The effect of retrograde autologous priming volume on haemodilution and transfusion requirements during cardiac surgery

Effect of Retrograde Autologous Priming on Coagulation Assessed by Rotation Thromboelastometry in Patients Undergoing Valvular Cardiac Surgery

OBJECTIVES

To investigate the effect of retrograde autologous priming (RAP) on coagulation function using rotation thromboelastometry (ROTEM) in patients undergoing valvular cardiac surgery.

DESIGN

A prospective, randomized, patient- and outcome assessor-blinded study.

SETTING

At a single-center university hospital.

PARTICIPANTS

Patients aged 20 years or older undergoing valvular cardiac surgery.

INTERVENTIONS

A total of 104 patients were allocated to the RAP or control group (1:1 ratio). In the RAP group, the prime was displaced into the collection bag before bypass initiation. ROTEM was performed at the induction of anesthesia, at the beginning of rewarming, and after the reversal of heparinization. Allogeneic plasma products and platelet concentrates were transfused according to ROTEM-based algorithms.

MEASUREMENTS AND MAIN RESULTS

An average volume of 635 ± 114 mL was removed using RAP (from the 1,600 mL initial prime volume). The hematocrit 10 minutes after cardiopulmonary bypass (CPB) was 24.7 ± 3.5% in the control group, and 26.1 ± 4.1% in the RAP group (p = 0.330). ROTEM, including EXTEM, INTEM, and FIBTEM, showed prolonged clotting time and decreased maximal clot firmness after CPB in both groups without intergroup differences. The number of patients who received intraoperative erythrocytes (27% v 25%, control versus RAP, p = 0.823), fresh frozen plasma (14% v 8%, control versus RAP, p = 0.339), cryoprecipitate (21% v 12%, control versus RAP, p = 0.185), or platelet concentrate transfusion (19% v 12%, control versus RAP, p = 0.277) did not differ between the groups.

CONCLUSIONS

Cardiopulmonary bypass induced impaired coagulation function on ROTEM. However, RAP did not improve coagulation function when compared with conventional priming in patients undergoing valvular cardiac surgery.

A novel approach to retrograde autologous priming for infant, pediatric and adult populations undergoing congenital heart surgery

INTRODUCTION

Retrograde Autologous Priming (RAP) of cardiopulmonary bypass (CPB) circuits is an effective way to reduce prime volume, commonly through the transfer of prime into separate reservoirs or circuit manipulation. We describe a simple and safe technique for RAP without the need for any circuit modifications or manipulations.

METHODS

For this technique, a separate roller pump for ultrafiltration (UF) is used. After adequate heparinization and arterial cannulation, the UF pump is initiated slowly, removing prime through the effluent of the UF, replacing with the patient's blood from the aortic cannula. Once the arterial line and UF circuit are autologous primed, the arterial head displaces reservoir crystalloid toward the UF circuit at a flow rate equal to the UF pump, displacing the crystalloid prime with blood from the UF circuit, autologous priming the boot and oxygenator with blood, crystalloid again being removed by the effluent. After venous cannulation, the venous line prime is replaced with autologous blood, the crystalloid removed by the effluent of the UF circuit via the arterial head. During RAP, if the patient becomes hypovolemic, either autologous volume is transfused back to the patient, or CPB is initiated, without the need for circuitry modifications.

RESULTS

The patient population in this sample consisted of 63 patients ranging between 6.1 kg and 115.6 kg. The smaller the patient, the less blood volume available for RAP and therefore the less prime volume able to be removed. Overall percent removal increases as our patients size increases compared to total circuit volume.

CONCLUSION

This RAP technique is a safe and effective way to achieve a standardized asanguinous prime for many regardless of patient or circuit size in the absence of contraindications such as low starting hematocrit, emergency surgery or physiologic instability. Most importantly, this potentially reduces the amount of hemodilution patients see from CPB initiation and therefore the lowest nadir hematocrit and consequently the amount of required homologous blood products needed during surgery.

Hematic Antegrade Repriming Reduces Emboli on Cardiopulmonary Bypass: A Randomized Controlled Trial

Particulate and gaseous microemboli (GME) are side effects of cardiac surgery that interfere with postoperative recovery by causing endothelial dysfunction and vascular blockages. GME sources during surgery are multiple, and cardiopulmonary bypass (CPB) is contributory to this embolic load. Hematic antegrade repriming (HAR) is a novel procedure that combines the benefits of repriming techniques with additional measures, by following a standardized procedure to provide a reproducible hemodilution of 300 ml. To clarify the safety of HAR in terms of embolic load delivery, a prospective and controlled study was conducted, by applying Doppler probes to the extracorporeal circuit, to determine the number and volume of GME released during CPB. A sample of 115 patients (n = 115) was considered for assessment. Both groups were managed under strict normothermia, and similar clinical conditions and protocols, receiving the same open and minimized circuit. Significant differences in GME volume delivery (control group [CG] = 0.28 ml vs. HAR = 0.08 ml; p = 0.004) and high embolic volume exposure (>1 ml) were found between the groups (CG = 30.36% vs. HAR = 4.26%; p = 0.001). The application of HAR did not represent an additional embolic risk and provided a four-fold reduction in the embolic volume delivered to the patient (coefficient, 0.24; 95% CI, 0.08-0.72; p = 0.01), which appears to enhance GME clearance of the oxygenator before CPB initiation.

Controversies in enhanced recovery after cardiac surgery

Advances in cardiac surgical operative techniques and myocardial protection have dramatically improved outcomes in the past two decades. An unfortunate and unintended consequence is that 80% of the preventable morbidity and mortality following cardiac surgery now originates outside of the operating room. Our hope is that a renewed emphasis on evidence-based best practice and standardized perioperative care will reduce overall morbidity and mortality and improve patient-centric care. The Perioperative Quality Initiative (POQI) and Enhanced Recovery After Surgery–Cardiac Society (ERAS® Cardiac) have identified significant evidence gaps in perioperative medicine related to cardiac surgery, defined as areas in which there is significant controversy about how best to manage patients. These five areas of focus include patient blood management, goal-directed therapy, acute kidney injury, opioid analgesic reduction, and delirium.

To RAP or Not to RAP: A Retrospective Comparison of the Effects of Retrograde Autologous Priming

Retrograde autologous priming (RAP) is a process used to reduce hemodilution associated with the initiation of cardiopulmonary bypass (CPB). Previous studies have reported potential benefits to RAP; however, many of these studies do not evaluate the benefits of RAP with limited preoperative fluid administration combined with a condensed CPB circuit. We examined clinical metrics of patients who underwent RAP versus those who did not undergo RAP prior to the initiation of CPB. This was a retrospective data review of 1,303 patients who underwent CPB in the setting of open-heart surgery for a 2-year period. RAP was used on all patients between June 1, 2017 and June 30, 2018 (n = 519) and not used on patients between July 1, 2018 and June 30, 2019 (n = 784). Both groups were subjected to a low-prime CPB circuit volume of 800-900 mL. We compared the clinical metrics for packed red blood cell (PRBC) transfusion, oxygen delivery, postoperative acute kidney injury (AKI), Albumin utilization, ventilator time, Intensive Care Unit length of stay (ICU LOS), and 30-day mortality between the two groups. Our data analysis showed there were no statistically significantly differences between the two groups on the incidence of postoperative AKI, PRBC administration, ventilator time, ICU LOS or 30-day mortality. In the RAP group, there was a statistically significant lower oxygen delivery and a statistically significant increased volume of Albumin administered postoperatively, although those differences were so small, they were potentially not clinically significant. Our analysis revealed no significant benefit to performing RAP with limited preoperative fluid administration and minimized CPB circuit prime volume. We formalized a process that included limiting preoperative fluid administration and minimizing the CPB circuit volume so that we were not required to RAP and did not simultaneously sacrifice patient outcomes in other areas.

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.

Albumin in adult cardiac surgery: a narrative review

PURPOSE

Intravascular fluids are a necessary and universal component of cardiac surgical patient care. Both crystalloids and colloids are used to maintain or restore circulating plasma volume and ensure adequate organ perfusion. In Canada, human albumin solution (5% or 25% concentration) is a colloid commonly used for this purpose. In this narrative review, we discuss albumin supply in Canada, explore the perceived advantages of albumin, and describe the clinical literature supporting and refuting albumin use over other fluids in the adult cardiac surgical population.

SOURCE

We conducted a targeted search of PubMed, Embase, Medline, Web of Science, ProQuest Dissertations and Theses Global, the Cochrane Central Register of Controlled trials, and the Cochrane Database of Systematic Reviews. Search terms included albumin, colloid, cardiac surgery, bleeding, hemorrhage, transfusion, and cardiopulmonary bypass.

PRINCIPAL FINDINGS

Albumin is produced from fractionated human plasma and imported into Canada from international suppliers at a cost of approximately $21 million CAD per annum. While it is widely used in cardiac surgical patients across the country, it is approximately 30-times more expensive than equivalent doses of balanced crystalloid solutions, with wide inter-institutional variability in use and no clear association with improved outcomes. There is a general lack of high-quality evidence for the superiority of albumin over crystalloids in this patient population, and conflicting evidence regarding safety.

CONCLUSIONS

In cardiac surgical patients, albumin is widely utilized despite a lack of high- quality evidence supporting its efficacy or safety. A well-designed randomized controlled trial is needed to clarify the role of albumin in cardiac surgical patients.

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.

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.

Is there any connection between method of priming extracorporeal circuit and cerebral oximetry results?

Objectives. To compare the influence of different priming techniques on cerebral oximetry results during CPB in adult patients.

Methods. This study is a single-center retrospective review of data collected from adult patients who underwent isolated CABG with CPB between January and December, 2016. The patients were divided into two standardized groups with the sole difference between them being the method of priming CPB circuit: the first one was the group where we used our modified retrograde method of priming (n = 45) and the second one was the group with standard priming (n = 45). Hematocrit, hemoglobin, cerebral oxygenation were evaluated at the following points: beginning of the operation, start of CPB, cross clamping, 15, 30, 45 minutes and the end of CPB and the end of operation.

Results. In the first group indices of cerebral oximetry were higher comparing to the second group at list of the 45 minutes of CPB (р < 0,001). For the first 15 minutes of CPB hematocrit was also higher in the first group. Priming volume and the need for blood transfusion or ultrafiltration were also smaller in the first group.

Conclusion. Modified priming technique allows to maintain higher indices of cerebral oximetry, decreases volume overload and the need for blood transfusion comparing to standard technique.

Mini-extracorporeal circulation technology, conventional bypass and prime displacement in isolated coronary and aortic valve surgery: a propensity-matched in-hospital and survival analysis

OBJECTIVES

Conventional cardiopulmonary bypass is the most commonly used means of artificial circulation in cardiac surgery. However, it suffers from the effects of haemodilution and activation of inflammatory/coagulation cascades. Prime displacement (PD) can offset haemodilution and mini-extracorporeal technology (MIECT) can offset both. So far, no study has compared all of these modalities together; hence, we compared the outcomes of these 3 modalities at our institution.

METHODS

This was a retrospective analysis of our cardiac surgical database. A total of 9626 patients underwent conventional bypass (CB), 3125 patients underwent a modification of CB, called PD, and 904 underwent MIECT. A 1:1 propensity-matching algorithm was employed using IBM SPSS 24 to match (i) 813 MIECT patients with 813 CB patients and (ii) 717 MIECT patients with 717 PD patients. The patients included coronary artery bypass grafting and valve surgery.

RESULTS

MIECT had significantly (P < 0.05) longer bypass and cross-clamp times compared to CB and PD. MIECT had significantly higher rates of postoperative atrial fibrillation associated with it compared to CB. The mean red cell blood transfusion was significantly lower in the MIECT group compared to the CB group as was the mean platelet transfusion and fresh frozen plasma transfusion. The overall 5-year survival was higher in the MIECT group compared to the CB group (log-rank, P = 0.018). Between the MIECT and the PD groups, we found the incidence of renal failure and gastrointestinal complications to be significantly higher in the PD group compared to the MIECT group.

CONCLUSIONS

MIECT has short-term advantages over CB and PD. However, due to the retrospective limitations of the study, including calendar time bias, a multicentre randomized controlled trial comparing all 3 modalities will be beneficial for the larger cardiac community.

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.

The Influence of Intraoperative Autotransfusion on Postoperative Hematocrit after Cardiac Surgery: A Cross-Sectional Study

Utilization of intraoperative autotransfusion (IAT) during cardiac surgery with cardiopulmonary bypass (CPB) has been shown to reduce allogeneic red blood cell transfusion. Previous research has emphasized the benefits of using IAT in the intraoperative period. The present study was designed to evaluate the effects of using IAT on overall hematocrit (Hct) drift between initiation of CPB and the immediate postoperative period. We reviewed 3,225 adult cardiac procedures occurring between February 2016 and January 2017 at 84 hospitals throughout the United States. Data were collected prospectively from adult patients undergoing cardiac surgery with CPB, and stored in the SpecialtyCare Operative Procedural rEgistry (SCOPE), a large quality improvement database. Patients receiving allogeneic transfusion and those with missing covariate data were excluded from analysis. The effect of IAT volume returned to patients on the primary endpoint, hematocrit change from CPB initiation to intensive care unit (ICU) entry, was assessed using a multivariable linear mixed effects regression model controlling for patient demographics, operative characteristics, surgeon, and hospital. Descriptive analysis showed greater positive hematocrit change with increasing autotransfusate volume returned. Those patients with no IAT volume returned saw a median hematocrit change of +2.00%, whereas those with more than 380 mL/m² BSA had a median Hct drift of +5.00% (p < .001). After controlling for known confounds, our regression estimate of the effect of IAT volume returned on Hct drift was +.0045% per 1 mL/m² BSA (p < .001). For a patient with the median autotransfusate volume returned (273 mL/m² BSA), and all other covariate values at their respective medians, this translates to a predicted hematocrit change of +3.6% (95% CI +3.1 to +4.1). These findings lend further support to the notion that autotransfusate volume is positively associated with increases in postoperative hematocrit.

Bloodless Repair of Aortic Arch with Dual Aortic Cannulation in a Jehovah's Witness Patient

Various methods for surgical repair of the aortic arch are described throughout the literature with many focused on cannulation techniques and degree of systemic cooling in an effort to reduce postoperative morbidities. Despite advancements in techniques, this surgery is still often associated with higher levels of blood loss and subsequent allogenic blood transfusions. Although blood products can be safely transfused to the majority of patients undergoing repair of the aortic arch, the complexity and risk is further multiplied when the patient is of Jehovah's Witness faith and refuses blood transfusions. This paper will detail our technique of surgical repair of the aortic arch in a Jehovah's Witness patient with dual aortic cannulation and our multidisciplinary approach to avoiding blood products.

The effectiveness of acute normolvolemic hemodilution and autologous prime on intraoperative blood management during cardiac surgery

Objective:

Intraoperative blood management during cardiac surgery is a multifaceted process incorporating various interventions directed at optimizing oxygen delivery and enhancing hemostasis. The purpose of this study was to evaluate the effects of acute normovolemic hemodilution (ANH) and autologous priming (AP) on preserving the hematocrit during cardiopulmonary bypass (CPB).

Method:

Case records from a national registry of adult patients who underwent cardiac surgery between January and October 2016 were reviewed. Groups were determined as follows: ANH, AP, ANH+AP or Neither. Primary endpoint was first the hematocrit on CPB with secondary endpoints of hematocrit drift and red blood cell (RBC) transfusion rate.

Results:

Eighteen thousand and twenty-four (18,024) consecutive patients were reviewed. The first CPB hematocrit was lowest in the ANH group (26.5%±4.4%) and highest in ANH+AP patients (27.5%±4.8%) (p<0.001). The change in hematocrit was greatest in the ANH group (8.3%±3.9%) compared to both the AP (6.4%±3.8%) and ANH+AP (6.9%±4.1%) groups (p<0.001). Intraoperative RBC transfusions were as follows: ANH 26 (7.8%), AP 2,531 (20.0%), ANH+AP 287 (10.3%) and Neither 592 (26.7%) (p<0.001).

Conclusions:

Regression results show that the use of ANH will result in the greatest decline in hematocrit values. When combined with AP, higher hematocrits and lower transfusions were seen.

Perioperative Coagulation Management of a Hemophilia A Patient During Cardiac Surgery

Perioperative management of cardiovascular surgical procedures requiring cardiopulmonary bypass (CPB) in patients with hemophilia A poses a clinical challenge in coagulation management. Use of CPB requires the administration of an anticoagulant, usually unfractionated heparin, and also causes dilutional coagulopathy, platelet dysfunction or platelet consumption coagulopathy. Hypothermia and activation of the inflammatory cascade also affect coagulation. The effects of CPB on circulating levels of factor VIII have not been clearly defined. In this review, the effects of CPB and hemodilution on FVIII are shown in a case presentation, and perioperative laboratory testing in patients with hemophilia A having cardiac surgery is discussed along with perioperative and postoperative coagulation management.

Blood conservation strategies in cardiac valve replacement: A retrospective analysis of 1645 patients

We aimed to evaluate whether blood conservation strategies including intraoperative autologous donation (IAD) could reduce perioperative blood transfusion for patients undergoing cardiac valve replacement including mitral valve replacement, aortic valve replacement (AVR), and double valve replacement (DVR).A total of 726 patients were studied over a 3-year period (2011-2013) after the implementation of IAD and were compared with 919 patients during the previous 36-month period (January 2008-December 2010). The method of small-volume retrograde autologous priming, strict blood transfusion standard together with IAD constituted a progressive blood-saving strategy.Baseline characteristics and preoperative information showed no statistically significant difference between IAD group and non-IAD group. Most of the postoperative morbidities are statistically the same in the 2 groups. Chest tube output (415.2 vs 1029.8 mL, P < 0.001) and postoperative respiratory failure (5.9% vs 8.6%, P = 0.039) favored the IAD group, whereas hematocrit levels were more favorable in the non-IAD group (30.3% vs 33.0% at the end of the operation, P < 0.001; 30.4% vs 31.5% at the time of discharge). The use of blood product transfusion was higher in the non-IAD group (22.6% vs 43.3%, P < 0.001). Binary multivariate logistic regression analysis showed that high age, non-IAD, DVR surgery, and absent smoking history are associated with a higher risk of intra-/postoperative blood transfusion.Blood conservation is effective and safe in cardiac valve replacement surgeries. The use of intraoperative autologous donation can lead to improved outcomes including a significantly lower rate of intra-/postoperative blood transfusion and postoperative complications.

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.

Hemodilution Combined With Hypercapnia Impairs Cerebral Autoregulation During Normothermic Cardiopulmonary Bypass

OBJECTIVE

To investigate the influence of hemodilution and arterial pCO2 on cerebral autoregulation and cerebral vascular CO2 reactivity.

DESIGN

Prospective interventional study.

SETTING

University hospital-based single-center study.

PARTICIPANTS

Forty adult patients undergoing elective cardiac surgery using normothermic cardiopulmonary bypass.

INTERVENTIONS

Blood pressure variations induced by 6/minute metronome-triggered breathing (baseline) and cyclic 6/min changes of indexed pump flow at 3 levels of arterial pCO2.

MEASUREMENTS AND MAIN RESULTS

Based on median hematocrit on bypass, patients were assigned to either a group of a hematocrit ≥28% or<28%. The autoregulation index was calculated from cerebral blood flow velocity and mean arterial blood pressure using transfer function analysis. Cerebral vascular CO2 reactivity was calculated using cerebral tissue oximetry data. Cerebral autoregulation as reflected by autoregulation index (baseline 7.5) was significantly affected by arterial pCO2 (median autoregulation index amounted to 5.7, 4.8, and 2.8 for arterial pCO2 of 4.0, 5.3, and 6.6 kPa, p≤0.002) respectively. Hemodilution resulted in a decreased autoregulation index; however, during hypocapnia and normocapnia, there were no significant differences between the two hematocrit groups. Moreover, the autoregulation index was lowest during hypercapnia when hematocrit was<28% (autoregulation index 3.3 versus 2.6 for hematocrit ≥28% and<28%, respectively, p = 0.014). Cerebral vascular CO2 reactivity during hypocapnia was significantly lower when perioperative hematocrit was<28% (p = 0.018).

CONCLUSIONS

Hemodilution down to a hematocrit of<28% combined with hypercapnia negatively affects dynamic cerebral autoregulation, which underlines the importance of tight control of both hematocrit and paCO2 during CPB.

Minimizing the perfusion system by integration of the components. Does it affect the hematocrit drop and transfused red blood cells? A retrospective audit

BACKGROUND

We evaluate the affect on the hematocrit (Hct) drop and the amount of transfused red blood cells (RBCs) during cardiopulmonary bypass (CPB) in adult cardiac surgery patients due to minimizing the CPB circuit by using integrated components.

METHODS

Two hundred and seventy-two patients were included in this retrospective audit. Patients were assigned to three cohorts: the first cohort consisted of patients operated on with a CPB circuit volume of 1630 ml in 2008; the second cohort of such patients in 2010, with 1380 ml; and the third cohort of such patients in 2011, with 1250 ml.

RESULTS

There were no significant differences with respect to patient demographics. The priming volume was consecutively significantly reduced; (1635 ± 84 ml, 1384 ± 72 ml and 1256 ± 130 ml, p<0.0001). A trend of decreased amount of RBCs during CPB was visible (cohort 1630: 98 ± 195 ml, cohort 1380: 35 ± 151 ml and cohort 1250: 48 ± 113 ml, p=0.02). Also, the amount of RBCs during the total CPB procedure shows a decreased trend (cohort 1630: 122 ± 230 ml, cohort 1380: 52 ± 180 ml and cohort 1250: 71 ± 156 ml, p=0.04). Blood loss during CPB was significantly lower in cohorts 1380 and 1250 (1630: 922 ± 378 ml, 1380: 706 ± 347 ml and 1250: 708 ± 418 ml, p<0.0001). The volume of diuresis was significantly larger in cohort 1630 (1630: 1166 ± 800 ml, 1380: 477 ± 530 ml and 1250: 523 ± 504 ml, p<0.0001). The Hct drop at the start and end of CPB was significantly reduced comparing cohort 1630 with cohort 1250 (1630: 32 ± 7%, 1380: 30 ± 7% and 1250: 28 ± 10%, p=0.002) at the start of CPB and (1630: 31 ± 7%, 1380: 29 ± 7% and 1250: 28 ± 8%, p=0.016) at the end of CPB. The Hct values at the start and end of CPB were significantly different between the cohorts (1680: 0.23 ± 0.03 L/L - 0.22 ± 0.02 L/L, 1380: 0.25 ± 0.03 L/L - 0.25 ± 0.03 L/L and 1250: 0.25 ± 0.03 L/L- 0.25 ± 0.03 L/L, p= 0.001 and 0.0001).

CONCLUSIONS

Minimizing our CPB circuit by using integrated components has affected the drop of Hct and the amount of transfused RBCs.

Effects of autologous priming on blood conservation after cardiac surgery

Objective:

Cardiopulmonary bypass can result in hemodilution due to the crystalloid prime, increasing the need for blood transfusion. Alternative perfusion techniques have the potential to decrease this hemodilution. The objective of this study was to determine whether a protocol of retrograde autologous prime (RAP) and venous antegrade prime (VAP) reduces the need for blood transfusion and increases the hematocrit following cardiac surgery.

Methods:

We performed a retrospective review of 140 consecutive non-randomized patients who underwent cardiac surgery with cardiopulmonary bypass between November 2011 and September 2012. RAP and VAP techniques were used in 70 patients while the other 70 were managed with conventional perfusion strategies. The primary outcome measure was a composite outcome of any blood transfusion or a discharge hematocrit less than 27%.

Results:

Baseline demographics and patient characteristics were similar between the two groups, with the exception of the RAP/VAP group having a lower baseline creatinine. There was a trend toward decreased perioperative blood transfusions in the RAP/VAP group (13/70, 19%) compared with the non-RAP/VAP group (23/70, 33%, p=0.053). RAP/VAP patients had a significantly higher hematocrit at hospital discharge (30.0 ± 4.3% vs. 28.3 ± 4.1%, p=0.012). The number of patients receiving a transfusion or being discharged with an hematocrit less than 27% was significantly less in the RAP/VAP group (21 vs. 41, p=0.001). This effect persisted on multivariable analysis.

Conclusions:

RAP and VAP perfusion techniques may reduce hemodilution, potentially resulting in less blood transfusions and higher postoperative hematocrits. These techniques should be considered in all patients undergoing cardiac surgery with cardiopulmonary bypass.