Comparative Efficacy of Balanced Crystalloids versus 0.9% Saline on Delayed Graft Function and Perioperative Outcomes in Kidney Transplantation: A Meta-Analysis of Randomised Controlled Trials

Academic Background

Kidney transplantation is an effective treatment for end-stage renal disease (ESRD), but delayed graft function (DGF) post-transplantation is a critical factor affecting transplant success. DGF is typically defined as the need for dialysis within the first week after kidney transplantation and is closely associated with reduced graft survival, increased chronic allograft injury, and lower patient survival rates. The incidence of DGF is relatively low in living donor transplants (%) but can be as high as 40% in deceased donor transplants. Due to the shortage of living donor organs, an increasing number of transplants rely on deceased donors, particularly those with comorbidities or after circulatory death. Therefore, DGF remains a significant clinical challenge, with no established preventive or therapeutic measures currently available.

Intraoperative fluid management is crucial for maintaining organ perfusion, and the choice of fluid may influence the incidence of DGF post-transplantation. Crystalloid solutions, such as 0.9% saline and balanced crystalloids, are the most commonly used fluids. Traditionally, 0.9% saline has been widely used due to its lack of potassium, but recent guidelines recommend balanced crystalloids for their superior metabolic profiles, such as a lower incidence of acidosis. However, the impact of balanced crystalloids on DGF remains unclear, especially in light of several randomized controlled trials (RCTs) conducted after 2021, including the largest trial to date, the “BEST-FLUIDS” trial, which demonstrated that balanced crystalloids reduce the incidence of DGF. Therefore, an updated review of the literature is necessary to further clarify the differences in efficacy between balanced crystalloids and 0.9% saline in kidney transplantation.

Source of the Paper

This paper was co-authored by Tzu Chang, Ming-Chieh Shih, Yi-Luen Wu, Tsung-Ta Wu, Jen-Ting Yang, and Chun-Yu Wu, affiliated with the Department of Anesthesiology at Taipei City Hospital, National Taiwan University Hospital, National Tsing Hua University College of Life Sciences and Medicine, and the University of Washington Department of Anesthesiology & Pain Medicine, among others. The paper was published on September 13, 2024, in the British Journal of Anaesthesia, titled Comparative efficacy of balanced crystalloids versus 0.9% saline on delayed graft function and perioperative outcomes in kidney transplantation: a meta-analysis of randomised controlled trials.

Research Methods

Literature Search and Screening

This study followed the Cochrane Collaboration methodology and adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. A systematic search was conducted in PubMed, Embase, and the Cochrane Central Registry of Clinical Trials from inception until February 29, 2024. Search terms included “balanced crystalloid,” “lactated Ringer,” “Plasma-Lyte,” etc., combined with “renal transplant” or “kidney transplantation.” Ultimately, 11 eligible RCTs were selected, involving a total of 1,717 patients.

Data Extraction and Analysis

The study extracted basic information from each trial, including the first author, publication year, country, sample size, donor type, type of balanced crystalloid used, and duration of intervention. Primary outcome measures included the incidence of DGF, intraoperative and postoperative vasopressor use, length of hospital stay, and postoperative metabolic indicators (e.g., serum pH, bicarbonate, chloride concentration). Data analysis employed a random-effects model to calculate risk ratios (RRs) or mean differences (MDs) with 95% confidence intervals (CIs). The Cochrane risk-of-bias tool was used to assess the risk of bias in individual studies, and the GRADE framework was used to evaluate the certainty of evidence.

Research Results

Incidence of DGF

The meta-analysis showed that balanced crystalloids significantly reduced the incidence of DGF compared to 0.9% saline (RR 0.82, 95% CI: 0.69–0.98, p=0.01, moderate certainty). This result indicates that balanced crystalloids effectively reduce the risk of delayed graft function post-transplantation.

Vasopressor Use and Length of Hospital Stay

There was no significant difference in vasopressor use between balanced crystalloids and 0.9% saline (RR 0.93, 95% CI: 0.78–1.10, moderate certainty). Similarly, there was no significant difference in the length of hospital stay between the two groups (MD -1.69 days, 95% CI: -5.11 to 1.72, moderate certainty).

Postoperative Metabolic Indicators

Balanced crystalloids significantly outperformed 0.9% saline in postoperative serum pH (MD 0.05, 95% CI: 0.04–0.06, high certainty) and bicarbonate concentration (MD 2.25, 95% CI: 1.25–3.25, moderate certainty), while serum chloride concentration was significantly lower (MD -7.25, 95% CI: -12.73 to -1.77, moderate certainty). However, there were no significant differences in serum potassium and sodium concentrations between the two groups.

Discussion and Conclusion

This study demonstrates that balanced crystalloids significantly reduce the incidence of DGF in kidney transplantation and exhibit superior effects on postoperative metabolic indicators. Although there were no significant differences in vasopressor use and length of hospital stay, balanced crystalloids showed clear advantages in maintaining more favorable serum chemistry profiles. These findings align with several recent studies, further supporting the clinical recommendation for using balanced crystalloids in kidney transplantation.

Key Findings

1. Significant Reduction in DGF Incidence: Balanced crystalloids significantly reduce the incidence of DGF, particularly in deceased donor transplants.
2. Metabolic Advantages: Balanced crystalloids perform better in maintaining postoperative serum pH and bicarbonate levels, reducing the risk of acidosis.
3. Broad Clinical Applicability: Although there were no significant differences in vasopressor use and length of hospital stay, the overall metabolic management advantages of balanced crystalloids make them the preferred fluid choice in kidney transplantation.

Limitations

1. Imbalanced Sample Sizes: Some studies had small sample sizes, particularly those involving living donor transplants, which may affect the generalizability of the results.
2. Lack of Long-Term Outcomes: This study did not analyze long-term graft function or the number of dialysis sessions, which could be explored in future research.
3. Heterogeneity in Vasopressor Use: Due to significant variations in vasopressor use and dosing across studies, a more detailed dose analysis was not feasible.

Conclusion

Balanced crystalloids demonstrate superior clinical efficacy in kidney transplantation, particularly in reducing DGF and maintaining postoperative metabolic balance. Although no significant differences were observed in some secondary outcomes, their advantages in primary outcomes make them the preferred fluid choice in kidney transplantation. Future research should further explore the impact of balanced crystalloids on long-term graft function and patient survival to provide more comprehensive clinical guidance.