Approach to Shock and Hemodynamics

Jiraporn sri-on Jiraporn sri-on Emergency medicineEmergency medicine

Bangkok metropolitan Bangkok metropolitan administration and vajira administration and vajira

hospitalhospital

OutlineOutlineShock

PathophysiologyDeterminants of oxygen deliveryShock syndromes

Hemodynamic monitoringCase discussion

QuestionQuestion #1#1Which of the following is necessary in

the definition of shock?(a) Hypotension(b) Tissue hypoxia(c) Use of pressors(d) Multiple organ dysfunction

Question #1Question #1Which of the following is necessary in

the definition of shock?(a) Hypotension(b) Tissue hypoxia(c) Use of pressors(d) Multiple organ dysfunction

ShockShocka multifactorial syndrome resulting

in inadequate tissue perfusion and cellular oxygenation.

Lead to tissue hypoxiaanaerobic metabolismactivation of an inflammatory cascadeorgan dysfunction hypotension

Irin and Rippe,s Intensive care medicine 6 th edition chapter161Michael L. Cheatham Ernest F. J. Block

PathophysiologyPathophysiologyOxygen demand can’t be evaluate

Determined by metabolic demandOxygen uptake (VO2) or Oxygen

supply(O2 uptake) VO2 = DO2 * ERO2

Oxygen delivery (DO2)

Oxygen extraction ratio (ERO2)proper distribution, SVR

PathophysiologyPathophysiology(O2 uptake) VO2 = DO2 * ERO2

Mark E Astiz critical care fifth edition chapter 107

O2 uptake(VO2)

O2 delivery (DO2)

shock

(O2 uptake) VO2 = DO2 * ERO2

normal

Question #2Question #2Which is the least important

determinant of O2 delivery(DO2) ?(a) Hemoglobin level(b) Cardiac output(c) PaO2

(d) SaO2

Oxygen Delivery (DO2)Oxygen Delivery (DO2)= Cardiac Output x Oxygen ContentOxygen Content= CO x [(1.3 x Hb x SaO2) + (0.003 x

PaO2)]Hb concentrationCO SaO2 % of O2 in artery

PaO2 (minimal) pressure of O2 in artery

Inadequate DO2 occurs most often because of low cardiac output

Cardiac OutputCardiac OutputDetermined by:

Stroke volumeHeart rate

Stroke volume determined byPreloadAfterloadContractility

CO = SV * HR

SV ~ Preload * Contractility

Afterload

ConclusionConclusionShock lead to tissue hypoxiaOxygen uptake (VO2) < Oxygen demandO2 uptake (VO2)

= O2 delivery (DO2) * O2 extraction ratio (ERO2)

O2 delivery (DO2) = Cardiac Output x Oxygen ContentOxygen Content = [SV x HR] x [(1.3 x Hb x SaO2) + (0.003 x PaO2)]

SV ~ (Preload * Contractility) / Afterload

Classification of shockClassification of shock

Hypodynamic CO

Hyperdynamic CO



Hypodynamichypovolemic (hemorrhagic, nonhemorrhagic)cardiogenic obstructive ( PE,cardiac temponade ,tension pneumothorax)


O2 delivery (DO2) = Cardiac Output x Oxygen ContentOxygen Content = [SV x HR] x [(1.3x Hb x SaO2) + (0.003x PaO2)]SV ~ Preload * Contractility

Afterload




O2 delivery (DO2) = Cardiac Output x Oxygen ContentOxygen Content = [SV x HR] x [(1.3x Hb x SaO2) + (0.003x PaO2)]SV ~ Preload (left heart) * Contractility

Afterload (right heart)


Hypodynamichypovolemic (hemorrhagic, nonhemorrhagic)cardiogenic obstructive ( PE, cardiac temponade, tension pneumothorax)



Afterload





Afterload

O2 extraction ratio (ERO2) proper distribution

Hyperdynamic CO but improper distribution, SVR

distributive sepsis adrenal insufficiencyanaphylaxis

O2 uptake (VO2) = O2 delivery(DO2) * O2 extraction ratio(ERO2)

DiagnosisDiagnosis of Shockof ShockLow BP or a rapid, thready pulse.without hypotension

Oliguria or mental status changePeripheral cyanosis and pallor, cool skin

Tachycardia Metabolic acidosis and elevated lactate

53-year-old female with Hx of hyperthyroidism

At 15.20น. 4/8/52

Case discussionCase discussion

CC:fever with dyspnea

Vital signs : T 37.2, BP 80/50, PR 100, RR 24

Oxygen Sat. 100% (RA)

Initial ManagementIV access with NSS starting with 1000 ml

loading in 15 minutesOn cardiac monitoringCollecting blood samples for laboratory

studies include : CBC, BUN, Cr, electrolytes, BS, lactate

Hemoculture x 2, TFT, cardiac markers

HPIShe has had low grade fever

(unmeasured) with dry cough for 2 weeks prior to presentation. The cough became worse when she laid down during the night. She walked up the stairs at home and developed very short of breath which made her come to our ED.

PMHx : Hyperthyroid[PTU(50)2x2 + Propranolol]

She has skipped the medication for nearly 2 weeks.

ALL : NKDA FHx : 2 Sisters with diabetes. SHx : Occasional alcohol

Regular use of over-the-counter drugs (for relieving pain, fatigue and muscle

strain)

General : Alert, middle-aged woman with moderate discomfort,shortness of breath and sweating.

HEENT : Mild pallor, anicteric sclera, no exopthalmos, no lid retraction, mild pharyngeal erythema.

CVS : mildly tachycardic, regular rhythm, no heart murmurs or gallops, no heaving.

RS : Clear bilaterally

Abdomen : Soft, not tender, liver and spleen not palpable.

Ext : No leg edema or tenderness

Skin : No abnormal skin rash

CBC : Hb 13.9, Hct 40, WBC 12000 (N64/L26) PLT 417000, Band 0

Blood ChemistryElectrolyte : Na 123, K 5.6, Cl 87, CO2 21

Cal 9.7, Mg 2.9, PO4 6.6BUN 23, Cr 0.8, BS 751Lactate 5.0CPK 984, Trop-T 4.28, CK-MB 179LFT AST 3164 ALT 2016 ALP 223 TB 0.6 DB 0.3 TP

5.3 Alb 2.3

• Urinalysis : Glu 4+•

Echo bedside : EF 40% IVC 1.4Global hypokinesia with mild

MR, mild TR RV not enlarge

Differential diagnosis

ManagementFluid resuscitationCVPAntibioticEchocardiography

Fluid Challenge Test

Initial CVP <8 8-15 >15 cm H2O PAOP <12 12-16 >16 mm Hg

Volume & Rate 200 mL/10 min 100 mL/10 min 50 mL/10 min

During infusion, CVP rises >5 cm H2O or PAOP rises >7 mm Hg Yes No

Stop challenge Complete the volumeWait 10 min Wait 10 min

CVP change >5 3-5 <2 3-5 <2PAOP change >7 4-7 <3 4-7 <3

CVP and Blood Volume (BV)

Normal CVP - Normovolemia - Hypovolemia c venoconstriction, ventricular

dysfunction - Hypervolemia c hyperdynamic heart function

Low CVP - Absolute or relative hypovolemia (vasodilatat

ion) - - - Hyper , hypo , or normovolemia c hyperdyna

mic heart or negative ITP High CVP

- Hypervolemia - - Hypo or normovolemia c positive ITP, ventric

ular dysfunction, obstruction of blood flow (TS , PS, cardial tamponade)

ข้�อบ่�งชี้�ข้อง Central Venous Line1. CVP measurement and

monitoring2. Lack of peripheral vein 3. Rapid venous access4. Administration of drugs

4.1 Hyperosmolar solution: TPN, hypertonic glucose

4.2Irritating solution: extreme pH, cancer chemotherapy, KCl >40 mEq/L

4.3 Vasopressor: high dose dopamine, NE, adrenaline

5. Frequent blood sampling6. Insertion of other catheters

Inotropic use:Commonly used First-Line Agents

Cause of Hypotension

Pulmonary Capillary Wedge Pressure

Cardiac Output

Systemic Vascular Resistance Preferred Agent(s)

Unknown ? ? ? Dopamine

Hypovolemia ↓ ↓ ↑ Nonea

Decompensated heart failure

↑ ↓ ↑ Dopamine, dobutamine

Cardiogenic shock ↑↔ ↓ ↑ Dopamine

Hyperdynamic sepsis

↓↔ ↑ ↓ Norepinephrine, dopamine

Sepsis with depressed cardiac function

? ↓ ↓ Dopamine, norepinephrine plus dobutamine

Anaphylaxis ? ? ↓ Epinephrine

Anesthesia-induced hypotension

? ? ↓ Phenylephrine, ephedrineb

aVolume resuscitation with intravenous fluids and/or blood products recommended.bFor obstetric patients.

Michael M. Givertz James C. Fang :Irwin and Rippe’s Intensive care medicine 6th edition 2008 pp 335

Ultrasound:Estimation of central venous pressure

IVC size (cm) Respiratory change RA pressure (cm)

<1.5 Total collapse 0-5

1.5-2.5 > 50% collapse 5-10

1.5-2.5 <50% collapse 11-15

>2.5 <50% collapse 16-20

>2.5 No change >20

Robert F.reardon and Scott A.joing : Emergency ultrasound pp 129

IVC measurement demonstrating normal IVC collapse.IVCDmax (expiration) 17.9 mm; IVCDmin (inspiration) 8.9 mm. IVC-CI : IVCDmax– IVCDmin/IVCDmax: (17.9 – 8.9)/17.9; 50% collapse.

Take Home PointsShock is defined by inadequate tissue

oxygenation, not hypotension

Oxygen delivery depends primarily on CO, Hb and SaO2 (not pO2)

Volume expand with crystalloids and blood, if indicated; then add vasoactive drugs to improve vital organ perfusion

Early treatment of shock is critical

Approach to Shock and Hemodynamics

Health & Medicine

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