I use a medical grade Nonin oximeter to determine what I need and when. 3 liters to get up and walk a short distance (like under 20 feet) 4 liters if I’m walking farther, and 5 liters for heavy exertion or when i’m walking on the treadmill. I use one liter per minute while awake at rest, 2 lpm when sleeping or when I’m moving my arms a lot while at rest. I drop to the low 70’s within 2 minutes of walking on room air. Thomas Petty (The father of Long Term Oxygen Thrapy) used to say. As an example, assume 0.5 liters/minuteĬalculate the duration of flow using the formula: Duration is the available liters divided by the flow rate.I change my oxygen flow many times throughout the day. The flow rate is prescribed by the physician and is expressed in liters per minute. Continuing with the example:Īvailable liters = 1,800 x 0.16 = 288 litersĭetermine the flow rate.

Oxygen tanks’ conversion factors vary with size according to the following schedule:Īs an example, assume a D size, which has a conversion factor of 0.16Ĭalculate the available liters of oxygen by multiplying the available cylinder pressure by the conversion factor. Using the example numbers:Īvailable cylinder pressure = 2000 psi – 200 psi = 1,800 psiįind the conversion factor to convert available cylinder pressure into available liters of oxygen. Because of the importance, the American Academy of Orthopedic Surgeons established a minimum safe residual level of 200 psi.Ĭalculate the available cylinder pressure by subtracting the safe residual level from the current cylinder pressure. Refer to the owner’s manual or contact your physician or therapist. This is a safety factor built in to ensure patients do not run completely out of oxygen. As an example, assume it’s 2000 pounds per square inch or “psi.”įind the safe residual level associated with the oxygen tank. Refer to the pressure gauge located on the cylinder of the oxygen tank. Many factors apply when calculating duration, including variables such as safe residual levels and the conversion factors required to convert tank cylinder pressure into liters of oxygen.ĭetermine the current cylinder pressure of the oxygen tank. For this reason, individuals must perform tank duration calculations to estimate the amount of time they can rely on one tank. Each tank carries a finite amount of oxygen. Oxygen tanks support individuals with respiratory disorders or individuals who need continuous oxygen as a result of a temporary illness or accident.

O2 etank at 3 lpm how long will it last