a pulmonary embolism. Air emboli can be avoided by making sure that there is no air in the system. A thromboembolism can be avoided by using a smaller cannula. phlebitis: an inflammation of the vein resulting from mechanical or chemical irritation or from an infection. Phlebitis can be avoided by carefully choosing the site for cannulation and by checking the type of infusate used. Nasal cannulation and oral-nasal cannulation A nasal cannula or an oral–nasal cannula consists of a flexible tube, usually with multiple short, open-ended branches for comfortable insertion into the nostrils and/or mouth, and may be used for the delivery of a gas (such as pure oxygen), a gas mixture (as, for example, during anesthesia), or to measure airflow into and out of the nose and/or mouth. Tracheotomy tube The removal of a tracheotomy tube is referred to as decannulation. Veterinary use A cannula is used in an emergency procedure to relieve pressure and bloating in cattle and sheep with ruminal tympany, due most commonly to their accidentally grazing wilted legume or legume-dominant pastures, particularly alfalfa, ladino, and red and white clover. Cannulas are a component used in the insertion of the Verichip. Much larger cannulas are used to research about the digestive system of cannulated cows. Aesthetic medicine and anti-ageing In aesthetic medicine, a blunt-tip cannula or microcannula (also called smooth tip microcannula, blunt tipped cannula, or simply microcannula) is a small tube with an edge that is not sharp and an extrusion port or pore near the tip which is designed for atraumatic subdermal injections of fluids or gels. Depending on the size of the internal diameter, it can be used either for the injection of cosmetic wrinkle fillers like hyaluronic acid, collagen, poly-L-lactic acid, CaHA, etc., or for fat transfer (Liposuction). The American Society for Aesthetic Plastic surgery notes additional soft tissue fillers like calcium hydroxy-apatite and polymethylmethacrylate. The advantage of using these is that they are less painful, have less risk of bruising, have less swelling, and a better safety profile. Accidental intravascular injections are more difficult with blunt-tip microcannulas, reducing the risk of skin necrosis, ulcers, and embolization to the retinal artery which can result in blindness. Indeed, in May 2015, the USA issued a warning of these risks as an FDA Safety Communication on the "Unintentional Injection of Soft Tissue Filler Into Blood Vessels In the Face". In January 2012, the "Dermasculpt"