Ventriculoperitoneal (VP) Shunt

A ventriculoperitoneal (VP) shunt treats hydrocephalus, a build-up of cerebrospinal fluid (CSF) that enlarges the ventricles inside the brain and raises the pressure in the skull. The cause may be congenital, or the result of a tumor, bleeding, infection such as meningitis, or narrowing of the aqueduct between the third and fourth ventricles. Infants with hydrocephalus have a growing head and swollen scalp veins. The shunt moves the extra fluid to the peritoneal cavity, where the body absorbs it. The peritoneum is the usual drain site because it avoids the heart and blood-vessel complications of a shunt into the right atrium, is quicker to place and is easier to revise; the pleural cavity or right atrium is used only when the abdomen cannot be. The system has a ventricular (proximal) catheter, often a reservoir, a one-way valve and a peritoneal (distal) catheter; unitized shunts come with the distal catheter already attached, so there are fewer connections to come apart. Most valves open when the pressure difference across them reaches a set level. Programmable valves, such as the Codman Hakim and the Medtronic Strata, can have their opening pressure changed through the skin with a magnet after surgery, so a new pressure does not mean a new operation. The reservoir lets the team tap the shunt with a needle to check pressure, take CSF or give medicine. What sets this case apart is the long, two-region field (head and abdomen prepped and draped together) and an implant that must be kept free of lint, air and blood. Complications include infection (usually skin bacteria), blockage, disconnection or breakage of the tubing, too much drainage, bleeding in or around the brain, and injury to abdominal organs or fluid collections in the abdomen. Shunts often need revision, especially in babies and young children. The scrub person's main jobs are keeping the implant clean and primed and having each part ready the moment it is needed.