Pediatric emergency medicine trisk 4653 4653

after each application The shunt tap is performed by inserting a 23- or 25-gauge butterfly obliquely into the reservoir and holding the butterfly tubing perpendicular to the floor The height of the CSF rise into the butterfly tubing, measured in centimeters, is the ICP Normal pressure is between and 10 cm H2 O; pressure of more than 20 cm H2 O is indicative of distal shunt malfunction requiring urgent revision Slow or absent flow from the proximal reservoir (especially with occlusion of the distal reservoir of a double-reservoir shunt) is highly predictive of proximal shunt obstruction In this case, the physician may notice that the reservoir collapses when gentle suction is applied to the butterfly with a syringe It is important to avoid further suctioning of this reservoir because this could lead to aspiration of debris into the proximal catheter, causing a blockage where one did not previously exist Poor flow during the shunt tap can also indicate noncommunicating hydrocephalus, which may be diagnosed by imaging studies and lumbar puncture The shunt tap can be therapeutic and diagnostic The child with a distal shunt obstruction or partial proximal obstruction may be eligible for urgent, rather than emergent, shunt revision if symptoms of increased ICP are alleviated after the tap However, removal of too much fluid should be avoided because abrupt fluid shifts within the cranial vault can lead to disruption of subdural vessels It is prudent to remove just enough fluid to decrease the ICP below 20 cm H2 O and repeat the procedure if symptoms return before definitive surgical management