Lecture on Shock

Understanding Shock

• Shock is a syndrome, not a standalone problem.
• It occurs due to decreased perfusion and impaired cellular metabolism.
• Considered as microcirculatory collapse due to an imbalance between supply and demand of oxygen and nutrients.

Types of Shock

1. Cardiogenic Shock

   • Caused by heart dysfunction, leading to low cardiac output.
   • High mortality rate (~60%).
   • Causes include acute myocardial infarction, cardiomyopathy, blunt cardiac injury, hypertension, cardiac tamponade.
   • Symptoms: Tachycardia, hypotension, pulmonary congestion, cool clammy skin, anxiety, confusion.

2. Hypovolemic Shock

   • Due to low fluid volume (absolute) or fluid not being in vascular space (relative).
   • Causes include hemorrhage, extreme diuresis, vomiting, diarrhea, third-spacing.
   • Symptoms similar to cardiogenic shock: tachycardia, decreased stroke volume, decreased urinary output.

3. Distributive Shock

   • Subtypes:
     • Neurogenic: Vasodilation due to loss of sympathetic tone, often from spinal injuries.
     • Anaphylactic: Allergic reaction causing vasodilation and edema.
     • Septic: Result of inflammatory response to infection, leading to organ dysfunction.
   • Symptoms: Bradycardia (neurogenic), tachycardia (anaphylactic/septic), warm skin, impaired perfusion.

4. Obstructive Shock

   • Caused by blockage of blood flow (e.g., cardiac tamponade, tension pneumothorax).
   • Symptoms: Decreased cardiac output, increased afterload, variable filling pressures.

Stages of Shock

1. Initial Stage

   • Metabolism shifts to anaerobic, lactic acidosis begins.

2. Compensatory Stage

   • Body tries to maintain perfusion via neural, hormonal, biochemical mechanisms.
   • Symptoms: Increased respiratory rate, cool pale skin, decreased urine output.

3. Progressive Stage

   • Compensatory mechanisms fail, worsening perfusion, edema.
   • Symptoms: Profound edema, weak pulse, ischemic tissues.

4. Refractory Stage

   • Severe metabolic acidosis, multi-organ failure, often irreversible.

Management and Treatment

• Prevention & Early Intervention: Monitor patients at risk for early signs of shock.
• Volume Resuscitation: Critical in hypovolemic, distributive, and anaphylactic shock.
• Cardiogenic Shock: Restore myocardial blood flow; may require angioplasty, valve replacement, or transplant.
• Septic Shock: Fluid resuscitation, vasopressors, antibiotics.
• Obstructive Shock: Immediate treatment of the obstruction is crucial.

General Interventions

• Ensure airway and breathing (ABCs), monitor vital signs.
• Utilize hemodynamic monitoring to guide treatment.
• Support organ functions through medication, nutrition.
• Collaboration with healthcare team for comprehensive care.

Special Considerations

• Continuous monitoring for effective response to interventions.
• Emotional support for patients and families due to the sudden and severe nature of shock.
• Focused rehabilitation and prevention of complications post-shock.