Continuous Ultrafiltration Enhances Recovery After Adult Cardiac Surgery With Cardiopulmonary Bypass: A Systematic Review and Meta-analysis

Background

Cardiac surgery with cardiopulmonary bypass is associated with systemic inflammation. Ultrafiltration used throughout the cardiopulmonary bypass time, continuously, is hypothesized to be an immunomodulatory therapy.

Methods

A systematic review and meta-analysis of randomized trials investigating continuous forms of ultrafiltration during adult cardiac surgery (CRD42020219309) was conducted and is reported following PRISMA guidelines. MEDLINE, Embase, CENTRAL, and Scopus were searched on November 3, 2021. The primary endpoint was operative mortality, and secondary outcomes included intensive care unit length of stay (ICU LOS), ventilation time, acute kidney injury or renal failure, and pneumonia. Each study was assessed for risk of bias using the Cochrane Risk-of Bias-Tool for Randomized Trials (RoB2) instrument. Outcomes were analyzed with inverse variance random-effects models and assessed for GRADE quality of evidence.

Results

Twelve randomized trials consisting of 989 adult patients undergoing coronary, valvular, or concomitant cardiac procedures were included. Compared to controls, patients receiving continuous ultrafiltration had no statistical difference in operative mortality; risk ratio of 0.32 (95% confidence interval [CI]: 0.10-1.03; P = 0.06). Reductions occurred in ICU LOS, by 7.01 hours (95% CI: 1.86-12.15; P = 0.008); ventilation time, by 2.11 hours (95% CI: 0.71-3.51; P = 0.003); and incidence of pneumonia, with a risk ratio of 0.33 (95% CI: 0.15-0.75; P = 0.008). There wasno difference in renal injury. The GRADE quality of evidence for these outcomes ranged from very low to low.

Conclusions

Continuous forms of ultrafiltration enhance recovery after adult cardiac surgery by reducing ICU LOS, ventilation time, and incidence of pneumonia. A multicentre randomized trial could confirm and generalize these findings.

Subzero balance - simple modified ultrafiltration (SBUF-SMUF) technique for pediatric cardiopulmonary bypass

The use of cardiopulmonary bypass (CPB) can be associated with significant hemodilution, coagulopathy and a systemic inflammatory response for infants and children undergoing cardiac surgery. Intra-operative ultrafiltration has been used for decades to ameliorate these harmful effects. The novel combination of a continuous and non-continuous form of ultrafiltration, Subzero Balance Simple Modified Ultrafiltration (SBUF-SMUF) here described, seeks to enhance recovery from pediatric cardiac surgery and CPB.

The effects of zero-balance ultrafiltration on postoperative recovery after cardiopulmonary bypass: a meta-analysis of randomized controlled trials

OBJECTIVE

Considered as a significant ultrafiltration technology during cardiopulmonary bypass (CPB), zero-balance ultrafiltration (Z-BUF) has always received controversial support regarding its effectiveness in reducing inflammatory mediators in plasma. Therefore, we conducted a meta-analysis to evaluate the clinical effect of Z-BUF through screening all relevant published randomized controlled trials (RCTs).

METHODS

A comprehensive search was conducted to screen all RCTs of Z-BUF. Three trained investigators searched databases, including PubMed, Embase, the Cochrane Library, Google scholar, and Chinese literature databases (CNKI, WanFang, WeiPu). RCTs that compared Z-BUF with non-ultrafiltration were included. We focused on clinical outcomes such as length of stay in ICU, duration of ventilation, hospital stay, total amount of chest tube drainage and mortality. Finally, a total of 7 studies containing appropriate criteria were divided into an adult group and a pediatric group. A random effects model was used to calculate weighted mean difference with 95% confidence intervals.

RESULTS

In the adult group, the benefits of Z-BUF in duration of ventilation (WMD=-2.77, 95% CI = [-6.26, 0.72], I(2)=71%, p=0.12) and the length of ICU stay (WMD=-4.13, 95% CI = [-10.09, 1.84], I(2)=77%, Z=1.36, p=0.17) were not apparent, with significant heterogeneity existing in the statistical results. The rest of the clinical parameters could not be evaluated due to insufficient data. In the pediatric group, combined analysis showed Z-BUF could reduce the duration of mechanical ventilation (WMD=3.07; 95%CI= [-7.56, -3.46], I(2)=17%, p=0.27). The advantage of Z-BUF was not observed in other clinical outcomes.

CONCLUSION

The benefits of Z-BUF were not apparent, according to the report. Further studies involving combined ultrafiltration are expected to provide improved ultrafiltration during CPB.