What neuroprotective measures can be utilized during cardiac arrest (cardiopulmonary arrest)?

From the Guidelines

Targeted temperature management (TTM) should be initiated as soon as possible after return of spontaneous circulation (ROSC), maintaining a temperature between 32-36°C for 24 hours, as it has been shown to reduce cerebral metabolic demands and mitigate reperfusion injury 1. During cardiac arrest, several neuroprotective strategies can be implemented to minimize brain damage. The most critical intervention is high-quality CPR with minimal interruptions, maintaining a rate of 100-120 compressions per minute and allowing complete chest recoil. Maintaining adequate oxygenation (targeting SpO2 of 94-98%) while avoiding hyperoxia is essential, as excessive oxygen can increase free radical production and oxidative stress 1. Blood glucose should be controlled between 140-180 mg/dL, as both hyperglycemia and hypoglycemia worsen neurological outcomes. Mean arterial pressure should be maintained above 65 mmHg to ensure adequate cerebral perfusion, using vasopressors like norepinephrine if necessary. Early seizure detection and treatment with medications such as levetiracetam (loading dose 20-30 mg/kg) is important, as post-arrest seizures can significantly worsen brain injury 2. Sedation and shivering management are also crucial, as they can help prevent recall in patients treated with neuromuscular blockers and mitigate the degree of shivering, which can be beneficial in patients receiving TTM 2. These interventions work together to preserve cerebral function by maintaining adequate oxygen delivery, reducing metabolic demands, and minimizing secondary injury mechanisms during the critical post-arrest period. Some key points to consider include:

• The optimal duration for mild induced hypothermia and TTM is unknown, although it is currently most commonly used for 24 hours 1.
• The term targeted temperature management or temperature control is now preferred over the previous term therapeutic hypothermia 1.
• TTM is recommended for adults after out-of-hospital cardiac arrest (OHCA) with an initial shockable rhythm who remain unresponsive after ROSC 1.
• Sedatives and analgesics can be beneficial in patients receiving TTM, but their use should be carefully managed to avoid excess sedation, which can aggravate haemodynamic instability and hinder accurate neuroprognostication 2.
• The routine use of coenzyme Q10 in patients treated with hypothermia is uncertain, and no neuroprotection benefit has been observed with the use of thiopental, glucocorticoids, nimodipine, lidoflazine, diazepam, and magnesium sulfate 3.
• Induction of moderate hypothermia after ROSC has been associated with improved functional recovery and reduced cerebral histological deficits in various animal models of cardiac arrest 4.

From the Research

Neuroprotective Efforts During Cardiac Arrest

There are several neuroprotective efforts that can be utilized during a cardiac arrest, including:

• Therapeutic hypothermia, which is the only strategy able to provide effective neuroprotection in clinical practice 5
• Early hemodynamic optimization to improve cerebral perfusion and minimize secondary brain injury 5
• Intra-arrest hypothermia, which may be a valid alternative to improve the effectiveness of therapeutic hypothermia 5
• Inhaled gases, such as xenon, argon, and nitric oxide, which are emerging as promising tools to improve neuroprotection 5
• Intravenous drugs, such as erythropoietin, which may also improve neuroprotection 5

Therapeutic Hypothermia

Therapeutic hypothermia has been widely studied as a neuroprotective strategy during cardiac arrest. Some studies have shown that it can improve neurological outcomes 6, while others have found little or no effect 6. The International Liaison Committee on Resuscitation currently recommends treating fever and keeping body temperature below 37.5°C, but the evidence for this is low-certainty 6.

Other Neuroprotective Strategies

Other neuroprotective strategies that have been studied include:

• Active compression decompression CPR and intrathoracic pressure regulation to improve brain perfusion during CPR 7
• Head Up CPR to decrease intracranial pressure and increase cerebral perfusion pressure and cerebral blood flow 7
• Sodium nitroprusside enhanced CPR to increase cerebral perfusion and improve neurologic survival 7
• Postconditioning with inhaled gases or intravenous drugs to protect the myocardium and potentially the neural tissue 7, 8

Individualized Temperature Management

Some studies suggest that the beneficial effect of hypothermic targeted temperature management differs according to the severity of post-cardiac arrest syndrome, and that individualized temperature management may be necessary to optimize outcomes 9.