Pulmonary - Critical Care Associates
of East Texas

Jeffrey M. Shea, M.D., F.C.C.P.
                              Catherine M. Martinez, M.D.

Introduction

Patients with lung disease such as chronic obstructive disease (COPD) and asthma use different respiratory devices and equipment to deliver medications to their lungs that helps optimize their respiratory function.

The metered-dose inhaler (MDI) is the most cost-effective, most convenient, and most routinely prescribed method of delivery for home bronchodilator therapy. It’s ideal for the patient because of its small size and ease of use. The MDI device delivers a single squirt or puff of a medication solution with each actuation. The puff lasts only a fraction of a second and must be inhaled promptly and correctly. Proper use of an MDI requires appropriate instruction and capability of coordinating hand and breathing movements. To use the MDI you hold it at least three fingers width away from your lips, blow out all of your air, tilt head back slightly, open mouth squirt the medicine once and inhale slowly and deep, hold breath for 5-10 seconds. There are patients who are unable to use MDIs due to their inability to coordinate the breathing technique. 10% to 20% of patients fail to receive optimal aerosol deposition. Devices such as a spacer can help with aerosol administration by eliminating the need to coordinate inhalation with activation of the MDI.

There are different variations on design of the spacer, but the more popular brand is called an Aerochamber. It is tubular in shape, opening on one end for the MDI, mouthpiece on the other end, and has a whistle alert to let the patient know when they are inhaling the medicine in to fast. It is easy to clean and use. When the MDI is used with a spacer, the patient actuates the MDI, aerosolizing the solution into the spacer, then inhales the aerosol from the spacer by use of the mouthpiece slow and deep then holding your breath for a count of 5-10 seconds. The spacer serves as two functions: to contain the aerosol to eliminate the need for hand-breath coordination, and to allow for impaction and fall out of large aerosol particles that would otherwise deposit in the mouth and throat and cause adverse effects.

This is used when a patient is unsuccessful at using an MDI; a compressor nebulizer is relatively inexpensive and a simple way for the patient to have home bronchodilator therapy. Small compressors with outputs of 7 to 10 liters per minute are used to power hand-held nebulizers. These can also be portable devices: internal batteries allow 60 total minutes of treatment time and DC adapters allow the patient to take treatments while in a vehicle. These units produce an aerosol on a continuous basis. The efficiency of nebulizers is dependent on the volume of fluid to nebulize and nebulizer design. Regardless though of design, all nebulizers have a dead volume, a volume of fluid that cannot be nebulized because of the design and operation of the unit. When the fluid nebulizes the solution cools because of evaporate heat loss, and the solution becomes more concentrated. The following guidelines should be followed when using a nebulizer: (1) Total amount of solution should be about 3ml, (2) Use a compressor to deliver room air. The higher the relative humidity the more stable the particle size of the solution.

Nebulizers are also used to deliver medication to help thin secretions. The patient must have an appropriate breathing pattern to ensure maximum penetration and deposition of the drug within the lung. Factors affecting penetration and deposition include breathing through the nose instead of the mouth, breathing to fast in and out, respirations should be slow deep breaths and holding of breath for 5-10 seconds every 2-3 minutes.

Patients with chronic obstructive disease (COPD) and resultant chronic hypoxemia represent one of the largest single population groups using home care equipment. Patients can increase survival and improve quality of life with continuous or near-continuous oxygen. There is no other modality of therapy available today that is more effective. Studies such as the North American Nocturnal Oxygen Therapy Trial (NOTT) showed that patients who used near-continuous oxygen had a significant improvement in neuropsychological function.

The most frequent used criteria for determining oxygen therapy are results from an arterial blood gas test or on an O2 saturation measurement by a pulse oximetry.

There are three types of stationary systems available to provide continuous in-home oxygen therapy:

• High-pressure cylinders

• Oxygen concentrators

• Liquid oxygen systems

There are two types of portable oxygen systems used to provide for use outside of the home:

• Lightweight smaller-sized cylinders

• Portable liquid oxygen

These are steel cylinders that contain gaseous oxygen under high pressure and are the oldest method of storing oxygen. These cylinders are of various sizes, H-tanks and E-tanks, with the H-tanks being the largest. The high-pressure stationary oxygen system has several advantages: no external power supply for operation; this system can be used to power other pieces of respiratory equipment such as nebulizers. There are, however several disadvantages to this system: each cylinder has a fixed capacity necessitating frequent changes and refills; high-pressure oxygen cylinders pose a safety risk and must be properly secured; moderate hand strength and dexterity are needed to open valves; patients or caregivers must be capable of reading gauges and meters, connecting regulators, and observing strict safety guidelines. Most important, high-pressure gaseous systems are useful in providing a backup to other stationary oxygen systems at risk for breakdown.

This is an electrically powered device capable of removing nitrogen from atmospheric gas. Concentrators use a molecular sieve to absorb nitrogen from room air gas that is drawn into a compressor, pressurized to a relatively low level, and directed through the sieve. As the gas passes through the sieve, nitrogen is absorbed, and the remaining oxygen is collected, concentrated, and passed through a flowmeter, where it is then delivered to the patient.

Oxygen concentrators offer many advantages. It has the ability to provide oxygen without resupply; concentrators are designed to run continuously and, when properly maintained, do so with minimum interruption; the console is pleasing in appearance; it is easy to operate for the patient; concentrators have casters and weigh approximately 50 lb., making it easy to move around in the home.

Disadvantages of the oxygen concentrator are: requires an adequate electrical power source (115 VAC), depending on the model, can consume up to 450 W/hour (many power companies allow special price breaks to patients using electrically powered life-support devices such as concentrators); any interruption of electrical power obviously makes the unit inoperable; depending on the model the extraneous noise can be bothersome, and there is a modest amount of heat generated.

Concentrators are a low-pressure system, so they are not able to power other respiratory equipment, such as nebulizers. Patients that use concentrators, a lightweight gaseous system are used to ambulate around outside of the home. These cylinders are E- or D-cylinders that are carried in a pouch or cart. They are capable of giving the patient several hours away from the stationary device.

Concentrators were introduced in 1974; they have become very popular and well accepted as a stationary in-home oxygen system. The Home Medical Equipment suppliers have and continue to successfully work around the problems associated with concentrators, and with newer technology will increase their reliability and performance.

Another method of providing continuous oxygen therapy in the home is the liquid oxygen system. The oxygen is stored in its liquid state at –297.3 Fahrenheit, in a special manufactured container that is in essence very sophisticated thermos bottles. These containers keep the oxygen in its liquid state and control the rate of evaporation through warming coils to provide sufficient gaseous oxygen.

A primary advantage of the liquid oxygen system is it’s portability, and may be called "doers". These "doers" can be used to refill a smaller, lightweight version of the larger stationary unit. The portable system, when full, weighs approximately 8 to 10 lbs and provide continuous oxygen at 2 liters per minute for up to 8 hours. There is no limit to how many times the portable unit can be refilled as long as there is an ample amount of liquid oxygen in the stationary unit. Other advantages with the stationary system are there is no need for external power and ability to power other respiratory equipment. A disadvantage of the stationary system is the "use-it or lose-it" feature. The "doers" are not capable of maintaining oxygen in the liquid state for an extended time. Under normal conditions, the amount of evaporation is controlled and immediately made available for use. If there is no flow (if the system is not being used) evaporation still occurs. If the system is not used for days it will run dry, through evaporative loss.

For the chronic hypoxemic patient that is very active this system may be of choice. You and your physician along with home care supply company can make the appropriate choice of system to use.

These devices are somewhat a new addition to oxygen therapy. Using a passive reservoir or electronic technology, these devices help extend the useful life of an oxygen canister (gaseous or liquid) through conservation. Instead of continuous flow of oxygen, oxygen-conserving devices deliver a large amount of oxygen intermittently at the initial part of the inspiratory phase of breathing.

Electronic devices are a "pulsing" effect of oxygen to the nose in response to a sensor detecting the beginning of the inspiratory effort. Electronic conserving devices, whether AC or DC powered, are not continuous flow systems. A disadvantage of the pulsing device is that because it is delivered on-demand, a patient will not receive oxygen should there be episodes of cessation in breathing patterns, such as during sleep.

Valve devices that allow inspiration, but only allow expiration through the valve if a prescribed pressure is developed. Maintains positive pressure within the airways and creates flow acceleration which clears secretions. These devices are usually very portable and easy to use.

This device consists of a mouthpiece and weighted ball. The weighted ball seals the opening until sufficient expiratory pressure is developed. Flow acceleration then occurs as the ball lifts up. The ball then falls sealing off the device. The flutter goes through this cycle of PEP and flow acceleration several times each second, producing what could be termed "oscillatory PEP" (move back and forth). The flutter is also very portable and easy to use.

A sigh is defined as a maneuver that produces an inspiratory volume at least three times that of a normal breath. As a patient sighs the airways are exposed to negative pressure, that is, there is an increased pressure difference between the inner and outer walls of the airways. Patients who have had surgery, pain and then pain medication have a decrease in the frequency of sighing, thus the patient develops atelectasis (unexpanded portion of the lung).

Incentive Spirometry is a device that encourages a patient to perform a voluntary hyperinflation maneuver that is then sustained at peak inspiration for 5-10 seconds. This maneuver is done 10-15 times over several times during the day.

With changing technology respiratory equipment is changing to become more convenient and easy for the patients to use, but it’s up to the patient and or family members to learn to use equipment properly to get the ultimate effect from their medication and optimize their condition.

See attached sheets for proper use of Metered-Dose Inhaler and How Full Is Your Inhaler.

You can find us on the internet at www.pcca.net for other pulmonary topics and patient information.

 

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