The United Network for Organ Sharing and the Organ Procurement and Transplant Network (OPTN) regulate Organ Procurement Organizations (OPO) with regard to procurement and distribution ethics and standards. OPOs are non-profit organizations charged with the evaluation, procurement and allocation of organs within their Designated Service Area (DSA). Once a donor has been evaluated and consent obtained, provisional allocation of organs commences. UNOS developed a computer program that automatically generates donor specific match lists for suitable recipients based on the criteria that the patient was listed with. OPO coordinators enter donor information into the program and run the respective lists. Organ offers to potential recipients are made to transplant centers to make them aware of a potential organ. The surgeon will evaluate the donor information and make a provisional determination of medical suitability to their recipient. Distribution varies slightly between different organs but is essentially very similar. When lists are generated many factors are taken into consideration; these factors include: distance of transplant center from the donor hospital, blood type, medical urgency, wait time, donor size and tissue typing. For heart recipients medical urgency is denoted by a recipients "Status" (Status 1A, 1B and status 2). Lungs are allocated based on a recipients Lung Allocation Score (LAS) that is determined based on the urgency of clinical need as well as the likelihood of benefit from the transplant. Livers are allocated using both a status system and MELD/PELD score (Model for End-stage Liver Disease/Pediatric End-stage Liver Disease).
Acute volvulus often requires immediate surgical intervention to untwist the affected segment of bowel and possibly resect any unsalvageable portion.Volvulus occurs most frequently in middle-aged and elderly men. Volvulus can also arise as a rare complication in persons with redundant colon, a normal anatomic variation resulting in extra colonic loops.Sigmoid volvulus is the most-common form of volvulus of the gastrointestinal tract. and is responsible for 8% of all intestinal obstructions. Sigmoid volvulus is particularly common in elderly persons and constipated patients. Patients experience abdominal pain, distension, and absolute constipation. Cecal volvulus is slightly less common than sigmoid volvulus and is associated with symptoms of abdominal pain and small bowel obstruction. Volvulus can also occur in patients with Duchenne muscular dystrophy due to smooth muscle dysfunction.Gastric volvulus causes nausea, vomiting, and pain in the upper abdomen. The Borchardt triad is a group of symptoms that help doctors to identify gastric volvulus. The symptoms are intractable retching, pain in the upper abdomen and inability to pass nasogastric tube into the stomach. Complications
Strangulation
Gangrene
Perforation
Faecal peritonitis
Recurrent volvulus

Causes
Midgut volvulus occurs in people (usually babies) that are predisposed because of congenital intestinal malrotation. Segmental volvulus occurs in people of any age, usually with a predisposition because of abnormal intestinal contents (e.g. meconium ileus) or adhesions. Volvulus of the cecum, transverse colon, or sigmoid colon occurs, usually in adults, with only minor predisposing factors such as redundant (excess, inadequately supported) intestinal tissue and constipation.