Fluid resuscitation practices in cardiac surgery patients in the USA: a survey of health care providers

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.

Perioperative fluid management: evidence-based consensus recommendations from the international multidisciplinary PeriOperative Quality Initiative

Fluid therapy is an integral component of perioperative management. In light of emerging evidence in this area, the Perioperative Quality Initiative (POQI) convened an international multiprofessional expert meeting to generate evidence-based consensus recommendations for fluid management in patients undergoing surgery. This article provides a summary of the recommendations for perioperative fluid management of surgical patients from the preoperative period until hospital discharge and for all types of elective and emergency surgery, apart from burn injuries and head and neck surgery. Where evidence was lacking, recommendations for future research were generated. Specific recommendations are made for fluid management in elective major noncardiac surgery, cardiopulmonary bypass, thoracic surgery, neurosurgery, minor noncardiac surgery under general anaesthesia, and critical illness. There are ongoing gaps in knowledge resulting in variation in practice and some disagreement with our consensus recommendations. Perioperative fluid management should be individualised, taking into account the type of surgery and important patient factors, including intravascular volume status and acute and chronic comorbidities. Recommendations are made for further research in perioperative fluid management to address important gaps.

Reduce intraoperative albumin utilisation in cardiac surgical patients: a quality improvement initiative

BACKGROUND

Albumin continues to be used routinely by cardiac anaesthesiologists perioperatively despite lack of evidence for improved outcomes. The Multicenter Perioperative Outcomes Group (MPOG) data ranked our institution as one of the highest intraoperative albumin users during cardiac surgery. Therefore, we designed a quality improvement project (QIP) to introduce a bundle of interventions to reduce intraoperative albumin use in cardiac surgical patients.

METHODS

Our institutional MPOG data were used to analyse the FLUID-01-C measure that provides the number of adult cardiac surgery cases where albumin was administered intraoperatively by anaesthesiologists from 1 July 2019 to 30 June 2022. The QIP involved introduction of the following interventions: (1) education about appropriate albumin use and indications (January 2021), (2) email communications reinforced with OR teaching (March 2021), (3) removal of albumin from the standard pharmacy intraoperative medication trays (April 2021), (4) grand rounds presentation discussing the QIP and highlighting the interventions (May 2021) and (5) quarterly provider feedback (starting July 2021). Multivariable segmented regression models were used to assess the changes from preintervention to postintervention time period in albumin utilisation, and its total monthly cost.

RESULTS

Among the 5767 cardiac surgery cases that met inclusion criteria over the 3-year study period, 16% of patients received albumin intraoperatively. The total number of cases that passed the metric (albumin administration was avoided), gradually increased as our interventions went into effect. Intraoperative albumin utilisation (beta=-101.1, 95% CI -145 to -56.7) and total monthly cost of albumin (beta=-7678, 95% CI -10712 to -4640) demonstrated significant decrease after starting the interventions.

CONCLUSIONS

At a single academic cardiac surgery programme, implementation of a bundle of simple and low-cost interventions as part of a coordinated QIP were effective in significantly decreasing intraoperative use of albumin, which translated into considerable costs savings.

Postoperative free water administration is associated with dysnatremia after congenital heart disease surgery in infants

Dysnatremia after congenital heart disease (CHD) surgery is common. European guidelines on intraoperative fluid therapy in children recommend isotonic solutions to avoid hyponatremia, but prolonged cardiopulmonary bypass and administration of high sodium-containing solutions (i.e., blood products and sodium bicarbonate) are associated with postoperative hypernatremia. The aim of the study was to describe fluid composition prior to and during the development of postoperative dysnatremia. A retrospective observational, single-center study including infants undergoing CHD surgery. Demographics and clinical characteristics were registered. Highest and lowest plasma sodium values were recorded and associations with perioperative fluid administration, blood products, crystalloids, and colloids were explored in relation to three perioperative periods. Postoperative dysnatremia occurred in nearly 50% of infants within 48 h after surgery. Hypernatremia was mainly associated with administration of blood products (median [IQR]: 50.5 [28.4-95.5] vs. 34.5 [18.5-61.1] mL/kg; p = 0.001), and lower free water load (1.6 [1.1-2.2] mL/kg/h; p = 0.01). Hyponatremia was associated with a higher free water load (2.3 [1.7-3.3] vs. 1.8 [1.4-2.5] mL/kg/h; p = 0.001) and positive fluid balance. On postoperative day 1, hyponatremia was associated with higher volumes of free water (2.0 [1.5-2.8] vs. 1.3 [1.1-1.8] mL/kg/h; p < 0.001) and human albumin, despite a larger diuresis and more negative daily fluid balance. Postoperative hyponatremia occurred in 30% of infants despite restrictive volumes of hypotonic maintenance fluid, whereas hypernatremia was mainly associated with blood product transfusion. Individualized fluid therapy, with continuous reassessment to reduce the occurrence of postoperative dysnatremia is mandatory in pediatric cardiac surgery. Prospective studies to evaluate fluid therapy in pediatric cardiac surgery patients are warranted.

Adult Cardiac Surgery-Associated Acute Kidney Injury: Joint Consensus Report

OBJECTIVES

Acute kidney injury (AKI) is increasingly recognized as a source of poor patient outcomes after cardiac surgery. The purpose of the present report is to provide perioperative teams with expert recommendations specific to cardiac surgery-associated AKI (CSA-AKI).

METHODS

This report and consensus recommendations were developed during a joint, in-person, multidisciplinary conference with the Perioperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society. Multinational practitioners with diverse expertise in all aspects of cardiac surgical perioperative care, including clinical backgrounds in anesthesiology, surgery and nursing, met from October 20 to 22, 2021, in Sacramento, California, and used a modified Delphi process and a comprehensive review of evidence to formulate recommendations. The quality of evidence and strength of each recommendation were established using the Grading of Recommendations Assessment, Development, and Evaluation methodology. A majority vote endorsed recommendations.

RESULTS

Based on available evidence and group consensus, a total of 13 recommendations were formulated (4 for the preoperative phase, 4 for the intraoperative phase, and 5 for the postoperative phase), and are reported here.

CONCLUSIONS

Because there are no reliable or effective treatment options for CSA-AKI, evidence-based practices that highlight prevention and early detection are paramount. Cardiac surgery-associated AKI incidence may be mitigated and postsurgical outcomes improved by focusing additional attention on presurgical kidney health status; implementing a specific cardiopulmonary bypass bundle; using strategies to maintain intravascular euvolemia; leveraging advanced tools such as the electronic medical record, point-of-care ultrasound, and biomarker testing; and using patient-specific, goal-directed therapy to prioritize oxygen delivery and end-organ perfusion over static physiologic metrics.

Perioperative Gelatin Use Is Associated With Increased Complication Rates and Does Not Prevent Postoperative Fluid Overload in Patients Undergoing Elective Cardiac Surgery

OBJECTIVES

The benefit of using gelatin solution in cardiac surgery is still controversial. Previous data suggested adverse interactions of gelatin infusion with acute kidney injury (AKI) or coagulopathy. The purpose of this study was to evaluate the association between perioperative gelatin use and fluid overload (FO), hemodynamic stability, and outcomes compared to crystalloid-based fluid management.

DESIGN

A retrospective study design.

SETTING

At a single-center tertiary university setting.

PARTICIPANTS

Propensity score-matched cohort study of 191 pairs of patients scheduled for cardiac surgery.

INTERVENTIONS

Patients received either gelatin + crystalloid or pure crystalloid-based perioperative fluid management. The primary outcomes were the frequency of FO and hemodynamic stability defined by the vasoactive-inotropic score. Postoperative complications and 3-year survival were analyzed also.

MEASUREMENTS AND MAIN RESULTS

Patients who received gelatin experienced more frequent postoperative FO than controls (11.0% v 3.1%, p = 0.006) despite comparable hemodynamic stability in both groups. Gelatin administration was linked with a higher rate of postoperative complications, including blood loss, AKI, and new-onset postoperative atrial fibrillation. Use of gelatin infusion resulted in an adjusted odds ratio of 1.982 (95% CI 1.051-3.736, p = 0.035) for developing early postoperative AKI. This study confirmed a dose-dependent relationship between gelatin infusion and AKI. Thirty-day mortality and 3-year survival were similar in the groups.

CONCLUSIONS

Gelatin administration versus crystalloid fluid management showed a significant association with a higher rate of FO and an increased risk for early postoperative AKI in a dose-dependent manner.

Albumin use for fluid resuscitation in cardiac surgical patients: a survey of Canadian perioperative care providers

PURPOSE

To evaluate the perceptions and practices of Canadian cardiovascular anesthesiologists and intensivists towards intravenous albumin as a resuscitation fluid in patients undergoing cardiac surgery.

METHODS

We conducted a cross-sectional survey of cardiac anesthesiologists and intensivists involved in the care of cardiac surgical patients. The 22-item survey included seven open-ended questions and assessed practice patterns and attitudes towards albumin. Descriptive statistics were analyzed using counts and proportions. Qualitative data were analyzed to identify themes describing albumin use patterns in Canada.

RESULTS

A total of 133 respondents from seven provinces participated, with 83 (62%) using albumin perioperatively. The majority of respondents (77%) felt a low fluid balance in cardiac surgical patients was important, and that supplementing crystalloids with albumin was helpful for this objective (67%). There was poor agreement among survey respondents regarding the role of albumin for faster vasopressor weaning or intensive care discharge, and ≥ 90% did not feel albumin reduced mortality, renal injury, or coagulopathy. Nevertheless, cardiac surgical patients were identified as a distinct population where albumin may help to minimize fluid balance. There was an acknowledged paucity of formal evidence supporting possible benefits. Fewer than 10% of respondents could identify institutional or national guidelines for albumin use. A lack of evidence supporting albumin use in cardiac surgical patients, especially those at highest risk of complications, was a frequently identified concern.

CONCLUSIONS

The majority of Canadian anesthesiologists and intensivists (62%) use albumin in cardiac surgical patients. There is clinical equipoise regarding its utility, and an acknowledged need for higher quality evidence to guide practice.

Hemodilution in high-risk cardiac surgery: Laboratory values, physiological parameters, and outcomes

BACKGROUND

Acute normovolemic hemodilution (ANH) is a blood conservation strategy in cardiac surgery, predominantly used in coronary artery bypass graft (CABG) and/or valve procedures. Although higher complexity cardiac procedures may benefit from ANH, concerns for hemodynamic instability, and organ injury during hemodilution hinder its wider acceptance. Laboratory and physiological parameters during hemodilution in complex cardiac surgeries have not been described.

STUDY DESIGN AND METHODS

This observational cohort (2019-2021) study included 169 patients who underwent thoracic aortic repair, multiple valve procedure, concomitant CABG with the aforementioned procedure, and/or redo sternotomies. Patients who received allogeneic blood were excluded. Statistical comparisons were performed between ANH (N = 66) and non-ANH controls (N = 103). ANH consisted of removal of blood at the beginning of surgery and its return after cardiopulmonary bypass.

RESULTS

Intraoperatively, the ANH group received more albumin (p = .04) and vasopressor medications (p = .01), while urine output was no different between ANH and controls. Bilateral cerebral oximetry (rSO₂ ) values were similar before and after hemodilution. During bypass, rSO₂ were discretely lower in the ANH versus control group (right rSO₂ p = .03, left rSO₂ p = .05). No differences in lactic acid values were detected across the procedural continuum. Postoperatively, no differences in extubation times, intensive care unit length of stay, kidney injury, stroke, or infection were demonstrated.

DISCUSSION

This study suggests hemodilution to be a safe and comparable blood conservation technique, even without accounting for potential benefits of reduced allogenic blood administration. The study may contribute to better understanding and wider acceptance of ANH protocols in high-risk cardiac surgeries.

Fluid resuscitation after cardiac surgery in the intensive care unit: A bi-national survey of clinician practice. (The FRACS-ICU clinician survey)

Context and Aims

To describe current fluid and vasopressor practices after cardiac surgery in Australia and New Zealand cardiothoracic intensive care units (ICU).

Design and Setting

This web-based survey was conducted in cardiothoracic ICUs in Australia and New Zealand.

Methods

Intensivists, cardiac surgeons, and anesthetists were contacted to complete the online survey that asked questions regarding first and second choice fluids and vasopressors and the tools and factors that influenced these choices.

Results

There were 96 respondents including 51 intensivists, 27 anesthetists, and 18 cardiac surgeons. Balanced crystalloids were the most preferred fluids (70%) followed by 4% albumin (18%) overall and among intensivists and anesthetists; however, cardiac surgeons (41%) preferred 4% albumin as their first choice. The most preferred second choice was 4% albumin (74%). Among vasopressors, noradrenaline was the preferred first choice (93%) and vasopressin the preferred second choice (80%). 53% initiated blood transfusion at a hemoglobin threshold of 70 g/L. Clinical acumen and mean arterial pressure were the most commonly used modalities in determining the need for fluids.

Conclusions

There is practice variation in preference for fluids used in cardiac surgical patients in Australia and New Zealand; however, balanced crystalloids and 4% albumin were the most popular choices. In contrast, there is broad agreement with the use of noradrenaline and vasopressin as first and second-line vasopressors. These data will inform the design of future studies that aim to investigate hemodynamic management post cardiac surgery.

A randomised controlled trial of succinylated gelatin (4%) fluid on urinary acute kidney injury biomarkers in cardiac surgical patients

Background

Fluid resuscitation is frequently required for cardiac surgical patients admitted to the intensive care unit. The ideal fluid of choice in regard to efficacy and safety remains uncertain. Compared with crystalloid fluid, colloid fluid may result in less positive fluid balance. However, some synthetic colloids are associated with increased risk of acute kidney injury (AKI). This study compared the effects of succinylated gelatin (4%) (GEL) with compound sodium lactate (CSL) on urinary AKI biomarkers in patients after cardiac surgery.

Methods

Cardiac surgical patients who required an intravenous fluid bolus of at least 500 mL postoperatively were randomly allocated to receive GEL or CSL as the resuscitation fluid of choice for the subsequent 24 h. Primary outcomes were serial urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C concentrations measured at baseline, 1 h, 5 h and 24 h after enrolment, with higher concentrations indicating greater kidney injury. Secondary biomarker outcomes included urinary clusterin, α1-microglobulin and F₂-isoprostanes concentrations. Differences in change of biomarker concentration between the two groups over time were compared with mixed-effects regression models. Statistical significance was set at P < 0.05.

Results

Forty cardiac surgical patients (n = 20 per group) with similar baseline characteristics were included. There was no significant difference in the median volume of fluid boluses administered over 24 h between the GEL (1250 mL, Q1–Q3 500–1750) and CSL group (1000 mL, Q1–Q3 500–1375) (P = 0.42). There was a significantly greater increase in urinary cystatin C (P < 0.001), clusterin (P < 0.001), α1-microglobulin (P < 0.001) and F₂-isoprostanes (P = 0.020) concentrations over time in the GEL group, compared to the CSL group. Change in urinary NGAL concentration (P = 0.68) over time was not significantly different between the groups. The results were not modified by adjustment for either urinary osmolality or EuroSCORE II predicted risk of mortality.

Conclusions

This preliminary randomised controlled trial showed that use of succinylated gelatin (4%) for fluid resuscitation after cardiac surgery was associated with increased biomarker concentrations of renal tubular injury and dysfunction, compared to crystalloid fluid. These results generate concern that use of intravenous gelatin fluid may contribute to clinically relevant postoperative AKI.

Trial registration ANZCTR.org.au, ACTRN12617001461381. Registered on 16th October, 2017, http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373619&isReview=true.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00412-9.

Rapid 500 mL albumin bolus versus rapid 200 mL bolus followed by slower continuous infusion in post-cardiac surgery patients: a pilot before-and-after study

Objective: To evaluate the haemodynamic effects of rapid fluid bolus therapy (FBT) (500 mL of 4% albumin over several minutes) versus combined FBT (rapid 200 mL FBT followed by a 300 mL infusion over 30 minutes). Design: Single centre, prospective, before-and-after trial. Setting: A tertiary intensive care unit in Australia. Participants: Fifty mechanically ventilated post-cardiac surgery patients. Interventions: Rapid 4% albumin FBT versus combined FBT. Main outcome measures: We recorded haemodynamic parameters from before FBT to 30 minutes after FBT. A mean arterial pressure (MAP) response was defined by a MAP increase > 10%, and a cardiac index (CI) response was defined by a CI increase > 15%. Results: Immediately after rapid FBT versus combined FBT, there was a CI response in 13 patients (52%) compared with five patients (20%) respectively (P = 0.038), and a MAP response in 11 patients (44%) in each group. However, from FBT administration to 30 minutes, there was a time and group interaction such that MAP was higher in the rapid FBT group (P = 0.003), as was the case for central venous pressure (P = 0.002) and mean pulmonary artery pressure (P < 0.001). Body temperature fell immediately and was lower with rapid FBT but became warmer than with combined FBT later (P < 0.001). At 30 minutes, a MAP response was seen in ten patients (40%) compared with nine patients (36%) (P < 0.99) and a CI response was present in eight patients (32%) compared with 11 patients (44%) (P = 0.56) in the rapid versus combined FBT groups respectively. Conclusion: Rapid FBT was superior to combined FBT in terms of mean MAP levels and immediate CI response. However, the number of MAP responders or CI responders was similar at 30 minutes.

A Multicenter, Open-Label, Randomized Controlled Trial of a Conservative Fluid Management Strategy Compared With Usual Care in Participants After Cardiac Surgery: The Fluids After Bypass Study

OBJECTIVES

There is little evidence to guide fluid administration to patients admitted to the ICU following cardiac surgery. This study aimed to determine if a protocolized strategy known to reduce fluid administration when compared with usual care reduced ICU length of stay following cardiac surgery.

DESIGN

Prospective, multicenter, parallel-group, randomized clinical trial.

SETTING

Five cardiac surgical centers in New Zealand conducted from November 2016 to December 2018 with final follow-up completed in July 2019.

PATIENTS

Seven-hundred fifteen patients undergoing cardiac surgery; 358 intervention and 357 usual care.

INTERVENTIONS

Randomization to protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid or usual care fluid administration until desedation or up to 24 hours. Primary outcome was length of stay in ICU. Organ dysfunction, mortality, process of care measures, patient-reported quality of life, and disability-free survival were collected up to day 180.

MEASUREMENTS AND MAIN RESULTS

Overall 666 of 715 (93.1%) received at least one fluid bolus. Patients in the intervention group received less bolus fluid (median [interquartile range], 1,000 mL [250-2,000 mL] vs 1,500 mL [500-2,500 mL]; p < 0.0001) and had a lower overall fluid balance (median [interquartile range], 319 mL [-284 to 1,274 mL] vs 673 mL [38-1,641 mL]; p < 0.0001) in the intervention period. There was no difference in ICU length of stay between the two groups (27.9 hr [21.8-53.5 hr] vs 25.6 hr [21.9-64.6 hr]; p = 0.95). There were no differences seen in development of organ dysfunction, quality of life, or disability-free survival at any time points. Hospital mortality was higher in the intervention group (4% vs 1.4%; p = 0.04).

CONCLUSIONS

A protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid when compared with usual care until desedation or up to 24 hours reduced the amount of fluid administered but did not reduce the length of stay in ICU.

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.

Year in Review 2020: Noteworthy Literature in Cardiothoracic Critical Care

This year will be forever marked by the drastic changes COVID-19 wrought on our personal and professional lives. New roles and challenges in critical care have forced us to be constantly nimble and flexible in how we approach medicine. The strain of these challenges is apparent throughout the health care community and our society as a whole. Despite this adversity, 2020 will also be remembered for fantastic advances in research. This article is a collection of influential and exciting studies published in 2020 encompassing a broad swath of critical care with a focus on cardiothoracic critical care. Themes include examinations of early extracorporeal membrane oxygenation support for out-of-hospital cardiac arrest patients, the impact of sedation and other risk factors on perioperative mortality, a novel fluid resuscitation strategy following cardiac surgery, and advances in the fields of heart and lung transplantation as well as how they were affected by COVID-19. Given that many cardiothoracic intensivists were redeployed to the care of SARS-CoV-2 patients, we also discuss important advances in therapeutics for the virus.

Temperature and haemodynamic effects of a 100 mL bolus of 20% albumin at room versus body temperature in cardiac surgery patients

Objective: To study the temperature and haemodynamic effects of room versus body temperature 20% albumin fluid bolus therapy (FBT). Design: Single-centre, prospective, before-after trial. Setting: A tertiary intensive care unit (ICU) in Australia. Participants: Sixty ventilated post-cardiac surgery patients. Intervention: Room versus body temperature 100 mL 20% albumin FBT. Main outcome measures: We recorded haemodynamic data from FBT start to 30 minutes after FBT. The cardiac index (CI) response was defined by a CI increase > 15%, and the mean arterial pressure (MAP) response was defined by a MAP increase > 10%. Outcomes: Immediately after FBT, median blood temperature decreased by -0.1°C (interquartile range [IQR], -0.1 to 0.0°C) with room temperature albumin versus 0.0°C (IQR, -0.1 to 0.0°C) with body temperature albumin (P < 0.001). The CI or MAP responses were similar. There was, however, a time and study group interaction for blood temperature (P < 0.001) for absolute and relative changes. In addition, mean pulmonary arterial pressure (PAP) (P = 0.002) increased more with body temperature albumin and remained higher for most of the observation period. Conclusion: Compared with room temperature albumin FBT, body temperature 20% albumin FBT prevents FBT-associated blood temperature fall and increases mean PAP. However, CI and MAP changes were the similar between the two groups, implying that fluid temperature has limited haemodynamic effects in these patients.

Prognostic Utility of KDIGO Urine Output Criteria After Cardiac Surgery

OBJECTIVES

Kidney Disease: Improving Global Outcomes (KDIGO) guidelines include assessment of creatinine and urine output to identify acute kidney injury (AKI). Whether urine output is an accurate indicator of AKI after cardiac surgery, however, is unclear. The authors' goal was to examine whether cardiac surgery patients who fulfilled criteria for AKI by KDIGO urine output criteria also demonstrated kidney injury by elevated creatinine, other kidney biomarkers, or had worse clinical outcomes.

DESIGN

Secondary analysis of prospectively collected data from a clinical trial, "6% Hydroxyethyl starch 130/0.4 in Cardiac Surgery (NCT02192502)."

SETTING

Academic, quaternary care hospital.

PARTICIPANTS

Patients undergoing elective aortic valve replacement INTERVENTIONS: None MEASUREMENTS AND MAIN RESULTS: One hundred forty-one patients were classified into AKI stage by KDIGO urine output criteria within 24 hours after surgery. Kidney biomarkers (serum creatinine, urinary neutrophil gelatinase-associated lipocalin [NGAL], urinary interleukin-18 [IL-18]) and hospital and intensive care unit length of stay were analyzed across AKI stages. Urine output criteria classified four times as many patients with AKI than creatinine criteria (95 [67%] v 21 [15%]). Most patients meeting KDIGO urine output criteria for AKI postoperatively did not satisfy KDIGO creatinine criteria for AKI within one week (77 of 95 [81%]) or six-to-12 months (27 of 29 [93%]). Higher AKI stage assessed by urine output was not associated with higher NGAL, IL-18, or longer hospital or intensive care unit stays.

CONCLUSIONS

Acute kidney injury classified by KDIGO urine output criteria was not associated with other biomarkers of kidney injury or worse patient outcomes. These data suggested that KDIGO urine output criteria after cardiac surgery may overclassify AKI stage; further research is needed.

Postoperative resuscitation with hypertonic saline or hyperoncotic albumin in patients following cardiac surgery: A review of the literature

BACKGROUND

Over-resuscitation in postcardiac surgery patients is associated with significant morbidity and mortality. Accordingly, there is a growing interest in hyperoncotic albumin and hypertonic saline for resuscitation in patients following cardiac surgery. In this article, we will review the use of hyperosmolar fluid therapies for resuscitation in postcardiac surgical patients from the current literature.

METHODS

A literature search was conducted in MEDLINE (PubMed) utilizing keywords, narrowing publications from 2009 to 2020.

RESULTS

Patients receiving concentrated albumin after cardiac surgery required less fluid bolus therapy, less time on vasopressors, and had a lower positive fluid balance compared with patients receiving crystalloids. There was no difference in mortality in those given 20% albumin compared with crystalloids postcardiac surgery. Patients administered hypertonic saline following cardiac surgery had increased urinary output but its effect on total fluid and body weight was not significantly different compared with crystalloids.

CONCLUSIONS

In this analysis, publications on resuscitation with hyperoncotic albumin and hypertonic saline in patients following cardiac surgery were reviewed. While there is data supporting the use of alternative fluid therapies in other critically ill populations, the limited literature focused on concentrated albumin and hypertonic saline for resuscitation following cardiac surgery is equivocal.

Albumin Use After Cardiac Surgery

Objectives

To investigate the effect of albumin exposure in ICU after cardiac surgery on hospital mortality, complications, and costs.

Design

A retrospective, single-center cohort study with economic evaluation.

Setting

Cardiothoracic ICU in Australia.

Patients

Adult patients admitted to the ICU after cardiac surgery.

Interventions

None.

Measurements and Main Results

Comparison of outcomes and costs in ICU after cardiac surgery based on 4% human albumin exposure. During the study period, 3,656 patients underwent cardiac surgery. After exclusions, 2,594 patients were suitable for analysis. One-thousand two-hundred sixty-four (48.7%) were exposed to albumin and 19 (1.4%) of those died. The adjusted hospital mortality of albumin exposure compared with no albumin was not significant (odds ratio, 1.24; 95% CI, 0.56-2.79; p = 0.6). More patients exposed to albumin returned to the operating theater for bleeding and/or tamponade (6.1% vs 2.1%; odds ratio, 2.84; 95% CI, 1.81-4.45; p < 0.01) and received packed red cell transfusions (p < 0.001). ICU and hospital lengths of stay were prolonged in those exposed to albumin (mean difference, 18 hr; 95% CI, 10.3-25.6; p < 0.001 and 87.5 hr; 95% CI, 40.5-134.6; p < 0.001). Costs (U.S. dollar) were higher in patients exposed to albumin, compared with those with no albumin exposure (mean difference in ICU costs, $2,728; 95% CI, $1,566-3,890 and mean difference in hospital costs, $5,427; 95% CI, $3,294-7,560).

Conclusions

There is no increased mortality in patients who are exposed to albumin after cardiac surgery. The patients exposed to albumin had higher illness severity, suffered more complications, and incurred higher healthcare costs. A randomized controlled trial is required to determine whether albumin use is effective and safe in this setting.

Hypertonic saline for fluid resuscitation in ICU patients post-cardiac surgery (HERACLES): a double-blind randomized controlled clinical trial

PURPOSE

Recent evidence questions a liberal approach to fluid resuscitation in intensive care unit (ICU) patients. Here, we assess whether use of hypertonic saline applied as single infusion at ICU admission after cardiac surgery can reduce cumulative perioperative fluid volume.

METHODS

Prospective randomized double-blind single-center clinical trial investigates effects of a single infusion of hypertonic saline (HS) versus normal saline (comparator). Primary endpoint was the cumulative amount of fluid administered in patients in the hypertonic saline versus the 0.9% saline groups (during ICU stay). Upon ICU admission, patients received a single infusion of 5 ml/kg body weight of 7.3% NaCl (or 0.9% NaCl) over 60 min. Patients undergoing cardiac surgery for elective valvular and/or coronary heart disease were included. Patients with advanced organ dysfunction, infection, and/or patients on chronic steroid medication were excluded.

RESULTS

A total of 101 patients were randomized to receive the study intervention (HS n = 53, NS n = 48). Cumulative fluid intake on the ICU (primary endpoint) did not differ between the HS and the NS groups [median 3193 ml (IQR 2052-4333 ml) vs. 3345 ml (IQR 2332-5043 ml)]. Postoperative urinary output until ICU discharge was increased in HS-treated patients [median 2250 ml (IQR 1640-2690 ml) vs. 1545 ml (IQR 1087-1976 ml)], and ICU fluid balance was lower in the HS group when compared to the NS group [296 ml (IQR - 441 to 1412 ml) vs. 1137 ml (IQR 322-2660 ml)].

CONCLUSION

In a monocentric prospective double-blind randomized clinical trial, we observed that hypertonic saline did not reduce the total fluid volume administered on the ICU in critically ill cardiac surgery patients. Hypertonic saline infusion was associated with timely increase in urinary output. Variations in electrolyte and acid-base homeostasis were transient, but substantial in all patients.

Evaluation of Albumin 25% Use in Critically Ill Patients at a Tertiary Care Medical Center

Background: Albumin 25% has been studied and has demonstrated benefit in a limited number of patient populations. The use of albumin 25% is associated with higher costs compared with crystalloid therapy. The aim of this study was to describe the prescribing practices of albumin 25% at a tertiary-care medical center and identify opportunities for restriction criteria related to its use to help generate cost savings. Methods: This evaluation was a retrospective, noninterventional, descriptive study of albumin 25% use between June 2015 and February 2016. Inclusion criteria consisted of patients ≥18 years old and who received at least one dose of albumin 25% while admitted to a Cleveland Clinic main campus intensive care unit (ICU). Inclusion was restricted to 150 randomly selected patients. Results: A total of 539 albumin 25% orders were placed for the 150 included patients. The cardiovascular ICU more frequently prescribed albumin 25% compared with the medical, surgical, neurosciences, and coronary ICUs (51% vs 23% vs 11% vs 9% vs 6%, respectively). Although the cardiovascular surgery ICU most frequently prescribed albumin 25% compared with other ICUs, the medical ICU prescribed a larger total quantity of albumin 25% compared with the cardiovascular, surgical, neurosciences, and coronary ICUs (8705 g vs 7275 g vs 3205 g vs 2162 g vs 625 g, respectively). The majority of patients (61%) did not have an indication listed for albumin 25% use and only 9% of patients were prescribed for indications supported by primary literature. Of the patients prescribed albumin for other indications not supported by primary literature (30%), the most common reasons for albumin 25% were hypotension, acute kidney injury, and volume resuscitation. The median cost per patient of albumin 25% was $417 with a total cost of $122 164 for the cohort. Only 19% of the total cost aligned with dosing regimens evaluated in primary literature. Conclusion: Prescribing patterns of albumin 25% at a tertiary academic medical center do not align with indications supported by primary literature. These findings identified a major opportunity for prescriber education and implementation of restriction criteria to target cost savings.

Postoperative management of patients undergoing cardiac surgery in Austria : A national survey on current clinical practice in hemodynamic monitoring and postoperative management

Background

No data are currently available regarding the current clinical practice in postoperative care of cardiac surgical patients in Austria.

Objective

The study investigated the current intensive care management concerning hemodynamic monitoring and strategies to treat common perioperative disorders of patients after cardiac surgery in Austria.

Methods

A survey consisting of 31 questions was sent to intensivists at all 9 hospitals offering cardiac surgery in Austria.

Results

The response rate was 100%. The mean number of procedures on cardiopulmonary bypass per centre was 722 ± 223. In the majority of cases postoperative critical care is performed by anesthesiologists. Blood gas analysis, pulse oximetry, electrocardiogram, temperature, central venous pressure, arterial pressure and hourly urine output are de facto standard monitoring in all centers. Transesophageal echocardiography is available in all centers and is frequently used. Crystalloids are the first choice for volume replacement, whereas levosimendan and adrenaline are employed for the treatment of low cardiac output syndrome.

Conclusions

This study provides insights into the current state of postoperative management of cardiac surgical patients in Austria. Standard monitoring as proposed by international guidelines is well established in Austrian intensive care units. Echocardiography is widely seen as a very important tool in the postoperative care of cardiac surgical patients. Knowledge about the status quo of postoperative intensive care management of cardiac surgical patients enables further development of patient care.

Electronic supplementary material

The online version of this article (10.1007/s00508-018-1403-3) contains supplementary material, which is available to authorized users.