Practice-Changing Developments in Neuroanaesthesia and Neurointensive Care 2024-2025
Post-Cardiac Arrest Temperature Management: A Major Paradigm Shift
The most significant practice change is that aggressive hypothermia (32-34°C) no longer shows benefit over normothermia/fever prevention in post-cardiac arrest neuroprotection, fundamentally altering decades of neurointensive care practice. 1
Key Evidence from 2024 International Consensus
The 2024 International Consensus on Cardiopulmonary Resuscitation analyzed 6 new trials (adding to 32 previous studies) comparing various temperature management strategies in comatose post-cardiac arrest patients 1. The findings are striking:
Hypothermia (32-34°C) vs. normothermia showed NO difference in:
33°C vs. 36°C showed equivalent outcomes with no survival or neurological benefit 1
Updated 2024 Recommendations
The new guideline recommends actively preventing fever by targeting temperature ≤37.5°C (weak recommendation, low-certainty evidence), rather than aggressive hypothermia. 1 This represents a fundamental shift from cooling to fever prevention as the primary temperature management strategy.
Prehospital cooling with rapid infusion of large volumes of cold intravenous fluid is now explicitly recommended AGAINST (strong recommendation, moderate-certainty evidence). 1 This directly contradicts previous emergency protocols that emphasized early aggressive cooling.
Clinical Implications
- Duration of temperature control: Neither 12-24 hours vs. 36 hours, nor 48 hours vs. 24 hours showed outcome differences 1
- Method of cooling: Endovascular vs. surface cooling showed no mortality or neurological outcome differences (RR 1.14,95% CI 0.93-1.38 for survival) 1
- Rewarming rate: Slow (0.25°C/h) vs. fast (0.50°C/h) rewarming showed no outcome differences 1
The practical takeaway: Simplify your protocol to fever prevention (≤37.5°C) using either surface or endovascular methods, abandon aggressive hypothermia targets, and avoid prehospital cold fluid boluses. 1
Traumatic Brain Injury Blood Pressure Management: Refined Targets
Higher Systolic Blood Pressure Thresholds
Maintain systolic blood pressure >110 mmHg (not just >90 mmHg) in severe traumatic brain injury patients, as mortality markedly increases below this threshold. 2 This represents a significant upward revision from traditional 90 mmHg targets.
For combined hemorrhagic shock and severe TBI, target MAP ≥80 mmHg. 2 This balances cerebral perfusion needs against permissive hypotension strategies used in hemorrhagic shock.
Cerebral Perfusion Pressure Targets
Target CPP between 60-70 mmHg in the absence of multimodal monitoring. 2 Importantly, CPP values >90 mmHg may worsen outcomes by aggravating vasogenic cerebral edema 2, establishing an upper limit that was previously less defined.
Monitoring and Measurement Precision
Use transduced direct arterial pressure monitoring with the transducer at the level of the tragus (not the phlebostatic axis) for accurate cerebral perfusion pressure calculations 2. If invasive monitoring is unavailable, use NIBP at 1-minute intervals during critical periods 2.
Practical Management Algorithm
- Immediate hypotension: Have ephedrine and metaraminol readily available 2
- Fluid resuscitation: Use 0.9% saline as preferred IV fluid; avoid hypotonic solutions like Ringer's lactate 2
- Hypertension management: Use labetalol; avoid aggressive BP reduction that compromises cerebral perfusion 2
- During intubation: Prioritize maintaining target BP over concerns about cerebral stimulation using high-dose fentanyl, alfentanil, or remifentanil 2
- Hemodynamically unstable patients: Consider ketamine 1-2 mg/kg (lower doses in polytrauma) 2
Acute Ischemic Stroke Transfer: Time-Critical Protocols
Mechanical Thrombectomy Window Extension
Mechanical thrombectomy now shows benefit up to 24 hours in selected patients (previously 6 hours) 1, dramatically expanding the treatment window and necessitating urgent transfer protocols even for delayed presentations.
Transfer Without Intubation
Patients with anterior circulation acute ischemic stroke for thrombectomy should be transferred WITHOUT delay and rarely need airway intervention. 1 This contradicts traditional neurointensive care teaching that emphasized prophylactic intubation for transfers.
Intubation is NOT required if adequate oxygenation and ventilation can be maintained with or without supplemental oxygen 1, and patients who are otherwise stable do not usually need a medical escort 1.
Oxygenation Targets
Do NOT prescribe supplemental oxygen routinely. 1 Titrate inspired oxygen to maintain SpO₂ 93-98% 1, as hyperoxia should be avoided, especially in acute ischemic stroke 2.
Critical Timing Emphasis
All efforts should be made to avoid delays; transfers are time-critical, with mechanical thrombectomy ideally performed within 6 hours when possible. 1 The mantra is now "time is brain" with every minute counting toward functional outcome.
Extracorporeal CPR (ECPR): Emerging Role in Refractory Cardiac Arrest
New Weak Recommendation for ECPR
The 2024 guidelines now include a weak recommendation for ECPR in selected patients with refractory cardiac arrest 1, representing formal recognition of this technology in neurointensive care settings.
Evidence Base
Recent randomized trials show variable but promising results 1:
- Yannopoulos et al (2020): 43% survival to discharge with ECPR vs. 7% with standard care (ARD 36%, 95% CI 7.4-65%) 1
- Belohlavek et al (2022): 42% vs. 33% survival (ARD 9.4%, 95% CI -2.4 to 21%) 1
- Favorable neurological outcomes at 6 months: 32-43% with ECPR vs. 0-22% with standard care 1
Patient Selection Caveat
Published trials use highly selected patients (initial shockable rhythms, specific time windows), not the general cardiac arrest population. 1 The intervention should be reserved for centers with established ECPR programs and appropriate patient selection protocols.
Common Pitfalls and Implementation Challenges
Temperature Management Transition
The biggest pitfall is continuing aggressive hypothermia protocols based on outdated evidence. 1 Many institutions have invested in cooling equipment and established protocols that now require revision. The transition to fever prevention requires:
- Protocol updates emphasizing ≤37.5°C targets 1
- Staff education on abandoning 32-34°C targets 1
- Elimination of prehospital cold fluid bolus protocols 1
Blood Pressure Management Complexity
Avoid the pitfall of applying single BP targets across all brain injury types. 2 TBI requires SBP >110 mmHg 2, while hemorrhagic shock with TBI requires MAP ≥80 mmHg 2, and ischemic stroke has different targets. Create diagnosis-specific protocols rather than universal "brain injury" targets.
Stroke Transfer Delays
The most common error is unnecessary intubation delaying thrombectomy transfer. 1 Anterior circulation strokes rarely require airway intervention 1, and the time lost to intubation directly impacts functional outcomes given the 24-hour treatment window 1.
Ventilation Targets
Maintain PaCO₂ between 4.5-5.0 kPa (33.8-37.5 mmHg), with brief periods of 4.0-4.5 kPa allowed only for impending uncal herniation. 2 Avoid prolonged hypocapnia as treatment for intracranial hypertension 2, as this can worsen cerebral ischemia.