This document defines and classifies shock, discusses its pathophysiology and clinical signs. It describes the different types of shock including hypovolemic, cardiogenic, obstructive, and distributive shock. For each type it discusses etiology, hemodynamics, laboratory tests, imaging and management approaches including fluid resuscitation and vasopressor/inotropic drug therapy.

1. shock
PROF. DR AHMED MOHAMMED HUSSIEN
LECTURER OF INTERNAL MEDICINE AND NEPHROLOGY
FACULTY OF MEDICINE , HELWAN UNIVERSITY

2. Shock definition
Acute circulatory failure wth inadequate
tissue perfusion resulting in generalized
cellular hypoxia.

3. Clinical signs
Tachycardia,tachypnea,oliguria,
encephalopathy,peripheral
hypoperfusion (mottled ,poor
capillary refill),hypotension.

4. Cardiac output (CO) is the amount of blood pumped by
the heart minute
SVR is the resistance in the circulatory system that is used
to create blood pressure, the flow of blood and is also a
component of cardiac function. When blood vessels
constrict (vasoconstriction) this leads to an increase in
SVR.
end-diastolic volume (EDV) is the volume of blood in the
right or left ventricle at end of filling in diastole
Preload is the initial stretching of the cardiac myocytes
(muscle cells) prior to contraction. It is related to
ventricular filling.
Afterload is the force or load against which the heart has
to contract to eject the blood.

5. Shock : classification
Hypovolemic shock due to decreased
circulatory blood volume in relation to the
total vascular capacity and characterized
by reduction of preload and diastolic filling
pressure .
Cardiogenic shock due to cardiac pump
failure related to loss myocardial
contractility /functional myocardium or
mechanical failure of cardiac anatomy
and characterized by decreased systolic ,
diastolic function.

6. obstructive shock refers to the anatomical obstruction
of the great vessels of the heart (e.g., superior vena
cava, inferior vena cava, and pulmonary vessels) that
leads to decreased venous return and/or excessive
afterload (i.e., the force that the left ventricle has to
overcome to eject blood through the aortic valve),
resulting in decreased cardiac output.
Distributive shock also known as vasodilatory shock,
refers to systemic vasodilation and decreased blood
flow to vital organs such as the brain, heart, and
kidneys. It can also cause fluid to leak from the
capillaries into the surrounding tissues as a result.
-Septic shock (from a bacterial infection). ...
-Anaphylactic shock (from an allergic reaction or
asthma attack). ...
-Neurogenic shock (from a spinal cord injury that has
damaged your nervous system).

7. Etiology of circulatory
shock
Hypovolemic shock :
hemorrhagic(trauma , Gastrointestinal , Retroperitoneal )
fluiddepletion ( external fluidloss : dehydration , vomiting , diarrhea
and polyuria
interstitial fluidredistribution : thermal injury , trauma , Anaphylaxis)
Cardiogenic : Myopathic (myocardial infarction , myocardial contusion ,
myocarditis cardiomyopathy, septic myocardial depression,
anthracycline cardiotoxicity , calcium channel blockers , valvular failue
(stenotic or reurge ) , hypertrophic cardiomyopathy , ventricular septal
defect , arrhythmia(bradycardia, tachycardia)

8. Obstructive : decreased ventricular preload
(Intrathoracic obstructive tumors, tension
pneumothorax, Mechanical ventilation, Asthma ) ,
decreased cardiac compliance ( constrictive
pericarditis, cardiac temponade ) .
increased venricular afterload (pulmonary
embolism , acute pulmonary hypertension ,
aortic dissection , saddle embolus ).
Distribuive : sepic (bacterial viral , fungal , rickettsial
, toxic shock syndrome , neurogenic spinal shock ,
adrenal crisis , thyroid storm , nitroprusside,
Anaphylactic and Anaphylactoid

9. Shock hemodynamics
Hypovolemic shock : decreased COP increased SVR
decreased EDV.
Cardiogenic shock : decreased COP increased SVR
increased EDV .
obstructive afterload : deceased COP increasedSVR
increased EDV .
Obstructive preload : decreased COP increased SVR
decreased EDV.
distributive :decreased COPincreased SVR decreased EDV.
Mechanisms of cellular injury in shock
1-cellular ischemia.
2-free radical reperfusion injury.
3-inflammatory mediators (local and circulating).

10. Laboratory
 Cbc (wbcs ,Hb ,Plt).
 Coagulation profile.
 BUNcreatitine.
 CaMg.
 Serum lactate .
 ECG .
 Arterial pressure catheter .
 CVP monitoring.
 Pulmonary artery pressure (+- RVEF
,OXIMETRY).

11. Radiology imaging
 Abdominal US .
 CT chest , Abdomen , Pelvis.
 Echocardiogram .
 Pulmonary perfusion scan .

12. Management
Goals of management
 Hemodynamic support MAP more than 60.
 Maintain oxygen deliveryhemoglobin Hb more than 9 – arterial
saturation more than 92 %-supplemental oxygen and
mechanical ventilation .
 Reversal of oxygen dysfunction decrease lactate less than 2.2
mML -maintain Urine Out Put – reverse encephalopathy –
improverenal function test and liver gunction tests .

13. Hypovolemic shock
 Rapid replacement of blood , colloid ,or
crystalloid.
 Identify source of blood or fluid loss .
 Endoscopy colonoscopy .
 Angiography .
 CTMRI .

14. Cardiogenic shock
 LV infarction : Intraaotic baloon pump , cardiac
angiography , Revascularization: angioplasty ,
coronary bypass.
 RV infarction : fluids and inotropes with PA catheter
monitoring.
 Mechanical abnormality : Echocardiography,
Cardiac Catheterization, Corrective Surgery.
 Pericardial temponade :pericardiocentesis , surgical
drainage if needed.
 Pulmonary Embolism : Heparin , Ventillation perfusion
lung scan , pulmonary angiography , thrombolytic
therapy or embolectomy at surgery .

15. Distributive shock ( septic shock ).
Depending on the cause of your distributive shock, your
provider willgive you the following medicines: Vasopressors
(epinephrine, vasopressin, norepinephrine or phenylephrine)
to raise your blood pressure. Antibiotics if there's an infection.
Antihistamines if you've had an allergic reaction

16. Fluid therapy
 Crystalloid :Lactated ringer , Normal saline .
 Colloid: ,Albumin .
 Packed RBCs .
Goals :
 Correct Hypotension first .
 Decrease heart rate .
 correct hypoperfusion abnormalities .
 Monitorfor deterioration of oxygenation.

17. Fluid therapy
 Resuscitation of hypovolemic shock or septic shock 20mlkg
rechallenge with 10 mlkg .
 100-200 ml challenges in cardiogenic shock .
Inotropes and vasopressors
 Nor epinephrine 2-20 mgmin (increase cardiac contractility
and vasoconstrictor effect).
 Epinephrine 1-20mg/min (increase cardiac contractility , heart
rate and vasocontrictor effect ).
 Vasopressin 0.01-0.04 mic/min as vasoconstrictor effect .
 Dopamine 1-4 mg/kg/min 4-20mg/kg/min (increase cardiac
contactility , heart rate and vasocontrictor ).
 Dobutamine 2-15 mg/kg/min (increase cardiac contractility
,heart rate and vasodilator effect) .
 Milrinone 37.5-75 mg/kg bolus then 0.375-0.75 mic/kg/min
(increase cardiac contractility and vasodilator effect ).