The impact of arterial catheter-to-vessel ratio on distal arterial flow and measured arterial pressures in a pulsatile arterial vessel phantom

Background: The effect of catheter size on distal arterial flow and measured arterial pressure remains underexplored. This study evaluates the relationship between catheter-to-vessel ratio (CVR), distal arterial flow, and measured blood pressures in a controlled pulsatile arterial vessel phantom. Methods: Using in vitro data simulating arterial conditions, distal peak systolic velocity, systolic (SBP), and diastolic (DBP) were analyzed across varying catheter sizes and vessel diameters. Pearson correlation and linear regression were used to assess the relationship between CVR and changes in relative distal velocity, SBP, and DBP. Results: Relative distal peak systolic velocity exhibited a strong inverse relationship with CVR ( r = −0.903, p < 0.001), with linear regression indicating that for every 10% increase in CVR, distal peak systolic velocity decreased by approximately 9.3%. Flow reduced >20% when CVR exceeded 0.6 and <5% when CVR was below 0.4. SBP demonstrated a strong positive correlation with CVR ( r = 0.88, p < 0.001). SBP increased by approximately 2.8% for every 10% increase in CVR. SBP increased by >10 mmHg when CVR exceeded 0.6 and <5 mmHg when CVR was below 0.4 Relative DBP showed no significant correlation with CVR ( r = 0.13, p = .61). Conclusions: Higher CVR in an in vitro model is associated with reduced distal flow and elevated systolic blood pressure in a phantom model. A CVR <0.4 (40%) appears to minimize flow and pressure changes. Appropriate selection of arterial catheter diameter for patient care may reduce risk of arterial catheter injuries and improve accuracy of clinical data.