Comparison of unplanned treatment interruption during CRRT in ICU patients under CVVH (pre + post dilution) or CVVHDF (post-dilution) mode: A retrospective cohort study

Abstract

Background: Continuous renal replacement therapy (CRRT) often becomes prematurely interrupted before the planned dose is reached for various reasons. This not only hampers therapeutic efficacy but also escalates blood loss for patients, thereby increasing the nursing workload and patient costs.

Aim: To assess the incidence and filter lifespan of unplanned interruptions in ICU patients undergoing CRRT, continuous veno-venous hemofiltration (CVVH) (pre + post dilution) mode was compared with continuous veno-venous haemodiafiltration (CVVHDF) (post dilution) mode.

Study design: We conducted a retrospective study involving 256 patients: 75 in the CVVH group and 181 in the CVVHDF group. Outcomes such as filter lifespan, unplanned treatment interruptions and catheter complications were compared across the three anticoagulation methods.

Results: A greater proportion of unplanned interruptions was observed in the CVVHDF group. Specifically, filter coagulation led to more frequent interruptions in CVVHDF (p < .05). With citrate anticoagulation, the filters in the CVVH group lasted significantly longer (p = .025). However, under low-molecular-weight heparin or no anticoagulation, filter survival rates were statistically similar between the groups (p > .05). Anticoagulation method (95% CI 1.163-44.95, p = .034), venous pressure (95% CI 0.001-0.004, p = .027) and total serum calcium (95% CI -0.936 to -0.042, p = .033) affect the incidence rate of unplanned treatment interruptions in CVVH (pre- and post-dilution) (p < .05). Venous pressure (95% CI 0.001-0.002, p < .001) and BMI (95% CI -0.936 to -0.042, p = .033) affect the incidence rate of unplanned treatment interruptions in CVVHDF (post-dilution) (p < .05). The adjusted results indicate that PT (HR = 1.09, 95% CI 1.011-1.176, p = .025), venous pressure (HR = 1.013, 95% CI 1.004-1.022, p = .003) and blood flow rate (HR = 1.028, 95% CI 1.002-1.054, p = .034) are potential risk factors for filter lifespan in CVVH (pre- and post-dilution). Venous pressure (HR = 1.005, 95% CI 1.003-1.007, p < .001) is a potential risk factor for filter lifespan in CVVHDF (post-dilution).

Conclusion: Using the CVVH mode with citrate anticoagulation significantly prolongs CRRT filter life and reduces unplanned treatment interruptions. Further prospective, randomised controlled studies are needed to confirm these findings.

Relevance to clinical practice: Exploring the reasons for unplanned treatment interruptions in ICU patients undergoing CRRT under common modes is crucial, serving as an important measure to ensure the quality of treatment. Nurses are the main implementers throughout the entire CRRT process. Understanding the risk factors for unplanned treatment interruptions and filter lifespan can help reduce the economic burden on patients, decrease the workload of medical staff and contribute to the development of plans aimed at improving the quality of care for critically ill patients receiving CRRT.

Keywords: CVVH; CVVHDF; ICU; retrospective study; unplanned treatment interruption.