Successful use of intra-operative continuous renal replacement therapy in pediatric liver transplant recipients: Single center case series.

BACKGROUND: Acute kidney injury (AKI) is common in pediatric patients undergoing liver transplantation (LT), with an incidence 17%-55%. Fluid, metabolic, and acid-base aberrancies are often pronounced pre-operatively and further worsened by events during LT, making intra-operative continuous renal replacement therapy (CRRT) an option for critically ill LT recipients. METHODS: All pediatric LT performed at our institution who underwent intra-operative CRRT between January 2017 and August 2021 were included. Patient demographics and clinical data including graft outcomes, intra-operative findings, and timing and indications for CRRT were collected from the electronic medical record. RESULTS: CRRT was used in nine of the 76 (12%) pediatric LT performed at our center during the study period. Ages at LT ranged from 39 to 17.7 years. Recipients requiring CRRT were more likely to have acute liver failure, status 1A, and higher calculated MELD/PELD scores. CRRT was initiated pre-transplant in three recipients and continued post-transplant in six recipients. Median duration of CRRT was two (range 0-14) days. Indications included hyperammonemia (3/9), acidosis (3/9), fluid overload (6/9), and hyperkalemia (2/9). The CRRT group had a significantly longer post-transplant intensive care unit length of stay in comparison to those that did not require CRRT (median 6, range 3-40 days vs. median 3, range 0-121 days, p = .02], but there were no significant differences in reoperations, hospital length of stay, or recipient or graft survival. CONCLUSIONS: We demonstrate that CRRT can be safely performed in pediatric LT recipients, including young infants through adolescents.

Immediate extubation following pediatric liver transplantation.

BACKGROUND: Immediate extubation (IE) following pediatric liver transplantation is being increasingly performed. The aim of this study was to characterize the rate of IE at our institution and identify recipient factors predictive of IE. METHODS: All pediatric liver transplants performed at our institution between January 1, 2015 and December 31, 2020 were reviewed. Retransplants and multi-organ transplants were excluded. IE was defined as extubation in the operating room following transplant. Backward stepwise logistic regression at a p-value threshold of .05 was performed to identify variables associated with IE. RESULTS: IE was achieved in 58 (72%) of the 81 pediatric liver transplants. The IE cohort had significantly shorter ICU length of stay and overall hospital length of stay, though IE was not an independent predictor of posttransplant length of stay. Age <2 years, preoperative mechanical ventilation, and total intraoperative epinephrine and dopamine infusion requirements were significant, independent risk factors against IE. This multivariable model was highly predictive of IE (area under the curve = 0.89). CONCLUSIONS: We describe the highest rate of IE postpediatric liver transplantation that has been reported to date and identified significant risk factors against successful IE.

Extracorporeal membrane oxygenation as rescue therapy in a pediatric liver transplant recipient with very severe hepatopulmonary syndrome.

BACKGROUND: In children with cirrhosis, the prevalence of HPS ranges from 3% to 20%, resulting in impaired gas exchange due to alterations in pulmonary microvasculature. LT is the gold-standard cure for cirrhosis complicated by HPS and should ideally be performed prior to the development of severe HPS due to increased risk for post-transplant hypoxia, right heart failure, and outflow obstruction. METHODS: We present a case of a 13-year-old man, who underwent pediatric LT for severe HPS complicated by postoperative respiratory collapse, requiring a 92-day course of veno-venous ECMO. RESULTS: Post-transplant, despite BiPAP, inhaled nitric oxide and isoproterenol infusion, he remained hypoxic postoperatively and acutely decompensated on postoperative day 25, requiring veno-venous ECMO. After 84 days on ECMO, a persistent large splenorenal shunt was identified that was embolized by interventional radiology, and 8 days after shunt embolization and ASD closure, he was successfully weaned off ECMO. CONCLUSIONS: This case describes the longest known duration of ECMO in a pediatric LT recipient and a unique improvement in hypoxemia following a portosystemic shunt closure. ECMO presents a heroic rescue measure for pediatric LT recipients with HPS that develops acute respiratory failure postoperatively refractory to alternative measures.

Bone Cement Hypersensitivity in Patients With a Painful Total Knee Arthroplasty: A Case Series of Revision Using Custom Cementless Implants.

Little is known about patients with bone cement hypersenstivity after total knee arthroplasty (TKA). We present 7 patients implanted with 8 TKAs with clinical failure and a cement hypersensitivity diagnosis. All demonstrated hypersensitivity to bone cement via skin patch and/or lymphocyte transformation testing. All 7 patients also showed hypersensitivity to metal, most commonly nickel. Patients underwent custom cementless TKA revision. Prerevision and postrevision outcome measures, radiographs, intraoperative findings, and postrevision complications are reported. Functional scores improved after revision except Veterans RAND-12 mental component scores, which declined. Four patients continue to exhibit symptoms postoperatively, while one patient has had 3 additional surgical procedures. Patients presenting with bone cement hypersensitivity after TKA are particularly challenging. Evidence-based guidelines are lacking, and revision surgery may not relieve the presenting symptoms.

Evidence for diversity in the activation of the melanocortin 2 receptor: A study on gar, elephant shark and stingray MC2Rs.

The melanocortin-2 receptor (MC2R) is a critical component of the HPI and HPA axes of cartilaginous fishes, teleosts and tetrapods. Studies on teleost and tetrapod orthologs suggest two contact sites between ACTH and the receptor involving the following motifs on ACTH: H6F7R8W9 and K15K16R17R18P19. Using spotted gar (g) MC2R as a representative bony fish MC2R ortholog, we found that activation of gMC2R in Chinese Hamster Ovary (CHO) cells was diminished following stimulation of the transfected cells with hACTH(1-24) analogs substituted with alanine at either the H6F7R8W9 or K15K16R17R18P19 motifs compared to stimulation with hACTH(1-24). This observation suggests two ligand contact sites necessary for activation of the gMC2R. The same experiments were done with elephant shark (es) MC2R, however only the H6F7R8W9 analogs blocked activation, pointing to a single contact on esMC2R. Conversely, the red stingray (sr) MC2R activation was blocked by both the H6F7R8W9 and K15K16R17R18P19 alanine-substituted analogs. Together these results build a picture of the evolution of the ligand and receptor interaction between ACTH and MC2R orthologs of different taxa. These results will be discussed in light of the parallel evolution of MC2R orthologs in cartilaginous fishes and bony vertebrates.