Since the initial reports of successful renal transplantation in children, pediatric kidney transplantation has expanded to become the most common pediatric transplant in the United States (Am J Surg 1983;145:243-7; J Pediatr 1982;100:675-80; asamonitor.pub/3TSvo4u). Following the COVID-19 pandemic, pediatric kidney transplant activity has normalized, with annual demand remarkably consistent secondary to inborn errors of metabolism as the predominant cause of renal failure (Pediatr Nephrol 2021;36:143-51). While overall transplant activity has not significantly changed, all clinical parameters, including waitlist dynamics, intent-to-treat survival, and post-transplant quality of life, have improved (Pediatrics 2022;149:e2020049632).

The Organ Procurement and Transplantation Network (OPTN) developed the Kidney Allocation System (KAS) in 2014 to help address challenges, inequity, and waste within the deceased-donor pool. Under KAS, children are preferentially allocated from premium donors with a kidney donor profile index (KDPI) <35%, similar to KDPI-based allocation in adult recipients. Initial reviews of the KAS system for pediatric patients demonstrated that deceased donor transplantation rates have increased; however, the increase was not distributed equally (Pediatr Transplant 2022;26:e14369). Adolescent-aged children demonstrated an increase in transplantation rates, while children ages 0-6 years experienced a decrease in access to transplantation (Am J Transplant 2018;18:1690-8). Additionally, waitlist times have increased under the KAS policy (Clin Transplant 2018;32:e13223). In 2019, KAS was further modified to address equity in distribution by increasing the offering distance to a 250-mile radius around the donor location (asamonitor.pub/3Q3iy22). This new system aims to improve geographic diversity, but also may lead to increased competition and operational challenges.

Optimal crystalloid solution for renal transplantation continues to be debated as pediatric kidney transplantation can demand large volumes, particularly in smaller patients with a significant graft-size mismatch. Normal saline, theoretically, prevents the addition of potassium in intravenous fluids but often results in hyperchloremia, which can promote acidosis and hyperkalemia. This phenomenon has been demonstrated in multiple adult studies, including in both living and deceased-donor kidney transplantation (Cochrane Database Syst Rev 2016;2016:CD010741).

Growing evidence indicates that normal saline may also impair allograft function. A 2021 study published in Anesthesiology demonstrated that a high percentage of normal saline administration (over 80%) was associated with a greater incidence of delayed graft function in adult kidney transplant recipients (Anesthesiology 2021;135:621-32). The balanced crystalloid solution versus saline in deceased-donor kidney transplantation (BEST-Fluids) study recently showed a statistically lower rate of delayed graft function in patients who received balanced crystalloid (PlasmaLyte) versus normal saline (Lancet 2023;402:105-17). The BEST-Fluids study included pediatric patients over 20 kg, but these findings have not been independently validated in a pediatric population.

Similar to pediatric renal transplantation, liver transplantation in children decreased briefly during COVID pandemic but has begun to normalize (Pediatr Transplant 2022;26:e14162). As congenital disease represents the principal indications for transplantation in children, overall transplant activity will vary with the birth rate. While pediatric liver transplantation has declined nationally, the discipline has been vibrant with continuous increases in the utilization of living donors and significantly improved outcomes, including wait-list performance, post-transplant survival, and intent-to-treat survival across all age groups (Pediatrics 2022;149:e2020049632). Currently, one- and five-year patient survival approximates are 95% and 85%, respectively.

Updates to the MELD (Model for End-State Liver Disease) and PELD (Pediatric End-Stage Liver Disease) classification system became effective July 2023 (asamonitor.pub/3vUb0rH). Pediatric candidates greater than 12 years are currently assigned a MELD score, while younger candidates receive a PELD score. Changes to MELD 3.0 were implemented to address transplant disparities that were seen in female candidates and to improve overall ranking. PELD Cr modifications have been added to improve ranking for all pediatric candidates as well. Age-adjusted mortality is included to standardize the mortality risk to an 18-year-old candidate with an equivalent MELD 3.0 score. Recent definition changes affect status 1A and 1B candidates, including updated definitions of hepatic encephalopathy and gastrointestinal bleeding. Other status 1B changes include removal of a MELD/PELD threshold of 25 and a new priority given to candidates with chronic liver disease.

Immediate extubation or extubation in the OR after liver transplantation continues to be controversial in pediatric liver transplantation due to a variety of factors. Patient size-graft mismatch, medical acuity, high transfusion requirements, and fear of respiratory complications are barriers to immediate extubation. Immediate extubation is achievable but requires multidisciplinary communication and careful patient selection. Successful immediate extubation has been associated with older age, lower PELD/MELD score, and admission from home (Pediatr Transplant 2022;26:e14352; Pediatr Transplant 2003;7:381-4; Transplant Proc 2023;55:1171-5; Paediatr Anaesth 2018;28:174-8). Surgical factors include type of graft (whole or split), intraoperative transfusion requirements, and partial versus full abdominal closure. The ICU team must be comfortable managing an extubated patient, potentially with partial abdominal mesh closure, through large postoperative fluid shifts and ongoing transfusion requirements. Overall data suggest early extubation, when applied appropriately, may decrease ICU and hospital length of stay as well as postoperative complications (Anesthesiology 2021;135:621-32; Paediatr Anaesth 2023;33:59-68).

Pediatric anesthesia liver transplant teams provide the opportunity for concentrated experience, skill proficiency, and multidisciplinary relationships. A recent study demonstrated that implementation of a liver transplant anesthesia team significantly increased the case numbers of team members and improved intraoperative outcomes, including early extubation and transfusion requirements (Paediatr Anaesth 2022;32:732-9). In addition, a recent survey of U.S. pediatric anesthesia liver transplant teams demonstrated that most centers had a named director of liver transplant anesthesia (Clin Transplant 2022;36:e14672). Despite the benefits of a designated pediatric anesthesia transplant team, training and case requirements remain undefined. Future collaboration between low- and high-volume centers may be necessary to optimize clinical experience as national procedure volumes decrease (Paediatr Anaesth 2021;31:309-15).

Pediatric abdominal organ transplantation remains one of the most challenging procedures within the field of anesthesiology. One must remain abreast of rapid changes in candidate selection, technical advances, novel immunosuppressive regimens, and clinical advances in addition to changes to the kidney and liver allocation policies that directly impact our patient population.