Oxygen concentrator-Applications and Maintenance

Oxygen Concentrator is a Medical Device used to produce Oxygen from Compressed Air . An oxygen concentrator takes in air and separates the oxygen and delivers it into a person via a nasal cannula. Air is 79% nitrogen and 21% oxygen and a concentrator that works by plugging into a source of electricity delivers air that is upto 95% oxygen. The Technology is known as Pressure Swing Adsorption technology or PSA Technology.

1. Let’s Learn Health Technology in Health Technology Management Series Topic-Oxygen Concentrators Health technology  is defined by the World  Health  Organization as the "application of organized knowledge and skills in the form of devices, medicines, vaccines, procedures, and systems developed to solve a  health  problem and improve quality of lives “

2. OXYGEN CONCENTRATOR AND OXYGEN CYLINDER PRAKASH MALLICK(BME-NHM,ODISHA Health Technology Management Series

3. Air Separation Air is used as feed stock Oxygen is separated based on Physical characteristics Must remove Nitrogen and Argon for Oxygen purity

4. Stage 1 Compressed air is fed into the first bed. Nitrogen and argon molecules are trapped, while oxygen is allowed to flow through.

5. Stage 2 The adsorbent in the first bed becomes saturated with nitrogen and argon molecules The airflow feed is directed into the second bed.

6. Stage 3 The adsorbent adsorbs nitrogen and argon in the second bed. The first bed is depressurized allowing argon and nitrogen to be purged out of the system and released to the atmosphere.

7. Stage 4 The process starts over. Compressed air is once again fed into the first bed. The second bed is depressurized releasing argon and nitrogen molecules to the atmosphere.

8. Oxygen Concentrators An oxygen concentrator draws in room air, separates the oxygen from the other gases in the air and delivers the concentrated oxygen to the patient. When set at a rate of two to three liters per minute, the gas that is delivered by the concentrator is more than 90% oxygen. It is used for situations where bottled gas supply is impractical or expensive, and can be used by patients in the hospital or the home.

9. DO NOT Do not operate the oxygen concentrator within a minimum of five feet (1.6m) from hot, sparking, or burning objects or naked flames. Do not use in rooms heated by paraffin or portable gas heaters. Do not place a humidifier with an oxygen patient unless prescribed by a physician and then only a bubble-type humidifier should be used. Do not use an electrical adapter or extension cord with the oxygen concentrator.

10. User Maintenance of Oxygen concentrator DAILY Cleaning Remove any dust / dirt with damp cloth and dry off Fill humidifier bottle up to marker with clean distilled water Visual checks Check all parts are present and tightly fitted Check all moving parts move freely Function checks Check the whole system function before use

11. WEEKLY Cleaning Unplug, clean inside and outside with damp cloth and dry off Wash filter in warm water and dry. Replace if damaged Clean humidifier bottle thoroughly and dry off Visual checks Replace humidifier bottle if covered with limescale . If mains plug, cable or socket are damaged, replace them. Function checks Run machine for two minutes and check no alarms occur. Check (see bubbles) that flow rate varies with flow control Every six months Technical check required

12. Troubleshooting – Oxygen Concentrators Fault Possible Cause Solution 1. Unit not operating, power failure alarm sounds No power from mains socket Concentrator circuit breaker has been set off. Electrical cable fault Check power switch is on. Replace fuse with correct voltage and current rating if blown. Check mains power is present at socket using equipment known to be working. Contact electrician for rewiring if power not present. Press reset button if present Try cable on another piece of equipment. Contact electrician for repair if required.

13. 2. No oxygen flow Flow not visible Tubes not connected tightly Water or matter blocking the oxygen tubing Blocked flow meter or humidifier bottle Place tube under water and look for bubbles. If bubbles emerge steadily, gas is indeed flowing Check tubing and connectors are fitted tightly Remove tubing, flush through and dry out before replacing Replace meter / bottle or refer to biomedical person 3.Unit not operating, no power failure alarm Alarm battery dead Replace battery and test as above 4. Temperature light or low oxygen alarm is on Unit overheated or obstructed Remove any obstruction caused by drapes, bedspread, wall, etc . Clean filters. Turn unit off, using standby oxygen system. Restart unit after 30 minutes. Call biomedical person if problem not solved 5. Electrical shocks Wiring fault Refer to electrician

14. PARTS OF OXYGEN CONCENTRATOR SIEVE BED BACTRIA FILTER INTAK FILTER CABINATE FILTER HOUR METER INTAK FILTER ZEOLITE MOTOR WITH COMPRESSOR COMPRESSOR IN OPEN CONDITION FLOW METER HUMIDIFERE BOTTLE

15. NB:-SPARE TO STORE FOR MAINTENANCE PURPOSE 1-CABINATE FILTER/PARTCLE FILTER 2-INTAK FILTER 3-BACTRIA FILTER 4-HUMIDIFIRE BOTTLE 5-POWER CORD 3MTR 6-GLASS FUSE(2AMP,3AMP,4AMP) 7-CIRCUIT BREAKER 8-ONOFF SWITCH 9-CAPACITOR

16. Oxygen Cylinders An oxygen cylinder is a cylindrically shaped metal container used to store oxygen that has been compressed to a very high pressure. Oxygen cylinders, which come in different sizes, are usually black coloured with a white top; in some cases, it may be a small cylinder that is entirely black. The black colour helps to differentiate it from other substances that are stored in similar containers. Cylinders are fitted with customized Valve with valve guards, which are opened with valve keys.

17. Oxygen Cylinders FLOW METER OXYGEN METER HUMIDIFERE BOTTLE FLOW METER OXYGEN CYLINDER OXYGEN REGULATOR NOZZEL FOR OXYGEN CYLINDER

18. Oxygen Cylinders A flowmeter is an instrument used to measure the flow rate of a liquid or a gas. In healthcare facilities, gas flowmeter are used to deliver oxygen at a controlled rate either directly to patients or through medical devices. Oxygen flowmeter are used on oxygen tanks and oxygen concentrators to measure the amount of oxygen reaching the patient or user. Sometimes bottles are fitted to humidify the oxygen by bubbling it through water. 1 L of liquid Oxygen = 860 L of gaseous Oxygen

19. User Maintenance of Oxygen Cylinders and Flow meters DAILY Cleaning Ensure delivery tubes and masks are sterile If humidifier bottle is used, refill with clean water Visual checks Check cylinder is correct type and marked oxygen Check all parts are fitted tightly and correctly Function checks Close cylinder valve after each use. Before use, ensure cylinder is filled and flow is present WEEKLY Cleaning Clean cylinder, valve and flowmeter with damp cloth. Visual checks Check for leakage: hissing sound or reduction in Function checks Remove valve dust with brief, fast oxygen flow Check flow can be varied using flow control

20. Troubleshooting – Oxygen Cylinders and Flowmeter Fault Possible Cause Solution 1. No oxygen is flowing Empty cylinder Flow meter knob or cylinder valve is closed. Faulty regulator Replace cylinder Open valves, then check flow meter registers flow Close all valves and replace regulator. 2. Leakage from flow meter or cylinder Cylinder is not connected to pressure regulator properly Faulty or missing washer between regulator and cylinder Flow meter seal damaged or loose Cylinder faulty Tighten all fittings Replace washer Tighten flow meter Label ‘Faulty’ and return to manufacturer

21. 3. Leakage cannot be located Leakage too small to be heard Apply detergent solution (NOT oily soap) to joints. Bubbles will show at leak point. Clean/replace washer and tighten at that joint. 4. Flow meter ball not moving, yet oxygen is flowing Faulty flow meter Close all valves, disconnect flow meter and clean inside. Reconnect and test. If problem persists, replace flow meter 5. Pressure gauge does not show pressure, yet oxygen is flowing Faulty pressure gauge Refer to biomedical person for replacement

22. SPARE TO STORE FOR MAINTENANCE PURPOSE 1-HUMIDIFIRE BOTTLE 2-WASHER 3-OXYGEN METER 4-FLOW METER

23. THANK YOU

24. What is the maximum concentration of oxygen that can be achieved with the concentrator? Up to 94%

25. What kind of maintenance is required for the oxygen concentrator? The device is as simple to manage as it looks. All that is required is that the coarse filter has to be washed each day and replace the other filters as per instructions of the company, which is usually at 6 months or 1500 hours of use. The filters may also need to be changed according to local conditions (dust, humidity) and the amount of use of the concentrator. Skilled mechanical maintenance is needed only yearly. There is a fourth filter, the bacterial filter, located before the oxygen outlet of the concentrator. Typically this must be changed every year, or more frequently, depending on the amount of use of the concentrator. The concentrator may work 24 hours a day, every day, as long as daily maintenance procedures are carried out. Every concentrator has an hour meter. The working hours should be written down in the service report.

26. How many babies can be treated at a time with the oxygen concentrator? Up to 4 babies using a splitter

27. Are there any limitations of the oxygen concentrator? In general oxygen concentrators have few problems during use but it is important to be aware of a few limitations.  When air is hot and humid, as may be the case in many tropical countries during summer season, the concentration of oxygen may be reduced to 70% because in these circumstances moisture is absorbed by the molecular sieve material in preference to nitrogen.  Low voltage may pose a similar problem by overheating the machine due to inefficient running of the motor. A voltage regulator should be used in these circumstances.  At high altitudes (4000 meters), the oxygen concentration may be reduced to 80% due to low oxygen concentration in the air itself, but this should not cause serious difficulties in most cases.  Small concentrators are not intended or suitable for compressed gas anaesthesia (Boyle's) machines or ventilators.

28. What are the Precautions during usage of the oxygen concentrator? The precautions to be observed are:  The concentrator should be placed as far away from the window as possible to avoid dust and moisture.  The concentrator should not be used to deliver oxygen through head box or face mask but use cannula .  It should be kept far away from open flames.  Oxygen cylinders are recommended as a backup oxygen supply system in case of power failure as the oxygen reservoir in the machine lasts for only 2-3 minutes.  When a flow-splitter is being used, the total flow should not exceed more than 4 liters per minute or the concentration of oxygen will decrease. This happens because the canisters have a defined volume and can only separate a known volume of nitrogen at a given time. Therefore, concentrators must not be used at flows higher than those stated by the manufacturer.

29. Has the concentrator been tested as to what is the exact concentration of oxygen being delivered to the patient and how long this concentration is constant? Does the concentration of oxygen decrease over time? The oxygen concentration measured both by an oxygen analyser and by Scholander gas analysis was 92% when the flow was 2 L./min and fell to 81% at 3 L./min. After the build-up from 21% to 80-90%, which occurred over 20 minutes, the concentration of oxygen remained virtually constant for periods up to 16 hours, which was the longest time tested. From day to day the oxygen concentration at 2 LPM did not vary by more than 2%. The composition of the gas mixture delivered by the oxygen concentrator was first measured by the usual chemical methods ( Scholander micro-analyser) and no carbon dioxide was detected. Further analysis by gas chromatography and mass spectrometry showed that apart from oxygen the mixture contained nitrogen and argon; traces of carbon dioxide and water vapour but no undesirable component such as carbon monoxide or oxides of sulphur or nitrogen were detected.

30. What are the other methods of providing oxygen therapy? The other methods of providing long term domiciliary oxygen are cylinders delivered to the patient's home (the most widely used method) and liquid oxygen in a domestic tank replenished twice weekly in some countries. The capacity of the oxygen cylinder can range from 40- 3445 liters capacity and cost between Rs. 2,625- 12,215. The cylinder can provide oxygen at 1 LPM for 11.3 hrs (e.g.680 litres capacity cylinder) or 4 LPM for 2.8 hrs. Thus the overall running costs turn out to be much higher than the oxygen concentrator. The use of a liquid oxygen system has been investigated in the United States. The apparatus consists of a portable "walker" and a reservoir which contains a supply for three to four days. Regular deliveries are required as for cylinders and this contributes appreciably to the cost.

31. Does the oxygen concentrator require an oxygen sensing device? Oxygen concentrator technology has improved rapidly and many concentrator companies are including oxygen sensing devices within the concentrator. The World Health Organization/UNICEF recommend that concentrators with sensing devices be purchased in countries where there is no other means of checking oxygen concentration. It is also prudent to have an oxygen analyzer for periodic checks (once every 3-6 months) of the oxygen concentration to be sure the sensing device is working properly.

32. What is the life of the Zeolite sieve filters? The life of the zeolite crystals can be expected to be at least 20,000 hours which in most situations would give about 10 years use.