Resistance to fluid flow through two spinal needles.
A new needle, 120 mm long and 26 gauge in diameter, has been introduced for subarachnoid anaesthesia. The resistance to flow through the needle was measured using a pressure monitor infusion pump and compared with the resistance to flow through a 90-mm 26-gauge needle; there was a threefold increase in resistance in the 120-mm needle compared to the 90-mm needle, which could not be explained by the difference in length alone and must reflect a decrease in the internal diameter of the long needle. This results in difficulty in identifying the subarachnoid space by backflow of cerebrospinal fluid.
Toomey
P J
PJ
Department of Anaesthesia, Leeds General Infirmary.
D000775:Anesthesia, Spinal / Q000295:instrumentation*; D009339:Needles; D011312:Pressure; D012212:Rheology