Comparison of effectiveness of the piston-pump method versus the pressure-infusor method for rapid infusion of...

The piston-pump method is a simple method for rapid administration of fluids but some problems are unsolved. We compared the effectiveness of using the piston-pump method with that of the pressure-infusor method.

Twelve anaesthetists were classified randomly into the piston-pump and pressure-infusor groups. They were asked to infuse 500 ml of saline three times successively through a 16-G intravenous cannula as rapidly as possible using a pump with a 50-ml syringe or a pressure-infusor at 300 mmHg. The time taken for infusion and the maximum or minimum pressure in the infusion circuit and substitute vessel were measured. Bacterial culture of the saline infused sterilely was performed to estimate bacterial contamination.

The pressure-infusor group led to faster infusion of 500 ml of saline (233 ± 19 s) than the piston-pump group (301 ± 48 s) (P < 0.01). The infusion time at the third attempt (316 ± 43 s) was significantly longer than that at the first attempt (285 ± 53 s) only in the piston-pump group (P < 0.05). The maximum pressure (mmHg) in the circuit was 131 ± 9 and > 200 (P < 0.01) and in the substitute vessel was 5 ± 1 and 17 ± 7 (P < 0.01) in the pressure-infusor and piston-pump groups, respectively. A pressure of <-200 mmHg occurred at all infusion attempts in the piston-pump group. Bacterial contamination was not observed in either group.

If fluids must be administered rapidly, the pressure-infusor method is more efficient than the piston-pump method because the latter is less effective in infusing fluids rapidly and associated with excessive positive and negative pressure in the infusion circuit.