46 yr old chronic smoker came to emergency dept with a history of difficulty in breathing & fever since 1day, postgraduate tells you to connect face mask to which pin index number

- Machines are usually equipped with one or two E type cylinders that hang on specific hanger yokes. - The medical gas pin-index safety system ensures that the correct medical gas cylinder is hung in the correct yoke. Gas Index Pins Oxygen 2,5 Nitrous oxide 3,5 Cyclopropane 3,6 O2-CO2 (CO2<7.5%) 2,6 O2-CO2(CO2>7.5%) 1,6 O2-he(He>80.5%) 4,6 O2-he(He<80.5%) 2,4 Air 1,5 Nitrogen 1,4 N2O-O 7