What is the goal for mean arterial pressure (MAP) in permissive hypertension?

Mean Arterial Pressure Goals in Permissive Hypertension

The target mean arterial pressure (MAP) goal in permissive hypertension should be 50-60 mmHg, as this range provides optimal balance between reducing blood loss while maintaining adequate organ perfusion. 1

Understanding Permissive Hypertension

Permissive hypertension (more accurately termed permissive hypotension) is a resuscitation strategy used primarily in trauma and hemorrhagic shock scenarios where deliberately maintaining a lower-than-normal blood pressure helps limit ongoing blood loss while still providing minimal perfusion to vital organs.

Optimal MAP Targets

Research evidence demonstrates that:

• A MAP of 50-60 mmHg represents the ideal target range for permissive hypotension in uncontrolled hemorrhagic shock 1
• This target range balances two competing priorities:
  • Minimizing blood loss (reduced to 52-69% of total blood volume at 50-60 mmHg MAP)
  • Maintaining adequate organ perfusion and mitochondrial function

Avoiding Extremes

• MAPs that are too low (≤40 mmHg):

  • While they further reduce blood loss (39% of total blood volume)
  • Lead to significantly worse organ function and decreased survival rates (only 20% survival) 1

• MAPs that are too high (≥80 mmHg):

  • Result in excessive blood loss (>100% of total blood volume)
  • Decrease vital organ function
  • Significantly reduce survival rates (only 10% survival) 1

Duration Considerations

The duration of permissive hypotension is equally important:

• 90 minutes appears to be the maximum tolerable duration for permissive hypotension
• Beyond 120 minutes, severe organ damage occurs regardless of the MAP target 1
• Extending permissive hypotension beyond 90 minutes significantly reduces survival rates

Clinical Implementation

When implementing permissive hypertension/hypotension:

1. Initial resuscitation: Target MAP of 50-60 mmHg until definitive hemorrhage control is achieved
2. Monitoring: Continuously assess vital organ function through clinical parameters and laboratory values
3. Time limitation: Aim to achieve definitive hemorrhage control within 90 minutes
4. Transition: Once bleeding is controlled, gradually increase MAP to normal targets (>65 mmHg for critically ill patients) 2

Special Considerations

• This strategy applies specifically to uncontrolled hemorrhagic shock scenarios
• It should not be confused with standard hypertension management, where targets are much higher (typically 130-140 mmHg systolic) 3
• The permissive hypotension strategy is primarily used in trauma and emergency settings, not in chronic hypertension management

Pitfalls to Avoid

• Maintaining permissive hypotension for too long (>90 minutes) can lead to irreversible organ damage
• Setting MAP targets too low (<50 mmHg) significantly increases mortality risk
• Setting MAP targets too high (>70 mmHg) can worsen hemorrhage and reduce survival

By maintaining a MAP of 50-60 mmHg for no more than 90 minutes in permissive hypotension scenarios, clinicians can optimize patient outcomes by balancing the competing needs of hemorrhage control and organ perfusion.