Edema has many possible causes: 1  Prolonged standing or sitting, especially in hot weather, can cause excess fluid to accumulate in the feet, ankles and lower legs. 2  Tiny valves inside the veins of the legs can become weakened, causing a common problem called venous insufficiency.
Cars with nitrous-equipped engines can be identified by the purge of the delivery system that most drivers perform prior to reaching the starting line. A separate electrically operated valve is used to release air and gaseous nitrous oxide trapped in the delivery system.
Nitrous oxide is a safe and effective sedative agent that is mixed with oxygen and inhaled through a small mask that fits over your nose to help you relax. Nitrous oxide, sometimes called âlaughing gas,â is one option your dentist may offer to help make you more comfortable during certain procedures. It is not intended to put you to sleep. You will be able to hear and respond to any requests or directions the dentist may have. Your dentist will ask you to breathe normally through your nose, and within a few short minutes you should start to feel the effects of the nitrous oxide.