Hemodynamic effects of slower versus faster intravenous fluid bolus rates in critically ill patients: An observational study

Abstract

Purpose

We compared the immediate and sustained effects of 500 mL of crystalloid administered at slow (333 mL/h) versus fast rates (999 mL/h) on mean arterial pressure (MAP) in critically ill patients.

Materials and methods

Hemodynamic variables were collected immediately before and every 30 min up to 60 min after the end of the infusion. The primary outcome was the adjusted difference in MAP.

Results

We included 146 patients (slow rate: 71, fast rate: 75). One hour after the end of the infusion, there was no difference in the overall mean marginal effect on MAP between the groups [1.9 mmHg (95 % CI: −1.5 to 5.3 mmHg), p = 0.27] or on the perfusion parameters. Similarly, no difference was found in the immediate effect after 90 min [overall marginal effect: 1.1 mmHg (95 % CI: −2.3 to 4.6 mmHg); p = 0.52]. In patients with cardiac output (CO) monitoring, there was an increase in CO in the fast rate group (overall mean marginal effect: 1.78 L/min (95 % CI: 0.08 to 3.48 L/min); p = 0.04).

Conclusion

In critically ill patients, crystalloid infusion at both fast and slow rates did not lead to immediate or sustained differences in MAP. However, fast infusion may result in a greater increase in CO.