Subcutaneous emphysema can be a complication of CO insufflation with laparoscopic surgery. Tubal insufflation is a standard procedure for testing patency. Oxygen can then be administered through this catheter via jet insufflation. Reported modalities of intake include oral consumption, insufflation, smoking, rectal and intravenous use. Positive airway pressure is a mode of mechanical or artificial ventilation based on insufflation. Nasal insufflation is the most common method of nasal administration. Routes of intake included oral, intravenous, and insufflation entry. The most common route of administration is via nasal insufflation (snorting). These are followed by suppository (anal or vaginal insertion), insufflation (snorting), and ingestion (swallowing). Rarely, an incompetent valve allows insufflation of air into the duct system. This minimizes insufflation of air into the patient's stomach, which might otherwise provoke regurgitation. In recent years a popular method of snuff insufflation has been the snuff bullet. The technique is also important in possibly preventing insufflation of gas into the stomach. Typically used for insufflation during surgery, and also used in laser surgeries. Excessive insufflation of the stomach is avoided at this stage.