Oxygen therapy is one of the most frequently used resources in respiratory support, and is indicated for patients with reduced blood oxygenation caused by different clinical conditions. The correct choice of device directly influences the concentration of oxygen delivered, patient comfort, and treatment effectiveness.
Although visually similar, the Simple Mask and the Reservoir Mask (non-rebreather) have distinct indications. While the simple mask is indicated for patients who need moderate oxygen supplementation, the reservoir mask allows for the administration of significantly higher concentrations, and is often used in urgent and emergency situations.
Comparison: Simple Mask × Reservoir Mask
| Characteristic | Simple Mask | Reservoir Mask |
|---|---|---|
| Reservoir bag | Does not have | Has |
| Approximate O₂ concentration (FiO₂)* | 35–60% | Up to 90–95% |
| Recommended flow | 5 to 10 L/min | 10 to 15 L/min |
| Main indication | Mild to moderate hypoxemia | Moderate to severe hypoxemia |
| Emergency use | Limited | Highly indicated |
| Oxygen consumption | Lower | Higher |
| Complexity of use | Simple | Requires reservoir bag monitoring |
*Values may vary according to flow adjustment, patient's breathing pattern, and device characteristics.
Simple Mask
The simple mask is a device used to deliver supplemental oxygen in moderate concentrations, and is widely used in hospital wards, outpatient clinics, emergency rooms, and home care.
Advantages
- Easy to use
- Good patient acceptance
- Suitable for most conventional therapies
- Lower oxygen consumption
Limitations
- Does not deliver high oxygen concentrations
- Not indicated for patients with severe hypoxemia
- Requires minimum flow to prevent CO₂ rebreathing
Main applications
- Mild hypoxemia
- Postoperative recovery
- Hospital wards
- Outpatient care
- Home Care
Reservoir Mask
The reservoir mask has a bag that stores oxygen during exhalation, allowing the patient to inhale a much higher concentration of oxygen. It is widely used in urgent and emergency situations.
Advantages
- High oxygen delivery
- Indicated for critically ill patients
- Rapid use
- Excellent initial support
Limitations
- Higher oxygen consumption
- Bag must remain partially inflated
- Not indicated for prolonged use without reevaluation
Main applications
- Emergencies
- Trauma
- Severe hypoxemia
- Transport of critical patients
- Emergency room
When to Use Each?
| Clinical situation | Mask indicated |
|---|---|
| Mild hypoxemia | Simple Mask |
| Moderate hypoxemia | Simple Mask (according to clinical evaluation) |
| Severe hypoxemia | Reservoir Mask |
| Pre-hospital care | Reservoir Mask |
| Anesthetic recovery | Simple Mask |
| Trauma | Reservoir Mask |
| Transport of critical patient | Reservoir Mask |
| Home Care | Simple Mask (when prescribed) |
Quick Guide by Environment
| Environment | Most used device |
|---|---|
| Consulting rooms | Simple Mask |
| Outpatient clinics | Simple Mask |
| Hospital wards | Simple Mask |
| Emergency room | Reservoir Mask |
| Surgical Center | Simple Mask |
| ICU | Reservoir Mask (as indicated) |
| Ambulances | Reservoir Mask |
| Home Care | Simple Mask |
Myths and Facts
| Statement | Myth or Fact? | Explanation |
|---|---|---|
| All oxygen masks deliver the same O₂ concentration. | Myth | Each device offers different concentrations. |
| The reservoir mask delivers a higher oxygen concentration. | Fact | The reservoir bag increases the inspired oxygen delivery. |
| The reservoir bag must remain empty during use. | Myth | It must remain partially inflated. |
| The simple mask requires minimum flow to prevent CO₂ rebreathing. | Fact | Very low flows increase this risk. |
| The choice of mask depends only on availability. | Myth | It must follow clinical evaluation and prescription. |
Most Common Mistakes
| Mistake | Recommended action |
|---|---|
| Using a simple mask for severe hypoxemia | Opt for the reservoir mask when indicated |
| Setting flow below recommended | Adjust according to clinical guidance and manufacturer |
| Not observing the reservoir bag | Keep partially inflated during use |
| Improperly fitting the mask to the face | Adjust to reduce leaks |
| Not monitoring saturation during therapy | Continuously reassess the patient |
Technical Glossary
| Term | Definition |
|---|---|
| Oxygen therapy | Supplemental administration of oxygen to correct hypoxemia. |
| FiO₂ | Fraction of inspired oxygen delivered to the patient. |
| Hypoxemia | Reduction of arterial blood oxygen concentration. |
| SpO₂ | Peripheral oxygen saturation measured by pulse oximeter. |
| Reservoir bag | Bag attached to the mask that stores oxygen to increase FiO₂. |
Frequently Asked Questions
Does the reservoir mask replace mechanical ventilation?
No. It provides high concentrations of oxygen but does not replace ventilatory support when needed.
Can I use a simple mask on any patient?
No. The choice depends on the oxygen need, the severity of the clinical condition, and the prescription.
Why should the reservoir mask bag remain inflated?
Because it stores oxygen to be inhaled by the patient, increasing the administered oxygen concentration.
Can the simple mask be used in Home Care?
Yes, when indicated and accompanied by a healthcare professional.
Checklist Before Purchase
- Does the patient require high oxygen concentration?
- Will the device be used in an emergency?
- Does the available flow meet the device's requirements?
- Is the usage environment hospital or home?
- Is the product regularly registered with ANVISA?
- Does the model comply with the institution's protocol?
Technical Standards
- NR-32 – Safety and Health at Work in Health Services
- RDC ANVISA nº 36/2013 – Patient Safety in Health Services
- ANVISA RDCs applicable to medical devices
- Institutional oxygen therapy protocols
- Manufacturer's recommendations for device use, flow, and monitoring
Conclusion
The Simple Mask and the Reservoir Mask play distinct roles in oxygen therapy. While the former is indicated for moderate oxygen supplementation in stable patients, the latter is intended for situations requiring higher oxygen delivery, such as urgent, emergency, and severe hypoxemia conditions. Correctly evaluating the patient's clinical need, selecting the appropriate device, and continuously monitoring the response to treatment are essential measures for safe and effective respiratory assistance.
