Strong ion difference and CVVH: Different response during nadroparin versus citrate anticoagulation

Area of Science:

• Nephrology
• Intensive Care Medicine
• Biochemistry

Background:

• Continuous veno-venous hemofiltration (CVVH) is a critical renal replacement therapy for ICU patients.
• Anticoagulation is essential for CVVH circuit patency.
• The choice of anticoagulant can influence acid-base balance and strong ion difference (SID).

Purpose of the Study:

• To investigate the impact of citrate versus nadroparin anticoagulation on the strong ion difference (SID) during CVVH.
• To assess changes in SID apparent (SIDa), SID effective (SIDe), and strong ion gap (SIG) with different anticoagulants.

Main Methods:

• A comparative study involving ICU patients with renal failure undergoing CVVH.
• Patients received either nadroparin (N) or sodium citrate (C) for anticoagulation.
• Calculation of SIDa, SIDe, and SIG at baseline (t=0) and after 24 hours (t=24h).
• Measurement of citrate concentration in patients receiving citrate anticoagulation.

Main Results:

• No significant change in SIDa was observed in either group.
• SIG significantly decreased with nadroparin but not with citrate.
• The reduction in SIG was significantly greater with nadroparin compared to citrate.
• SIDe increased significantly more with nadroparin than with citrate.

Conclusions:

• Citrate anticoagulation leads to a persistently elevated SIG during CVVH compared to nadroparin.
• This sustained high SIG is attributed to the presence of unmeasured anions, such as citrate, in the systemic circulation.
• The findings highlight the distinct effects of citrate and nadroparin on acid-base balance during CVVH.