Permissive Hypotension in Trauma 

🔹 Definition:

• A resuscitation strategy that limits intravenous (IV) fluid administration to maintain a lower-than-normal blood pressure (BP) until surgical bleeding control is achieved.

• The goal is to avoid excessive fluid resuscitation, which can worsen bleeding due to clot disruption and dilution of coagulation factors.

🔹 Physiological Rationale:

excessive crystalloid resuscitation may result in the following:

• A rise in cardiac output, thus increasing the MAP, reducing peripheral vasoconstriction, and causing more bleeding
• Hypothermia
• Edema causing abdominal compartment syndrome
• Organ failure

• Maintaining lower BP reduces bleeding by preventing clot disruption.

📌 Key Concept: Permissive hypotension is based on the principle that higher BP increases hemorrhage before definitive hemostasis.

2. Target Blood Pressure in Permissive Hypotension

Penetrating Trauma (without TBI): 60-70 mmHg.

Penetrating trauma (with TBI): 80-90 mmHg

Blunt Trauma (without TBI): 80-90 mmHg,• Mean Arterial Pressure (MAP) target: 50–65 mmHg

Blunt Trauma (with TBI and spine injury): SBP =100-110 mmHg,MAP be greater than 80 mm Hg

📌 Exception: TBI patients should NOT undergo permissive hypotension, as cerebral perfusion is crucial.

3. Indications & Contraindications of Permissive Hypotension

✅ Indications

✔️ Penetrating trauma (e.g., gunshot, stab wounds)

✔️ Blunt trauma with hemorrhage (without TBI)

✔️ Ruptured abdominal aortic aneurysm (AAA)

✔️ Uncontrolled internal bleeding before surgical control

❌ Contraindications

❌ Traumatic Brain Injury (TBI) → Requires higher BP to maintain cerebral perfusion.

❌ Spinal Cord Injury → Risk of worsening ischemia.

❌ Elderly patients with pre-existing cardiovascular disease.

❌ Severe hemorrhagic shock with end-organ failure (e.g., anuric AKI, metabolic acidosis).

📌 Key Concept: Avoid permissive hypotension in head injuries and elderly patients.

4. Steps in Management

1. Recognize hemorrhagic shock (low BP, tachycardia, cold extremities).

2. Limit IV fluids → Only small boluses of crystalloids (250-500 mL) if needed.

3. Prioritize blood products over crystalloids → Whole blood or 1:1:1 (PRBC:FFP:Platelets) resuscitation.

4. Maintain SBP at 80-90 mmHg until surgical control.

5. Once bleeding is controlled, switch to normotensive resuscitation.

📌 Key Concept: Blood products are preferred over crystalloids to prevent dilutional coagulopathy.

6. MCQs on Permissive Hypotension

Question 1:What is the recommended SBP target for permissive hypotension in blunt trauma patients?

A. 100-120 mmHg

B. 80-90 mmHg

C. 60-70 mmHg

D. >120 mmHg

✅ Answer: B. 80-90 mmHg

Question 2:Which of the following is a contraindication to permissive hypotension?

A. Ruptured abdominal aortic aneurysm

B. Penetrating trauma with ongoing hemorrhage

C. Traumatic brain injury (TBI)

D. Gunshot wound to the abdomen

✅ Answer: C. Traumatic brain injury (TBI)

Question 3:Which of the following is the primary reason permissive hypotension is beneficial in trauma?

A. Reduces cardiac workload

B. Prevents clot dislodgement and excessive hemorrhage

C. Increases urine output

D. Reduces the need for transfusion

✅ Answer: B. Prevents clot dislodgement and excessive hemorrhage

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