The effect of combined conventional and modified ultrafiltration on mechanical ventilation and hemodynamic changes in congenital heart surgery

Safety and utility of modified ultrafiltration in pediatric cardiac surgery

INTRODUCTION

Modified ultrafiltration (MUF) is employed at the termination of cardiopulmonary bypass (CPB) in pediatric and neonatal patients undergoing congenital heart surgery to reduce the accumulation of total body water thus increasing the concentration of red blood cells and the other formed elements in the circulation. Modified ultrafiltration has been reported to remove circulating pro-inflammatory mediators that result in systemic inflammatory response syndrome (SIRS) postoperatively.

METHODS

Four hundred patients undergoing cardiac surgery requiring cardiopulmonary bypass and weighing less than or equal to 12 kg were retrospectively evaluated for the effectiveness of MUF. After the termination of CPB, blood was withdrawn through the aortic cannula and passed through a hemoconcentrator attached to the blood cardioplegia set and returned to the patient through the venous cannula. The entire CPB circuit volume in addition to the patient's circulating blood volume were concentrated until the hematocrit value displayed on the CDI cuvette within the MUF circuit reached 45% or there was no more volume to safely remove. At the same time a full unit of FFP can be infused as water is being removed, thus maintaining euvolemia.

RESULTS

MUF was performed in all 400 patients with no MUF-related complications. Following the conclusion of MUF, anecdotal observations included improved surgical hemostasis, improved hemodynamic parameters, decreased transfusion requirements, and decreased ventilator times.

CONCLUSIONS

Complete MUF enables the clinician to safely raise the post-CPB hematocrit to at least 40% while potentially removing mediators that could result in SIRS. In addition a full unit of FFP can be administered while maintaining euvolemia.

Higher total ultrafiltration volume during cardiopulmonary bypass-assisted infant cardiac surgery is associated with acute kidney injury and fluid overload

BACKGROUND

Ultrafiltration (UF) is used for fluid removal during and after infant cardiopulmonary bypass (CPB) surgery to reduce fluid overload. Excessive UF may have the opposite of its intended effect, resulting in acute kidney injury (AKI), oliganuria, and fluid retention.

METHODS

This is a single-center, retrospective review of infants treated with conventional and/or modified UF during CPB surgery. UF volume was indexed to weight. AKI was defined using serum creatinine "Kidney Disease Improving Global Outcome (KDIGO)" criteria. Fluid balance was defined according to: [Formula: see text]. Peak fluid overload was determined on postoperative day 3. Multivariable logistic regression adjusted for multiple covariates was used to explore associations with UF, AKI, and fluid overload.

RESULTS

Five hundred thirty subjects < 1 year of age underwent CPB-assisted congenital heart surgery with UF. Sixty-four (12%) developed postoperative AKI. On multivariable regression, higher indexed total UF volume was associated with increased AKI risk (OR 1.11, 95% CI=1.04-1.19, p = 0.003). UF volume > 119.9 mL/kg did not reduce peak fluid overload. Subjects with AKI took longer to reach a negative fluid balance (2 vs. 3 days, p = 0.04). Those with more complex surgery were at highest AKI risk (STAT 3 [25-75 percentile: 3-4] in AKI group versus STAT 3 [25-75 percentile: 2-4] in non-AKI group, p = 0.05). AKI was reduced in subjects undergoing more complex surgery and treated with UF volume < 119.9 mL/kg.

CONCLUSIONS

Judicious use of UF in more complex congenital cardiac surgery reduces the risk of AKI.

Modified ultrafiltration and postoperative course in patients undergoing repair of tetralogy of fallot

BACKGROUND

Expected benefits of modified ultrafiltration (MUF) include increased hematocrit, reduction of total body water and inflammatory mediators, improved left ventricular systolic function, and improved systolic blood pressure and cardiac index (CI) following cardiopulmonary bypass (CPB). This prospective randomized trial tested this hypothesis.

METHODS

Seventy-nine patients undergoing intracardiac repair of tetralogy of fallot were randomized to conventional ultrafiltration (CUF) + MUF (n = 39) or only CUF group (n = 40). The primary outcome was a change in hematocrit. Secondary outcomes were changes in peak airway pressures, ventilatory support, blood transfusions, time to peripheral rewarming, mean arterial pressure, central venous pressure, inotrope score (IS), and CI. Serum inflammatory markers were measured.

RESULTS

Baseline hematocrit was 50.6 ± 10.02 in the only CUF group whereas it was 43.9 ± 5.55 in the CUF + MUF group (p = .36). Following MUF, the CUF + MUF group had higher hematocrit (44.7 ± 0.50 g/dl) compared to the only CUF group (37.2 ± 0.49 g/dl), p ≤ .001 after adjusting for baseline hematocrit. Central venous pressure (mmHg) immediately following sternal closure was 9.27 ± 3.12 mmHg in the CUF + MUF group and 10.52 ± 2.2 mmHg in the only CUF group (p = .04). In the intensive care unit (ICU), they were 11.52 ± 2.20 mmHg in the only CUF group and 10.84 ± 2.78 mmHg in the CUF + MUF group (p = .02). Time to peripheral rewarming was 6.30 ± 3.91 h in the CUF + MUF group and 13.67 ± 3.91 h in the only CUF group (p = .06). Peak airway pressures in ICU were 17 ± 2 mmHg versus 20.55 ± 2.97 mmHg in CUF + MUF group & only CUF group, respectively, p < .001). Duration of mechanical ventilation was 6.3 ± 2.7 h in CUF + MUF group compared to 14.7 ± 3.5 h in the only CUF group (p = .002). IS was 11.52 ± 2.20 in the only CUF group compared to 10.84 ± 2.78 in CUF + MUFs group. Eight of 39 (20.5%) patients in the CUF + MUF group had IS > 10 compared to 22 of 40 (55%) patients in the only CUF group (p = .02). Serum Troponin-T and interleukin-6 levels were lower in the CUF + MUF group; TNF-α and CPK-MB were similar. ICU and hospital stay were similar.

CONCLUSION

Patients undergoing a combination of CUF and MUF had higher postoperative hematocrit, decreased duration of mechanical ventilation, lower need for inotropes and lower interleukin-6 and Troponin-T levels. This group had better postoperative outcomes. This study was registered with the Clinical trials registry of India (CTRI/2017/11/010512) before commencement.

Effects of modified ultrafiltration and conventional ultrafiltration combination on perioperative clinical outcomes in pediatric cardiac surgery: A meta-analysis

BACKGROUND

This meta-analysis was performed to review the effects of the addition of modified ultrafiltration (MUF) and conventional ultrafiltration (CUF) to CUF alone on postoperative hemoglobin, surgical and ultrafiltration data, and postoperative clinical outcomes in pediatric patients undergoing cardiac surgery.

METHODS

A systematic search was performed to identify randomized controlled clinical trials that compared MUF and CUF combination with CUF alone in pediatric cardiac surgery undergoing cardiopulmonary bypass (CPB) in PubMed, Embase, Cochrane Library, and Web of Science without any language or date limitation in February 2020. For each included trial, the primary outcomes including post-CPB and postoperative hematocrit, surgical and ultrafiltration data, postoperative clinical outcomes including volume of chest tube drainage within 48 hours after surgery and perioperative blood requirement, ventilation support duration, and length of stay day in the intensive care unit (ICU) and hospital were collected and analyzed. The analysis was conducted using STATA version 12.0.

RESULTS

A total of 8 trials encompassing 405 patients were included in this analysis. Analysis indicated that MUF + CUF increased the post-CPB hematocrit (Standard mean difference, SMD = 1.85, 95% confidence interval, 95% CI 0.91-2.79). Meanwhile, ultrafiltration volume was higher in CUF+MUF infants than CUF-alone infants (SMD = 1.46, 95% CI 0.51-2.41, P = .003). The clinical outcomes, including postoperative hemodynamic changes, prime volume, blood requirement, chest tube drainage volume, mechanical ventilation duration, and ICU duration, were unclear because of the unstable sensitivity analyses.

CONCLUSIONS

Beneficial effects of using MUF and CUF for pediatric cardiac surgery, including increase post-CPB hematocrit and ultrafiltration volume when compared with CUF alone. Meanwhile, MUF and CUF did not significantly influence the postoperative hospital stay duration, CPB, and aortic occlusion duration.

American Society of ExtraCorporeal Technology: Development of Standards and Guidelines for Pediatric and Congenital Perfusion Practice (2019)

The development of standards and guidelines by professional societies offers clinicians guidance toward providing evidence-based care. The ultimate goals of standards and guidelines are to standardize care and improve patient safety and outcomes while also minimizing risk. The American Society of ExtraCorporeal Technology (AmSECT) currently offers perfusionists several clinical resources, primarily the Standards and Guidelines for Perfusion Practice; however, no document exists specific to pediatric perfusion. Historically, the development of a pediatric-specific document has been limited by available scientific evidence because of smaller patient populations, sample sizes, and variable techniques among congenital perfusionists. In the current setting of evolving clinical practices and increasingly complex cardiac operations, a subcommittee of pediatric perfusionists developed the Standards and Guidelines for Pediatric and Congenital Perfusion Practice. The development process included a comprehensive literature review for supporting evidence to justify new recommendations or updates to the existing AmSECT Adult Standards and Guidelines document. Multiple revisions incorporating feedback from the community led to a finalized document accepted by the AmSECT member and made available electronically in May 2019. The Standards and Guidelines for Pediatric and Congenital Perfusion Practice is an essential tool for pediatric perfusionists, serves as the backbone for institutionally based protocols, promotes improved decision-making, and identifies opportunities for future research and collaboration with other disciplines. The purpose of this article is to summarize the process of development, the content, and recommended utilization of AmSECT's Standards and Guidelines for Pediatric and Congenital Perfusion Practice. AmSECT recommends adoption of the Standards and Guidelines for Pediatric and Congenital Perfusion Practice to reduce practice variation and enhance clinical safety.

American Society of ExtraCorporeal Technology: Development of Standards and Guidelines for Pediatric and Congenital Perfusion Practice (2019)

The development of standards and guidelines by professional societies offers clinicians guidance toward providing evidence-based care. The ultimate goals of standards and guidelines are to standardize care and improve patient safety and outcomes while also minimizing risk. The American Society of ExtraCorporeal Technology (AmSECT) currently offers perfusionists several clinical resources, primarily the Standards and Guidelines for Perfusion Practice; however, no document exists specific to pediatric perfusion. Historically, the development of a pediatric-specific document has been limited by available scientific evidence due to smaller patient populations, sample sizes, and variable techniques among congenital perfusionists. In the current setting of evolving clinical practices and increasingly complex cardiac operations, a subcommittee of pediatric perfusionists developed the Standards and Guidelines for Pediatric and Congenital Perfusion Practice. The development process included a comprehensive literature review for supporting evidence to justify new recommendations or updates to the existing AmSECT Adult Standards and Guidelines document. Multiple revisions incorporating feedback from the community led to a finalized document accepted by the AmSECT membership and made available electronically in May 2019. The Standards and Guidelines for Pediatric and Congenital Perfusion Practice is an essential tool for pediatric perfusionists and serves as the backbone for institutionally based protocols, promotes improved decision-making, and identifies opportunities for future research and collaboration with other disciplines. The purpose of this manuscript is to summarize the process of development, the content, and recommended utilization of AmSECT's Standards and Guidelines for Pediatric and Congenital Perfusion Practice.