These catheters were connected to a 1 liter saline bag and flow rate was assessed either by standard gravity flow at 1 meter height versus flow rate with the saline bag pressurized to 250 mm Hg.

• 我们通过将盐水袋悬挂在1米高度形成的标准重力流来评估流量，或者将盐水袋加压到250毫米汞柱。