Figure 3
From: Hydrodynamics of the Certas™ programmable valve for the treatment of hydrocephalus
Measured value of shunt opening pressure for the 8 settings (solid black squares) and the manufacturer’s specifications for each shunt setting (open black circles) plotted against the manufacturer’s specification for opening pressure. Error bars show the 95% confidence level based on the six shunts. Tolerance limits for each shunt setting per manufacturer’s specifications are shown as solid lines for comparison. For the highest setting, only the lower limit of opening pressure > 400 mm H2O is specified by the manufacturer; thus, no upper tolerance limit is shown.