High-Flow Contrast Injection via High-Pressure CVC in Critically Ill Patients

Overview

This study evaluated computed tomography image quality using high-flow contrast media injection through high-pressure central venous catheters (HP CVC) versus standard flow rates through standard CVC in critically ill patients. Despite significantly higher injection flow rates with HP CVC, no improvement in objective image quality metrics was observed. No adverse events related to high-flow injection were reported.

Background

Contrast-enhanced computed tomography (CECT) is essential for diagnosing critically ill patients, with contrast media typically injected via central venous catheters (CVC). Image quality depends on factors including injection flow rate, which is limited by catheter type and safety concerns. Standard CVCs allow injection rates up to 5 mL/s but are not recommended for high-pressure injections. Recently developed HP CVCs permit higher flow rates, potentially improving image quality or reducing contrast volume and associated risks. However, the impact of high-flow contrast injection via HP CVCs on CECT image quality had not been previously studied.

Data Highlights

Key Findings

• HP CVCs enabled significantly higher median contrast injection flow rates (7.7 mL/s) compared to standard CVCs (3.5 mL/s; p < 0.001).
• No significant differences were observed in aortic and liver signal-to-noise ratio (SNR) or contrast-to-noise ratio (CNR) during arterial and portal phases between groups.
• Theoretical maximum flow rate of 10 mL/s was not achieved; effective median was 7.7 mL/s, possibly due to injector calibration or contrast viscosity variations.
• No adverse events such as catheter displacement, ballooning, rupture, or contrast extravasation occurred with high-flow injections via HP CVC.
• Contrast media volume and iodine dose normalized to body weight were similar between groups.
• Acquisition timing was unchanged despite different injection flow rates, which may affect image quality optimization.

Clinical Implications

High-pressure central venous catheters allow safe administration of contrast media at higher flow rates in critically ill patients without increasing adverse events. However, higher injection flow rates did not translate into improved objective image quality in this cohort. Clinicians should consider that optimizing acquisition timing and patient-specific factors may be necessary to enhance image quality when using high-flow injections.

Conclusion

In critically ill patients, high-flow contrast injection via HP CVCs is feasible and safe but does not improve computed tomography image quality compared to standard flow rates. Further research is warranted in specific populations with altered cardiac output or particular imaging indications.

References

1. Original Article -- Enhancing Computed Tomography Image Quality with High-Flow Contrast Administration via High-Pressure Central Venous Catheter in Critically Ill Patients