Effect and safety of 4% albumin in the treatment of cardiac surgery patients: study protocol for the randomized, double-blind, clinical ALBICS (ALBumin In Cardiac Surgery) trial

Comparison of 4% Albumin and Ringer's Acetate on Hemodynamics in On-pump Cardiac Surgery: An Exploratory Analysis of a Randomized Clinical Trial

OBJECTIVES

Compare hemodynamics between 4% albumin and Ringer's acetate.

DESIGN

Exploratory analysis of the double-blind randomized ALBumin In Cardiac Surgery trial.

SETTING

Single-center study in Helsinki University Hospital.

PARTICIPANTS

We included 1,386 on-pump cardiac surgical patients.

INTERVENTION

We used 4% albumin or Ringer's acetate administration for cardiopulmonary bypass priming, volume replacement intraoperatively and 24 hours postoperatively.

MEASUREMENTS AND MAIN RESULTS

Hypotension (time-weighted average mean arterial pressure of <65 mmHg) and hyperlactatemia (time-weighted average blood lactate of >2 mmol/L) incidences were compared between trial groups in the operating room (OR), and early (0-6 hours) and late (6-24 hours) postoperatively. Associations of hypotension and hyperlactatemia with the ALBumin In Cardiac Surgery primary outcome (≥1 major adverse event [MAE]) were studied. In these time intervals, hypotension occurred in 118, 48, and 17 patients, and hyperlactatemia in 313, 131, and 83 patients. Hypotension and hyperlactatemia associated with MAE occurrence. Hypotension did not differ between the groups (albumin vs Ringer's: OR, 8.8% vs 8.5%; early postoperatively, 2.7% vs 4.2%; late postoperatively, 1.2% vs 1.3%; all p > 0.05). In the albumin group, hyperlactatemia was less frequent late postoperatively (2.9% vs 9.1%; p < 0.001), but not earlier (OR, 22.4% vs 23.6%; early postoperatively, 7.9% vs 11.0%; both p > 0.025 after Bonferroni-Holm correction).

CONCLUSIONS

In on-pump cardiac surgery, hypotension and hyperlactatemia are associated with the occurrence of ≥1 MAE. Compared with Ringer's acetate, albumin did not decrease hypotension and decreased hyperlactatemia only late postoperatively. Albumin's modest hemodynamic effect is concordant with the finding of no difference in MAEs between albumin and Ringer's acetate in the ALBumin In Cardiac Surgery trial.

Association between whole blood ratio and risk of mortality in massively transfused trauma patients: retrospective cohort study

BACKGROUND

Although whole blood (WB) transfusion was reported to improve survival in trauma patients with hemorrhagic shock, little is known whether a higher proportion of WB is associated with an improved survival. This study aimed to evaluate the association between whole blood ratio (WBR) and the risk of mortality in trauma patients requiring massive blood transfusion.

METHODS

We performed a retrospective cohort study from the ACS-TQIP between 2020 and 2021. Patients were aged ≥ 18 years and received WB within 4 h of hospital arrival as a part of massive blood transfusion. Study patients were categorized into four groups based on the quartiles of WBR. Primary outcome was 24-h mortality and secondary outcome was 30-day mortality. Multivariable logistic regression analysis, fitted with generalized estimating equations, was performed to adjust for confounding factors and accounted for within-hospital clustering.

RESULTS

A total of 4087 patients were eligible for analysis. The median age was 37 years (interquartile range [IQR]: 27-53 years), and 85.0% of patients were male. The median number of WB transfusions was 2.3 units (IQR 2.0-4.0 units), and the total transfusion volume was 4940 ml (IQR 3350-8504). When compared to the lowest WBR quartile, the highest WBR quartile had lower adjusted 24-h mortality (adjusted odds ratio [AOR]: 0.61, 95% confidence interval [CI]: 0.46-0.81) and 30-day mortality (AOR 0.58; 95% CI 0.45-0.75).

CONCLUSION

The probability of mortality consistently decreased with higher WBR in trauma patients requiring massive blood transfusion.

Optimization of cardiopulmonary bypass prime fluid to preserve microcirculatory perfusion during on-pump coronary artery bypass graft surgery: PRIME study protocol for a double-blind randomized trial

BACKGROUND

Acute microcirculatory perfusion disturbances and organ edema are important factors leading to organ dysfunction during cardiac surgery with cardiopulmonary bypass (CPB). Priming of the CPB system with crystalloid or colloid fluids, which inevitably leads to hemodilution, could contribute to this effect. However, there is yet no optimal evidence-based strategy for this type of priming. Hence, we will investigate different priming strategies to reduce hemodilution and preserve microcirculatory perfusion.

METHODS

The PRIME study is a single-center double-blind randomized trial. Patients undergoing elective coronary artery bypass graft surgery with CPB will be randomized into three groups of prime fluid strategy: (1) gelofusine with crystalloid, (2) albumin with crystalloid, or (3) crystalloid and retrograde autologous priming. We aim to include 30 patients, 10 patients in each arm. The primary outcome is the change in microcirculatory perfusion. Secondary outcomes include colloid oncotic pressure; albumin; hematocrit; electrolytes; fluid balance and requirements; transfusion rates; and endothelial-, glycocalyx-, inflammatory- and renal injury markers. Sublingual microcirculatory perfusion will be measured using non-invasive sidestream dark field video microscopy. Microcirculatory and blood measurements will be performed at five consecutive time points during surgery up to 24 h after admission to the intensive care unit.

DISCUSSION

PRIME is the first study to assess the effect of different prime fluid strategies on microcirculatory perfusion in cardiac surgery with CPB. If the results suggest that a specific crystalloid or colloid prime fluid strategy better preserves microcirculatory perfusion during on-pump cardiac surgery, the current study may help to find the optimal pump priming in cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05647057. Registered on 04/25/2023.

CLINICALTRIALS

gov PRS: Record Summary NCT05647057, all items can be found in the protocol.

How do we achieve blinding in modern electronic and paper medical records during the conduct of transfusion trials?

BACKGROUND

Regulatory aspects of transfusion medicine add complexity in blinded transfusion trials when considering various electronic record keeping software and blood administration processes. The aim of this study is to explore strategies when blinding transfusion components and products in paper and electronic medical records.

METHODS

Surveys were collected and interviews were conducted for 18 sites across various jurisdictions in North America to determine solutions applied in previous transfusion randomized control trials.

RESULTS

Sixteen responses were collected of which 11 had previously participated in a transfusion randomized control trial. Various solutions were reported which were specific to the laboratory information system (LIS) and electronic medical record (EMR) combinations although solutions could be grouped into four categories which included the creation of a study product code in the LIS, preventing the transmission of data from the LIS to the EMR, utilizing specialized stickers and labels to conceal product containers and documents in the paper records, and modified bedside procedures and documentation.

DISCUSSION

LIS and EMR combinations varied across sites, so it was not possible to determine combination-specific solutions. The study was able to highlight solutions that may be emphasized in future iterations of LIS and EMR software as well as procedural changes that may minimize the risk of unblinding.

Albumin and Cardioprotection in On-Pump Cardiac Surgery-A Post Hoc Analysis of a Randomized Trial

OBJECTIVES

To study the quantitative potency of plasma albumin on cardioprotection in terms of creatinine kinase-myocardial band mass (CK-MBm) in on-pump cardiac surgery.

DESIGN

Post hoc analysis of a double-blinded randomized clinical trial.

SETTING

Single-center study in the Helsinki University Hospital.

PARTICIPANTS

A total of 1,386 adult on-pump cardiac surgical patients.

INTERVENTION

Administration of 4% albumin (n = 693) or Ringers acetate (n = 693) for cardiopulmonary bypass priming and volume replacement intraoperatively and postoperatively during the first 24 hours.

MEASUREMENTS AND MAIN RESULTS

Albumin concentration was measured preoperatively and intraoperatively (after protamine administration), and CK-MBm on the first postoperative morning. Multivariate linear regression analyses were measured in the whole cohort and the Ringer group. Plasma albumin concentration did not differ between the groups preoperatively (Ringer v albumin: 38.3 ± 5.0 g/L v 38.6 ± 4.5 g/L; p = 0.171) but differed intraoperatively (29.5 ± 5.2 g/L v 41.5 ± 6.0 g/L; p < 0.001). Creatinine kinase-myocardial band mass was higher in the Ringer (32.0 ± 34.8 μg/L) than in the albumin group (24.3 ± 33.0 μg/L) (p < 0.001). Aortic cross-clamping time associated with CK-MBm in the whole cohort (standardized β = 0.376 [95% CI 0.315-0.437], p < 0.001) and the Ringer group (β = 0.363 [0.273-0.452]; p < 0.001). Albumin administration in the whole cohort (β = -0.156 [-0.201 to -0.111]; p < 0.001) and high intraoperative albumin concentration in the Ringer group (β = -0.07 [-0.140 to -0.003]; p = 0.04) associated with reduced CK-MBm. Compared with ischemia-induced increase in CK-MBm, albumin's potency to reduce CK-MBm was 41% in the whole cohort (β-value ratio of -0.156/0.376) and 19% in the Ringer group (β-value ratio of -0.07/0.363).

CONCLUSION

Both endogenous and exogenous albumin appear to be cardioprotective regarding CK-MBm release in on-pump cardiac surgery.

Acute Kidney Injury after Cardiac Surgery: Prediction, Prevention, and Management

Acute kidney injury (AKI) is a common complication in cardiac surgery patients, with a reported incidence of 20 to 30%. The development of AKI is associated with worse short- and long-term mortality, and longer hospital length of stay. The pathogenesis of cardiac surgery-associated AKI is poorly understood but likely involves an interplay between preoperative comorbidities and perioperative stressors. AKI is commonly diagnosed by using increases in serum creatinine or decreased urine output and staged using a standardized definition such as the Kidney Disease Improving Global Outcomes classification. Novel biomarkers under investigation may provide earlier detection and better prediction of AKI, enabling mitigating therapies early in the perioperative period. Recent clinical trials of cardiac surgery patients have demonstrated the benefit of goal-directed oxygen delivery, avoidance of hyperthermic perfusion and specific fluid and medication strategies. This review article highlights both advances and limitations regarding the prevention, prediction, and treatment of cardiac surgery-associated AKI.

Albumin Infusion and Blood Loss After Cardiac Surgery

BACKGROUND

In the recent ALBICS (ALBumin In Cardiac Surgery) trial, 4% albumin used for cardiopulmonary bypass priming and volume replacement increased perioperative bleeding compared with Ringer acetate. In the present exploratory study, albumin-related bleeding was further characterized.

METHODS

Ringer acetate and 4% albumin were compared in a randomized, double-blinded fashion in 1386 on-pump adult cardiac surgery patients. The study end points for bleeding were the Universal Definition of Perioperative Bleeding (UDPB) class and its components.

RESULTS

The UDPB bleeding grades were higher in the albumin group than the Ringer group: "insignificant" (albumin vs Ringer: 47.5% vs 62.9%), "mild" (12.7% vs 8.9%), "moderate" (28.7% vs 24.4%), "severe" (10.2% vs 3.2%), and "massive" (0.9% vs. 0.6%; P < .001). Patients in the albumin group received red blood cells (45.2% vs 31.5%; odds ratio [OR], 1.80; 95% CI, 1.44-2.24; P < .001), platelets (33.3% vs 21.8%; OR, 1.79; 95% CI, 1.41-2.28; P < .001), and fibrinogen (5.6% vs 2.6%; OR, 2.24; 95% CI, 1.27-3.95; P < .05), and underwent resternotomy (5.3% vs 1.9%; OR, 2.95; 95% CI, 1.55-5.60, P < .001) more often than patients in the Ringer group. The strongest predictors of bleeding were albumin group allocation (OR, 2.18; 95% CI, 1.74-2.74) and complex (OR, 2.61; 95% CI, 2.02-3.37) and urgent surgery (OR, 1.63; 95% CI, 1.26-2.13). In interaction analysis, the effect of albumin on the risk of bleeding was stronger in patients on preoperative acetylsalicylic acid.

CONCLUSIONS

Perioperative administration of albumin, compared with Ringer's acetate, resulted in increased blood loss and higher UDBP class. The magnitude of this effect was similar to the complexity and urgency of the surgery.

Definitions of massive transfusion in adults with critical bleeding: a systematic review

BACKGROUND

Definitions for massive transfusion (MT) vary widely between studies, contributing to challenges in interpretation of research findings and practice evaluation. In this first systematic review, we aimed to identify all MT definitions used in randomised controlled trials (RCTs) to date to inform the development of consensus definitions for MT.

METHODS

We systematically searched the following databases for RCTs from inception until 11 August 2022: MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Cumulative Index to Nursing and Allied Health Literature, and Transfusion Evidence Library. Ongoing trials were sought from CENTRAL, ClinicalTrials.gov, and World Health Organisation International Clinical Trials Registry Platform. To be eligible for inclusion, studies had to fulfil all the following three criteria: (1) be an RCT; (2) include an adult patient population with major bleeding who had received, or were anticipated to receive, an MT in any clinical setting; and (3) specify a definition for MT as an inclusion criterion or outcome measure.

RESULTS

Of the 8,458 distinct references identified, 30 trials were included for analysis (19 published, 11 ongoing). Trauma was the most common clinical setting in published trials, while for ongoing trials, it was obstetrics. A total of 15 different definitions of MT were identified across published and ongoing trials, varying greatly in cut-offs for volume transfused and time period. Almost all definitions specified the number of red blood cells (RBCs) within a set time period, with none including plasma, platelets or other haemostatic agents that are part of contemporary transfusion resuscitation. For completed trials, the most commonly used definition was transfusion of ≥ 10 RBC units in 24 h (9/19, all in trauma), while for ongoing trials it was 3-5 RBC units (n = 7), with the timing for transfusion being poorly defined, or in some trials not provided at all (n = 5).

CONCLUSIONS

Transfusion of ≥ 10 RBC units within 24 h was the most commonly used definition in published RCTs, while lower RBC volumes are being used in ongoing RCTs. Any consensus definitions should reflect the need to incorporate different blood components/products for MT and agree on whether a 'one-size-fits-all' approach should be used across different clinical settings.

The prognostic value of fibrinogen to albumin ratio in malignant tumor patients: A meta-analysis

Background

Recent studies have shown that the fibrinogen to albumin ratio (FAR) is closely related to the prognosis of various cancers. The aim of this systematic review and meta-analysis was to investigate the prognostic value of FAR in malignancies based on the available evidence.

Method

To systematically search the Cochrane Library, Embase, PubMed, Google Scholar, Baidu scholars, CNKI and VIP databases for relevant studies published before April 1, 2022, and to evaluate the fibrinogen-to-albumin ratio (FAR) and survival of patients with malignant tumors through a meta-analysis relationship between the results. Results. This meta-analysis included 19 eligible studies involving 5926 cancer patients. We found that high FAR was associated with poor overall survival (HR=2.25, 95%CI 1.86-2.74, p&lt;0.001), recurrence-free survival (HR=2.29, 95%CI 1.91-2.76, P&lt;0.001), progression-free survival (HR: 2.10, 95%CI 1.58-2.79, p&lt;0.001), disease-free survival (HR=1.52, 95%CI 1.17-1.96, p=0.001), and time to recurrence (HR: 1.555, 95%CI 1.031-2.346, P=0.035) was significantly correlated.

Conclusions

High FAR is significantly associated with poor clinical outcomes in cancer, suggesting that it may be an important predictor of prognosis in patients with malignancies.

Effect of 4% Albumin Solution vs Ringer Acetate on Major Adverse Events in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass: A Randomized Clinical Trial

IMPORTANCE

In cardiac surgery, albumin solution may maintain hemodynamics better than crystalloids and reduce the decrease in platelet count and excessive fluid balance, but randomized trials are needed to compare the effectiveness of these approaches in reducing surgical complications.

OBJECTIVE

To assess whether 4% albumin solution compared with Ringer acetate as cardiopulmonary bypass prime and perioperative intravenous volume replacement solution reduces the incidence of major perioperative and postoperative complications in patients undergoing cardiac surgery.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, double-blind, single-center clinical trial in a tertiary university hospital during 2017-2020 with 90-day follow-up postoperatively involving patients undergoing on-pump coronary artery bypass grafting; aortic, mitral, or tricuspid valve surgery; ascending aorta surgery without hypothermic circulatory arrest; and/or the maze procedure were randomly assigned to 2 study groups (last follow-up was April 13, 2020).

INTERVENTIONS

The patients received in a 1:1 ratio either 4% albumin solution (n = 693) or Ringer acetate solution (n = 693) as cardiopulmonary bypass priming and intravenous volume replacement intraoperatively and up to 24 hours postoperatively.

MAIN OUTCOMES AND MEASURES

The primary outcome was the number of patients with at least 1 major adverse event: death, myocardial injury, acute heart failure, resternotomy, stroke, arrhythmia, bleeding, infection, or acute kidney injury.

RESULTS

Among 1407 patients randomized, 1386 (99%; mean age, 65.4 [SD, 9.9] years; 1091 men [79%]; 295 women [21%]) completed the trial. Patients received a median of 2150 mL (IQR, 1598-2700 mL) of study fluid in the albumin group and 3298 mL (IQR, 2669-3500 mL) in the Ringer group. The number of patients with at least 1 major adverse event was 257 of 693 patients (37.1%) in the albumin group and 234 of 693 patients (33.8%) in the Ringer group (relative risk albumin/Ringer, 1.10; 95% CI, 0.95-1.27; P = .20), an absolute difference of 3.3 percentage points (95% CI, -1.7 to 8.4). The most common serious adverse events were pulmonary embolus (11 [1.6%] in the albumin group vs 8 [1.2%] in the Ringer group), postpericardiotomy syndrome (9 [1.3%] in both groups), and pleural effusion with intensive care unit or hospital readmission (7 [1.0%] in the albumin group vs 9 [1.3%] in the Ringer group).

CONCLUSIONS AND RELEVANCE

Among patients undergoing cardiac surgery with cardiopulmonary bypass, treatment with 4% albumin solution for priming and perioperative intravenous volume replacement solution compared with Ringer acetate did not significantly reduce the risk of major adverse events over the following 90 days. These findings do not support the use of 4% albumin solution in this setting.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02560519.

Renal injury in cardiorenal syndrome type 1 is mediated by albumin

Cardiorenal syndrome type 1 (CRS‐1) acute kidney injury (AKI) is a critical complication of acute cardiovascular disease but is poorly understood. AKI induces acute albuminuria. As chronic albuminuria is associated with worsening kidney disease and albumin has been implicated in tubular epithelial injury, we investigated whether albumin participates in CRS‐1, and whether CRS‐1 alters renal albumin handling. We report the role of albumin in in vivo and in vitro CRS‐1 models. An established translational model, cardiac arrest and cardiopulmonary resuscitation (CA/CPR) induced severe acute albuminuria which correlated with tubular epithelial cell death. In vivo microscopy demonstrated CA/CPR‐induced glomerular filtration of exogenous albumin, while administration of exogenous albumin after CA/CPR worsened AKI compared to iso‐oncotic control. Increased albumin signal was observed in the proximal tubules of CA/CPR mice compared to sham. Comparison of albumin flux from tubular lumen to epithelial cells revealed saturated albumin transport within minutes of albumin injection after CA/CPR. In vitro, HK2 cells (human kidney tubular epithelial cells), exposed to oxygen‐glucose deprivation were injured by albumin in a dose dependent fashion. This interference was unchanged by the tubular endocytic receptor megalin. In conclusion, CRS‐1 alters albumin filtration and tubular uptake, leading to increased tubular exposure to albumin, which is injurious to tubular epithelial cells, worsening AKI. Our findings shed light on the pathophysiology of renal albumin and may guide interventions such as albumin resuscitation to improve CRS‐1 outcomes. This investigation may have important translational relevance for patients that receive exogenous albumin as part of their CRS‐1 treatment regimen.

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.

Albumin use in bleeding cardiac surgical patients and associated patient outcomes

PURPOSE

Albumin solution is a colloid used for resuscitation in cardiac surgical patients, but it is unclear if it offers advantages over crystalloids. We examined current clinical practice across 11 cardiac surgical centres and the association of albumin with outcomes in a cohort of bleeding cardiac surgical patients.

METHODS

This was a post hoc analysis of data from the Effect of Fibrinogen Concentrate vs Cryoprecipitate on Blood Component Transfusion After Cardiac Surgery (FIBRES) trial. Multivariable regression models adjusted for demographic and surgical characteristics were used to examine predictors of early albumin administration (within the initial 24 perioperative hours), late albumin administration (from 24 hr to seven days after cardiopulmonary bypass), and the association of albumin use with 28-day acute kidney injury, mortality, and length of hospital and intensive care unit (ICU) stay.

RESULTS

Of the 735 patients included, 525 (71%) received albumin, ranging from 4.8% to 97.4% of patients across institutions, with 475 (64.6%) receiving albumin early (5% or 25% solution). In the adjusted models, female sex and preoperative hospital admission were associated with early use, while heart failure, female sex, bleeding severity, older age, and prior albumin use were predictors of later administration. Early albumin use was not associated with differences in acute kidney injury (adjusted odds ratio [aOR] 1.77; 95% confidence interval [CI], 0.96 to 3.27; P = 0.07), mortality (aOR 1.66; 95% CI, 0.99 to 2.78; P = 0.05), or length of ICU stay (P = 0.11) or hospital stay (P = 0.67).

CONCLUSIONS

Albumin use is common but highly variable within and across sites. Albumin use was not associated with improved outcomes. High quality randomized controlled trials should clarify its role in cardiac surgical patients.

Early Albumin Exposure After Cardiac Surgery

OBJECTIVES

To determine whether the early use of albumin after cardiac surgery in the first 24 hours in the intensive care unit (ICU) is associated with reduced mortality.

DESIGN

A single-center nonrandomized retrospective cohort study using the Medical Information Mart in Intensive Care IV database.

SETTING

A single cardiothoracic ICU in the United States during a period between 2008 to 2019.

PARTICIPANTS

Patients undergoing valvular and/or cardiac bypass graft surgeries.

INTERVENTIONS

Albumin administered during the first 24 hours of the ICU admission.

MEASUREMENTS AND MAIN RESULTS

A total of 8,136 patients were included in this study, of whom 4,444 (54.6%) received albumin at any stage during the first 24 hours of ICU admission, and 69 (1.6%) of those patients died. The patient population exposed to albumin had higher comorbidities and illness severity compared to the no-albumin group. Patients exposed to albumin during the first 24 hours of ICU admission had a statistically significant reduction in mortality (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.48-0.97, p < 0.05) after adjustment for age, the Oxford Acute Severity of Illness Score, and the Charlson comorbidity index. A sensitivity analysis of patients who received albumin at any stage during ICU admission showed increased mortality (OR, 1.93; 95% CI, 1.26-3.07, p < 0.01). Patients exposed to albumin had a significant increase in adjusted ICU length of stay (LOS) (geometric mean ratio 1.09; 95% CI, 1.05-1.10, p = < 0.001) and hospital LOS (geometric mean ratio 1.08; 95% CI, 1.05-1.10, p < 0.001).

CONCLUSIONS

Exposure to albumin in the first 24 hours after cardiac surgery is associated with a reduction in adjusted hospital mortality and an increase in both hospital and ICU lengths of stay.

Air, inflammation and biocompatibility of the extracorporeal circuits

The inflammatory response in cardiac surgery using extracorporeal circulation (ECC) has been widely discussed in the literature with analysis on cytokines released in humans; demonstrating manifold trigger causes. To mitigate this response-mainly linked to the contact and recognition by the blood of a "non-self" surface-many efforts have been made to make the circuits of the extra-corporeal circulation "biomimetics"; trying to emulate the cardio-vascular system. In other words, biomedical companies have developed many biocompatible products in order to reduce the invasiveness of the ECC. One of the techniques used to reduce the contact of blood with "nonself" surfaces is the "coating" of the internal surfaces of the ECC. This can be done with phospholipidic, electrically neutral, and heparin derivates with anticoagulant activity. The coating can be divided into two categories: the "passive coating" with Phosphorylcholine by biomedical companies and the administration of albumin added to the "priming" during the filling of the circuit by the perfusionist. Alternatively, we have the "active" coating: treatment of the internal surfaces in contact with the blood with neutral proteins and heparin. The latter are different according to the production company, but the aim is always to maintain high levels of systemic and local anticoagulation, inactivating the "contact" coagulation between the blood and the surfaces. A recent study demonstrates that the use of an "active coating" is associated with better preservation of the endothelial glycocalyx compared with "passive coating" circuits.