Coronary Artery Disease, Fluid Overload, Hemodilution
Conditions
Keywords
retrograde autologous priming, mannitol, cardiopulmonary bypass, cardiac surgery, hemodilution
Brief summary
Hemodilution reduces concentrations of blood constituents: concentration of hemoglobin, red blood cells (hematocrit), physiological ions and coagulation factors that can contribute to impaired hemostasis and increasing the risk of perioperative blood transfusions. This pilot study will assess the feasibility of a large RCT to evaluate 2 techniques for reducing hemodilution during cardiac surgery: 1) retrograde autologous priming and 2) intraoperative mannitol. The aim of this pilot trial is to demonstrate feasibility of a larger trial to evaluate whether retrograde autologous priming and/or mannitol are superior to conventional priming alone.
Detailed description
The use of large volumes of artificial priming fluids is still very high in cardiac surgery for routine CABG surgery with cardiopulmonary bypass. The resulting hemodilution is deleterious for patients and often requires counter measures to maintain fluid balance during and after surgery. Retrograde autologous priming and mannitol are simple low-cost solutions to the problem of hemodilution but their effectiveness, either alone or in combination, is unclear due to a lack of high-quality evidence. RAPPER-MAN is a single-centre 2x2 factorial cluster randomized trial. Participants will be randomly assigned (1:1:1:1 ratio) to the intervention groups: 1) Retrograde autologous priming (≥600 mL) + mannitol (0.3 g/kg bolus), 2) Retrograde autologous priming (≥600 mL) alone, 3) Conventional priming + mannitol (0.3 g/kg bolus), and 4) Conventional priming alone. The primary outcome is the change in hemoglobin concentration during cardiopulmonary bypass. Retrograde autologous priming will be performed within 10 minutes before, and mannitol will be added to the venous reservoir of the CPB machine within 5 minutes before, the start of cardiopulmonary bypass. The results of the larger trial are expected to have broad implications for fluid management in cardiac surgery in Canada.
Interventions
PROCEDURERetrograde autologous priming
Priming solution (≥600 mL) will be removed from the extracorporeal circuit within 10 minutes before the initiation of cardiopulmonary bypass. Priming solution may be removed from 3 locations within the extracorporeal circuit (i.e. arterial, venous and cardioplegia lines) as determined by the perfusionist team.
DRUGMannitol
Mannitol will be added as a bolus (0.3 g/kg) to the venous reservoir of the cardiopulmonary bypass machine within 5 min before the start of cardiopulmonary bypass.
PROCEDUREConventional Priming
The conventional priming procedure will be used in the standardized cardiopulmonary machine used at the Hamilton General Hospital.
Sponsors
McMaster University
Hamilton Health Sciences Corporation
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Intervention model description
single-centre, single blinded, 2x2 factorial, cluster randomized trial
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. ≥18 years of age. 2. Undergoing a first-time cardiac surgical procedure (i.e. isolated CABG, isolated single cardiac valve surgery or a combination of both or isolated ascending aorta replacement) with the use of cardiopulmonary bypass (CPB) and median sternotomy.
Exclusion criteria
1. Left ventricle ejection fraction \<25% 2. Emergency surgery 3. History of bleeding disorder 4. Inherited thromboembolic or infective endocarditis (active) 5. Previous cardiac surgery 6. Severe renal impairment (serum creatinine \>250 μmol/L) 7. Hemoglobin \<80 g/L 8. Thrombocytopenia (\<50,000 platelets per μL) 9. Expected circulatory arrest 10. Body weight ≤50 kg 11. Allergy to mannitol 12. Pregnancy or breast feeding
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Feasibility Outcomes | Start to end of study recruitment, which is anticipated to take 20 weeks | Feasibility will be established in the pilot phase if all the following criteria are met: 1. Average recruitment rate of 7 patients per week. 2. Complete Hb data before and after cardiopulmonary bypass in 90% of patients. 3. Compliance of the research team members, OR staff and ward medical staff with the protocol of 90%. |
| Change in hemoglobin concentration during cardiopulmonary bypass | Start to end of cardiopulmonary bypass | Change in arterial hemoglobin concentration during cardiopulmonary bypass |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in hemoglobin concentration after cardiopulmonary bypass | Start of cardiopulmonary bypass to hospital discharge or 5 days maximum (whichever occurs first) | Change in arterial hemoglobin concentration from baseline to discharge |
Other
| Measure | Time frame | Description |
|---|---|---|
| Hyponatremia | Before and 24 hours after surgery | Sodium concentration of less than 135 mmol/L (135 mEq/L) |
| Diuresis | Within 24 hours of surgery | Total volume of urine within 24 hours of surgery |
| Hemofiltration use | During cardiopulmonary bypass | Proportion of patients undergoing hemofiltration |
| Blood transfusion | Start of surgery to hospital discharge or 5 days maximum (whichever occurs first) | Proportion of patients experiencing red blood cell transfusion |
| Acute kidney injury | Start of surgery to hospital discharge or 5 days maximum (whichever occurs first) | Acute kidney injury as measured by peak postoperative creatinine and KDIGO |
| Length of hospital stay | Time from admission to hospital discharge or 5 days maximum (whichever occurs first) | Length of hospital stay (days) |
| Major adverse cardiovascular events | Start of surgery to hospital discharge or 5 days maximum (whichever occurs first) | Composite outcome of cardiovascular death, non-fatal myocardial infarction or stroke |
| Fluid balance | Daily in ICU from admission to hospital discharge or 5 days maximum (whichever occurs first) | Net fluid balance (intake minus output) calculated using a cumulative fluid chart |
| Change in oxygen consumption during cardiopulmonary bypass | Start to end of cardiopulmonary bypass | Change in oxygen consumption during cardiopulmonary bypass |
| Autologous prime volume | Within 10 minutes before cardiopulmonary bypass | Total prime volume removed from the extracorporeal circuit during the retrograde autologous priming procedure |
Countries
Canada
Outcome results
None listed