Observation for signs of increased ICP, which indicate obstruction of the shunt, is continued. Neurologic assessment includes pupil dilation (pressure causes compression or stretching of the oculomotor nerve, producing dilation on the same side as the pressure) and blood pressure (hypoxia to the brainstem causes variability in these vital signs). The child is also observed for abdominal distention because CSF may cause peritonitis or a postoperative ileus as a complication of distal catheter placement.