BTF 2023 — Key Changes in TBI Management
Brain Trauma Foundation Prehospital Guidelines 3rd Edition (2023)
The BTF 2023 update changes blood pressure thresholds for TBI. The old SBP >90 mmHg threshold is replaced with higher, more protective targets based on newer evidence from the Arizona EPIC initiative and large prehospital databases.
| Parameter | Old Threshold | BTF 2023 Updated Target | Why |
|---|
| Adult SBP target | SBP >90 mmHg (avoid hypotension) | SBP ≥110 mmHg (Strong) — optimal targets may be higher | Studies show SBP <110 associated with worse outcomes even when >90; threshold region should be avoided |
| Oxygen target | SpO₂ ≥90% | SpO₂ ≥90% maintained; avoid hypoxia (<90%) as strongly harmful | Even brief hypoxia is profoundly harmful — continuously monitor and correct immediately |
| Hyperventilation | No prophylactic hyperventilation | Avoid EtCO₂ <35 mmHg (prophylactic hyperventilation harmful) — Strong rec | Hyperventilation → cerebral vasoconstriction → ↓ CBF → ischaemia. Only brief use for herniation |
| Temperature | Avoid hyperthermia | Monitor continuously; avoid both hyperthermia AND hypothermia; treat fever aggressively | Both extremes worsen TBI outcome |
| Prehospital antibiotics | Not specifically addressed | Addressed in context of overall prehospital care; minimise on-scene time; transport priority | Time to definitive neurosurgical care is critical |
How TBI Works — Pathophysiology
🔬 How TBI causes secondary brain injury
TriggerPrimary injury — DAI, contusion, haematoma (immediate, irreversible)
Triggers the secondary injury cascade (hours–days — the treatment target)
Cerebral oedema (vasogenic + cytotoxic) + haematoma↑ intracranial volume
Excitotoxicity (glutamate→NMDA→Ca²⁺) + inflammationcellular injury
Monro–Kellie: ↑ volume → ↑ ICP → ↓ CPP (MAP − ICP) → ↓ CBF → ischaemia → more oedemavicious cycle
Pathological stateSecondary brain injury → herniation (preventable — the goal of all TBI care)
Primary Brain Injury (Immediate — Unchangeable)
Direct mechanical injury at moment of trauma: axonal shearing (diffuse axonal injury — DAI), contusions, haematomas, lacerations. Occurs in microseconds. No medical intervention can reverse it. All ICU care focuses on preventing secondary brain injury.
Secondary Brain Injury (Hours to Days — Preventable)
The secondary injury cascade is triggered by the primary injury and evolves over hours to days. Every element is a potential treatment target:
- Cerebral oedema: Vasogenic (BBB disruption → protein leak) + cytotoxic (cellular swelling from Na-K ATPase failure) → ↑ intracranial volume
- Raised ICP: ↑ intracranial volume → ↑ ICP → ↓ CPP (CPP = MAP − ICP) → ↓ CBF → ischaemia → more oedema → vicious cycle
- Excitotoxicity: Glutamate flood → NMDA receptor activation → Ca²⁺ influx → mitochondrial dysfunction → cell death
- Inflammation: Microglial activation → cytokines → BBB breakdown → oedema amplification
- Ischaemia: Haematoma compression, ↑ICP, hypotension, hypoxia, vasospasm — all reduce O₂ delivery to already-injured brain
- Seizures: ↑ metabolic demand, excitotoxicity, cortical spreading depolarisations
The Monro-Kellie Doctrine
The skull is a rigid box. Total intracranial volume = Brain (80%) + CSF (10%) + Blood (10%) = CONSTANT. Any increase in one component must be compensated by decrease in another. Once compensatory mechanisms are exhausted → small increases in volume cause exponential rises in ICP → brainstem compression → death.
The 4 Absolute Killers in TBI — Prevent These
- Hypotension: SBP <110 mmHg → ↓ CPP → ischaemia → secondary injury (BTF 2023: keep SBP ≥110)
- Hypoxia: SpO₂ <90% → ↓ O₂ delivery to injured brain → ischaemia (even brief episodes are harmful)
- Hyperventilation (prophylactic): ↓ PaCO₂ → cerebral vasoconstriction → ↓ CBF → ischaemia
- Hyperthermia: ↑ metabolic demand → ↑ ICP → worsens injury (aggressive fever management)
Classification of TBI
Severity (GCS-Based)
| Severity | GCS Score | Clinical Features | Imaging Needed |
|---|
| Mild | 13–15 | Brief LOC (<30 min); post-traumatic amnesia <24h; normal CT | CT if: high-risk (anticoagulants, age >65, focal deficit, vomiting, severe HA) |
| Moderate | 9–12 | LOC 30 min to 24h; amnesia 24h to 7 days; CT may show abnormality | CT head mandatory; admit for observation |
| Severe | ≤8 | LOC >24h OR coma; CT usually abnormal | CT head + CT spine; ICU admission; neurosurgery consult |
Intracranial Haematomas
| Type | Location | Classic Presentation | CT Finding |
|---|
| Extradural (EDH) | Between skull and dura | Lucid interval → rapid deterioration; young patient; temporal skull fracture | Biconvex (lens-shaped) hyperdense collection; does NOT cross suture lines |
| Subdural (SDH) | Between dura and arachnoid | Variable; acute = high-energy trauma; chronic = elderly, anticoagulants | Concave (crescent-shaped) hyperdense (acute) or hypodense (chronic); crosses suture lines |
| Contusion | Brain parenchyma | Often frontal/temporal; may worsen over 24–72h ("contusion expansion") | Heterogeneous mixed density; may expand on repeat CT |
| DAI | White matter tracts | Severe mechanism; immediate coma; CT may be normal | CT often normal; MRI (DWI/SWI) shows punctate haemorrhages at grey-white junction |
Primary Survey — ABCDE in TBI
In TBI, ABCDE must occur simultaneously. A is addressed while B and C are managed. The brain cannot tolerate ANY period of hypoxia or hypotension.
| Step | Action | TBI-Specific Considerations |
|---|
| A — Airway | Ensure patent airway; C-spine protection | GCS ≤8: intubate. Use RSI. Assume C-spine injury in all high-velocity injuries. Manual inline stabilisation during intubation. |
| B — Breathing | O₂, ventilation | SpO₂ ≥90% mandatory (BTF: monitor continuously; correct immediately). EtCO₂ 35–45 mmHg — no prophylactic hyperventilation. |
| C — Circulation | BP, haemorrhage control | SBP ≥110 mmHg (BTF 2023). Treat hypotension aggressively with fluids (isotonic). Control external haemorrhage. Cushing response (↑BP + ↓HR + irregular breathing) = imminent herniation. |
| D — Disability | GCS, pupils, limb movements | GCS: open eyes/verbal/motor. Pupils: unilateral fixed dilated = uncal herniation (surgical emergency). Bilateral fixed dilated = bilateral herniation or death. |
| E — Exposure/Environment | Temp, spine, other injuries | Prevent hypothermia AND hyperthermia. Full spine clearance. Secondary survey for other injuries. |
Blood Pressure & Oxygenation Targets — BTF 2023
BTF 2023 — Updated BP Targets (Strong Recommendation)
- Adults: SBP ≥110 mmHg (optimal targets may be even higher — evidence evolving)
- Children >6 years and adolescents: SBP ≥100 mmHg
- Children 1–5 years: SBP ≥90 mmHg
- Children 1–12 months: SBP ≥84 mmHg
- Adults (Weak recommendation): SBP ≥110 provides better outcomes; avoid the threshold zone even below 110
Fluid choice for resuscitation: 0.9% Normal Saline (isotonic) — NOT hypotonic fluids (D5W, Ringer's Lactate in some formulations). Hypotonic fluids lower plasma osmolality → free water shifts into brain → worsens cerebral oedema.
Vasopressors: If BP unresponsive to fluids → noradrenaline. Maintain CPP ≥60 mmHg (ICP + MAP).
Oxygenation Targets
- SpO₂ ≥90% (Strong recommendation — BTF 2023)
- PaO₂ ≥60 mmHg
- Monitor continuously with pulse oximetry — even brief desaturation episodes are profoundly harmful
- Supplemental O₂ freely — hyperoxia does not worsen outcomes in TBI (unlike asthma/COPD)
ICP Management
ICP Monitoring — BTF Guidelines
ICP monitoring recommended for all severe TBI (GCS ≤8) with abnormal CT scan. Normal ICP: 7–15 mmHg. Treat ICP >22 mmHg (BTF threshold). Target CPP 60–70 mmHg.
Tier 1 — First-Line ICP Management
- Head of bed 30° elevation; maintain neutral head position (no neck rotation)
- Optimise analgesia and sedation (pain/agitation = ↑ ICP)
- Normocapnia: PaCO₂ 35–45 mmHg; EtCO₂ 35–40 mmHg
- Normothermia: Treat fever aggressively (paracetamol + cooling)
- Normoglycaemia: Target 140–180 mg/dL (hypoglycaemia severely harmful)
- CSF drainage via EVD (if in situ)
Tier 2 — Osmotherapy (Second-Line)
| Agent | Dose | Mechanism | Monitoring | Notes |
|---|
| Mannitol 20% | 0.25–1 g/kg IV bolus over 15–20 min | Osmotic gradient → draws water from brain parenchyma; also ↑ CBF by ↓ viscosity | Serum osmolality (target <320 mOsm/kg); serum Na; UO | Requires adequate BP; avoid if SBP <90; repeat q4–6h; hold if osm gap >20 |
| Hypertonic Saline (3% or 23.4%) | 3%: 250 ml IV bolus; 23.4%: 30 ml IV push | ↑ plasma osmolality → draws water from brain; also ↑ CBF; no renal loss | Serum Na (target 150–155 mEq/L); osmolality | Preferred if hypotension or Na depletion; can use via peripheral line; 23.4% = central line only |
Tier 3 — Refractory Elevated ICP
- Barbiturate coma: Thiopentone or pentobarbital — burst suppression on EEG; only when all other measures failed; monitor cardiac function (profound myocardial depression)
- Decompressive craniectomy: For refractory ICP >25 mmHg unresponsive to medical therapy — DECRA trial (modest ICP reduction, no mortality benefit); RESCUEicp trial (survival benefit but more vegetative state)
- Hypothermia: 35–36°C — may reduce ICP but no overall mortality benefit (Eurotherm3235 trial); rewarming complications; use selectively
ICU Management Targets
| Parameter | Target | Rationale |
|---|
| ICP | <22 mmHg | Above 22 = treat; BTF threshold |
| CPP (MAP − ICP) | 60–70 mmHg | Ensures adequate cerebral perfusion pressure |
| MAP | ≥80 mmHg (to maintain CPP >60 if ICP = 20) | Keep CPP adequate despite raised ICP |
| SBP | ≥110 mmHg (BTF 2023, adults) | New higher threshold |
| SpO₂ | ≥90–95% | Avoid hypoxia; supplemental O₂ freely |
| PaCO₂ | 35–45 mmHg (normocapnia) | No prophylactic hyperventilation; hypocapnia = vasoconstriction = ischaemia |
| Temperature | 36–37.5°C (normothermia) | Fever = ↑ metabolic demand = ↑ ICP; treat aggressively |
| Blood glucose | 140–180 mg/dL | Hypoglycaemia severely harmful to injured brain; tight control also harmful |
| Serum Na | 140–155 mEq/L (allow mild hypernatraemia) | Hyponatraemia = cerebral oedema; avoid hypotonic fluids |
| Hb | ≥7 g/dL (some guidelines ≥9 in severe TBI) | O₂-carrying capacity; anaemia worsens outcome |
Specific Interventions
Seizure Prophylaxis
Levetiracetam 1000 mg BD × 7 days — first-line for post-traumatic seizure prophylaxis in severe TBI (GCS ≤8). Prevents early post-traumatic seizures (within 7 days) — NOT late seizures. Levetiracetam preferred over phenytoin (no cognitive impairment, no drug interactions).
DVT Prophylaxis
- Mechanical: Graduated compression stockings + intermittent pneumatic compression from day 1
- Pharmacological: Start LMWH after 24–48h IF intracranial haemorrhage is stable on repeat CT and no active bleeding
Nutrition
Early enteral nutrition within 24–48h. TBI patients are hypercatabolic. Target 25–30 kcal/kg/day. Avoid prolonged NPO — gut feeds maintain gut integrity and reduce infection risk.
Steroids
Steroids are CONTRAINDICATED in TBI
CRASH trial (2004, n=10,008): Methylprednisolone in TBI → INCREASED 14-day mortality. Strong evidence of harm. Do NOT give steroids for TBI under any circumstances.
Hyperventilation — Only as Rescue
Brief hyperventilation (PaCO₂ 30–35 mmHg) for imminent herniation (dilating pupil, Cushing's triad) as a BRIDGE to definitive treatment (mannitol, surgery, EVD). NOT for prophylaxis. Duration: minutes to hours only.
Surgical Indications
| Lesion | Surgical Indication | Urgency |
|---|
| Extradural Haematoma | Volume >30 ml OR thickness >15 mm OR midline shift >5 mm OR any EDH with neurological deterioration | EMERGENCY — can deteriorate in minutes. Every minute counts. |
| Acute Subdural Haematoma | Thickness >10 mm OR midline shift >5 mm. GCS drop of ≥2 points from injury to hospital. | URGENT — within 4h ideally |
| Intracerebral Contusion/Haematoma | Volume >20 ml in temporal lobe; >30 ml in other locations; GCS worsening; refractory ICP | Often observe; surgery if neurological worsening or refractory ICP |
| Depressed Skull Fracture | Displacement > skull thickness; open fractures; underlying haematoma | Urgent (usually within 24h) |
| Decompressive Craniectomy | Refractory ICP >25 mmHg unresponsive to all medical management | Semi-elective (after medical measures exhausted) |
Clinical Pearls
💡 Pearl 1 — BTF 2023: SBP ≥110 mmHg Not ≥90
The old SBP >90 threshold is obsolete. BTF 2023 Strong recommendation: SBP ≥110 mmHg in adults. Evidence shows worse outcomes even with SBP 90–110. Keep the injured brain well-perfused.
💡 Pearl 2 — Steroids Kill in TBI
CRASH trial: methylprednisolone in TBI → increased mortality. Steroids are ABSOLUTELY CONTRAINDICATED in TBI. If you see a patient getting steroids for TBI, stop it immediately.
💡 Pearl 3 — Hyperventilation = Temporary Bridge Only
Prophylactic hyperventilation (PaCO₂ <35) causes cerebral vasoconstriction → ischaemia → worsens TBI. Use hyperventilation ONLY as emergency bridge to buy time for definitive treatment (EVD, mannitol, OR) when there's imminent herniation.
💡 Pearl 4 — Hypotonic Fluids are Contraindicated in TBI
Ringer's Lactate (slightly hypotonic) and D5W: AVOID in TBI. Hypotonic fluids lower plasma osmolality → free water shifts into brain → worsens cerebral oedema. Use 0.9% Normal Saline or hypertonic saline for resuscitation.
💡 Pearl 5 — Cushing's Triad = Surgical Emergency
Hypertension + Bradycardia + Irregular respirations = Cushing's triad = brainstem compression from raised ICP. This is a pre-terminal finding. Give mannitol 1 g/kg IV NOW and call neurosurgeon IMMEDIATELY. Brief hyperventilation as bridge.
💡 Pearl 6 — Levetiracetam Not Phenytoin
Levetiracetam 1000 mg BD × 7 days for post-traumatic seizure prophylaxis. Both work equally for early seizures, but levetiracetam has no cognitive side effects, no drug interactions, and no need for monitoring levels.
💡 Pearl 7 — "Talk and Die" — Lucid Interval in EDH
Extradural haematoma classically presents with lucid interval — initial concussion, brief LOC, then recovery (because EDH expands slowly at first), then rapid deterioration as haematoma grows and herniates. Young patients with temporal skull fracture: always rule out EDH even if GCS 15.
💡 Pearl 8 — CPP = MAP − ICP
Cerebral Perfusion Pressure = MAP − ICP. Target CPP 60–70 mmHg. If ICP = 20 and MAP = 80, CPP = 60 (adequate). If MAP drops to 70, CPP = 50 (inadequate — injury). Two levers: lower ICP or raise MAP.
Common Mistakes
❌ Mistake 1 — Giving Steroids for TBI
CRASH trial proved methylprednisolone increases mortality in TBI. Steroids are absolutely contraindicated. Never give dexamethasone or methylprednisolone for head injury.
❌ Mistake 2 — SBP Target of 90 mmHg
BTF 2023 updated this to SBP ≥110 mmHg in adults. The zone 90–110 is no longer considered adequate. Studies show worse neurological outcomes even when SBP stays above 90 but below 110.
❌ Mistake 3 — Prophylactic Hyperventilation
Routine hyperventilation (PaCO₂ 30–35) causes cerebral vasoconstriction → ischaemia. Only use for imminent herniation as a bridge to definitive treatment. Target normocapnia (PaCO₂ 35–45) in ICU.
❌ Mistake 4 — Using Hypotonic Fluids
Ringer's Lactate (slightly hypotonic at 254 mOsm/L vs plasma 285) lowers plasma osmolality → free water enters brain → worsens oedema. Use 0.9% NaCl or hypertonic saline for TBI resuscitation. KDIGO 2026 also recommends 0.9% NaCl for TBI specifically.
❌ Mistake 5 — Phenytoin for Seizure Prophylaxis
Levetiracetam is preferred over phenytoin for post-traumatic seizure prophylaxis. Phenytoin has cardiovascular side effects (hypotension with IV loading), drug interactions, cognitive impairment, and requires level monitoring. Same efficacy, worse side effect profile.
Exam Pearls (DrNB / PDCC / IFCCM)
Q: BTF 2023 SBP target in adult TBI? → SBP ≥110 mmHg (Strong recommendation). This is updated from the old ≥90 mmHg threshold. Optimal targets may be even higher.
Q: Steroid use in TBI? → ABSOLUTELY CONTRAINDICATED. CRASH trial: methylprednisolone → increased 14-day mortality in TBI. Never give steroids for head injury.
Q: What is CPP and target in severe TBI? → CPP = MAP − ICP. Target 60–70 mmHg. Treat ICP >22 mmHg and/or CPP <60 mmHg with escalating interventions (CSF drainage, osmotherapy, sedation, surgical).
Q: Drug of choice for post-traumatic seizure prophylaxis? → Levetiracetam 1000 mg BD × 7 days (prevents early post-traumatic seizures only — not late). Preferred over phenytoin.
Q: CT findings in EDH vs SDH? → EDH: Biconvex (lens-shaped), hyperdense, does NOT cross suture lines (bounded by dura attachment). SDH: Concave (crescent-shaped), crosses suture lines (no dural attachment).
Q: Why avoid Ringer's Lactate in TBI? → Slightly hypotonic (254 mOsm/L) → lowers plasma osmolality → free water shifts into brain → worsens cerebral oedema. Use 0.9% NaCl or hypertonic saline for TBI resuscitation.
Q: Cushing's triad significance? → Hypertension + Bradycardia + Irregular respirations = brainstem compression from severely raised ICP = imminent death. Emergency: Mannitol 1 g/kg IV + brief hyperventilation + call neurosurgeon immediately.
References
- Lulla A, Lumba-Brown A, Totten AM, et al. Brain Trauma Foundation: Prehospital Guidelines for the Management of Traumatic Brain Injury – 3rd Edition. Prehospital Emergency Care. 2023;27(Sup1):S1–S100.
- Carney N, Totten AM, O'Reilly C, et al. Guidelines for the Management of Severe Traumatic Brain Injury, 4th Edition. Neurosurgery. 2017;80(1):6–15.
- Edwards P, Arango M, Balica L, et al. (CRASH trial collaborators). Final results of MRC CRASH, a randomised placebo-controlled trial of intravenous corticosteroid in adults with head injury. Lancet. 2005;365(9475):1957–1959.
- Hutchinson PJ, Kolias AG, Timofeev IS, et al. (RESCUEicp). Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension. N Engl J Med. 2016;375(12):1119–1130.
- Cooper DJ, Rosenfeld JV, Murray L, et al. (DECRA). Decompressive Craniectomy in Diffuse Traumatic Brain Injury. N Engl J Med. 2011;364(16):1493–1502.
- Andrews PJD, Sinclair HL, Rodriguez A, et al. (Eurotherm3235). Hypothermia for Intracranial Hypertension after Traumatic Brain Injury. N Engl J Med. 2015;373(25):2403–2412.
- Inaba K, Menaker J, Branco BC, et al. A prospective multicenter comparison of levetiracetam versus phenytoin for early post-traumatic seizure prophylaxis. J Trauma Acute Care Surg. 2013;74(3):766–771.
- Oh TE (ed). Oh's Intensive Care Manual, 8th edition. Chapter 49: Head Injuries. Elsevier; 2018.
- Marino PL. The ICU Book, 4th edition. Chapter 44: Traumatic Brain Injury. Lippincott Williams & Wilkins; 2014.