Shock and Resuscitation

Shock: Definition & Types - The Basics Blitz

Shock: Cellular hypoxia from inadequate tissue perfusion.

• Stages of Shock:

  • Compensated: Tachycardia, vasoconstriction maintain BP; cool peripheries.
  • Progressive: Hypotension, oliguria, acidosis, altered mental status.
  • Irreversible: Anuria, profound hypotension, coma, MODS; often fatal.

• Classification & Hemodynamic Profiles:

  Type	Common Causes	CO	SVR	PCWP	CVP
  Hypovolemic	Hemorrhage, burns, dehydration	↓	↑	↓	↓
  Cardiogenic	MI, acute MR/VSD, arrhythmia, cardiomyopathy	↓	↑	↑	↑
  Distributive	Systemic Vasodilation
  - Septic	Infection + SIRS	↑/↔	↓	↔/↓	↔/↓
  - Anaphylactic	IgE-mediated; drugs, venom	↓	↓	↓	↓
  - Neurogenic	Spinal injury (≥T6), high spinal	↓	↓	↓	↓
  Obstructive	Tamponade, massive PE, tension pneumo	↓	↑	↔/↑	↑

⭐ In neurogenic shock, bradycardia may occur despite hypotension due to loss of sympathetic tone. 📌 (Unopposed Vagal Tone)

Hemorrhagic Shock: Trauma Focus - Trauma's Red Alert

• Initial Assessment & Recognition:
  • ABCDE approach (Airway, Breathing, Circulation, Disability, Exposure).
  • Recognize shock: Tachycardia (often earliest sign), hypotension (late sign), tachypnea, altered mental status, cool/clammy skin, ↓ urine output (<0.5 mL/kg/hr).
  • FAST scan (Focused Assessment with Sonography for Trauma) for internal bleeding.
• Lethal Triad: Acidosis, Coagulopathy, Hypothermia (📌 A-C-H: "Aches" in trauma).

ATLS Classification of Hemorrhagic Shock:

Start["⚠️ Trauma Patient
• Suspect hemorrhage• Assess stability"]

Survey["📋 Primary Survey
• ABCDE protocol• Rapid assessment"]

Bleed["🩸 Bleeding Control
• Apply pressure• Tourniquet if needed"]

Access["💊 IV Access
• 2x large bore IVs• IO if IV fails"]

Fluids["💊 Initial Fluids
• Warm crystalloids• 1L bolus dose"]

Assess["📋 Assess Response
• Vitals and FAST• Lactate deficit"]

MTP["⚠️ Activate MTP
• Massive transfusion• Blood products"]

Care["✅ Definitive Care
• Continued support• Surgical repair"]

Start --> Survey Survey --> Bleed Bleed --> Access Access --> Fluids Fluids --> Assess

Assess -->|Response| Care Assess -->|No Response| MTP MTP --> Care

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![Trauma Hemorrhage and Hypotension Management](https://ylbwdadhbcjolwylidja.supabase.co/storage/v1/object/public/notes/L1/Anesthesiology_Trauma_Anesthesia_Shock_and_Resuscitation/0f528ec6-828c-4abb-87ed-5a4229c2f2ec.png)

> ⭐ In trauma, a base deficit > **-6** mEq/L on ABG is a strong indicator of significant hemorrhage and shock, correlating with increased mortality.


## Resuscitation Rally - The Fluid Fight

**Damage Control Resuscitation (DCR) Principles:**
*   Permissive Hypotension: SBP **80-90 mmHg** (SBP >**110 mmHg** if TBI for CPP). Avoid over-resuscitation.
*   Hemostatic Resuscitation: Early blood products (PRBC:FFP:PLT ~**1:1:1**) for coagulopathy.
*   Lethal Triad Prevention (📌 Hypothermia <**35°C**, Acidosis pH <**7.2**, Coagulopathy):
    - Actively warm patient & fluids.
    - Optimize perfusion; use balanced crystalloids.
    - Early products, TXA, Ca++; guide with TEG/ROTEM.

**Fluid Choices:**
*   Crystalloids: Balanced (LR/Plasmalyte) > NS. Limit volume.
*   Colloids: Limited role.

**Massive Transfusion Protocol (MTP):**
*   Triggers: ABC score ≥**2**, Class III/IV shock, specific injuries, gestalt.
*   Ratio: PRBC:FFP:Platelets **1:1:1** (ideal) or **1:1:2**. Mimics whole blood.
*   TXA: **1g** IV load <3hrs injury, then **1g**/8hrs infusion.
*   Calcium: Monitor & replete IV (citrate binds Ca++).

![HMC Trauma Anaesthesiology Guidelines](https://ylbwdadhbcjolwylidja.supabase.co/storage/v1/object/public/notes/L1/Anesthesiology_Trauma_Anesthesia_Shock_and_Resuscitation/2d2a0a76-9f6c-445a-9ee6-5423a1ea8be9.jpg)



**Vasopressors/Inotropes:**
*   Norepinephrine: For refractory hypotension (MAP <**65 mmHg**) post-volume.
*   Inotropes: If cardiac dysfunction.

**Endpoints of Resuscitation:**
*   Urine Output: >**0.5 ml/kg/hr**.
*   Lactate/Base Deficit: Normalize.
*   ScvO2: >**70%**.
*   Hemodynamics: Stable.

> ⭐ Early TXA (**1g** IV <3 hrs injury, then **1g**/8 hrs) reduces bleeding mortality in trauma.


##  High‑Yield Points - ⚡ Biggest Takeaways

> * **Hemorrhagic shock** is the most common cause in trauma; **Class III/IV** requires aggressive resuscitation.
> * **Permissive hypotension** (target SBP **80-90 mmHg**) is crucial in penetrating trauma without **traumatic brain injury (TBI)** until bleeding is controlled.
> * **Massive Transfusion Protocol (MTP)** aims for a balanced resuscitation with a **1:1:1 ratio** of PRBCs:FFP:Platelets.
> * Administer **Tranexamic Acid (TXA)** within **3 hours** of injury in bleeding trauma patients to reduce mortality.
> * Actively prevent and treat the **"lethal triad"** of trauma: **hypothermia, acidosis, and coagulopathy**.
> * **Goal-directed resuscitation** utilizes endpoints like lactate clearance, base deficit, and urine output to guide therapy effectively.
> * Early **calcium replacement** is vital during massive transfusions to prevent citrate-induced hypocalcemia and myocardial depression.