Comparison of Fluid Flow Rates by Fluid Height and Catheter Size in Normal and Hypertensive Blood-Pressure Scenarios

Abstract

Objectives: This study is performed to determine the effects of fluid height, inner catheter diameter, and peripheral venous pressure on room-temperature intravenous fluid administration.

Methods: We employed the Bernoulli equation, with frictional forces considered for volumetric analysis.

Results: The results of this study demonstrate that infusion-set height, catheter size, fluid type, and blood pressure significantly affect flow rates. Under normotensive conditions, flow rates ranged from 58.2 to 10,743.18 cc/h, with the highest rates observed at a 1 m infusion-set height and larger catheters. Additionally, 6% hetastarch exhibited the lowest flow rates, while 0.9% normal saline showed the highest. Under hypertensive conditions, slightly higher infusion-set elevations were required for measurable flow rates, but they remained lower than those under normotensive conditions.

Conclusion: This study investigates the mechanics of peripheral venous fluid therapy and provides foundational data for future nursing research on fluid management.

Keywords: flow rate; fluid dynamics; fluid therapy; infusion system; peripheral intravenous catheter.

Figure 1

System Structure. h: Height of the infusion set is 0–100 cm; Point 1: Midpoint of the drip chamber of the infusion set; Point 2: Connection point between the infusion set and the peripheral venous catheter; Point 3: Tip of the peripheral venous catheter.

Figure 2

Analysis of flow rate based on infusion set height by peripheral venous catheter size in blood-pressure type.