An evaluation of methods of increasing the flow rate of i.v. fluid administration

Abstract

I have evaluated in vitro methods of increasing the flow rate of clear fluids through an i.v. cannula at room temperature. These included, alone and in combination: increasing the height of a gravity-fed system; increasing the i.v. cannula diameter, manual compression of the lower drip chamber and the use of pressure bags. Flow rate was measured using a uroflowmeter, which was found to be reliable and reproducible. The most effective methods of increasing flow were the use of a 14-gauge cannula rather than a 16-gauge cannula, which resulted in a 50% increase, and the use of a 300-mm Hg pressure bag with automatic adjustable pressure regulator, which doubled the flow rate. The combination of these two tripled the overall flow to nearly 600 ml min-1. Manual compression of the drip chamber, despite producing peak pressures of more than 100 cm H2O, was an inefficient method of improving flow compared with an external pressure bag.

Safety of Rapid Intravenous Infusion of Acetaminophen

“…Th e infusion time using fully open secondary intravenous tubing was decreased from 15 minutes to a median time of 3 minutes and 41 seconds. Two potential confounding variables in the infusion time that were not controlled for in this study were cannula gauge and site (5,6). However, our preoperative nursing staff protocol indicates that a 20-gauge cannula and a hand site are preferred.…”

The viscous behaviour of HES 130/0.4 (Voluven®) and HES 260/0.45 (Pentaspan®)

“…33 The flow rate was also lower for Gelofusine when pressurized to 300 mmHg; however, the difference was clinically insignificant. 33 It should be pointed out that the viscosity of Gelofusine is appreciably lower than HES 260/0.45, although it is comparable with HES 130/0.4 at 37°C (Table).…”

“…33 The flow rate was also lower for Gelofusine when pressurized to 300 mmHg; however, the difference was clinically insignificant. 33 It should be pointed out that the viscosity of Gelofusine is appreciably lower than HES 260/0.45, although it is comparable with HES 130/0.4 at 37°C (Table). Given the importance of rapid fluid replacement in hypovolemic patients, reduction in flow rate can be minimized by warming the HES to 37°C and by using pressure bags and large bore cannulas.…”

“…32 Given the differences in viscosity of these fluids, variations in infusion rates can also be expected. Stoneham 33 compared the gravity-fed flow rates of 0.9% saline and Gelofusine, a colloid plasma substitute with a viscosity of 1.9 cP at 37°C, through a 14G cannula at room temperature.…”

“…Given the importance of rapid fluid replacement in hypovolemic patients, reduction in flow rate can be minimized by warming the HES to 37°C and by using pressure bags and large bore cannulas. 33 …”