Dip. Software based statistics PhD ( physiology), FICA , IDRA Anesthesia cylinders Dr. S. Parthasarathy MD., DA., DNB, Dip. Diab. DCA, Dip. Software based statistics PhD ( physiology), FICA , IDRA

Definition !! Gas cylinder is a term that is commonly used to describe a pressurized container used for storage and transport. Use ??

Modern cylinders are manufactured using lightweight strong chrome-molybdenum steels which, as well as conforming to stringent material standards, can be filled to pressures of up to 300 bar g. It is made of an alloy !! What s that ??

Iron approx – 97- 98 %

aluminium liner which is then strengthened by wrapping a filament material, such as Kevlar or carbon-fibre, coated in epoxy resin circumferentially along the parallel length of the cylinder. Special cylinders made from aluminum are useful in magnetic resonance imaging (MRI) room

Parts Body Shoulder Neck Neck is tightened with a valve Woods metal is the paste used which melts with to allow gas to leak No explosion Disc rupture is also there

Valve – brass or bronze

Routine anesthesia machine These are fitted to large cylinders of medical oxygen, medical air, Entonox used in pipeline manifolds

Bull nose F and G type = bigger ones Pressure relief device

Bull nose O ring Fit proper Change the O if leaks

Hand wheel Large nitrous oxide cylinders for use on cylinder manifolds and carbon dioxide cylinders of size F and G are fitted with handwheel valves which are surrounded by a protective Guard and have a gas specific, male thread, side outlet.

Integral valves manufactured in a clean environment eliminates the risk of incorrect regulator attachment Two outlets Easier to use Pressure gauges

Neck label It is marked with the gas chemical symbol, tare weight, pressure at the last hydraulic test serial number Tag is different

Pin index safety system There are seven hole positions on the circumference of a circle of 9/16 inch radius centered in the port. Pins project from yolk side and holes in the cylinder The pins are 4 mm in diameter and 6 mm long. Assigned number for gases

Bodok seal

PIN index is there But manual opening of newer valves

Return check valve and yolk plug Oxygen to nitrous No flow One cylinder is attached – no leak Use yoke plug Get it to the spring to avoid getting lost

Oxygen and air are compressed gases while nitrous is liquified Gauge – oxygen – OK but While using a cylinder of N2O with a continuous flow of 6 litres/minute, the cylinder pressure tends to fall mainly due to cooling of the liquid as it vaporizes and the consequent fall in vapour pressure. If the flow is interrupted for a brief period, the gauge will again read full.

Colour coding Due to variation in color tones, chemical changes in paint pigments, color should not be used as a primary means for identification of cylinders

Pictures taken from internet for closed academic purpose only Sizes !!! Pictures taken from internet for closed academic purpose only

Sizes according to us !! it’s A B C D !! A corresponds to E Oxygen 2000 psi and 660 litres approx B type 1350 litres Bulk or D type - 7000 litres Oxygen does not come in C CO2 cylinders for pneumoperitoneum are C type Nitrous – A type -750 psi and 1500 litres approx

How much oxygen is there ?? Approximate remaining in hours = O2 cylinder pressure in psi/200 × O2 flow rate per minute.

Complete filling ?? These cylinders (liquid) are not filled completely, but only up to a filling ratio Weight of gas in a cylinder/weight of water that cylinder can hold at 60° F The filling ratio of nitrous oxide is 0.75, but 0.67 in the tropics But – liquids – tare weight and difference 90 % is nitrous in cylinder – that’s is different volume Vs weight

100 kPa=1000mbar=760mm of Hg=1030cm of H2O=14.7psi=1atmosphere

Storage Not stored along with non medical cylinders be under covered and not subjected to extremes of heat kept dry, clean and well ventilated good access for deliveries and a reasonably level floor allow segregation of ‘full’ and ‘empty’ cylinders permit separation of different gases and cylinder sizes allow for strict stock rotation to enable cylinders with the oldest fill date to be used first

Storage No sources of heat or ignition nearby Prohibiting smoking or naked lights in the vicinity large cylinders - stored vertically in concrete pens small cylinders - horizontally in wooden or plastic racks to prevent damage to the cylinders not allow the temperature to fall below 10°C where full Entonox cylinders are stored No unauthorized entry

Safe use ?? CRACKING—reduces possibility of flash fire A sealing washer in good condition Open valve before bringing the apparatus to the patient. Close Flow control valve before the cylinder valve is opened While opening, stand to the side; not in front or back Quick opening can generate heat  flame

Rules for safe use open the cylinder, check the pressure Hissing sound= leak tightenstill leak replace washer. Where is the leak ? soap water. If leak in valve itself, tighten the packing nut by turning it in a clockwise direction Even if no hissing sound, check for loss of pressure when no gas is being used Valve should be fully open when in use- minimum three rounds !!

Safe use An empty should not be left on anaesthesia machine close the valve before removing from a regulator or yoke tag - removed when cylinder is empty Caps to be replaced before sending for refill

Valve breaks – so dangerous OK Ok Ok but ?? Valve breaks – so dangerous

Remove the seal Seal may go in the speed and block gases later Danger

So many

Testing the cylinder by the factory !! Must be tested at least every 5 years. Hydraulic test Tensile test Flattening test Impact test Bend test External and endoscopic examination

Flattening test The cylinder is kept between two compression blocks and pressure is applied from both sides until the distance between blocks remains 6 times the thickness of the wall of cylinder. The walls should not crack. Pressure test: the cylinder is subjected to high pressures of about 22 000 kPa, which is more than 50% above their normal working pressure.

Dangers Cylinder Transfilling Transfilling contents from one cylinder to another should not be performed by the user Incorrect Cylinder Valves Contents Color No odor for gases

Hazards – continue Asphyxia Projectile damage Fires Cold thermal injury The gases and vapours should be free of water vapour when stored in cylinders. Water vapour freezes and blocks the exit port when the temperature of the cylinder decreases on opening

What is the carry home message ?? Summary Cylinders – made of what ? Parts Valves Pin index Colour coding Sizes Safe use Testing Hazards What is the carry home message ??