Slow continuous ultrafiltration: just fluids?

Introduction

Slow continuous ultrafiltration (SCUF) is known to reduce extravascular water [1, 2]. We hypothesized that, in acute decompensated heart failure, SCUF may reduce both the cardiac preload and the respiratory workload.

Methods

Ten patients (six males, four females; age 76 ± 4 years, NYHA classes III–IV) admitted to our medical ICU for acute decompensated heart failure were treated with SCUF (Aquadex-flex flow; CHF USA). The heart rate (HR), mean arterial pressure (MAP), arterial blood gas analysis and inferior vena cava (IVC) diameter with M-mode subcostal echocardiography were evaluated before (T0) and immediately after (T1) SCUF.

Results

The mean ultrafiltration time was 25.5 ± 5 hours with a mean volume of 259 ml/hour and a total ultrafiltrate production of 6.6 ± 2 l. Differences between T0 and T1 parameters are presented in Table 1. No hemodynamic instability was observed. A significant reduction of IVC diameters and PCO₂ was founded, with a near 30% PCO₂ reduction in hypercapnic patients (4/10).

Table 1

Conclusion

In our preliminary report, SCUF seems to improve cardiac preload in congestive heart failure and to correct carbon dioxide in those patients who are hypercapnic too. The latter is probably due to both lung water [3] and respiratory workload reduction.