Approach to Shock and Hemodynamics

Jiraporn sri-on Emergency medicine Bangkok metropolitan administration and vajira hospital

Outline
Shock
Pathophysiology
Determinants of oxygen delivery
Shock syndromes
Hemodynamic monitoring
Case discussion

Question #1
Which of the following is necessary in the definition of shock?
(a) Hypotension
(b) Tissue hypoxia
(c) Use of pressors
(d) Multiple organ dysfunction

Shock
a multifactorial syndrome resulting in inadequate tissue perfusion and cellular oxygenation.
Lead to tissue hypoxia
anaerobic metabolism
activation of an inflammatory cascade
organ dysfunction hypotension
Irin and Rippe,s Intensive care medicine 6 th edition chapter161 Michael L. Cheatham Ernest F. J. Block

Pathophysiology
Oxygen demand can’t be evaluate
Determined by metabolic demand
Oxygen uptake (VO 2 ) or Oxygen supply
(O 2 uptake) VO 2 = DO 2 * ERO 2

Oxygen delivery (DO 2 )
Oxygen extraction ratio (ERO 2 )
proper distribution, SVR
Pathophysiology

Mark E Astiz critical care fifth edition chapter 107 O 2 uptake (VO 2 ) O 2 delivery (DO 2 )
normal shock

Question #2
Which is the least important determinant of O2 delivery(DO2) ?
(a) Hemoglobin level
(b) Cardiac output
(c) PaO 2
(d) SaO 2

Oxygen Delivery (DO2)
= Cardiac Output x Oxygen Content
= CO x [(1.3 x Hb x SaO 2 ) + (0.003 x PaO 2 )]
Hb concentration
CO
SaO 2  % of O 2 in artery
PaO 2 (minimal)  pressure of O 2 in artery
Inadequate DO 2 occurs most often because of low cardiac output

Cardiac Output
Determined by:
Stroke volume
Heart rate
Stroke volume determined by
Preload
Afterload
Contractility
CO = SV * HR
SV ~ Preload * Contractility
Afterload

Conclusion
Shock lead to tissue hypoxia
Oxygen uptake (VO 2 ) < Oxygen demand
O 2 uptake (VO 2 )
= O2 delivery (DO2) * O2 extraction ratio (ERO2)
O2 delivery (DO2)
= [SV x HR] x [(1.3 x Hb x SaO 2 ) + (0.003 x PaO 2 )]
SV ~ (Preload * Contractility) / Afterload

Classification of shock
Hypodynamic CO
Hyperdynamic CO
Mark E Astiz critical care fifth edition chapter 107

Hypodynamic
hypovolemic (hemorrhagic , nonhemorrhagic)
cardiogenic
obstructive
( PE,cardiac temponade ,tension pneumothorax)
O2 delivery (DO2)
= [SV x HR] x [(1.3x Hb x SaO 2 ) + (0.003x PaO 2 )]
Afterload

Hypodynamic
hypovolemic (hemorrhagic, nonhemorrhagic )
cardiogenic
obstructive
O2 delivery (DO2)
Afterload

Hypodynamic
hypovolemic (hemorrhagic, nonhemorrhagic)
cardiogenic
obstructive
O2 delivery (DO2)
= [SV x HR ] x [(1.3x Hb x SaO 2 ) + (0.003x PaO 2 )]
Afterload

Hypodynamic
cardiogenic
obstructive
( PE ,cardiac temponade ,tension pneumothorax)
O2 delivery (DO2)
SV ~ Preload (left heart) * Contractility
Afterload (right heart)

Hypodynamic
cardiogenic
obstructive
( PE, cardiac temponade , tension pneumothorax)
O2 delivery (DO2)
Afterload

Hypodynamic
cardiogenic
obstructive
( PE,cardiac temponade , tension pneumothorax )
O2 delivery (DO2)
Afterload

O2 extraction ratio (ERO2) proper distribution
Hyperdynamic
CO but improper distribution, SVR
distributive sepsis
adrenal insufficiency
anaphylaxis
O 2 uptake (VO 2 ) = O2 delivery(DO2) * O2 extraction ratio(ERO2)

Diagnosis of Shock
Low BP or a rapid, thready pulse.
without hypotension
Oliguria or mental status change
Peripheral cyanosis and pallor, cool skin
Tachycardia
Metabolic acidosis and elevated lactate

53-year-old female with Hx of hyperthyroidism At 15.20 น . 4/8/52 Case discussion

CC:fever with dyspnea
Vital signs : T 37.2, BP 80/50, PR 100, RR 24 Oxygen Sat. 100% (RA)

Initial Management
IV access with NSS starting with 1000 ml loading in 15 minutes
On cardiac monitoring
Collecting blood samples for laboratory studies include : CBC, BUN, Cr, electrolytes, BS, lactate
Hemoculture x 2, TFT, cardiac markers

HPI
She 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 Chemistry
Electrolyte : Na 123 , K 5.6 , Cl 87, CO 2 21
Cal 9.7, Mg 2.9, PO 4 6.6
BUN 23, Cr 0.8, BS 751
Lactate 5.0
CPK 984 , Trop-T 4.28 , CK-MB 179
LFT 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 1.4
Global hypokinesia with mild MR, mild TR RV not enlarge

Differential diagnosis

Management
Fluid resuscitation
CVP
Antibiotic
Echocardiography

Fluid Challenge Test Initial CVP <8 8-15 >15 cm H 2 O 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 H 2 O or PAOP rises >7 mm Hg Yes No Stop challenge Complete the volume Wait 10 min Wait 10 min CVP change >5 3-5 < 2 3-5 < 2 PAOP 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 (vasodilatation)
- Hyper-, hypo-, or normovolemia c hyperdynamic heart or negative ITP
High CVP
- Hypervolemia
- Hypo- or normovolemia c positive ITP, ventricular dysfunction, obstruction of blood flow (TS, PS, cardial tamponade)

ข้อบ่งชี้ของ Central Venous Line
1. CVP measurement and monitoring
2. Lack of peripheral vein
3. Rapid venous access
4. Administration of drugs
4.1 Hyperosmolar solution: TPN, hypertonic glucose
4.2 Irritating solution: extreme pH, cancer chemotherapy, KCl >40 mEq/L
4.3 Vasopressor: high dose dopamine, NE, adrenaline
5. Frequent blood sampling
6. Insertion of other catheters

Inotropic use:Commonly used First-Line Agents Michael M . Givertz James C . Fang :Irwin and Rippe’s Intensive care medicine 6 th edition 2008 pp 335 Cause of Hypotension Pulmonary Capillary Wedge Pressure Cardiac Output Systemic Vascular Resistance Preferred Agent(s) Unknown ? ? ? Dopamine Hypovolemia ↓ ↓ ↑ None a 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, ephedrine b a Volume resuscitation with intravenous fluids and/or blood products recommended. b For obstetric patients.

Ultrasound:Estimation of central venous pressure Robert F.reardon and Scott A.joing : Emergency ultrasound pp 129 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

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 Points
Shock is defined by inadequate tissue oxygenation, not hypotension
Oxygen delivery depends primarily on CO, Hb and SaO 2 (not pO 2 )
Volume expand with crystalloids and blood, if indicated; then add vasoactive drugs to improve vital organ perfusion
Early treatment of shock is critical

http://www.taem.or.th	189
http://www.slideshare.net	5
http://webcache.googleusercontent.com	1

Approach to Shock and Hemodynamics

by Society of Thai Emergency Physicians on Aug 13, 2009

Accessibility

Categories

Upload Details

Usage Rights

3 Embeds 195

Statistics

Approach to Shock and Hemodynamics — Presentation Transcript