What is the role of permissive hypotension in trauma patients with hypotension (low blood pressure)?

From the Guidelines

Permissive hypotension is a recommended strategy for managing trauma patients with hypotension, aiming to maintain a systolic blood pressure of 80-90 mmHg until definitive hemorrhage control is achieved, as supported by the most recent European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1. The goal of permissive hypotension is to prevent dislodging of forming clots and exacerbating internal bleeding while maintaining minimal perfusion to vital organs. This approach is primarily used for penetrating torso injuries and should be avoided in patients with traumatic brain injury or spinal cord injury. To implement permissive hypotension, limit fluid resuscitation and use small boluses of isotonic crystalloids (250-500 mL) titrated to maintain the target blood pressure, as recommended by the European guideline 1. Some key points to consider when implementing permissive hypotension include:

• Avoid excessive fluid administration that could exacerbate bleeding by disrupting clot formation
• Use a 0.9% sodium chloride or balanced crystalloid solution for fluid therapy, as recommended by the European guideline 1
• Avoid hypotonic solutions such as Ringer’s lactate in patients with severe head trauma, as recommended by the European guideline 1
• Restrict the use of colloids due to their adverse effects on haemostasis, as recommended by the European guideline 1
• Continuously monitor vital signs, mental status, and urine output during this period, and transition to normal blood pressure targets once hemorrhage control is achieved to ensure adequate organ perfusion. It is essential to note that permissive hypotension should be used for a limited time (typically less than 1-2 hours) until definitive surgical intervention can be performed, and the concept of permissive hypotension should be carefully considered in elderly patients and may be contraindicated if the patient suffers from chronic arterial hypertension, as mentioned in the European guideline 1.

From the Research

Role of Permissive Hypotension in Trauma Patients

The concept of permissive hypotension, also known as hypotensive resuscitation, has been explored in various studies as a strategy for managing trauma patients with hypotension. The main idea behind this approach is to limit fluid administration and maintain a lower blood pressure until bleeding is controlled.

• Definition and Purpose: Permissive hypotension involves less aggressive fluid administration to maintain blood pressure until bleeding is controlled 2. This strategy aims to prevent excessive fluid resuscitation, which can promote continued bleeding and increase mortality 3.
• Benefits and Outcomes: Studies have shown that permissive hypotension can reduce transfusion requirements and severe postoperative coagulopathy in trauma patients with hemorrhagic shock 4. Additionally, this strategy may improve clinical outcomes by reducing the risk of early postoperative death and coagulopathy 4.
• Guidelines and Recommendations: While there is no clear consensus on the optimal resuscitation strategy in trauma patients, most trauma surgeons propose a policy of judicious fluid administration to maintain the mean arterial pressure (MAP) in the 60-80 mmHg range 3. Some studies suggest that a target MAP of 50 mmHg may be sufficient for hypotensive resuscitation 4.
• Challenges and Limitations: The implementation of permissive hypotension requires careful consideration of the patient's condition and the risk of tissue hypoperfusion, organ failure, and death 3. Further research is needed to determine the optimal strategy for permissive hypotension in trauma patients, including the ideal target blood pressure and fluid administration protocol 2, 5.