What is the target mean arterial pressure (MAP) for patients with spinal cord injury?

Target Mean Arterial Pressure for Spinal Cord Injury

For patients with spinal cord injury, a mean arterial pressure (MAP) of at least 70 mmHg should be maintained during the first week after injury to optimize neurological outcomes and reduce mortality. 1, 2

Blood Pressure Management Algorithm

1. Initial Assessment Phase:

   • Maintain systolic blood pressure >110 mmHg before injury assessment 1, 2
   • Hypotension (SBP <110 mmHg) is an independent factor for increased mortality 1, 2

2. Acute Management Phase (First Week):

   • Target MAP ≥70 mmHg for the first 7 days post-injury 1, 2
   • Use continuous arterial pressure monitoring via arterial catheter 1
   • Consider higher MAP targets (75-80 mmHg) for complete spinal cord injuries 3

3. Monitoring Considerations:

   • Place arterial line for continuous monitoring as MAP falls below target approximately 25% of the time without continuous monitoring 2
   • Monitor spinal cord perfusion pressure (SCPP) if available - target >50 mmHg 1

Evidence Analysis

The recommendation for MAP ≥70 mmHg is based on several key findings:

• A small retrospective study found a reverse correlation between time spent with MAP <65-70 mmHg and neurological improvement 1
• Recent evidence correlates spinal perfusion pressure >50 mmHg with better neurological status at 6 months 1, 2
• Analysis of different relative risks combining MAP variations determined an optimal MAP level >70 mmHg 1

While the American Association of Neurological Surgeons/Congress of Neurological Surgeons has previously recommended higher MAP targets (>85 mmHg), this recommendation was based on limited evidence from two prospective interventional studies without control groups 1. The more recent 2020 French guidelines recommend MAP ≥70 mmHg as there is insufficient evidence to support higher targets 1, 2.

Vasopressor Selection

When pharmacological support is needed to maintain MAP targets:

• Norepinephrine is preferred for cervical and upper thoracic injuries 4
• Phenylephrine or norepinephrine for mid to lower thoracic injuries 4
• Avoid dopamine due to higher complication rates compared to other vasopressors 4

Common Pitfalls and Caveats

1. Pre-specialized unit hypotension: Many patients experience periods of relative hypotension before arrival at specialized spinal units, with 40-52% of MAP measurements <80 mmHg in emergency settings 5

2. Monitoring challenges: MAP is below the determined objective approximately 25% of the time without continuous monitoring, highlighting the importance of arterial line placement 1, 2

3. Duration considerations: The correlation between MAP level and neurological improvement appears strongest for MAP values >70-75 mmHg during the first 2-3 days after admission 1, 6

4. Facility selection: Transfer patients with traumatic spinal cord injury to specialized care units (Level 1 trauma centers) to decrease morbidity and long-term mortality 1, 2

The evidence supports maintaining MAP ≥70 mmHg during the first week after spinal cord injury, with continuous monitoring via arterial catheter to ensure adequate spinal cord perfusion and optimize neurological outcomes.