Imagine a scenario where a patient's kidney function is failing, and continuous kidney replacement therapy (CKRT) is initiated to save their life. But what if the very treatment designed to help is compromised by an underrecognized issue? This is the case with vascular access recirculation (AR) during CKRT, a condition that can lead to inadequate solute clearance and potentially worsen patient outcomes. But here's where it gets controversial: AR often goes unnoticed, lacking obvious warning signs like circuit pressure alarms or hemodynamic instability. This delay in diagnosis can be critical, especially in patients with complex medical histories, such as a 75-year-old woman with diabetes, hypertension, and cervical cancer, who underwent total pelvic exenteration and ileal conduit creation. Her postoperative course was complicated by acute kidney injury, requiring CKRT with regional citrate anticoagulation (RCA). Despite initial improvements, she developed persistent metabolic acidosis and worsening uremia, raising suspicions of AR. And this is the part most people miss: the unique calcium profile, with rising systemic total and ionized calcium levels, yet a stable total-to-ionized calcium ratio, became a crucial diagnostic clue. This case highlights the importance of strategic diagnostic sampling from systemic, access, and circuit ports to identify AR, even when standard monitoring parameters appear normal. The question remains: Are we doing enough to recognize and address this silent complication in CKRT?
