O2 in Industry: Uses, Production Methods, and Safety Tips

O2 and Health: How Oxygen Therapy Works and When It’s UsedOxygen (O2) is a colorless, odorless gas that is essential for life. In the human body it powers cellular respiration — the process by which cells produce energy — and without adequate oxygen, organs and tissues fail. Oxygen therapy is a medical treatment that delivers supplemental oxygen to people whose blood oxygen levels are lower than normal. This article explains how oxygen therapy works, the main types and delivery methods, common medical indications, benefits and risks, practical considerations, and recent developments.

How oxygen supports the body

Oxygen travels from the lungs to the bloodstream, where it binds mainly to hemoglobin in red blood cells and is carried to tissues. Cells use oxygen in mitochondria to convert nutrients into adenosine triphosphate (ATP), the molecule that powers most cellular functions. When oxygen levels fall (hypoxemia), tissues receive less oxygen (hypoxia), impairing organ function and potentially causing damage.

• Normal arterial oxygen saturation (SpO2) measured by pulse oximetry is typically 95–100% in healthy adults.
• Symptoms of low oxygen can include shortness of breath, rapid breathing, confusion, fainting, cyanosis (bluish skin), and organ dysfunction.

How oxygen therapy works

Oxygen therapy increases the amount of oxygen available to the lungs and bloodstream. Therapies raise the fraction of inspired oxygen (FiO2) and/or improve lung ventilation and gas exchange, helping restore adequate tissue oxygenation. Mechanisms include:

• Increasing the partial pressure of oxygen in the alveoli, which enhances diffusion into pulmonary capillaries.
• Raising arterial oxygen content by loading more hemoglobin with oxygen and increasing dissolved oxygen in plasma.
• Reducing the work of breathing for patients who are hypoxemic or fatigued.

Main delivery methods

1. Nasal cannula

   • Low-flow device that delivers 24–44% FiO2 depending on flow (1–6 L/min) and patient breathing.
   • Comfortable, allows eating/talking, suitable for mild to moderate hypoxemia.

2. Simple face mask

   • Delivers roughly 40–60% FiO2 at 5–10 L/min.
   • Used when higher FiO2 is needed than a cannula can provide.

3. Non-rebreather mask

   • Delivers up to ~90–100% FiO2 when set correctly with high flow (10–15 L/min) and a proper reservoir.
   • Used for severe hypoxemia or acute events.

4. Venturi mask (air-entrainment)

   • Provides precise FiO2 (e.g., 24%, 28%, 31%, 35%, 40%, 50%) useful for patients requiring controlled oxygen, such as COPD patients at risk for CO2 retention.

5. High-flow nasal cannula (HFNC)

   • Delivers warmed, humidified oxygen at high flows (up to 60 L/min) with adjustable FiO2 up to 100%.
   • Improves oxygenation, reduces work of breathing, and can provide some positive airway pressure.

6. Noninvasive ventilation (NIV) — CPAP/BiPAP

   • Delivers pressurized air/oxygen mix without an invasive airway.
   • Supports ventilation and oxygenation in respiratory failure, pulmonary edema, or COPD exacerbations.

7. Invasive mechanical ventilation

   • Endotracheal tube or tracheostomy with a ventilator delivers precise FiO2 and ventilatory support in critical illness.

8. Hyperbaric oxygen therapy (HBOT)

   • Patient breathes 100% oxygen at pressures greater than atmospheric (commonly 1.5–3.0 ATA).
   • Used for specific conditions like decompression sickness, certain non-healing wounds, carbon monoxide poisoning, and gas gangrene.

Common indications for oxygen therapy

• Acute hypoxemic respiratory failure (e.g., pneumonia, acute respiratory distress syndrome [ARDS])
• Chronic hypoxemia due to COPD, interstitial lung disease, cystic fibrosis, or pulmonary hypertension
• Acute cardiac events with hypoxemia or shock (note: routine oxygen in normoxic myocardial infarction is no longer recommended)
• Postoperative hypoxemia
• Carbon monoxide poisoning (100% oxygen and often hyperbaric oxygen)
• Severe trauma, major blood loss, or shock states causing poor tissue oxygenation
• Cluster headaches and some migraine protocols (100% oxygen inhalation)
• Hyperbaric indications listed above (HBOT)

Clinical guidelines typically specify target oxygen saturation ranges rather than universal high-flow oxygen. For most acutely ill patients, aiming for SpO2 92–96% is common; for patients at risk of CO2 retention (e.g., COPD), targets are lower, often 88–92%, to avoid suppressing respiratory drive and worsening hypercapnia.

Benefits

• Rapid correction of hypoxemia, protecting organs from hypoxic injury.
• Symptom relief: reduces breathlessness and improves exercise tolerance.
• Supports tissue healing in ischemic conditions.
• In acute care, oxygen can be life-saving when provided promptly and appropriately.

Risks and contraindications

• Oxygen toxicity: prolonged high FiO2 can damage lungs (absorption atelectasis, oxygen free radical injury), particularly at FiO2 >60% over extended periods.
• Hypercapnia in vulnerable patients: in some COPD patients, high oxygen can reduce hypoxic respiratory drive and worsen CO2 retention — monitor arterial blood gases.
• Fire risk: oxygen-enriched environments increase combustion risk — strict safety precautions required.
• Barotrauma with mechanical ventilation or HBOT if pressures/volumes are excessive.
• Drying of mucosa and discomfort with unhumidified high flows.

Monitoring and titration

• Pulse oximetry is the primary bedside tool for continuous monitoring of SpO2.
• Arterial blood gas (ABG) analysis provides PaO2, PaCO2, and acid–base status when needed.
• Titrate oxygen to the lowest flow and FiO2 that achieves the target SpO2 range for the clinical context.
• Reassess frequently after changes in flow or device, and escalate to higher support if hypoxemia persists.

Practical considerations

• Nasal cannula is first-line for mild hypoxemia; masks or HFNC for moderate-to-severe cases.
• In resource-limited settings, concentrators (which extract oxygen from ambient air) provide continuous oxygen supply for many patients.
• Home oxygen therapy: prescribed for chronic hypoxemia based on ABG or oximetry, with ongoing monitoring and equipment education for patients.
• Education for patients and caregivers is essential: device use, tubing safety, fire precautions, and recognizing warning signs (increased breathlessness, altered mental status).

Special populations

• COPD: Use conservative oxygen targets (typically 88–92%) and monitor for hypercapnia.
• Neonates: Premature infants require carefully controlled oxygen to avoid retinopathy of prematurity; targets differ by gestational age.
• Palliative care: Oxygen may relieve dyspnea for some patients; benefits should be balanced with burden and goals of care.
• COVID-19 and viral pneumonia: Oxygen remained a cornerstone of supportive care; HFNC and prone positioning have been used to improve oxygenation in severe cases.

Recent and evolving areas

• High-flow nasal cannula has increasingly become an intermediate option between conventional oxygen and intubation, showing benefits in selected patients with respiratory failure.
• Better oxygen-conserving systems and portable concentrators have expanded home oxygen accessibility.
• Research continues on optimal oxygenation targets in various acute conditions to balance benefit and harm.

Conclusion

Oxygen therapy is a fundamental, often life-saving treatment that restores tissue oxygenation across a wide range of acute and chronic conditions. Its effectiveness depends on choosing the appropriate delivery method, carefully titrating to target saturations, and monitoring for complications like oxygen toxicity and hypercapnia. When used thoughtfully, oxygen improves symptoms, preserves organ function, and supports recovery.