What is a Bubble Humidifier Illustration

What is a Bubble Humidifier? (2024)

by | Updated: Jan 8, 2024

When it comes to providing supplemental oxygen therapy, ensuring patient comfort and safety is a top priority. One device that plays a crucial role in this process is a bubble humidifier.

Often used in healthcare settings, bubble humidifiers serve to moisten the dry oxygen gas, making it more comfortable for the patient to inhale.

Dry oxygen can cause irritation or damage to the patient’s airways, especially when used for prolonged periods.

Thus, the purpose of a bubble humidifier is not only to alleviate these discomforts but also to enhance the effectiveness of oxygen therapy.

In this article, we’ll provide a comprehensive overview of bubble humidifiers, their uses, and their importance in the context of oxygen therapy and respiratory care.

What is a Bubble Humidifier?

A bubble humidifier is a device often used in healthcare to provide moistened oxygen to patients who require supplemental oxygen. Oxygen gas by itself can be very dry and can lead to discomfort or damage to the airways when inhaled directly, especially for long periods of time.

By passing the oxygen through a bubble humidifier filled with sterile water, the oxygen gets humidified, which can help to alleviate these problems.

The device typically consists of a container filled with sterile water and a place to connect the oxygen supply tube on one side.

The oxygen enters the humidifier and is bubbled through the water, picking up moisture before it is delivered to the patient via a delivery tube. The top part of the humidifier typically includes an outlet for the humidified oxygen to exit the device and a pressure relief valve for safety purposes.

These devices are especially common in home care settings, where patients with chronic lung diseases like chronic obstructive pulmonary disease (COPD) may need long-term oxygen therapy.

Bubble Humidifier Illustration Vector

When to Use a Bubble Humidifier?

A bubble humidifier becomes particularly necessary when a patient is receiving supplemental oxygen therapy via a nasal cannula or a simple mask and the flow rate exceeds 4 L/min. At these higher flow rates, the oxygen can be quite dry and can cause discomfort or even damage to the patient’s nasal passages due to dryness.

Therefore, using a bubble humidifier is beneficial as it moisturizes the oxygen, enhancing comfort and preventing dryness.

Furthermore, even at lower flow rates, if a patient complains about nasal dryness, introducing a bubble humidifier into the oxygen delivery system could provide significant relief and improve the overall therapy experience.

Bubble Humidifier Components

Bubble Humidifier Components Illustration

Bubble humidifiers consist of several key components that allow them to effectively humidify oxygen before it’s delivered to a patient:

  • Reservoir or Bottle: This is where the sterile water is stored. The oxygen gas is bubbled through this water to pick up moisture.
  • Oxygen Inlet: This is where the oxygen supply tube is connected. Oxygen flows from the supply source, into the humidifier through this inlet.
  • Diffuser: This is typically located at the base of the reservoir. It helps to break up the incoming oxygen into smaller bubbles, maximizing the surface area of gas coming into contact with the water, which aids in effective humidification.
  • Delivery Tube: This tube carries the humidified oxygen from the bubble humidifier to the patient.
  • Pressure Relief Valve (Pop-off Valve): This is a safety feature designed to release pressure if it builds up too high within the system, usually above 2 psi or 40 mmHg. This valve helps to prevent the humidifier from bursting.
  • DISS (Diameter Index Safety System) Connector: This is the standard system for gas connections in healthcare applications. In bubble humidifiers, it ensures that only the correct type of gas (oxygen) is connected to the humidifier.
  • Lid: The lid is used to seal the reservoir, creating a closed system for the oxygen to be humidified. It typically contains the DISS connector and pressure relief valve.

Note: These components together allow the bubble humidifier to perform its function of moisturizing oxygen for more comfortable and safer delivery to patients.

How Does a Bubble Humidifier Work

Bubble humidifiers operate by dispersing a gas stream into tiny bubbles beneath the water surface. This dispersion process is made more effective by the use of a foam or mesh diffuser, which produces tinier bubbles compared to a simple open lumen, thus maximizing the surface area for interaction between the gas and water.

These unheated bubble humidifiers are typically paired with oxygen delivery systems to elevate the water vapor content of the gas to match the environment’s humidity levels.

Such unheated bubble humidifiers can achieve absolute humidity (AH) values roughly between 15 and 20 mg/L. At room temperature, an AH of 10 mg/L equates to about 80% Relative Humidity (RH) but only about 25% of the body’s humidity.

As the gas flow increases, the humidifier’s reservoir experiences cooling, and the gas-water interaction time decreases, diminishing its effectiveness at flow rates beyond 10 L/min.

While warming the reservoirs can boost humidity content, it’s not generally advised since the cooling process generates a condensate that can block the small delivery tubes.

How to Use a Bubble Humidifier

Bubble humidifiers are made up of a pre-filled jar containing sterile water and a lid that includes a Diameter Index Safety System (DISS) oxygen connector.

To use it, first, turn on the flowmeter to ensure that oxygen is streaming through the delivery tube and generating bubbles in the water. If there’s no bubbling action, it generally signifies that either the jar isn’t securely fastened or the delivery tube has an obstruction.

If the latter is the case and the tube cannot be unclogged, a replacement will be necessary.

Many bubble humidifiers are designed with a safety feature in the form of a high-pressure relief valve that automatically activates when the pressure reaches 40 mmHg or 2 psi.

To test this valve, you can close off or squeeze the small-bore tubing to build up pressure. You should be able to sense the escaping gas from the valve once it pops off.

Some valves also emit a whistling sound to alert users of a gas leak. Avoid using a device where the pop-off valve does not activate under pressure.

Bubble Humidifier Troubleshooting

Bubble humidifiers are designed with a straightforward pressure-relief valve, or pop-off, to alert users of obstructions in the flow path and avert the risk of the humidifier bottle bursting.

This pop-off valve, which typically operates based on gravity or spring-loaded mechanisms, is activated when pressures exceed 2 psi. Ideally, the pop-off valve should both audibly and visibly signal high pressure, and return to its regular state once the pressure normalizes.

The pop-off valve can also serve as a tool to check an O2 delivery system for potential leaks. This can be done by blocking the delivery tube at or close to the point where it connects to the patient.

If the pop-off valve activates and sounds an alarm, it suggests that the system is free from leaks.

Conversely, if the pop-off doesn’t sound, it may hint at either a system leak or a malfunctioning pop-off valve.

With increased gas flow, bubble humidifiers can generate aerosols. While these are typically invisible to the naked eye, they consist of water droplet suspensions that could potentially transport harmful bacteria from the humidifier’s reservoir to the patient.

Note: Given the high infection risk associated with any device that produces aerosols, stringent infection-control measures are imperative whenever using these systems.

FAQs About Bubble Humidifiers

What is Oxygen Therapy?

Oxygen therapy is a form of medical treatment that provides supplemental oxygen, a gas that your body needs to function properly.

It’s typically prescribed for individuals who have conditions that prevent them from getting adequate oxygen naturally, such as chronic obstructive pulmonary disease (COPD), pneumonia, asthma, heart failure, or trauma to the respiratory system.

The therapy can be delivered through various devices, including nasal prongs (cannulas), face masks, or ventilators, depending on the patient’s condition and the oxygen levels needed.

What is a Bubble and Jet Humidifier?

Bubble and jet humidifiers are two types of humidifiers commonly used in healthcare to add moisture to the oxygen or air that a patient breathes in.

A bubble humidifier works by allowing oxygen to bubble through a reservoir of sterile water, picking up moisture that can then be breathed in by the patient. A jet humidifier, on the other hand, uses a high-speed jet of gas to blow tiny water droplets into the airstream.

Both types aim to moisturize the gas and make it more comfortable for the patient to inhale, but they function using different mechanisms.

What is a Bubble Humidifier Used For?

A bubble humidifier is used in conjunction with an oxygen delivery system to add moisture to the oxygen that a patient breathes in.

Oxygen gas can be very dry and potentially damaging to the airways when breathed in directly over extended periods.

By passing the oxygen through a bubble humidifier filled with sterile water, the oxygen is humidified, helping to alleviate these potential issues.

These devices are often used in home care settings or hospitals for patients who require supplemental oxygen, such as those with chronic lung diseases.

Why Does a Bubble Humidifier Make a Whistling Noise?

A bubble humidifier may make a whistling noise due to its pressure relief valve, also known as a “pop-off” valve. This is a safety feature designed to prevent excessive pressure build-up within the system.

If the pressure in the humidifier exceeds a certain limit (usually around 2 psi or 40 mmHg), the valve opens, releasing the excess pressure.

The release of this pressurized gas can create a whistling sound.

The noise serves as an audible indicator that the pressure relief valve is functioning properly, or it can also signal that there’s an obstruction in the delivery system.

What is the Absolute Humidity of a Bubble Humidifier?

The absolute humidity provided by an unheated bubble humidifier typically falls between approximately 15 and 20 mg/L.

This measure represents the actual amount of water vapor present in the gas delivered to the patient, regardless of the temperature.

How Much Body Humidity Does a Bubble Humidifier Provide?

When operating at room temperature, an unheated bubble humidifier provides an absolute humidity (AH) of around 10 mg/L, which translates to roughly 25% of body humidity.

Body humidity refers to the ideal humidity level required to keep the human respiratory tract tissues healthy and comfortable, which is generally at a much higher relative humidity than ambient conditions.

How to Attach a Bubble Humidifier to Oxygen?

To attach a bubble humidifier to an oxygen source, follow these steps:

  1. Ensure the humidifier bottle is filled with sterile water up to the fill line.
  2. Screw the lid with the connected tubing onto the humidifier bottle.
  3. Connect the oxygen source to the inlet on the bubble humidifier.
  4. Connect the delivery tube (often a nasal cannula or simple mask) to the outlet on the bubble humidifier.
  5. Turn on the oxygen supply and adjust the flow rate as prescribed by the healthcare provider.
  6. Check for bubbles in the humidifier bottle, which indicates that the system is working properly.

Note: Always follow the manufacturer’s instructions, as procedures may vary slightly between different models.

Can You Use a Bubble Humidifier with a Simple Mask?

Yes, you can use a bubble humidifier with a simple mask. A bubble humidifier is beneficial when oxygen is delivered at a flow rate greater than 4 L/min, as it can make the oxygen more comfortable to breathe by adding moisture.

A simple mask, designed to cover the nose and mouth can effectively deliver these higher flow rates, so combining it with a bubble humidifier is common and recommended.

Can You Use a Bubble Humidifier with an Oxygen Concentrator?

Yes, you can use a bubble humidifier with an oxygen concentrator. Oxygen concentrators often deliver dry gas, which can lead to discomfort or irritation in the airways.

By incorporating a bubble humidifier in the system, the moisture content of the oxygen is increased, making it more comfortable for the patient.

However, it’s important to follow the manufacturer’s instructions when connecting these devices, as not all oxygen concentrators may require or be compatible with humidifiers.

How Do You Clean a Bubble Humidifier?

Cleaning procedures can vary depending on the manufacturer’s guidelines, but the general steps are:

  1. Disconnect the bubble humidifier from the oxygen source and delivery device.
  2. Empty any remaining water from the reservoir.
  3. Fill the reservoir with a mixture of mild dish soap and warm water.
  4. Securely close the lid and shake the bottle gently.
  5. Rinse thoroughly with warm water until all soap residue is gone.
  6. Air dry on a clean, lint-free towel.

Note: Some models may also be dishwasher-safe. Always refer to the manufacturer’s instructions for specific cleaning guidelines.

Where to Buy a Bubble Humidifier?

Bubble humidifiers can be purchased from a variety of sources. Medical supply stores, both physical and online, often carry these devices.

Many online marketplaces like Amazon also offer a selection of bubble humidifiers.

If the humidifier is being purchased for home use, a healthcare provider or home healthcare company may also be able to suggest reputable vendors or even supply the device directly.

Always ensure to buy from a trusted source to guarantee the quality and safety of the device.

Our Top Pick
HEALTHLINE Bubble Humidifier Water Bottle

The HEALTHLINE Bubble Humidifier Water Bottle is a reliable, easy-to-use accessory designed to add moisture to oxygen therapy, enhancing patient comfort and respiratory health.

If you click this link and make a purchase, we earn a commission at no additional cost to you.

Final Thoughts

Bubble humidifiers represent a pivotal component in the delivery of supplemental oxygen therapy. These devices enhance the comfort and safety of the patient by adding moisture to the typically dry oxygen gas.

This is especially important for patients with chronic respiratory diseases who require long-term oxygen therapy or those who require higher oxygen flow rates.

Furthermore, the careful management and troubleshooting of bubble humidifiers is critical to ensuring their effective operation and patient safety.

With a clear understanding of the role, operation, and maintenance of bubble humidifiers provided in this article, healthcare providers, caregivers, and patients themselves can better manage oxygen therapy, thereby improving health outcomes.

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


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