E.g. An intubated patient is transported to ICU using an ambubag ventilating at a rate of 10liter/min from an E type cylinder showing pressure of 800 PSI. How long (in mints)will you have before your E cylinder of oxygen runs empty?Hint; the initial filling pressure is 1900 PSI and volume of the cylinder when it is full is 660 liters.

Here's how to calculate the remaining time for the E cylinder:<br /><br />1. **Determine the remaining oxygen:** E cylinders are considered empty when the pressure drops to 200 PSI. So, the usable pressure in this cylinder is 800 PSI - 200 PSI = 600 PSI.<br /><br />2. **Calculate the fraction of oxygen remaining:** The initial filling pressure is 1900 PSI. The fraction of usable oxygen remaining is 600 PSI / 1700 PSI (1900 PSI - 200 PSI) = 6/17.<br /><br />3. **Calculate the remaining liters of oxygen:** The full cylinder contains 660 liters. Therefore, the remaining liters are (6/17) * 660 liters ≈ 232.9 liters.<br /><br />4. **Calculate the time until the cylinder is empty:** The ambu bag uses oxygen at a rate of 10 liters/min. So, the remaining time is 232.9 liters / 10 liters/min ≈ 23.3 minutes.<br /><br />Therefore, the E cylinder will last approximately $\boxed{23}$ minutes.<br />