Acute Kidney Failure, Acute Kidney Injury, Hemofiltration, Renal Replacement Therapy
Conditions
Brief summary
Prospective observational study of all consecutive cardio-vascular surgical patients treated with post-dilution hemofiltration with regional citrate anticoagulation as first-choice anticoagulation method. The filter life-span was assessed in the context of postoperative cardiac surgical antithrombotic prophylaxis. Reasons for termination of hemofiltration sessions were assessed. The second aim of this study was to assess the influence ACD-A based anticoagulation protocol on acid-base and ion homeostasis in cardiac surgical patients with acute renal failure.
Detailed description
All consecutive cardio-vascular surgery patients treated with post-dilution hemofiltration with regional citrate anticoagulation (HF RCA) from August 2015 through November 2017 were included to prospective audit. Indication to hemofiltration treatment was based on clinical assessment of patients renal function and clinical status by attending physician and conformed conventional indications to renal replacement therapy (RRT) in intensive care unit (ICU). Severe chronic liver disease or acute liver injury with INR \> 2 and refractory shock with lactate increasing above 8 mmol/L were considered as contraindication to RCA. Initially set blood flow was 5 times higher than filtrate flow, which makes filtration fraction of 20%. To reduce the risk of metabolic alkalosis, ACD-A citrate solution was proposed instead of most commonly used trisodium citrate solution, and relatively low target citrate concentration (2.8 mmol/L) was adopted. In case of pH increase above 7.5 or bicarbonate concentration above 40 mmol/L filtrate flow was decreased from initial 35 ml/kg/hour down to 25 ml/kg/hour which should reduce bicarbonate synthesis by 25%. If metabolic alkalosis persisted, the second step involved reduction of blood flow from initial 5 times down to 4 times filtrate flow, which reduced citrate flow by the same factor. In order to avoid hypomagnesemia resulting from magnesium binding to citrate, and its removal with ultrafiltrate not balanced with magnesium content in replacement fluid, the original protocol was modified by connecting magnesium sulfate solution 2g/50 ml 0.9% NaCl at the flow 1 mL/hour. All sessions stopped due to patients death before 48 hours of HF treatment were excluded from the analysis. Similarly, all cases where hemofiltration session was stopped before 48 hours of treatment due to organizational reasons, recovery of renal function, change of therapy, and when patients were treated with heparin infusion due to surgical indications were excluded from further circuit survival analysis. Blood gas parameters together with pH, bicarbonate concentration, Na, Cl, K, Ca, hemoglobin concentration, hematocrit, lactate, and anion gap were analyzed every 6 hours. Post filter ionized calcium concentration was not assessed. Serum phosphate, magnesium and total calcium was assessed every 24 hours during hemofiltration treatment with RCA.
Interventions
PROCEDUREHemofiltration with regional citrate anticoagulation
To reduce risk of metabolic alkalosis during hemofiltration treatment, ACD-A citrate solution was proposed instead of most commonly used trisodium citrate solution and relatively low target citrate concentration (2.8 mmol/L) was adopted. In case of pH increase above 7.5 or bicarbonate concentration above 40 mmol/L filtrate flow was decreased from initial 35 ml/kg/hour down to 25 ml/kg/hour which reduced bicarbonate delivery by 25%. If metabolic alkalosis persisted, the second step involved reduction of blood flow from initial 5 times down to 4 times filtrate flow, which reduced citrate flow by the same factor.
Sponsors
Medical University of Gdansk
Study design
Observational model
CASE_ONLY
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 90 Years
Healthy volunteers
No
Inclusion criteria
* cardiac and vascular surgery patients treated with continuous hemofiltration with regional citrate anticoagulation
Exclusion criteria
* severe chronic liver disease, acute liver injury with INR \> 2, and refractory shock with lactate increasing above 8 mmol/L
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hemofiltration circuit survival time | up to 120 hours from the beginning of hemofiltration session | in hours |
| Incidence of metabolic alkalosis | From the beginning of hemofiltration session until 6 hours after its end | Arterial blood pH\>7.5 or BE \> 40 mmol/L |
| Incidence of hypernatremia and hyponatremia | From the beginning of hemofiltration session until 6 hours after its end | Incidence of hypernatremia\> 150 mmol/L and hyponatremia \< 130 mmol/L in arterial blood sample |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of citrate accumulation | From the beginning of hemofiltration session until 24 hours after its end | Incidence of total to ionized calcium ratio \> 2,5 in arterial blood sample |
Countries
Poland
Outcome results
None listed