What are the Brain Trauma Foundation (BTF) guidelines for blood pressure and medication in traumatic brain injury (TBI) management?

Brain Trauma Foundation Guidelines for Blood Pressure and Medication in TBI Management

The Brain Trauma Foundation recommends maintaining systolic blood pressure (SBP) ≥110 mmHg for patients aged 15-49 years or >70 years, and ≥100 mmHg for patients aged 50-69 years, with mean arterial pressure (MAP) >90 mmHg in all traumatic brain injury patients. 1, 2

Blood Pressure Targets by Age Group

The BTF guidelines establish age-specific thresholds that must be maintained to prevent secondary brain injury:

• Ages 15-49 years: SBP ≥110 mmHg 1, 2
• Ages 50-69 years: SBP ≥100 mmHg 1, 2
• Ages >70 years: SBP ≥110 mmHg 1, 2
• All ages: MAP ≥90 mmHg 2

For TBI patients with concurrent hemorrhagic shock, maintain MAP ≥80 mmHg until major bleeding is controlled. 2

Upper Blood Pressure Limits

• SBP should be kept <150 mmHg if within 6 hours of symptom onset when immediate surgery is not planned 1, 2
• This upper limit prevents exacerbation of intracranial hemorrhage and cerebral edema 1

Cerebral Perfusion Pressure (CPP) Targets

• Target CPP: 60-70 mmHg 3
• CPP values >90 mmHg should be avoided as they may worsen neurological outcomes by aggravating vasogenic cerebral edema 2
• CPP is calculated as: MAP - Intracranial Pressure (ICP) 3

Medications for Blood Pressure Management

For Hypotension (SBP below target):

First-line approach: Correct hypovolemia with 0.9% saline (the only isotonic crystalloid appropriate for TBI) 1, 2

Vasopressors (after volume resuscitation):

• Ephedrine or metaraminol: Small boluses for immediate hypotension 1, 2
• Metaraminol infusion: For sustained hypotension after bolus 1
• Noradrenaline infusion: Only via central venous catheter 1

For Hypertension (SBP above target):

First-line: Increase sedation if patient is intubated 1

Antihypertensive medication:

• Labetalol: Small boluses for blood pressure control 1, 2
• Avoid aggressive BP reduction that might compromise cerebral perfusion 2

Fluid Management

Use only 0.9% saline for resuscitation and maintenance 1, 2

Avoid these hypotonic solutions (they worsen cerebral edema):

• Ringer's lactate (compound sodium lactate) 1, 2
• Ringer's acetate 1
• Gelatins 1
• Albumin and synthetic colloids 1

The rationale is that only 0.9% saline is truly isotonic when measured by real osmolality (mosmol/kg) rather than theoretical osmolarity (mosmol/L), preventing increases in brain water 1

Critical Management Principles

Hypotension is Absolutely Prohibited:

• Never transfer a hypotensive TBI patient who is actively bleeding 1
• Hypotension (SBP <90 mmHg) is associated with unfavorable neurological outcomes 1
• Even brief hypotensive episodes should be minimized, particularly during bleeding control 1
• Permissive hypotension should only be considered in exceptional circumstances and requires escalation to trauma/critical care networks 1

Monitoring Requirements:

• Use transduced direct arterial pressure monitoring with transducer at the level of the tragus 1, 2
• If invasive monitoring unavailable before intubation, use non-invasive blood pressure (NIBP) at 1-minute intervals 1, 2
• Continuous arterial waveform monitoring facilitates stable hemodynamic management 1

Special Considerations for Intubation

When intubating TBI patients, maintaining target blood pressure outweighs concerns about cerebral stimulation from laryngoscopy 1, 2

Induction medications:

• High-dose opioids: Fentanyl 3-5 µg/kg, alfentanil 10-20 µg/kg, or remifentanil TCI (target concentration ≥3 ng/mL) 1, 2
• Ketamine 1-2 mg/kg: Useful in hemodynamically unstable trauma patients 1, 2
• Use lower opioid doses in unstable patients with multiple trauma 1, 2

Hemoglobin Transfusion Threshold

Maintain hemoglobin ≥7 g/dL in TBI polytrauma patients 1

• Higher thresholds (10 g/dL) showed no neurological benefit and increased adverse events 1
• Consider higher thresholds for elderly patients or those with limited cardiovascular reserve 1

Common Pitfalls to Avoid

1. Do not use the traditional trauma threshold of SBP >90 mmHg - this is too low for TBI patients and recent evidence suggests even higher thresholds may be needed 1

2. Do not apply permissive hypotension strategies from hemorrhagic shock protocols - the injured brain cannot tolerate low perfusion pressures 1, 2

3. Do not use Ringer's lactate or other "balanced" crystalloids - despite being marketed as physiologic, they are hypotonic and worsen cerebral edema 1, 2

4. Do not target CPP >70 mmHg routinely - this increases risk of acute respiratory distress syndrome (ARDS) without clear benefit 2

5. Control bleeding before transfer - never attempt to transfer an actively bleeding, hypotensive TBI patient 1