HELIUM, USP
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HELIUM, USP (HELIUM, USP).
Helium is an inert gas that reduces airway resistance and improves laminar flow due to its low density, thereby decreasing work of breathing and facilitating gas exchange. It also enhances diffusion of carbon dioxide and oxygen.
| Metabolism | Not metabolized; eliminated unchanged by exhalation. |
| Excretion | Helium is an inert gas. Following administration, it is eliminated unchanged via exhalation (essentially 100% pulmonary excretion). Renal, biliary, or fecal elimination is negligible. |
| Half-life | Helium has no true elimination half-life in the body as it is not metabolized and its elimination is entirely dependent on ventilation. The washout half-life from blood and tissues is approximately 2-4 minutes with normal ventilation, but can be prolonged in hypoventilation or in poorly perfused compartments. |
| Protein binding | 0% bound. Helium is chemically inert and does not bind to plasma proteins. |
| Volume of Distribution | Approximately 0.36 L/kg in adults, reflecting distribution into total body water and body fat, but distribution is rapid and homogeneous in well-perfused tissues. |
| Bioavailability | Inhalation: 100% (due to complete absorption into blood across the alveolar-capillary membrane). Other routes (oral, IV) are not clinically used. |
| Onset of Action | Inhalation: Immediate (within 1-2 breaths) for reducing gas density and lowering airway resistance. Intravenous: Not clinically relevant. |
| Duration of Action | Duration is directly related to the duration of administration. Effects (e.g., lowered airway resistance, improved gas flow) persist only during exposure and rapidly reverse after discontinuation (within minutes). Clinical use is typically limited to short-term procedures. |
Inhaled admixture of 60-80% helium with 20-40% oxygen via face mask or endotracheal tube; titrated to clinical response for upper or lower airway obstruction.
| Dosage form | GAS |
| Renal impairment | No dosage adjustment required; helium is not renally cleared. |
| Liver impairment | No dosage adjustment required; helium is not hepatically metabolized. |
| Pediatric use | Inhaled admixture of 60-80% helium with 20-40% oxygen via face mask or endotracheal tube; titrated to clinical response. Weight-based dosing not applicable as it is a gas mixture adjusted by effect. |
| Geriatric use | No specific adjustment; use with caution in elderly patients due to potential comorbidities affecting gas exchange. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HELIUM, USP (HELIUM, USP).
| Breastfeeding | No data on excretion into breast milk. Due to its inert nature and rapid elimination, systemic absorption in infant is negligible. M/P ratio: Not determined. |
| Teratogenic Risk | No specific teratogenic risk data available for helium; as an inert gas, it is not expected to cause fetal harm. However, hypoxia due to improper administration may pose risks to the fetus. First trimester: No known risk. Second trimester: No known risk. Third trimester: No known risk, but avoid hypoxia. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
None absolute. Relative contraindications include severe respiratory acidosis requiring immediate intubation, and patients with inadequate oxygen supply when helium is used in high concentrations (e.g., >80% helium).
| Precautions | Helium should only be administered with adequate oxygen (typically 20-40% oxygen) to prevent hypoxia. Monitor oxygen saturation continuously. Use with caution in patients with severe hypoxia or respiratory failure. Heliox therapy may obscure the accuracy of some monitoring devices. Hypothermia risk with prolonged inhalation due to high thermal conductivity. |
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| Monitor maternal oxygen saturation and respiratory status; avoid hypoxia. Fetal heart rate monitoring if maternal hypoxia occurs. |
| Fertility Effects | No known effects on fertility. |