168 bpm R 38 BPM MM: Pale CRT: > 2 secondsMM: Pale CRT: > 2 seconds Weak peripheral pulses Weak peripheral pulses Lung sounds increased (no crackles or wheezes)Lung sounds increased (no crackles or wheezes) Mentally depressedMentally depressed

Is shock present?

ZolaZola

Physical examinationPhysical examination T 98.6 P 168 bpm R 38 BPMT 98.6 P 168 bpm R 38 BPM MM: Pale CRT: > 2 secondsMM: Pale CRT: > 2 seconds Weak peripheral pulses Weak peripheral pulses Lung sounds increased (no crackles or wheezes)Lung sounds increased (no crackles or wheezes) Mentally depressedMentally depressed

Is shock present?

ZolaZola

Physical examinationPhysical examination T 98.6 T 98.6 P 168 bpmP 168 bpm R 38 BPM R 38 BPM MM: Pale CRT: > 2 secondsMM: Pale CRT: > 2 seconds Weak peripheral pulsesWeak peripheral pulses Lung sounds increased (no crackles or wheezes)Lung sounds increased (no crackles or wheezes) Mentally depressedMentally depressed

ShockShock

Immediate therapy Immediate therapy Place 2 large bore 18 g cathetersPlace 2 large bore 18 g catheters

Difficult IV Access?Difficult IV Access?

Intraosseous catheter:Intraosseous catheter:


Intraosseous catheter:Intraosseous catheter:



Emergency Venous CutdownEmergency Venous Cutdown

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Emergency Venous CutdownEmergency Venous Cutdown

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Venous Jugular CutdownVenous Jugular Cutdown




Bone intraosseous gun?Bone intraosseous gun?

ShockShock

Immediate therapy Immediate therapy Place 2 large bore 18 g cathetersPlace 2 large bore 18 g catheters Collect pre-treatment blood samplesCollect pre-treatment blood samples

Zola: Minimum Data BaseZola: Minimum Data Base

Big 5 resultsBig 5 results Hct 38% Hct 38% (37-55)(37-55) TS 5.5 mg/dL TS 5.5 mg/dL (6.0-7.8)(6.0-7.8) BUN 15-26 BUN 15-26 (<26)(<26) Glu 185 mmol/LGlu 185 mmol/L (70-120)(70-120) Lac 11.3 mmol/L Lac 11.3 mmol/L (<2.5)(<2.5)

Zola: Minimum Data BaseZola: Minimum Data Base

Blood pressure 76 mmHg systolicBlood pressure 76 mmHg systolic

ECGECG

Shock Therapy for ZolaShock Therapy for Zola

DO2 = C.O x CaODO2 = C.O x CaO22

Increase C.O: Increase C.O: Fluid therapyFluid therapy Correct arrhythmia?Correct arrhythmia?

Increase CaOIncrease CaO22 Administer oxygenAdminister oxygen Blood transfusion?Blood transfusion?

Shock TherapyShock Therapy

If cardiogenic shock can be ruled out, fluid If cardiogenic shock can be ruled out, fluid resuscitation is the cornerstone of therapy resuscitation is the cornerstone of therapy for all other forms of shockfor all other forms of shock

What is a Shock Dose of Fluids?What is a Shock Dose of Fluids?


90 ml/kg/hr in dogs90 ml/kg/hr in dogs40-60 ml/kg/hr in cats40-60 ml/kg/hr in cats


90 ml/kg/hr in dogs90 ml/kg/hr in dogs40-60 ml/kg/hr in cats40-60 ml/kg/hr in cats

Is every animal that receives the same Is every animal that receives the same “shock dose” going to respond in the “shock dose” going to respond in the same manner?same manner?


Goal of shock fluid therapy?Goal of shock fluid therapy?


Goal of shock fluid therapy?Goal of shock fluid therapy? 1) reverse the symptoms of shock1) reverse the symptoms of shock


Goal of shock fluid therapy?Goal of shock fluid therapy? 1) reverse the symptoms of shock 1) reverse the symptoms of shock 2) as quickly as possible2) as quickly as possible


Goal of shock fluid therapy?Goal of shock fluid therapy? 1) reverse the symptoms of shock 1) reverse the symptoms of shock 2) as quickly as possible2) as quickly as possible 3) while minimizing side effects3) while minimizing side effects

Fluid ResuscitationFluid Resuscitation

This may require less than 90 ml/kgThis may require less than 90 ml/kg



May require more than 90 ml/kgMay require more than 90 ml/kg


May require more than 90 ml/kgMay require more than 90 ml/kg

May need to be given faster than 1 hourMay need to be given faster than 1 hour

90 ml/kg/hr90 ml/kg/hrX



Calculate shock doseCalculate shock dose Administer 1/4 to 1/3 the shock dose over 10 Administer 1/4 to 1/3 the shock dose over 10

minutes minutes (20-30 ml/kg for isotonic crystalloids)(20-30 ml/kg for isotonic crystalloids)


Calculate shock doseCalculate shock dose Administer 1/4 to 1/3 the shock dose Administer 1/4 to 1/3 the shock dose over 10 over 10

minutesminutes (20-30 ml/kg for isotonic crystalloids)(20-30 ml/kg for isotonic crystalloids)


Calculate shock doseCalculate shock dose Administer 1/4 to 1/3 the shock dose Administer 1/4 to 1/3 the shock dose over 10 over 10

minutesminutes (20-30 ml/kg for isotonic crystalloids) (20-30 ml/kg for isotonic crystalloids) Continue with 1/4 to 1/3 shock doses every Continue with 1/4 to 1/3 shock doses every

10 minutes……..10 minutes……..


When do we stop fluid resuscitation for When do we stop fluid resuscitation for shock?shock?A)A) Animal is cardiovascularly stable Animal is cardiovascularly stableB)B) Intravascular volume is maximized Intravascular volume is maximized


How do we determine when an animal is How do we determine when an animal is cardiovascularly stable?cardiovascularly stable?


Assess parameters that indicated the animal Assess parameters that indicated the animal was unstablewas unstable


Assess parameters that indicated the animal Assess parameters that indicated the animal was unstablewas unstable

Try to re-establish normal values for those Try to re-establish normal values for those parameters that indicated the patients was parameters that indicated the patients was unstableunstable

End Points of ResuscitationEnd Points of Resuscitation

Zola: Initial ResuscitationZola: Initial Resuscitation

7.5% hypertonic saline : 4-6 ml/kg IV7.5% hypertonic saline : 4-6 ml/kg IV


7.5% hypertonic saline : 4-6 ml/kg IV7.5% hypertonic saline : 4-6 ml/kg IV Concerns for concurrent cerebral or pulmonary edemaConcerns for concurrent cerebral or pulmonary edema


7.5% hypertonic saline : 4-6 ml/kg IV7.5% hypertonic saline : 4-6 ml/kg IV Concerns for concurrent cerebral or pulmonary edemaConcerns for concurrent cerebral or pulmonary edema

Search for causeSearch for cause low TS, low normal PCV: search for hemorrhagelow TS, low normal PCV: search for hemorrhage

ZolaZola

AbdominocentesisAbdominocentesis

Abdominal PCV 33%Abdominal PCV 33% Peripheral PCV 32%Peripheral PCV 32%

Abdominal CounterpressureAbdominal Counterpressure

T 0 HR 186 bpm

ZolaZola

ZolaZola

T10 HR 154 bpmHypertonic SalineHydromophone

Recheck: Hct 28% TS 3.8 mg/dl, Lactate 7.1mmol /LABP: 86 mmHg

ZolaZola


30 ml/kg bolus LRS

ZolaZola


30 ml/kg bolus LRS

PCV 21% TS 2.4 mg/dLABP 98 mmHg

ZolaZola


30 ml/kg bolus LRS

2 units PRB’s


Animal remains unstable - how much fluid Animal remains unstable - how much fluid can be given before edema occurs?can be given before edema occurs?


Measure central venous pressureMeasure central venous pressure (N = <5cm H(N = <5cm H220)0)

Risk of edema increases around 10 cm HRisk of edema increases around 10 cm H2200


How do you determine intravascular volume How do you determine intravascular volume without a manometer?without a manometer?

Estimating CVPEstimating CVP

Positioning is importantPositioning is importantSternal recumbencySternal recumbencyHead elevatedHead elevatedNeck gently extendedNeck gently extendedShaving to visualize Shaving to visualize

the jugular furrowthe jugular furrow


Normal animalsNormal animals

Jugular pulse < 1/3 of the way up the neckJugular pulse < 1/3 of the way up the neck

Jugular distension < 1/3 of the way up the Jugular distension < 1/3 of the way up the neckneck


What if the animal remains unstable but What if the animal remains unstable but Intravascular volume is maximized?Intravascular volume is maximized?


What if the animal remains unstable but What if the animal remains unstable but Intravascular volume is maximized?Intravascular volume is maximized?Search for an underlying cause Search for an underlying cause

Myocardial depression, electrolytes, acid base, Myocardial depression, electrolytes, acid base, glucose, glucose, on going hemorrhage,on going hemorrhage, relative adrenal relative adrenal insufficiency? insufficiency?

Consider vasopressorsConsider vasopressorsConsider emergency surgeryConsider emergency surgery

After resuscitative efforts have been exhaustedAfter resuscitative efforts have been exhausted

Why differentiate forms Why differentiate forms of shock?of shock?

Tailored TherapiesTailored Therapies

Cardiogenic shock: Cardiogenic shock: Reduce preload : furosemideReduce preload : furosemide Reduce afteroad: arterial/venous vasodilatorsReduce afteroad: arterial/venous vasodilators Antiarrhythmia medications: lidocaine, procainomideAntiarrhythmia medications: lidocaine, procainomide Heart rate reducers (beta blockers, digoxin, calcium channel)Heart rate reducers (beta blockers, digoxin, calcium channel) Positive ionotropes: Dobutamine, pimobendanPositive ionotropes: Dobutamine, pimobendan


Sepsis: Sepsis: AntibioticsAntibiotics Blood glucose concentrationsBlood glucose concentrations Surgical excision and debridementSurgical excision and debridement Relative adrenal insufficiency: physiologic steroidsRelative adrenal insufficiency: physiologic steroids


Vasodilatory shockVasodilatory shock Vasopressor supportVasopressor support Epinephrine for anaphylactic shockEpinephrine for anaphylactic shock


Hemorrhagic shockHemorrhagic shock Transfusion therapyTransfusion therapy Possible surgical control of hemorrhagePossible surgical control of hemorrhage

SummarySummary

Consider the factors contributing to Consider the factors contributing to decreased oxygen deliverydecreased oxygen delivery

Rule out cardiogenic shockRule out cardiogenic shock Start fluid resuscitation while underlying Start fluid resuscitation while underlying

cause is soughtcause is sought Tailor therapies once underlying cause is Tailor therapies once underlying cause is

identifiedidentified





Questions?Questions?

The Many Faces Of Shock

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