Assessing the effectiveness of retrograde autologous priming of the cardiopulmonary bypass machine in isolated coronary artery bypass grafts

Balanced forced-diuresis as a renal protective approach in cardiac surgery: Secondary outcomes of electrolyte changes

Objectives

Forced‐diuresis during cardiopulmonary bypass (CPB) can be associated with significant electrolyte shifts. This study reports on the serum electrolyte changes during balanced forced‐diuresis with the RenalGuard® system (RG) during CPB.

Methods

Patients at risk of acute kidney injury (AKI)—(history of diabetes &/or anaemia, e‐GFR 20–60 ml/min/1.73 m², anticipated CPB time >120 min, Log EuroScore >5)—were randomized to either RG (study group) or managed as per current practice (control group).

Results

The use of RG reduced AKI rate (10% for RG and 20.9% in control, p = .03). Mean urine output was significantly higher in the RG group during surgery (2366 ± 877 ml vs. 765 ± 549 ml, p < .001). The serum potassium levels were maintained between 3.96 and 4.97 mmol/L for the RG group and 4.02 and 5.23 mmol/L for the controls. Median potassium supplemental dose was 60 (0–220) mmol (RG group) as compared to 30 (0–190) mmol for control group over first 24 h (p < .001). On Day 1 post‐op, there were no significant differences in the serum sodium, potassium, calcium, magnesium, phosphate, and chloride levels between the two groups. Otherwise, postoperative clinical recovery was also similar.

Conclusions

Balanced forced‐diuresis with the RG reduced AKI rates after on‐pump cardiac surgery compared to controls. Although the RG group required higher doses of IV potassium replacement in the postoperative period, normal serum levels of potassium were maintained by appropriate intravenous potassium supplementation and the clinical outcomes between groups were similar.

Retrograde autologous priming in cardiac surgery: a systematic review and meta-analysis

OBJECTIVES

Guidelines recommend retrograde autologous priming (RAP) of the cardiopulmonary bypass circuit. However, the efficacy and safety of RAP is not well-established. We performed a systematic review and meta-analysis to determine the effects of RAP on transfusion requirements, morbidity and mortality.

METHODS

We searched Cochrane Central Register of Controlled Trials, Medline, ScienceDirect, Cumulative Index to Nursing and Allied Health Literature and Embase for randomized controlled trials (RCTs) and observational studies comparing RAP to no-RAP. We performed title and abstract review, full-text screening, data extraction and risk of bias assessment independently and in duplicate. We pooled data using a random effects model.

RESULTS

Twelve RCTs (n = 1206) and 17 observational studies (n = 3565) were included. Fewer patients required blood transfusions with RAP [RCTs; risk ratio 0.58 [95% confidence interval (CI): 0.51, 0.65], P < 0.001, and observational studies; risk ratio 0.65 [95% CI: 0.53, 0.80], P < 0.001]. The number of units transfused per patient was also lower among patients who underwent RAP (RCTs; mean difference -0.38 unit [95% CI: -0.72, -0.04], P = 0.03, and observational studies; mean difference -1.03 unit [95% CI: -1.76, -0.29], P < 0.006).

CONCLUSIONS

This meta-analysis supports the use of RAP as a blood conservation strategy since its use during cardiopulmonary bypass appears to reduce transfusion requirements.

Retrograde Autologous Priming in Cardiac Surgery: Results From a Systematic Review and Meta-analysis

BACKGROUND

Retrograde autologous priming (RAP) before cardiopulmonary bypass (CPB) may minimize allogeneic red cell transfusion. We conducted a systematic review of the literature to examine the impact of RAP on perioperative allogeneic red cell transfusions in cardiac surgical patients.

METHODS

This study involved a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies evaluating the use of RAP in cardiac surgery involving CPB. The primary outcome was intraoperative allogeneic red cell transfusion. Secondary outcomes included whole hospital allogeneic transfusions and adverse events such as acute kidney injury (AKI) and stroke.

RESULTS

A total of 11 RCTs (n = 1337 patients) were included, comparing RAP patients (n = 674) to control (n = 663). In addition, 10 observational studies (n = 2327) were included, comparing RAP patients (n = 1257) to control (n = 1070). Overall, RAP was associated with a significantly reduced incidence of intraoperative red cell transfusion (n = 18 studies; odds ratio [OR] = 0.34; 95% confidence interval [CI], 0.22-0.55, P < .001) compared to controls. This effect was seen among RCTs (n = 10 studies; OR = 0.19; 95% CI, 0.08-0.45, P < .001) and observational studies (n = 8 studies; OR = 0.66; 95% CI, 0.50-0.87, P = .004) in isolation. RAP was also associated with a significantly reduced incidence of whole hospital red cell transfusion (n = 5 studies; OR = 0.28; 95% CI, 0.19-0.41, P < .001). Among the studies that reported AKI and stroke outcomes, there was no statistically significant increased odds of AKI or stroke in either RAP or control patients.

CONCLUSIONS

Based on the pooled results of the available literature, RAP is associated with a significant reduction in intraoperative and whole hospital allogeneic red cell transfusion. Use of RAP may prevent hemodilution of cardiac surgical patients and thus, lessen transfusions. Additional high-quality prospective studies are necessary to determine the ideal priming volume necessary to confer the greatest benefit without incurring organ injury.

Effect of Retrograde Autologous Blood Priming of Cardiopulmonary Bypass on Hemodynamic Parameters and Pulmonary Mechanics in Pediatric Cardiac Surgery: A Randomized Clinical Study

The present study aimed to assess the impact of retrograde autologous priming (RAP) on hemodynamics and pulmonary mechanics in children subjected to cardiothoracic surgery. This prospective randomized study analyzed the clinical records of 124 children with risk adjustment in congenital heart surgery-1 left to right lesions subjected to cardiac surgery. They comprised 64 patients in RAP group and 60 patients in the conventional priming group. The preoperative, intraoperative and postoperative data of the studied patients were reported. The outcome measures included hematocrit (Hct) value, blood gases, lung mechanics parameters, transfusion needs, ICU stay, postoperative complications and mortality. Preoperatively, there were no significant differences between the studied groups regarding the demographic data, underlying lesions, laboratory data, blood gases and pulmonary mechanics parameters. Intraoperatively, RAP group patients had significantly lower amount of blood loss, less frequent need to packed red blood cells (RBC)s transfusion and better Hct values when compared with the control group. Postoperatively, RAP group patients had significantly higher Hct% at ICU arrival, significantly better pulmonary mechanics parameters and significantly shorter duration on mechanical ventilation. RAP in children older than 12 months subjected to cardiac surgery for risk adjustment in congenital heart surgery-1 left to right lesions is associated with less transfusion needs and better pulmonary mechanics.

Retrograde autologous priming to reduce allogeneic blood transfusion requirements: a systematic review

Background:

Efforts have been made to minimize transfusion of packed red blood cells in patients undergoing cardiac surgery with cardiopulmonary bypass. One method concerns retrograde autologous priming. Although the technique has been used for decades, results remain contradictory in terms of transfusion requirements.

Objective:

This systematic literature review aimed to summarize the evidence for the efficacy of retrograde autologous priming in terms of decreasing perioperative packed red blood cell requirements in adults.

Methods:

Two researchers independently searched PubMed for articles published in the past 10 years. The modified Cochrane collaboration Risk of Bias Tool and the Research Triangle Institute Item Bank were used to assess bias.

Results:

Eight studies were included, of which two randomized and six observational studies. Five studies, including one randomized study, report a significant decrease in packed red blood cell use in the retrograde autologous priming group compared to no retrograde autologous priming used. All studies are flawed by at least a high risk bias of bias score on one item of the bias assessment.

Conclusion:

Although most studies reported significantly fewer packed red blood cell transfusions in the retrograde autologous priming group, it is important to note that relatively few articles are available which are flawed by several types of bias. Prospective, randomized multi-center trials are warranted to conclude decisively on the benefits of retrograde autologous priming.

The Effect of Standardizing Autologous Prime Techniques in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass

Autologous priming (AP) of the extracorporeal circuit has been used as a technique to reduce iatrogenic anemia in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). The purpose of this study was to review the results of standardizing AP techniques to reduce variation among clinicians and its effect on clinical outcomes. Standardized goal-directed protocols for AP were established by the cardiac team and applied to all adult cardiac surgical patients where CPB was used. Following Institutional Review Board approval, data were analyzed for two sequential groups of patients: Non-standardized AP (NST-AP) and standardized AP (ST-AP). Exclusion criteria included pre-CPB hemodynamic instability and preoperative hematocrit (Hct) values less than 30%. The primary end point was the transfusion of red blood cells (RBCs), whereas secondary end points included Hct change and other perioperative allogeneic blood product transfusions. Data are presented as mean and SD. Of the 192 patients evaluated, 82 were in the NST-AP group and 110 in the ST-AP group. There were no preoperative demographic differences across groups. Total AP volume was lower in the NST-AP group than in the ST-AP patients (486.8 ± 259.6 mL vs. 1,048.2 ± 218.7 mL, p < .001). Whereas pre-CPB Hct values were identical between the groups, the first on-CPB (25.7% ± 4.5% vs. 27.9% ± 4.2%, p < .001), high CPB (27.7% ± 3.5% vs. 29.1% ± 3.6%, p < .008), and first postoperative (32.5% ± 4.0% vs. 34.3% ± 3.9%, p < .003) were all significantly higher in ST-AP patients. Perioperative transfusion rate was higher in NST-AP patients (63.6%) vs. ST-AP (44.6%), p < .01. There was no difference in intraoperative RBC transfusion, but postoperatively, more patients in the NST-AP group received RBCs than those in the ST-AP group (51.2% vs. 28.2%, p < .01). The application of an ST-AP protocol was effective in reducing hemodilution, which was associated within higher Hcts and lower postoperative transfusion rates.

Association of Primary Hemodilution and Retrograde Autologous Priming with Transfusion in Cardiac Surgery: Analysis of the Perfusion Case Database of the Japanese Society of Extra-Corporeal Technology in Medicine

It is important to avoid unnecessary blood cell transfusion. However, the associations of hemodilution and retrograde autologous priming with red blood cell transfusion during and after cardiopulmonary bypass (CPB) in cardiac surgery in Japan are currently unclear. We analyzed these associations using data for 3,090 adults from the Perfusion Case Database of the Japanese Society of Extra-Corporeal Technology in Medicine. Percent hemodilution was calculated by total priming volume and weight. Logistic regression models were used to adjust for covariates including type of surgery, gender, age, hemoglobin concentration before CPB, CPB time, urine volume during CPB, and institution. The percentages of red blood cell transfusions during CPB for patients with <15, 15 to <20, 20 to <25, 25 to <30, and ≥30% hemodilution were 43.0, 51.5, 68.9, 77.3, and 87.7%, respectively. This increase in line with increasing dilution was significant after adjusting for covariates. The percentage of red blood cell transfusion after CPB also increased slightly between 39.0 and 49.4% with percent hemodilution, but the trend after adjusting for covariates was not significant. Use of retrograde autologous priming was significantly associated with blood cell transfusion during CPB after adjusting for covariates, but was not significantly related to blood cell transfusion after CPB. These results suggest that optimizing the percent hemodilution and use of retrograde autologous priming might reduce the use of red blood cell transfusion during CPB in clinical practice in Japan.

Lean Flow: Optimizing Cardiopulmonary Bypass Equipment and Flow for Obese Patients-A Technique Article

The goal of this chart review was to investigate the use of down-sized cardiopulmonary bypass (CPB) circuits for obese patients. The effects of transitioning from larger to smaller oxygenators, reservoirs, and arteriovenous tubing loops were evaluated through a retrospective review of 2,816 adult non-congenital procedure perfusion records. This technique report and case series is a continuation of our original prescriptive CPB circuit quality improvement project. An algorithm was derived to adjust body surface area (BSA) to lower body mass index (BMI) to provide down-sized extracorporeal circuit components capable of meeting the metabolic needs of the patient. As a result of using smaller circuits, decreased priming volumes led to significantly increased hemoglobin (HB) nadirs (p < .05) leading to significant decreases in homologous donor blood product exposures (p < .05). Patients with large BSAs were supported safely with smaller circuits by using lean body mass (LBM)-adjusted BSA and target blood flow algorithm. Based on this case series, large BMI patients may be safely supported with smaller circuits selected based on BSAs adjusted more toward LBM. Use of smaller circuits in high BMI patients led to higher HB nadirs and less donor blood components during the surgical procedure. Renal function and hospital stay were not affected by this approach.

Short-Term Effects and Safety Analysis of Retrograde Autologous Blood Priming for Cardiopulmonary Bypass in Patients with Cardiac Valve Replacement Surgery

This randomized, double-blind study evaluated the short-term effects and safety of perioperative retrograde autologous priming (RAP) for cardiopulmonary bypass (CPB) in patients with cardiac replacement surgery to determine if this approach is a better substitute for crystal liquids priming in patients with valvular heart disease. We observed that RAP significantly decreased the actual priming volume, preserved the hematocrit and hemoglobin level during CPB to a certain degree, and decreased lactate accumulation in CPB period. Moreover, RAP lowered the volume of transfusion and dosage blood products. Thus, our results showed that RAP approach effectively improved tissue perfusion and lowered intraoperative Lac levels, by reducing the hemodilution, which safely and reliably improve the microcirculation perfusion.

Clinical applications of retrograde autologous priming in cardiopulmonary bypass in pediatric cardiac surgery

Retrograde autologous priming (RAP) has been routinely applied in cardiac pediatric cardiopulmonary bypass (CPB). However, this technique is performed in pediatric patients weighing more than 20 kg, and research about its application in pediatric patients weighing less than 20 kg is still scarce. This study explored the clinical application of RAP in CPB in pediatric patients undergoing cardiac surgery. Sixty pediatric patients scheduled for cardiac surgery were randomly divided into control and experimental groups. The experimental group was treated with CPB using RAP, while the control group was treated with conventional CPB (priming with suspended red blood cells, plasma and albumin). The hematocrit (Hct) and lactate (Lac) levels at different perioperative time-points, mechanical ventilation time, hospitalization duration, and intraoperative and postoperative blood usage were recorded. Results showed that Hct levels at 15 min after CPB beginning (T2) and at CPB end (T3), and number of intraoperative blood transfusions were significantly lower in the experimental group (P<0.05). There were no significant differences in CPB time, aortic blocking time, T2-Lac value or T3-Lac between the two groups (P>0.05). Postoperatively, there were no significant differences in Hct (2 h after surgery), mechanical ventilation time, intensive care unit time, or postoperative blood transfusion between two groups (P>0.05). RAP can effectively reduce the hemodilution when using less or not using any banked blood, while meeting the intraoperative perfusion conditions, and decreasing the perioperative blood transfusion volume in pediatric patients.