1. By Dr. Ishara Maduka M.B.B.S.(Colombo)
Shock
Differential Diagnosis and Hemodynamic Monitoring By
Dr. Ishara Maduka M.B.B.S.(Colombo)

2. Shock Shock is a Cardiovascular Derangement.
1. Deliver Oxygen and Metabolic Substrates
2. Remove Products of Cellular Metabolism
3. Thermoregulation
Definition:
A physiological state characterized by a significant, systemic reduction in tissue perfusion, resulting in decreased tissue oxygen delivery and insufficient removal of cellular metabolic products, resulting in tissue injury.

3. Classification of Shock
Hypovolemic
Septic/Inflammatory
Cardiogenic (Intrinsic, compressive & Obstructive)
Neurogenic
Anaphylactic

4. Clinical Markers of Shock
Brachial systolic blood pressure: <110mmHg
Sinus tachycardia: >90 beats/min
Respiratory rate: <7 or >29 breaths/min
Urine Output: <0.5cc/kg/hr
Metabolic acidemia: [HCO3]<31mEq/L or base deficit>3mEq/L
Hypoxemia: 0-50yr: <90mmHg; 51-70yr: <80mmHg; >71yo<70mmHg;
Cutaneous vasoconstriction vs. vasodilation.
Mental Changes: anxiousness, agitation, indifference, lethargy, obtundation

5. Hypovolemic Shock
Decreased preload->small ventricular end-diastolic volumes -> inadequate cardiac generation of pressure and flow
Causes:
-- bleeding: trauma, GI bleeding, ruptured aneurysms, hemorrhagic pancreatitis
-- protracted vomiting or diarrhea
-- adrenal insufficiency; diabetes insipidus
-- dehydration

6. Hypovolemic Shock
Signs & Symptoms: Hypotension, Tachycardia, Oliguria, Low volume Pulses.
Markers: monitor UOP,CVP, BP, HR, Hct,CO, lactic acid and PCWP
Treatment: ABCs, IVF (crystalloid), Transfusion Stem ongoing Blood Loss
Patients on β-blockers, w/ spinal shock & athletes may not be tachycardic

7. Septic/Inflammatory Shock
Mechanism: release of inflammatory mediators leading to
Disruption of the microvascular endothelium
Cutaneous arteriolar dilation and increased capillary permeability
Causes:
Anaphylaxis, drug, toxin reactions
Trauma: crush injuries, major fractures, major burns.
infection/sepsis: G(-/+ ) speticemia, pneumonia, peritonitis, meningitis, cholangitis, pyelonephritis, necrotic tissue, pancreatitis, wet gangrene, toxic shock syndrome, etc.

8. Septic/Inflammatory Shock
Signs: Early– warm peripheries with vasodilatation, often adequate urine output, febrile, tachypnoeic. Late-- vasoconstriction, hypotension, oliguria, altered mental status.

9. Cardiogenic Shock
Mechanism: Intrinsic abnormality of heart -> inability to deliver blood into the vasculature with adequate power
Causes:
Cardiomyopathies: myocardial ischemia, myocardial infarction, cardiomyopathy, myocardiditis, myocardial contusion
Mechanical: cardiac valvular insufficiency, papillary muscle rupture, septal defects, aortic stenosis
Arrythmias: bradyarrythmias (heart block), tachyarrythmias (atrial fibrillation, atrial flutter, ventricular fibrillation)
Obstructive disorders: PE, tension peneumothorax, pericardial tamponade, constrictive pericaditis, severe pulmonary hypertension

10. Cardiogenic Shock Characterized by high preload (CVP) with low CO
Signs: Dyspnea, rales, loud P2 gallop, low BP, oliguria

11. Neurogenic Shock
Mechanism: Loss of autonomic innervation of the cardiovascular system (arterioles, venules, small veins, including the heart)
Causes:
Spinal cord injury
Regional anesthesia
Drugs
Neurological disorders

12. Neurogenic Shock Characterized by loss of vascular tone & reflexes.
Signs: Hypotension, Bradycardia, Accompanying Neurological deficits.

13. Monitoring Adjuncts in Shock
Sphyngmomanometry
Pulse Oximeter
Arterial Line
Central Venous Line (Triple Lumen, Pulmonary Artery Catheter)

14. Questions List the types of shock.
List the clinical features of shock.
Briefly explain the pathophysiology of each type of shock.

15. Thank You!