2013 Pediatric Subspecialty Boot Camp_SHOCK

PEDIATRIC SHOCKAyse Akcan Arikan

Texas Children’s Hospital

Pediatric Critical Care Section

Fellows Bootcamp 2013

Objectives

• By the end of this workshop, the learner will be able to:• Differentiate between septic and cardiogenic shock states according to clinical assessment and evaluation

• Generate a therapeutic/diagnostic plan according to institutional and SCCM guidelines where applicable

What is shock?

a. BP less than 5th percentile of age normal

b. Uncontrolled fluid loss/blood loss

c. Tachycardia and hypotension

d. Acidosis and increased lactate

e. Signs of organ dysfunction with decreased UOP, altered mental status, etc.

Pediatric Shock• Definition – what it is and what it is not• Pathophysiology• Recognition – early is key!• Management- guidelines• Case scenarios• Ask for references, and you shall receive

PumpFluidPipesSite of exchange

Pediatric shock• Cellular pathology• Has nothing to do with blood pressure (until very late),

cardiac output, heart rate• Inability to meet the metabolic demands (=oxygen) of the

tissue – or inability of the cell to use oxygen• Supply-demand imbalance

What is shock?

• A hemodynamic abnormality that leads to inability to meet tissue metabolic demands.

• Dynamic, progressive.

• A systemic reduction in tissue perfusion decreased tissue O2 delivery. • A shift to anaerobic metabolism• Less efficient – 20-fold less ATP generated• Leads to lactic acidosis

• Over time, progresses to,• Cell membrane ion pump dysfunction• Cellular edema, leakage of cells’ contents• Inadequate regulation of intracellular pH• Cell death, organ failure, cardiac arrest, and death.

Pediatric shock• Dynamic process

• Progressive• Changing physiology*

• Requires bedside management• Oxygen debt• Energy uncoupling

Vocabulary• CO –cardiac output• CI cardiac index – CO indexed to BSA• SVR, SVRI - systemic vascular resistance• PVR,PVRI – pulmonary vascular resistance• MAP – mean arterial pressure• CVP – central venous pressure• SV – stroke volume• PAP – pulmonary artery pressure• DO2 – oxygen delivery• VO2 – oxygen consumption

Vocabulary - II• CO – cardiac output: volume of blood ejected by the heart

in one minute 4-8 L/min• Heart rate• Stroke volume

• Contractility• Afterload• Preload

• SVR = MAP – CVP / CO

Oxygen Delivery – DO2• Oxygen delivery= CO X CaO2 (Arterial oxygen content)• CO=Heart rate X Stroke volume• Stroke volume depends on preload, afterload and

contractility

•Arterial Oxygen content (CaO2) = Hb x Sa02 x 1.34 +(0.003 x Pa02)

Oxygen Consumption – VO2• VO2 = CO x (CaO2 – CvO2)• Under normal conditions DO2 >> VO2 (physiological

reserve) – this is why you can exercise and don’t die

Oxygen delivery – consumption imbalance in shock

Shock pathophysiology

• Oxygen delivery DO2 < oxygen demand VO2

OXYGEN DELIVERY

CARDIAC OUTPUT X ARTERIAL OXYGEN CONTENT

Cardiac Output

Arterial oxygen content

Heart rate Stroke Volume

PreloadAfterloadContractility

HemoglobinOxygen SaturationPartial pressure of oxygen dissolved in plasma

Oxygen extraction ratio= (SaO2-SmvO2)/SaO2SmvO2 = mixed venous oxygen saturations (PA)ScvO2 = upper extremity line

Shock – signs and symptoms• Evidence of end organ hypoperfusion

• Decreased urine output• Altered mental status• Poor peripheral perfusion

• Metabolic dysfunction• Lactic acidosis• Altered metabolic demands

Shock: Feel the feet, look at the neck• Tachycardia? - Non-specific, but early• Skin changes? - Prolonged cap refill (vasoconstriction) with

compensated shock. Flash refill with early distributive shock and with irreversible shock.

• Pallor? – If Hb is fine, is your patient acidotic

• Impaired mental status? – Fussy, irritable? Sleepy?

• Oliguria? – When was the last diaper?

• Hypotension? – You have missed the ball • Widened pulse pressure (>40 mmHg)? - distributive shock, aortic insufficiency,

AVMs?

Compensatory Mechanisms• Baroreceptors-In aortic arch and carotid sinus, low MAP

cause vasoconstriction, increases BP, CO and HR• Chemoreceptors- Respond to cellular acidosis, results in

vasoconstriction and respiratory stimulation

• Renin Angiotensin Aldosterone - Decreased renal perfusion leads to angiotensin causing vasoconstriction and aldosterone causing salt and water retentions

• Humoral Responses-Catecholamines• Autotransfusion-Reorientation of extravascular fluid

Stages of Shock

• Compensated Shock: • Cardiac output (HR x SV) and systemic vascular resistance (peripheral

vasoconstriction) work to keep BP within normal limits. • Tachycardia; decreased pulses & cool extremities in cold shock; flushing

and bounding pulses in warm shock; oliguria; may have mild lactic acidosis

• Uncompensated Shock: • Compensatory mechanisms are overwhelmed.• Hypotension, altered mental status; increased lactic acidosis• Generally quick progression to cardiac arrest.

• Irreversible Shock: • Irreversible organ damage, cardiac arrest, death.

• Compensated

• Uncompensated

• Irreversible

Act quicklyThink slowly

DEATH

Types of shock

•Hypovolemic•Hemorrhagic

•Cardiogenic•Distributive

•Septic*•Obstructive

Classifications of Shock

• Hypovolemic Shock• Decreased preload due to

internal or external losses.

• Distributive Shock• Decrease in SVR, with

abnormal distribution of blood flow functional hypovolemia, decreased preload.

• Typically, NL or CO.

• Cardiogenic Shock• “Pump failure.” CO,

systolic function.

• Obstructive Shock• Outflow from left or

right side of heart physically obstructed.

© 2009 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins. Published by Lippincott Williams & Wilkins, Inc.

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Table 2.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine *.Brierley, Joe; Carcillo, Joseph; Choong, Karen; Cornell, Tim; DeCaen, Allan; Deymann, Andreas; Doctor, Allan; Davis, Alan; Duff, John; Dugas, Marc-Andre; Duncan, Alan; Evans, Barry; Feldman, Jonathan; Felmet, Kathryn; Fisher, Gene; Frankel, Lorry; Jeffries, Howard; Greenwald, Bruce; Gutierrez, Juan; Hall, Mark; Han, Yong; Hanson, James; Hazelzet, Jan; Hernan, Lynn; Kiff, Jane; Kissoon, Niranjan; Kon, Alexander; Irazusta, Jose; Lin, John; Lorts, Angie; Mariscalco, Michelle; Mehta, Renuka; Nadel, Simon; Nguyen, Trung; Nicholson, Carol; Peters, Mark; Okhuysen-Cawley, Regina; Poulton, Tom; Relves, Monica; Rodriguez, Agustin; Rozenfeld, Ranna; Schnitzler, Eduardo; Shanley, Tom; Skache, Sara; Skippen, Peter; Torres, Adalberto; von Dessauer, Bettina; Weingarten, Jacki; Yeh, Timothy; Zaritsky, Arno; Stojadinovic, Bonnie; Zimmerman, Jerry; Zuckerberg, Aaron

Critical Care Medicine. 37(2):666-688, February 2009.DOI: 10.1097/CCM.0b013e31819323c6

Table 2. American College of Critical Care Medicine hemodynamic definitions of shock

Type of shock Mechanism of circulatory failure

Signs and symptoms

Interventions

Hypovolemic Volume depletion absolute or relative, CO ↓, SVR ↑

Tachycardia, diminished pulses, sunken eyes and fontanels, oliguria, prolonged cap refill time

Crystalloid bolus 20 ml/kg until hemodynamics improve, reassess after each bolus, blood products in hemorrhagic shock

Cardiogenic CO ↓, SVR ↑ Tachycardia, diminished pulses, hepatomegaly, JVD

Inotropic agents dopamine, dobutamine, epinephrine, milrinoneSmall volume boluses 5-10 ml/kg might be administered carefully while monitoring responseGet echo earlyConsider PGE


Signs and symptoms

Interventions

DistributiveAnaphylacticNeurogenic

CO ↑, then ↓, SVR ↓↓

Angioedema, respiratory distress, stridor, wheezing, early hypotension

Start adrenergic support while giving fluids, obtain vascular access early, supratherapeutic doses of inotropes might be required

CO normal, SVR ↓ Hypotension in the absence of tachycardia

Support SVR with vasopressors, phenylephrine might be required, give fluids as necessary

Obstructive Preload ↓, CO ↓, SVR normal to ↑

Tachycardia, hypotension, JVD, tracheal deviation if pneumothorax, equalization of pressures with elevated CVP if invasive monitoring in place

Rapidly fatal if underlying process not recognized and reversed, fluid boluses should be given while preparation is made for emergent drainage


Signs and symptoms Interventions

Septic “Warm shock” CO ↑, SVR↓

Tachycardia, bounding pulses, warm extremities with hypotension, hyperpnoea, altered mentation

Crystalloid boluses of 20 ml/kg repeat until hemodynamics stable, first choice agents vasopressors (dopamine or norepinephrine)

“Cold shock” CO ↓, SVR ↑(60% of pediatric cases)

Tachycardia, poor peripheral perfusion, diminished pulses, hyperpnoea, altered mentation

Crystalloid boluses of 20 ml/kg, repeat until hemodynamics stable, early inotropic support with dopamine or epinephrine might be required, echocardiography might be useful to guide therapy

CO ↓, SVR ↓ Tachycardia, diminished pulses, with hypotension, hyperpnoea, altered mentation

Crystalloid boluses of 20 ml/kg repeat until hemodynamics stable, early inotropic support with dopamine or epinephrine might be required, echocardiography might be useful to guide therapy


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Table 3.



Table 3. Threshold heart rates and perfusion pressure mean arterial pressure-central venous pressure or mean arterial pressure-intra-abdominal pressure for age

What is the goal of shock treatment ?

•Optimizing oxygen content of the blood

• Improving volume and distribution of cardiac output

•Reducing oxygen demand•Correcting metabolic derangements

Treatment• Overall goal: Normalization of tissue perfusion and

homeostasis• A - airway

• Secure, patent• Oxygen administration – 100% FiO2 (except in some cases of

cardiogenic shock)

• B - breathing• Decrease WOB, intubation-mechanical ventilation may be

necessary (decrease oxygen consumption)

• C - circulation• Improve cardiac output• Ensure adequate preload – FLUIDS!!!

Treatment - II• Have I mentioned fluids?• Give lots of fluids – fast!• Then – give some more –up to 200 ml/kg may be required• REASSESS! (After every step/intervention)• Pay attention to hepatomegaly, JVD, rales, worsening

respiratory distress – if your patient is not responding to the fluids, reconsider your diagnosis

• Once you reach 60 ml/kg, consider starting vasoactive infusions –more on this later

Treatment - III• D – “derangements”

• Correct metabolic abnormalities – hypoglycemia, hypocalcemia, etc

• Etiology specific treatment

•DO NOT DELAY ANTIBIOTICS FOR ANY REASON IF YOU SUSPECT SEPTIC SHOCK !• Source control

• Consider transfusion of PRBCs

Assessing efficacy of treatment

• Blood pressure: Normal *• Quality of central and peripheral pulses: Strong, distal

pulses equal to central pulses.• Skin perfusion: Warm, with capillary refill 1-2 seconds.• Mental status: Normal. Urine output: >1 mL/kg per hour, once effective

circulating volume is restored.

Sepsis• High mortality despite improvements

• KID database : 4.2% in all-comers, 2.3% in previously healthy, 7.8% in chronically ill

• Guidelines are not effective unless protocol driven• Early intervention is critical – no delay is acceptable. • Every hour spent without reversing shock increases OR of

mortality

SIRS SEPSIS SEVERESEPSIS

SEPTIC SHOCK

T > 38.5 or < 36

Tachycardia

Tachypnea

WBC

SIRS +

Infection

(suspected or proven)

SEPSIS +

CV dysfunction or

ARDS or

≥ 2 organ failures

SEPSIS +

CV dysfunctiondespite >40 ml/kg in 1 hr

2 of the above 4

Early Goal-directed Therapy

Pediatrics 2003; 112:793

Early Resuscitation


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Figure 1.



Figure 1. Algorithm for time sensitive, goal-directed stepwise management of hemodynamic support in infants and children. Proceed to next step if shock persists. 1) First hour goals-Restore and maintain heart rate thresholds, capillary refill MAP]-central venous pressure [CVP]) for age, central venous O2 saturation >70%, and CI >3.3, 2 in pediatric intensive care unit (PICU). Hgb, hemoglobin; PICCO, pulse contour cardiac output; FATD, femoral arterial thermodilution; ECMO, extracorporeal membrane oxygenation; CI, cardiac index; CRRT, continuous renal replacement therapy; IV, intravenous; IO, interosseous; IM, intramuscular.

TCH Shock Protocol

Definitions• Pressor-increases SVR, and therefore BP• Inotrope-Increases contractility, SV• Chronotrope- increases HR• Lusitrope- improves diastolic relaxation, SV• Vasodilator- decreases SVR, afterload• “Inodilator”

TCH BOOTCAMPShock II – Cardiogenic shock

PumpFluidPipesSite of exchange

• Tachycardia• Tachypnea• Hx of sweating/tiring with feeds• Vomiting, feeding intolerance• Fussiness• Gallop• Hepatomegaly• Rales• Decreased UOP• Cardiomegaly• Altered mentation• “Septic” newborn !• Cyanosis

VENTRICULAR FUNCTION CURVESNORMAL AND FAILING LV

Cardiogenic shock• Electrical failure• Mechanical failure

• Myocarditis• Cardiomyopathy• Anatomic

• Obstructive• Congestive

• Ischemic• Trauma

Cardiogenic shock• Anatomic

• Left sided obstructive = ductal dependent systemic flow IAA, critical AS, HLHS, etc HCM*

• Congestive • large L R shunts• Acute valvular regurgitation

• Ductal dependent pulmonary blood flow• Parallel circulation – TGA-IVS• Obstructed pulmonary flow – TAPVR, obstructed

Ischemic Heart Disease in Children

• ALCAPA• Anomalous Left Coronary Artery arising from the Pulmonary

Artery

• Kawasaki Disease• Aneurysms

• Other vasculitis

Treatment• Support the failing pump• Decrease oxygen consumption/metabolic demand

• Intubation*, mechanical ventilation• Sedation, NMB• Prevention of fever, stress

• Consider bolus 5-10 ml/kg• Consider PGE• Echo early

Treatment - II• Optimize contractility

• Correct metabolic derangements• Inotropic support

• Afterload reduction• Decongestion• Address the underlying cause – surgery?• Mechanical support

• ECMO• Implantable devices, VAD, EXCOR, etc


Signs and symptoms

Interventions

Hypovolemic Volume depletion absolute or relative, CO ↓, SVR ↑

Tachycardia, diminished pulses, sunken eyes and fontanels, oliguria, prolonged cap refill time

Crystalloid bolus 20 ml/kg until hemodynamics improve, reassess after each bolus, blood products in hemorrhagic shock

Cardiogenic CO ↓, SVR ↑ Tachycardia, diminished pulses, hepatomegaly, JVD

Inotropic agents dopamine, dobutamine, epinephrine, milrinoneSmall volume boluses 5-10 ml/kg might be administered carefully while monitoring responseGet echo earlyConsider PGE

Question• 13 month old patient with DCM, HR 180 (sinus), CVP 25

mm Hg, BP 55/24, lactate 4->8, SvO2 50%, cap refill of 5 seconds, best choice of action is:

a. Epinephrine gtt

b. Milrinone gtt

c. Phenylephrine gtt

d. NS bolus 20 ml/kg

e. Esmolol (B-blocker) for HR control

Question • 12 year old female presents with fever, tachycardia, right

flank pain, WBC count is elevated. Vital signs are HR 155, RR 35, BP 124/73, T 102. She is somnolent. Working diagnosis is sepsis secondary to pyelonephritis. What is the next most appropriate intervention?

A. Renal US

B. Normal saline bolus

C. Antibiotics

D. Vasopressor infusion

E. Urinalysis

Question • 12 year old female presents with fever, tachycardia, right

flank pain, WBC count is elevated. Vital signs are HR 110, RR 25, BP 124/83, T 102. She is AAO x 3 and is . Working diagnosis is sepsis secondary to pyelonephritis. What is the next most appropriate intervention?

A. Renal US

B. Normal saline bolus

C. Antibiotics

D. Vasopressor infusion

E. Urinalysis

Case 1

• 15-year-old male is just transferred to 11 WT from PICU, POD #3 from partial small bowel resection after multiple gunshot wounds to the abdomen. The nurse calls an RRT because his HR has increased in the last hour from 90 to 130, despite pain score of 1/10 on morphine drip. On exam, he is afebrile, HR is 140, BP 80/50. Cap refill is >3 seconds in his cool extremities and pulses are 1+.

• What is your assessment?• What is the stage of shock?• What is the classification of shock?• What is your initial management?

Case 2

• 6-year-old previously healthy girl is transferred from West Campus ER with fever, bloody diarrhea x 1 day. She’s had no urine x 24 hrs and is becoming harder to awaken. On exam, her HR is 152, BP 72/32, temp 103. She’s sleepy but arousable.

She’s flushed with capillary refill <1 second.

• What is your assessment?• What is the stage of shock?• What is the classification of shock?• What is your differential for the etiology?• What is your initial management? If a higher level of care is needed,

how would you obtain it?

Case 3

• 4-month-old boy former premie, presents to ED with decreased po x 2 days with 2 times daily emesis, following what sounds like viral URI. Urine output has been 3 wet diapers daily. He is afebrile with HR 180; BP has not been obtained. He has a weak cry, is mottled with 3-second capillary refill, pulses 1+ in all extremities. Liver is palpable 4 cm below RCM. S4 is present without murmur.

• What is your assessment?• What is the stage of shock?• What is the classification of shock? • What is your differential for the etiology?• What is your initial management?

What is the end goal for resuscitation ?

• Mixed venous sats• Lactate clearance• Traditional clinical variables –UOP, perfusion, pulses, CVP• Combination of all three with common sense

Minimize variationEarly Resuscitation

Intensive Care Med 2008; 34:1065

Intensive Care Med 2008; 34:1065

Minimize variationEarly Resuscitation

• crashingpatient.com• ccmtutorials.com• cvphysiology.com• learnhemodynamics.com*• library.med.utah.edu

Health & Medicine

2013 Pediatric Subspecialty Boot Camp_SHOCK