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