Nikkiso Aquarius™ System RCA
Regional citrate anticoagulation in CVVH mode — differing from the other devices presented here, which typically run in CVVHD/CVVHDF mode.
→ Official manufacturer site: Nikkiso Acute Blood Purification
This page summarizes Nikkiso's "Aquarius™ System RCA Pocket Guide", which in turn is based on two publications (Kirwan et al., Blood Purif 2016; Prowle, Royal London Hospital Pilot Protocol 2015). Verify your center-specific, approved protocol before use.
Important: CVVH instead of CVVHD/CVVHDF
The Aquarius protocol is designed for CVVH mode (AQUALINE RCA set, AQUAMAX filter) — with Accusol solution as the post-dilution replacement fluid. There is no separate dialysate as in CVVHD procedures.
Step 1 — Preparation
Set up Aquarius in CVVH mode with the AQUALINE RCA set and a matching AQUAMAX filter. Prepare Accusol solution per local standard.
| Systemic ionized calcium | Approach |
|---|---|
| < 1.0 mmol/l | Connect dilute CaCl₂ solution: 10 ml calcium chloride 10% + 990 ml NaCl 0.9% (= 10 mmol/l), change daily |
| ≥ 1.0 mmol/l | Connect a 1 L bag of NaCl 0.9% with a "NO CALCIUM" sticker instead of the calcium solution |
Initial CaCl₂ rate by systemic calcium
| Systemic ionized Ca | Initial CaCl₂ rate |
|---|---|
| < 0.8 mmol/l | Do NOT start RCA — medical correction of calcium first |
| 0.8–0.9 mmol/l | 75 ml/h (0.75 mmol/h) |
| 0.9–1.0 mmol/l | 50 ml/h (0.5 mmol/h) |
| > 1.0 mmol/l | 0 ml/h — use "NO CALCIUM" bag |
"Orange" protocol — target: clearance (35 ml/kg/h, 20% filtration fraction)
| IBW (kg) | Blood pump (ml/min) | ACD-A/citrate (ml/h) | Accusol post-dilution (ml/h) |
|---|---|---|---|
| < 50 | 120 | 180 | 1400 |
| 50–59 | 150 | 230 | 1800 |
| 60–69 | 180 | 270 | 2100 |
| 70–79 | 200 | 300 | 2400 |
| > 80 | 230 | 350 | 2700 |
If pH > 7.5 or HCO₃⁻ > 40: reduce to 25 ml/kg/h or specifically treat metabolic alkalosis.
"Purple" protocol — target: maintenance dose (25 ml/kg/h, 20% filtration fraction)
| IBW (kg) | Blood pump (ml/min) | ACD-A/citrate (ml/h) | Accusol post-dilution (ml/h) |
|---|---|---|---|
| < 50 | 100 | 150 | 1100 |
| 50–59 | 110 | 170 | 1300 |
| 60–69 | 130 | 200 | 1500 |
| 70–79 | 140 | 210 | 1700 |
| > 80 | 160 | 240 | 1900 |
Further protocols for alkalosis/clotting
| Situation | Switch to | Key feature |
|---|---|---|
| Alkalosis under "Purple" (pH > 7.5 / HCO₃⁻ > 40) | "Green" protocol — target: metabolism | 25 ml/kg/h, but 25% filtration fraction; below 60 kg IBW: minimum blood flow reached → discontinue RCA |
| Filter clotting < 12 h under "Green" | "Grey" protocol — target: anticoagulation | 25 ml/kg/h with higher citrate concentration; do not switch from "Green" to "Grey" if the patient was previously on "Green" (see note in the original document) |
Step 3 — Calcium fine-tuning (after 1 hour, then every 6 h)
| ABG ionized Ca | CaCl₂ adjustment (max. 175 ml/h) | Recheck after |
|---|---|---|
| < 0.8 | Physician gives 5 ml CaCl₂ 10% (3.4 mmol) as a slow IV bolus immediately; increase CaCl₂ rate by 50 ml/h; if already at 175 ml/h: stop RCA, inform physician | 1 h |
| 0.8–0.89 | Increase CaCl₂ rate by 25 ml/h; if already at 175 ml/h: stop RCA, inform physician | 3 h |
| 0.9–1.2 | No change (target range) | 6 h |
| > 1.2 | Decrease CaCl₂ rate by 25 ml/h; inform physician if Ca rises above 1.5 | 3 h |
Source: Nikkiso "Aquarius™ System RCA Pocket Guide" (PM-0111-09/2016-3, Copyright 2017), based on: (1) Kirwan CJ et al., "Implementation of a Simplified Regional Citrate Anticoagulation Protocol...", Blood Purif 2016;42:349–355; (2) Prowle JR, "Royal London Hospital Pilot Regional Citrate Anticoagulation Protocol for Aquarius CRRT Platform", 2015. With thanks to the Adult Critical Care Unit, Royal London Hospital, Barts Health NHS Trust.