What is the treatment for cardiac arrest due to helium inhalation?

Treatment of Cardiac Arrest Due to Helium Inhalation

Treat cardiac arrest from helium inhalation using standard Advanced Cardiovascular Life Support (ACLS) protocols without modification, as there is no evidence supporting helium-specific interventions and the primary pathophysiology is asphyxia-induced cardiac arrest. 1, 2

Immediate Resuscitation

• Begin high-quality CPR immediately with chest compressions at least 5 cm (2 inches) deep at a rate of 100-120 compressions per minute, allowing complete chest recoil between compressions 1, 2
• Apply an automated external defibrillator (AED) or manual defibrillator as soon as available while continuing CPR 2
• Minimize interruptions in chest compressions to maintain coronary and cerebral perfusion 1, 2
• Switch compressors every 2 minutes or sooner if fatigued to maintain effective compressions 2
• For patients without an advanced airway, use a 30:2 compression-to-ventilation ratio 2

Airway Management and Oxygenation

• Establish an advanced airway (endotracheal intubation or supraglottic airway device) promptly to ensure adequate oxygenation and ventilation 1, 2
• Confirm correct placement using waveform capnography 1, 2
• After advanced airway placement, provide 1 breath every 6 seconds (10 breaths/minute) with continuous chest compressions 2
• Provide 100% oxygen initially during resuscitation, as helium inhalation causes profound hypoxia through displacement of oxygen 1, 2
• Monitor PETCO2 (typically 35-40 mm Hg) to assess CPR quality and detect return of spontaneous circulation 1, 2

Defibrillation and Medications

• For ventricular fibrillation or pulseless ventricular tachycardia, defibrillate according to standard ACLS protocols 1, 2
• Resume CPR immediately after shock delivery for 2 minutes before reassessing rhythm 2
• For shock-refractory VF/pVT, administer amiodarone (300 mg IV/IO bolus, then 150 mg) or lidocaine (1-1.5 mg/kg IV/IO) 2
• Administer standard-dose epinephrine (1 mg IV/IO every 3-5 minutes) according to ACLS protocols 1

Address Reversible Causes

The primary reversible cause in helium inhalation is hypoxia from oxygen displacement:

• Hypoxia: Aggressively oxygenate with 100% oxygen once airway is secured 1, 2
• Evaluate for tension pneumothorax, which can occur from pressurized helium inhalation causing barotrauma 3
• Consider other "H's and T's": hypovolemia, hydrogen ion (acidosis), hypo/hyperkalemia, hypothermia, cardiac tamponade, toxins, and thrombosis 1, 2

Critical pitfall: Unlike carbon monoxide poisoning, helium does not bind to hemoglobin or cause direct tissue toxicity—it simply displaces oxygen. Once removed from the helium source and provided with supplemental oxygen, the helium is rapidly eliminated through normal respiration. 4

Post-Resuscitation Care (If ROSC Achieved)

• Recognize ROSC by presence of pulse, blood pressure, and abrupt sustained increase in PETCO2 (typically >40 mm Hg) 2
• Titrate inspired oxygen to achieve arterial oxygen saturation of 94% to avoid oxygen toxicity once stabilized 1, 2
• Target ventilation to achieve PETCO2 of 35-40 mm Hg or PaCO2 of 40-45 mm Hg 1, 2
• Avoid hyperventilation, as it decreases cerebral blood flow and may worsen neurological outcomes 1
• Elevate head of bed 30° if tolerated to reduce cerebral edema, aspiration, and ventilator-associated pneumonia 1, 2

Neuroprotective Measures

• Consider therapeutic hypothermia (32-34°C) for 24 hours in comatose survivors after ROSC to optimize neurological recovery 1, 2
• Control body temperature to optimize survival and neurological outcomes 2
• Maintain normocapnia and avoid both hypocapnia and hypercapnia 1
• Optimize cardiopulmonary function and vital organ perfusion 1, 2

Special Considerations for Helium Inhalation

Cerebral gas embolism: If helium was inhaled from a pressurized tank (not a balloon), consider the possibility of cerebral gas embolism from direct vascular injection of helium bubbles 3

• Manifestations include focal neurological deficits, seizures, or altered mental status disproportionate to the duration of hypoxia 3
• If cerebral gas embolism is suspected, consider hyperbaric oxygen therapy after stabilization, though transport risks must be weighed against potential benefits 1, 3
• Maintain patient in supine position (not Trendelenburg) during transport 3
• Avoid air transport at high altitudes if cerebral gas embolism is present, as decreased atmospheric pressure will expand gas bubbles 3

Key distinction: Helium used therapeutically in ventilation (as a carrier gas mixed with oxygen) is safe and has been studied for neuroprotection after cardiac arrest 5, 6. However, this is entirely different from helium inhalation causing cardiac arrest through asphyxiation.

Prognosis and Disposition

• Most patients who develop cardiac arrest from asphyxiant gas inhalation have poor outcomes, with survival dependent on duration of hypoxia and time to ROSC 4
• Transport to a facility with comprehensive post-cardiac arrest care capabilities, including targeted temperature management and advanced neurological monitoring 1, 2
• Avoid early prognostication, especially if therapeutic hypothermia is used, as many predictors of poor outcome are unreliable in this context 1