The Effect of Postoperative Fluid Balance on the Occurrence and Progression of Acute Kidney Injury After Cardiac Surgery

Perioperative Bleeding Is Not an Independent Risk Factor for Acute Kidney Injury in On-pump Cardiac Surgery-A Post-hoc Analysis of a Randomized Clinical Trial

OBJECTIVES

To study the association between bleeding and acute kidney injury (AKI).

DESIGN

Post-hoc study of a randomized trial of 4% albumin versus Ringer's acetate for cardiopulmonary bypass priming and perioperative volume replacement.

SETTING

Single-center study.

PATIENTS

1,386 on-pump cardiac surgical patients.

MEASUREMENTS AND RESULTS

AKI was defined by the Kidney Disease: Improving Global Outcomes creatinine criteria, and bleeding by the Universal Definition of Perioperative Bleeding (UDPB) classification. With univariably independent factors, two logistic regression analyses (Model 1: AKI Risk Score, EuroSCORE II, and UDPB class; Model 2: risk scores, components of the UDPB classification, and factor VIII/von Willebrand factor concentrate) and a mediation analysis (Model 3: risk scores, UDPB class, and perioperative factors) were performed. A total of 139 (10%) patients developed AKI. In Model 1, UDPB class "severe" (odds ratio: 2.16, 95% confidence interval: 1.19-3.89), "massive" bleeding (6.78, 1.8-25.33), and AKI Risk Score (1.51, 1.29-1.78) were associated with AKI. In Model 2, AKI Risk Score (1.55, 1.33-1.82) and fresh frozen plasma transfusion (1.29, 1.06-1.58) were associated with AKI. In Model 3, the combined UDPB classes "severe" and "massive" bleeding did not have a direct effect (regression coefficient: 0.32, 95% confidence interval: -0.26 to 0.91), while mean arterial pressure (0.08, 0.003-0.21) and fluid balance (0.12, 0.17-0.27) had indirect effects on AKI.

CONCLUSIONS

In on-pump cardiac surgery, perioperative bleeding was not an independent risk factor for AKI but manifested as AKI via hypotension and higher fluid balance. Prevention of bleeding may reduce AKI in cardiac surgery.

Association between the intraoperative fluid balance during cardiac surgery and postoperative sequential organ failure assessment score: a post hoc analysis of the BROTHER study, a retrospective multicenter cohort study

Although intraoperative intravenous fluids are commonly administered to reverse intraoperative hypotension during cardiac surgery, the appropriate volume remains unclear. This study aimed to evaluate the relationship between the intraoperative fluid balance and sequential organ failure assessment (SOFA) score in patients undergoing cardiac surgery to determine the impact of intraoperative intravenous fluids on their organs. This was a post hoc analysis using data from a multicenter, retrospective, observational study across 14 intensive care units (ICUs) in Japan. Adult patients admitted to ICUs after elective coronary artery bypass grafting or valve surgery from January 1 to December 31, 2018 were enrolled. We compared patients with intraoperative fluid balance < 20 ml/kg to those with fluid balance ≥ 20 ml/kg and conducted a multiple regression analysis for the SOFA score within 24 h of ICU admission. Of the 1567 included patients, 870 met the eligibility criteria. A total of 725 patients (83%) had an intraoperative fluid balance of ≥ 20 ml/kg. In the univariate analysis, the SOFA score (interquartile range) was 7 (6-8) and 7 (6-9) in the intraoperative fluid balance < 20 ml/kg and ≥ 20 ml/kg groups, respectively (p = 0.017). Multiple regression analysis showed a positive association between intraoperative fluid balance and SOFA score within 24 h of ICU admission [standardized coefficient 0.0065 (95% confidence interval 0.0036-0.0095), p < 0.001]. Intraoperative fluid balance in patients undergoing cardiac surgery was significantly associated with higher SOFA scores within 24 h of ICU admission.

Perioperative continuous body weight measurements with load cells under the bed legs in patients undergoing abdominal surgery

BACKGROUND

Both excessive positive fluid balance and body weight increase after surgery are risk factors for poor postoperative outcomes. The use in clinical practice and the value of perioperative body weight measurements are unclear at present, possibly due to difficulty in measuring body weight in patients lying on the bed and insufficient clinical research.

OBJECTIVES

To investigate the relationship between intraoperative fluid balance and body weight change and perioperative nightly body weight change pattern throughout the hospital stay with contact-free unconstraint load cells placed under the bed legs.

DESIGN

Observational and exploratory study.

SETTING

A single university hospital.

PATIENTS

Twenty adult patients were undergoing elective abdominal surgery under general anaesthesia.

MAIN OUTCOME MEASURES

Body weight.

RESULTS

Immediately after surgery, body weight increased significantly by 2.7 ± 1.3 kg, equivalent to a 5% increase from the preoperative body weight. This increase was not correlated with (P = 0.178) the intraoperative fluid balance and was significantly greater than the intraoperative fluid balance 1.5 ± 0.4 kg (P < 0.001). The body weight returned to the preoperative level on postoperative day (POD)3 and further significantly decreased to 97% of the preoperative body weight at POD6 (P < 0.001). This physiological nocturnal weight loss pattern was maintained throughout hospitalisation except when fluid was infused. Compared with their preoperative status, patients stayed in bed longer with smaller body movements and left the bed less frequently during the daytime until POD3. Conversely, the patients had greater body movements in bed during the night leading to smaller diurnal variation in the body movements in bed after POD4.

CONCLUSION

Both perioperative fluid balance calculation and body weight measurement may have different but mutually complementary roles in perioperative managements. Postoperative fluid and nutrition management strategies are potentially new directions for treatment through continuous weight monitoring during the perioperative period.

Trial registration

: UMIN Clinical Trials Registry (UMIN000040164).

Postoperative Weight Gain within Enhanced Recovery after Cardiac Surgery

Optimal fluid therapy during perioperative care as part of enhanced recovery after cardiac surgery (ERACS) should improve the outcome. Our objective was finding out the effects of fluid overload on outcome and mortality within a well-established ERACS program. All consecutive patients undergoing cardiac surgery between January 2020 and December 2021 were enrolled. According to ROC curve analysis, a cut-off of ≥7 kg (group M, n = 1198) and <7 kg (group L, n = 1015) was defined. A moderate correlation was shown between weight gain and fluid balance r = 0.4, and a simple linear regression was significant p < 0.0001, R² = 0.16. Propensity score matching showed that increased weight gain was associated with a longer hospital length of stay (LOS) (L 8 [3] d vs. M 9 [6] d, p < 0.0001), an increased number of patients who received pRBCs (L 311 (36%) vs. M 429 (50%), p < 0.0001), and a higher incidence of postoperative acute kidney injury (AKI) (L 84 (9.8%) vs. M 165 (19.2%), p < 0.0001). Weight gain can easily represent fluid overload. Fluid overload after cardiac surgery is common and is associated with prolonged hospital LOS and increases the incidence of AKI.

Incidence and peri-operative risk factors for development of acute kidney injury in patients after cardiac surgery: A prospective observational study

BACKGROUND

Patients admitted to intensive care unit (ICU) after cardiac surgery develop acute kidney injury (AKI) immediately post-operation. We hypothesized that AKI occurs mainly due to perioperative risk factors and may affect outcome.

AIM

To assess peri-operative risk factors for AKI post cardiac surgery and its relationship with clinical outcome.

METHODS

This was an observational single center, tertiary care setting study, which enrolled 206 consecutive patients, admitted to ICU after cardiac surgery. Patients were followed-up until ICU discharge or death, in order to determine the incidence of AKI, perioperative risk factors for AKI and its association with outcome. Univariate and multivariate logistic regression analysis was performed to assess predictor variables for AKI development.

RESULTS

After ICU admission, 55 patients (26.7%) developed AKI within 48 h. From the logistic regression analysis performed, high EuroScore II (OR: 1.18; 95%CI: 1.06-1.31, P = 0.003), white blood cells (WBC) pre-operatively (OR: 1.0; 95%CI: 1.0-1.0, P = 0.002) and history of chronic kidney disease (OR: 2.82; 95%CI: 1.195-6.65, P = 0.018) emerged as independent predictors of AKI among univariate predictors. AKI that developed AKI had longer duration of mechanical ventilation [1113 (777–2195) vs 714 (511–1020) min, P = 0.0001] and ICU length of stay [70 (28–129) vs 26 (21–51) h, P = 0.0001], higher rate of ICU-acquired weakness (16.4% vs 5.3%, P = 0.015), reintubation (10.9% vs 1.3%, P = 0.005), dialysis (7% vs 0%, P = 0.005), delirium (36.4% vs 23.8%, P = 0.001) and mortality (3.6% vs 0.7%, P = 0.046).

CONCLUSION

Patients present frequently with AKI after cardiac surgery. EuroScore II, WBC count and chronic kidney disease are independent predictors of AKI development. The occurrence of AKI is associated with poor outcome.

Perioperative Management of the Patient at High-Risk for Cardiac Surgery-Associated Acute Kidney Injury

Acute kidney injury (AKI) is one of the most common major complications of cardiac surgery, and is associated with increased morbidity and mortality. Cardiac surgery-associated AKI has a complex, multifactorial etiology, including numerous factors such as primary cardiac dysfunction, hemodynamic derangements of cardiac surgery and cardiopulmonary bypass, and the possibility of a large volume of blood transfusion. There are no truly effective pharmacologic therapies for the management of AKI, and, therefore, anesthesiologists, intensivists, and cardiac surgeons must remain vigilant and attempt to minimize the risk of developing renal dysfunction. This narrative review describes the current state of the scientific literature concerning the specific aspects of cardiac surgery-associated AKI, and presents it in a chronological fashion to aid the perioperative clinician in their approach to this high-risk patient group. The evidence was considered for risk prediction models, preoperative optimization, and the intraoperative and postoperative management of cardiac surgery patients to improve renal outcomes.

Association Between Syndecan-1, Fluid Overload, and Progressive Acute Kidney Injury After Adult Cardiac Surgery

Background: Acute kidney injury (AKI) is a common complication after cardiac surgery and the prognosis of AKI worsens with the increase in AKI severity. Syndecan-1(SDC-1) is a biomarker of endothelial glycocalyx degradation. Fluid overload (FO) is associated with poor outcomes in AKI patients and may be related to the damage of endothelial function. This study aimed at demonstrating the association between elevated SDC-1, FO, and AKI progression. Methods: In this prospective study, we screened patients who underwent cardiac surgery and enrolled patients who experienced an AKI within 48 h after surgery from December 1, 2018 to January 31, 2019. Blood and urine samples were collected at the time of AKI diagnosis for plasma SDC-1 (pSDC-1) and urine SDC-1 (uSDC-1) measurements. Fluid balance (FB) = accumulated [fluid intake (L) - fluid output (L)]/body weight (kg) × 100%. FO was defined as FB > 5%. The primary endpoint was progressive AKI, defined as AKI progression from a lower to a higher stage. The patients were divided into progressive AKI group vs. non-progressive AKI group. Results: The quartiles of pSDC-1 concentration (117.3 [67.4, 242.3] ng/mL) showed a graded association with the incidence of progressive AKI, ranging from 5.0, 11.9, 32.6 to 52.4% (p for trend < 0.001). Multivariate logistic regression showed that increased pSDC-1 was an independent risk factor for progressive AKI. The AUC-ROC area of pSDC-1 concentration in predicting AKI progression was 0.847. Linear regression showed a positive correlation between FB and pSDC-1 concentration (R ² = 0.384, p < 0.001). In patients with FO, the progressive AKI incidence was significantly higher in the high pSDC-1 (≥117.3 ng/mL) subgroup than in the low pSDC-1 subgroup (58.3 vs. 17.6%, OR = 9.167, P = 0.005). In patients without FO, the progressive AKI incidence was also significantly higher in the high pSDC-1 subgroup with a lower odds ratio (30.4 vs. 7.4%, OR = 6.714, P = 0.002). Conclusion: Elevated pSDC-1 concentration was associated with progressive AKI after cardiac surgery and showed good predictive ability for progressive AKI. FB was related to the increase of pSDC-1. The interaction between pSDC-1 and FB may further aggravate the progression of AKI.