SHOCKSHOCK

Aayed Al-Qahtani, FRCSC, FACSAayed Al-Qahtani, FRCSC, FACS

Ass. Prof. & Consultant Ass. Prof. & Consultant Department of SurgeryDepartment of Surgery

Division of Pediatric SurgeryDivision of Pediatric SurgeryCollege of medicineCollege of medicine

KSUKSU

To understand Physiology of sustaining blood To understand Physiology of sustaining blood pressurepressure

To learn about the classifications of shockTo learn about the classifications of shock

To understand the consequences of the natural To understand the consequences of the natural history of shockhistory of shock

To be able to diagnose and plan appropriate To be able to diagnose and plan appropriate treatments for different types of shocktreatments for different types of shock

OBJECTIVESOBJECTIVES

Intravascular volumeIntravascular volume

HeartHeart

Arteriolar bedArteriolar bed

Capillary exchange networkCapillary exchange network

VenulesVenules

Venous capacitance circuitVenous capacitance circuit

Large vessel patencyLarge vessel patency

CHANGES IN MANY ELEMENTS CHANGES IN MANY ELEMENTS REGULATE BP AND PERFUSIONREGULATE BP AND PERFUSION

Decreased peripheral resistanceDecreased arterial blood pressure (MAP = CO X PR)

Increased peripheral resistanceDecreased venous returnDecreased EDVDecreased SVDecreased CO (CO = HR X SV)Decreased arterial blood pressure (MAP=CO X PR)

Heart Rate X Stroke Volume = Cardiac Output

Cardiac Output X Peripheral Resistance = Arterial Pressure

CARDIAC OUTPUT

ARTERIAL PRESSURE

CARDIAC OUTPUT = CARDIAC OUTPUT = HR X SVHR X SV

BradycardiaBradycardia

Vasodilatation: Vasodilatation: decreased EDVdecreased EDV

MI (pump failure)MI (pump failure)

                   Portion of the circulatory system contains 80% of the Portion of the circulatory system contains 80% of the

intravascular volumeintravascular volume

Decrease in effective circulating blood volume and MAP Decrease in effective circulating blood volume and MAP caused by:caused by:

Decreases in venous toneDecreases in venous toneIncreases in venous vascular capacitanceIncreases in venous vascular capacitance

HOW DOES THEHOW DOES THEVENOUS CAPACITANCE CIRCUITVENOUS CAPACITANCE CIRCUIT

AFFECT BP AND PERFUSION?AFFECT BP AND PERFUSION?

NORMALNORMAL INCREASED VENOUS INCREASED VENOUS CAPACITANCECAPACITANCE

Decreased effective blood volumeDecreased effective blood volumeDecreased MAPDecreased MAP

                                 Obstruction of the systemic or pulmonic circuit will Obstruction of the systemic or pulmonic circuit will

decrease ventricular ejection and systemic perfusiondecrease ventricular ejection and systemic perfusion

Venous obstruction will decrease venous returnVenous obstruction will decrease venous return

Examples of obstructive shock:Examples of obstructive shock:

Massive pulmonary embolism Massive pulmonary embolism Venous occlusionVenous occlusion

HOW DOESHOW DOESLARGE VESSEL PATENCY LARGE VESSEL PATENCY

AFFECT BP AND PERFUSION?AFFECT BP AND PERFUSION?

VENOUS VENOUS OBSTRUCTIONOBSTRUCTION

Decreased effective blood volume

Decreased MAP

DEFINITION OF SHOCKDEFINITION OF SHOCK

State of altered tissue perfusion severe State of altered tissue perfusion severe

enough to induce derangements in enough to induce derangements in

normal cellular metabolic functionnormal cellular metabolic function

TYPES OF SHOCK*TYPES OF SHOCK* 

Type of Shock

 

 Clinical causes

 Primary mechanism

 Hypovolemic

 Volume loss

 Exogenous blood, plasma, fluid or electrolyte loss

 

Cardiogenic Pump failure Myocardial infarction, cardiac arrhythmias, heart failure

 

Distributive Increased venous capacitance or arteriovenous shunting

Septic shock, spinal shock, autonomic blockade, drug

overdose 

Obstructive Extra-cardiac obstruction of blood flow

Vena caval obstruction, cardiac tamponade, pulmonary embolism, aortic compression or dissection

 

*MORE THAN ONE TYPE MAY BE PRESENT*MORE THAN ONE TYPE MAY BE PRESENT

The clinical signs and symptoms of shock relate to decreased organ

perfusion                    Mental status changes: Mental status changes: decreased cerebral perfusiondecreased cerebral perfusion

Decreased urine output: Decreased urine output: decreased renal perfusion decreased renal perfusion

Cold clammy extremities: Cold clammy extremities: Decreased perfusion to the skin due to diverted Decreased perfusion to the skin due to diverted

blood blood flowflow

EKG changes: EKG changes: 1. 1. May indicate myocardial ischemiaMay indicate myocardial ischemia

2. May be primary event (cardiogenic shock) or due 2. May be primary event (cardiogenic shock) or due to to decreased myocardial perfusion due to shock from decreased myocardial perfusion due to shock from

other causesother causes

               Heart rate Heart rate

Initial tachycardia (attempt to increase CO)Initial tachycardia (attempt to increase CO)

Rhythm Rhythm Regular and tachycardicRegular and tachycardic

Blood pressure Blood pressure LowLow

Cardiac outputCardiac outputUsually lowUsually low

HEMODYNAMIC PARAMETERS THAT HEMODYNAMIC PARAMETERS THAT MAY INDICATE SHOCKMAY INDICATE SHOCK

EFFECTS OF SHOCK AT THE ORGAN EFFECTS OF SHOCK AT THE ORGAN LEVELLEVEL

KidneyKidneyOliguric renal failureOliguric renal failure

LiverLiverLiver failureLiver failure

GI tractGI tract Failure of intestinal barrier (sepsis, bleeding)Failure of intestinal barrier (sepsis, bleeding)

LungLungCapillary leak associated with or caused by sepsis and Capillary leak associated with or caused by sepsis and infection (ARDS = adult respiratory distress syndrome)infection (ARDS = adult respiratory distress syndrome)

HEMODYNAMIC RESPONSE TO SHOCKHEMODYNAMIC RESPONSE TO SHOCKMechanisms for restoring cardiovascular homeostasisMechanisms for restoring cardiovascular homeostasis

Redistribution of blood flow Redistribution of blood flow Attempt to preserve perfusion to vital organsAttempt to preserve perfusion to vital organs

Augmentation of cardiac outputAugmentation of cardiac outputIncreased heart rateIncreased heart rateIncreased peripheral resistanceIncreased peripheral resistance

Restoration of intravascular volumeRestoration of intravascular volume

NEUROENDOCRINE STIMULATIONNEUROENDOCRINE STIMULATION

HYPOTENSIONHYPOTENSION

BLOOD FLOW PROTECTEDBLOOD FLOW PROTECTEDHeartHeartBrainBrain

Adrenal/pituitary glandAdrenal/pituitary gland

BLOOD FLOW DECREASEDBLOOD FLOW DECREASEDSkinSkin

MuscleMuscleSplanchnic circulationSplanchnic circulation

HEMODYNAMIC RESPONSE TO SHOCKHEMODYNAMIC RESPONSE TO SHOCKREDISTRIBUTION OF BLOOD FLOWREDISTRIBUTION OF BLOOD FLOW

HEMODYNAMIC RESPONSE TO SHOCKHEMODYNAMIC RESPONSE TO SHOCKVenoconstrictionVenoconstriction Reduced venous Reduced venous

capacitancecapacitance

Arteriolar constrictionArteriolar constriction

Decreased capillary PDecreased capillary P

Fluid shift from interstitium into Fluid shift from interstitium into vascular compartmentvascular compartment

Increased distal tubular Increased distal tubular reabsorptionreabsorption

Increased proximal tubular Increased proximal tubular reabsorptionreabsorption

Increased myocardial Increased myocardial contractilitycontractility

Restoration of Restoration of blood volumeblood volume

Increased Increased ventricular ventricular

filling Pfilling P

Increased ventricular Increased ventricular ejection fractionejection fraction

Increased Increased stroke volumestroke volume

IncreasedIncreasedCOCO

IncreasedIncreasedBPBP

Increased heart rateIncreased heart rate

Increased SVR due to Increased SVR due to arteriolar constructionarteriolar construction

CLINICAL FINDINGS

HypotensionTachycardiaTachypnea

Oliguria

DECREASED CARDIAC FUNCTIONDecreased ventricular function

Myocardial infarctionPericaridal tamponadeTension pneumothorax

Ineffective cardiac contractionPrimary arrhythmias

CARDIOGENIC SHOCKCARDIOGENIC SHOCK

1. Decreased 1. Decreased myocardial blood flowmyocardial blood flow

2. Decreased 2. Decreased contractility=decreased contractility=decreased

stroke volumestroke volume

3. Heart rate increases 3. Heart rate increases to maintain CO to maintain CO (CO=HR X SV)(CO=HR X SV)

5. Decreased 5. Decreased myocardial perfusion myocardial perfusion

leads to further leads to further decrease in decrease in contractilitycontractility

4. If HR cannot 4. If HR cannot maintain CO, then maintain CO, then compromised end-compromised end-

organ perfusionorgan perfusion

HYPOVOLEMIC SHOCKHYPOVOLEMIC SHOCK

DECREASE IN INTRAVASCULAR BLOOD VOLUME

DECREASE IN CARDIAC OUTPUT AND TISSUE PERFUSION

Hemorrhage

Vomiting

Diarrhea

Fluid sequestrationIntraluminal – bowel obstruction

Intraperitoneal – pancreatitis

Interstitial - burns

HYPOVOLEMIC SHOCKHYPOVOLEMIC SHOCKDECREASE IN INTRAVASCULAR

BLOOD VOLUME

BLOOD DIVERTED FROM SKIN TO MAINTAIN ORGAN PERFUSION

Pale and cool skinPostural hypotension and tachycardia

BLOOD DIVERTED PREFERENTIALLY TO HEART AND BRAIN

OliguriaTachycardiaHypotension

END-STAGE SHOCK

BradycardiaArrythmias

Death

DECREASED BLOOD FLOW TO BRAIN AND HEART

Restless, agitated, confusedHypotensionTachycardiaTachypnea

HYPOVOLEMIC SHOCKHYPOVOLEMIC SHOCK

SEPTIC SHOCKSEPTIC SHOCKSEVERE INFECTION W RELEASE OF

MICROBIAL PRODUCTSRelease of vasoactive mediators

HYPERDYNAMIC STATEPeripheral vasodilation

Increased cardiac output

Fever, tachycardia, tachypnea, warm skin

MAINTENANCE OF INTRAVASCULAR VOLUME

Hyperdynamic shock

FAILURE TO MAINTAIN INTRAVASCULAR VOLUME

Hypodynamic shock

Cool skin, tachycardia, hypotension, oliguria

Systemic Inflammatory Response Syndrome (SIRS)

The patients demonstrate a similar response as sepsis but without infective agents.

The criteria are : (two or more to call it SIRS) Temperature >38 or < 36 Heart rate >90 RR > 20 or a pco2 < 34 mmHg (4.3 kpa) WBC > 12,000 0r < 4,000 with more than 10% bands

Neurogenic Shock

It is a shock that result from a high spinal cord injury ( e.g Cervical spine injury)

This will result in loss of sympathetic tone Loss of sympathetic tone will result in:

Arterial and venous dilatation causing hypotension. Bradycardia as a result of unopposed vagal tone.

The typical feature is hypotension with bradycardia

Management of neurogenic shock

Assessment of airway Stabilization of the entire spine Volume resuscitation R/O other causes of shock High dose corticosteroids.

PRINCIPLES OF PRINCIPLES OF RESUSCITATIONRESUSCITATION

Maintain ventilation: ensure oxygen deliveryMaintain ventilation: ensure oxygen delivery

Enhance perfusionEnhance perfusion

Treat underlying causeTreat underlying cause

SUMMARYSUMMARY Shock is an altered state of tissue Shock is an altered state of tissue

perfusion severe enough to induce perfusion severe enough to induce derangements in normal cellular functionderangements in normal cellular function

Neuroendocrine, hemodynamic and Neuroendocrine, hemodynamic and metabolic changes work together to metabolic changes work together to restore perfusionrestore perfusion

Shock has many causes and often may be Shock has many causes and often may be diagnosed using simple clinical indicatorsdiagnosed using simple clinical indicators

Treatment of shock is primarily focused Treatment of shock is primarily focused on restoring tissue perfusion and oxygen on restoring tissue perfusion and oxygen delivery while eliminating the causedelivery while eliminating the cause

10 yo female10 yo female

Fell off bike riding down a hill. Initially well but 4 Fell off bike riding down a hill. Initially well but 4 hrs later complained of abd pain and L shoulder hrs later complained of abd pain and L shoulder painpain

VS: BP 90/60, P 120 (tachycardic), RR 30 VS: BP 90/60, P 120 (tachycardic), RR 30 (tachypneic), T 100.1, O(tachypneic), T 100.1, O22 sat 95% (low) sat 95% (low)

GEN: pale, anxiousGEN: pale, anxious

LUNG: clear to auscultationLUNG: clear to auscultation

COR: tachycardic with murmur best at baseCOR: tachycardic with murmur best at base

ABD: diffuse tenderness w/o peritonitis or massABD: diffuse tenderness w/o peritonitis or mass

Hb 7.5 (low)Hb 7.5 (low)

CASE PRESENTATION CASE PRESENTATION CIRCULATORY SHOCKCIRCULATORY SHOCK

ABD CT:ABD CT: splenic laceration with free peritoneal fluid splenic laceration with free peritoneal fluid

TimeTime

% % survivasurviva

ll

Fast rateFast rate

Slow rateSlow rate

NoneNone

ResuscitationResuscitation

RESUSCITATIONRESUSCITATIONNEED FOR SPEEDNEED FOR SPEED

17 yo male17 yo male

Diving into waterDiving into water

VS: BP 90/60 (low), P 110 (high), RR 24 (high)VS: BP 90/60 (low), P 110 (high), RR 24 (high)

PE: paralysis below C5PE: paralysis below C5

Cervical X-ray: C5 fractureCervical X-ray: C5 fracture

Hemodynamics:Hemodynamics:Central venous pressureCentral venous pressure DecreasedDecreasedCardiac outputCardiac output DecreasedDecreasedSystemic vascular resistanceSystemic vascular resistance DecreasedDecreased

CASE PRESENTATION CASE PRESENTATION NEUROGENIC SHOCKNEUROGENIC SHOCK

15 yo male15 yo male

4 day history of abdominal pain, N/V and anorexia4 day history of abdominal pain, N/V and anorexia

VS: BP 70/60 (low), P 130 (high), RR 28 (high), T102.4, OVS: BP 70/60 (low), P 130 (high), RR 28 (high), T102.4, O22 sat sat 99%99%

GEN: moderate distress from abd painGEN: moderate distress from abd pain

COR: tachycardicCOR: tachycardic

ABD: diffuse tenderness w peritonitisABD: diffuse tenderness w peritonitis

WBC 19,600 (high), 90% segs, Hb 14.2WBC 19,600 (high), 90% segs, Hb 14.2

Hemodynamics:Hemodynamics:Cardiac outputCardiac output IncreasedIncreasedSystemic vascular resistanceSystemic vascular resistance DecreasedDecreased

CASE PRESENTATION CASE PRESENTATION SEPTIC SHOCKSEPTIC SHOCK

Splenic laceration with Splenic laceration with hypovolemia (blood loss)hypovolemia (blood loss)

Decreased CO Decreased CO

Decreased oxygen delivery, increased Decreased oxygen delivery, increased oxygen requirementoxygen requirement

Metabolic acidosis, hypoxemia Metabolic acidosis, hypoxemia tachypneatachypnea

SBP 60, P 150, RR 32, O2 sat 89%

TREATMENT:TREATMENT:Primary resuscitationPrimary resuscitation

OxygenOxygenMechanical ventilation if neededMechanical ventilation if needed

TREATMENT OF RESPIRATORY FAILURETREATMENT OF RESPIRATORY FAILURE

17 yo male17 yo male

Training for track teamTraining for track team

VS: BP 70/50 (low), P 140 (high), RR 35 (high), OVS: BP 70/50 (low), P 140 (high), RR 35 (high), O22 sat 88%sat 88%

PE: absent breath sounds in L lung field, PE: absent breath sounds in L lung field, distended neck veinsdistended neck veins

DX: tension pneumothoraxDX: tension pneumothorax

Hemodynamics:Hemodynamics:Central venous pressureCentral venous pressure IncreasedIncreasedCardiac outputCardiac output DecreasedDecreasedSystemic vascular resistanceSystemic vascular resistance NormalNormal

CASE PRESENTATIONCASE PRESENTATIONCARDIOGENIC SHOCKCARDIOGENIC SHOCK

15 yo male15 yo male

4 day history of abdominal pain, N/V and anorexia4 day history of abdominal pain, N/V and anorexia

VS: BP 70/60 (low), P 130 (high), RR 28 (high), T102.4, OVS: BP 70/60 (low), P 130 (high), RR 28 (high), T102.4, O22 sat sat 99%99%

GEN: moderate distress from abd painGEN: moderate distress from abd pain

COR: tachycardicCOR: tachycardic

ABD: diffuse tenderness w peritonitisABD: diffuse tenderness w peritonitis

WBC 19,600 (high), 90% segs, Hb 14.2WBC 19,600 (high), 90% segs, Hb 14.2

Hemodynamics:Hemodynamics:Cardiac outputCardiac output IncreasedIncreasedSystemic vascular resistanceSystemic vascular resistance DecreasedDecreased

DX:DX: perforated appendicitis perforated appendicitis

CASE PRESENTATION CASE PRESENTATION SEPTIC SHOCKSEPTIC SHOCK

3 yo male3 yo male

Clothes ignited from roaster at ThanksgivingClothes ignited from roaster at Thanksgiving

VS: BP 60/60 (low), P 170 (high), RR 35 (high), VS: BP 60/60 (low), P 170 (high), RR 35 (high), T102.4, OT102.4, O22 sat 89% sat 89%

GEN: moderate distressGEN: moderate distress

LUNG: tachypneic, clear to auscultationLUNG: tachypneic, clear to auscultation

COR: tachycardic, regularCOR: tachycardic, regular

SKIN: 60% TBSA partial and full thickness burnSKIN: 60% TBSA partial and full thickness burn

Hemodynamics:Hemodynamics:Cardiac outputCardiac output DecreasedDecreasedSVRSVR IncreasedIncreased

CASE PRESENTATIONCASE PRESENTATIONCAPILLARY LEAKCAPILLARY LEAK

DX:DX: 60% TBSA burn 60% TBSA burn

HYPOVOLEMIC SHOCK (LOSS OF FLUID INTO INTERSTITIUM)HYPOVOLEMIC SHOCK (LOSS OF FLUID INTO INTERSTITIUM)

10 yo female10 yo female

Fell off bike riding down a hill. Initially well but 4 Fell off bike riding down a hill. Initially well but 4 hrs later complained of abd pain and L shoulder hrs later complained of abd pain and L shoulder painpain

VS: BP 90/60, P 120 (tachycardic), RR 30 VS: BP 90/60, P 120 (tachycardic), RR 30 (tachypneic), T 100.1, O(tachypneic), T 100.1, O22 sat 95% (low) sat 95% (low)

GEN: pale, anxiousGEN: pale, anxious

COR: tachycardic with murmur best at baseCOR: tachycardic with murmur best at base

ABD: diffuse tenderness w/o peritonitis or massABD: diffuse tenderness w/o peritonitis or mass

Hb 7.5 (low)Hb 7.5 (low)

Hemodynamics:Hemodynamics:Central venous pressureCentral venous pressure DecreasedDecreasedCardiac outputCardiac output DecreasedDecreasedSystemic vascular resistanceSystemic vascular resistance DecreasedDecreased

CASE PRESENTATION CASE PRESENTATION CIRCULATORY SHOCKCIRCULATORY SHOCK

• Circulatory shockCritical reduction in tissue perfusionResults in organ dysfunction and, if not treated, deathUsually accompanied by signs and symptoms:

OliguriaMental status changesWeak thready pulseCool clammy limbs

• Septic shockHypotensionVasodilatation with warm limbs.

OVERVIEWOVERVIEWGENERIC CLASSIFICATIONS OF SHOCKGENERIC CLASSIFICATIONS OF SHOCK

MAINTAIN VENTILATIONMAINTAIN VENTILATIONIncreased oxygen Increased oxygen

demanddemand

HyperventilationHyperventilation

Respiratory fatigueRespiratory fatigue

Respiratory failureRespiratory failureRespiratory acidosis, lethargy-coma, hypoxiaRespiratory acidosis, lethargy-coma, hypoxia

Especially in:Especially in:

SepsisSepsisHypovolemiaHypovolemia

TraumaTrauma

• Vasodilatation

• A-V shunting

• Maldistribution of flow

• Increased capillary permeability + interstitial edema

• Decreased oxygen extraction

• Primary defect of oxygen utilization at cellular level

CAPILLARY LEAK SYNDROMECAPILLARY LEAK SYNDROME