Continuous Kidney Replacement Therapy and Survival in Children and Young Adults: Findings From the Multinational WE-ROCK Collaborative.

RATIONALE & OBJECTIVE: There are limited studies describing the epidemiology and outcomes in children and young adults receiving continuous kidney replacement therapy (CKRT). We aimed to describe associations between patient characteristics, CKRT prescription, and survival. STUDY DESIGN: Retrospective multicenter cohort study. SETTING & PARTICIPANTS: 980 patients aged from birth to 25 years who received CKRT between 2015 and 2021 at 1 of 32 centers in 7 countries participating in WE-ROCK (Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Diseases). EXPOSURE: CKRT for acute kidney injury or volume overload. OUTCOMES: Death before intensive care unit (ICU) discharge. ANALYTICAL APPROACH: Descriptive statistics. RESULTS: Median age was 8.8 years (IQR, 1.6-15.0), and median weight was 26.8 (IQR, 11.6-55.0) kg. CKRT was initiated a median of 2 (IQR, 1-6) days after ICU admission and lasted a median of 6 (IQR, 3-14) days. The most common CKRT modality was continuous venovenous hemodiafiltration. Citrate anticoagulation was used in 62%, and the internal jugular vein was the most common catheter placement location (66%). 629 participants (64.1%) survived at least until ICU discharge. CKRT dose, filter type, and anticoagulation were similar in those who did and did not survive to ICU discharge. There were apparent practice variations by institutional ICU size. LIMITATIONS: Retrospective design; limited representation from centers outside the United States. CONCLUSIONS: In this study of children and young adults receiving CKRT, approximately two thirds survived at least until ICU discharge. Although variations in dialysis mode and dose, catheter size and location, and anticoagulation were observed, survival was not detected to be associated with these parameters. PLAIN-LANGUAGE SUMMARY: In this large contemporary epidemiological study of children and young adults receiving continuous kidney replacement therapy in the intensive care unit, we observed that two thirds of patients survived at least until ICU discharge. However, patients with comorbidities appeared to have worse outcomes. Compared with previously published reports on continuous kidney replacement therapy practice, we observed greater use of continuous venovenous hemodiafiltration with regional citrate anticoagulation.

Clearance and nutrition in neonatal continuous kidney replacement therapy using the Carpediem™ system.

BACKGROUND: Infants with kidney failure (KF) demonstrate poor growth partly due to obligate fluid and protein restrictions. Delivery of liberalized nutrition on continuous kidney replacement therapy (CKRT) is impacted by clinical instability, technical dialysis challenges, solute clearance, and nitrogen balance. We analyzed delivered nutrition and growth in infants receiving CKRT with the Cardio-Renal, Pediatric Dialysis Emergency Machine (Carpediem™). METHODS: Single-center observational study of infants receiving CKRT with the Carpediem™ between June 1 and December 31, 2021. We collected prospective circuit characteristics, delivered nutrition, anthropometric measurements, and illness severity Score for Neonatal Acute Physiology-II. As a surrogate to normalized protein catabolic rate in maintenance hemodialysis, we calculated normalized protein nitrogen appearance (nPNA) using the Randerson II continuous dialysis model. Descriptive statistics, Spearman correlation coefficient, Mann Whitney, Wilcoxon signed rank, receiver operating characteristic curves, and Kruskal-Wallis analysis were performed using SAS version 9.4. RESULTS: Eight infants received 31.9 (22.0, 49.7) days of CKRT using mostly (90%) regional citrate anticoagulation. Delivered nutritional volume, protein, total calories, enteral calories, nPNA, and nitrogen balance increased on CKRT. Using parenteral nutrition, 90 ml/kg/day should meet caloric and protein needs. Following initial weight loss of likely fluid overload, exploratory sensitivity analysis suggests weight gain occurred after 14 days of CKRT. Despite adequate nutritional delivery, goal weight (z-score = 0) and growth velocity were not achieved until 6 months after CKRT start. Most (5 infants, 62.5%) survived and transitioned to peritoneal dialysis (PD). CONCLUSIONS: Carpediem™ is a safe and efficacious bridge to PD in neonatal KF. Growth velocity of infants on CKRT appears delayed despite delivery of adequate calories and protein.

Review of acute kidney injury and progression to chronic kidney disease in pediatric patients undergoing hematopoietic cell transplant.

While acute kidney injury (AKI) after hematopoietic cell transplant (HCT) has been well-described in pediatric patients, literature regarding the long term renal consequences of HCT-related AKI, the development of chronic kidney disease (CKD), and CKD care in pediatric patients post-HCT is limited. CKD affects almost 50% of patients after HCT with multifactorial etiology including infection, nephrotoxic medications, transplant-associated thrombotic microangiopathy, graft-versus-host disease, and sinusoidal obstruction syndrome. As renal function declines in CKD, eventually progressing to end stage kidney disease (ESKD), mortality increases and is more than 80% among patients requiring dialysis. Using society guidelines and current literature, this review summarizes definitions and etiologies of and management strategies among patients with AKI and CKD post-HCT with an emphasis on albuminuria, hypertension, nutrition, metabolic acidosis, anemia, and mineral bone disease. The goal of this review is to aid early identification and intervention in patients with renal dysfunction prior to development of ESKD, and to discuss ESKD and renal transplant in these patients post-HCT.

Role of therapeutic apheresis in the treatment of pediatric kidney diseases.

Therapeutic apheresis utilizes apheresis procedures in the treatment of a variety of conditions including kidney disease. Therapeutic plasma exchange (TPE) is the most common modality employed with the rationale of rapid reduction of a pathogenic substance distributed primarily in the intravascular compartment; however other techniques which adsorb such pathogenic substances or alter the immune profile have been utilized in diseases affecting native and transplanted kidneys. This article discusses the modalities and technical details of therapeutic apheresis and summarizes its role in individual diseases affecting the kidney. Complications related to pediatric apheresis procedures and specifically related to apheresis in kidney disease are also discussed. Though therapeutic apheresis modalities are employed frequently in children with kidney disease, most experiences are extrapolated from adult studies. International and national registries need to be established to elucidate the role of apheresis modalities in children with kidney disease.

Therapeutic plasma exchange: single-center experience in children with kidney disorders.

BACKGROUND: Therapeutic plasma exchange (TPE) is used in kidney diseases as an adjunct treatment. Little has been described as to its effectiveness in kidney disorders in children. This study aimed to assess the safety, efficacy, and outcomes of patients who underwent TPE for kidney indications. METHODS: Retrospective chart review of patients receiving TPE from 2010 to 2018 for kidney indications, such as antibody-mediated rejection, bone marrow transplant-associated thrombotic microangiopathy (TA-TMA), atypical hemolytic uremic syndrome, transplant recurrence of focal segmental glomerulosclerosis, and glomerulonephritis. Outcomes assessed were trends in kidney function, mortality, and progression to stage 5 chronic kidney disease (CKD 5). Significant hypocalcemia was defined as ionized calcium < 1 mmol/L. RESULTS: A total of 641 TPE procedures were performed on 47 patients (25 male). Average age was 12.8 ± 5.9 years. Median glomerular filtration rate (GFR) improved from baseline to end of TPE treatments (pre 44.9 (19.8, 79), end 56.1 (23, 98) [p = 0.02]). Ten out of 47 children developed CKD 5. Seven out of 47 patients died; 5 had TA-TMA. Initial 7 consecutive sessions were reviewed for complications. Among 335 procedures, 41 episodes of significant hypocalcemia were noted (12.2%); only 1 was symptomatic. Of the 26 episodes (7.7%) of allergic reactions, all were associated with the use of FFP; 5 were anaphylactic. No TPE-associated mortality was noted. CONCLUSIONS: TPE is a relatively well-tolerated useful adjunct therapy in children with kidney indications. The benefit of TPE has to be balanced with risks such as hypocalcemia and allergic reactions which can occur more frequently with FFP. Graphical abstract.

RECK and TIMP-2 mediate inhibition of MMP-2 and MMP-9 by Annona muricata.

Up-regulation of MMP-2 and MMP-9 plays a significant role in promoting cancer progression by degrading the components of the extracellular matrix, thereby enhancing the migration of tumor cells. Although the antiproliferative and apoptotic effect of Annona muricata is well established, its effect on MMP-2 and MMP-9, a major target in several types of cancers, has not been studied. Powdered samples of various parts of A. muricata like fruit, stem, seed, and twig extracted using aqueous methanol showed significant dose-dependent inhibition of MMP-2 and MMP-9 in a highly metastatic fibrosarcoma cell line, HT1080. Additionally, these extracts also up-regulated the expression of several endogenous inhibitors of MMP-2 and MMP-9 like REversion-inducing Cysteine-rich protein with Kazal motifs (RECK) and Tissue Inhibitor of Metalloproteinase- 2 (TIMP-2). Furthermore, primary cells developed from tumor tissues obtained from patients not exposed to chemotherapy, also exhibited similar results. Remarkably, the inhibition of MMP-2 and MMP-9 observed was tumor specific, with the A. muricata fruit extract showing only 2% inhibition in cells obtained from normal tissues, when compared to 60% inhibition observed in cells obtained from tumor samples. The present study elucidates a novel mechanism by which A. muricata extracts selectively exhibit their anti-cancer activity in tumor cells by down-regulating MMP-2 and MMP-9 that are important biomarkers in cancer.

The impact of fluid balance on outcomes in premature neonates: a report from the AWAKEN study group.

BACKGROUND: We evaluated the epidemiology of fluid balance (FB) over the first postnatal week and its impact on outcomes in a multi-center cohort of premature neonates from the AWAKEN study. METHODS: Retrospective analysis of infants <36 weeks' gestational age from the AWAKEN study (N = 1007). FB was defined by percentage of change from birth weight. OUTCOME: Mechanical ventilation (MV) at postnatal day 7. RESULTS: One hundred and forty-nine (14.8%) were on MV at postnatal day 7. The median peak FB was 0% (IQR: -2.9, 2) and occurred on postnatal day 2 (IQR: 1,5). Multivariable models showed that the peak FB (aOR 1.14, 95% CI 1.10-1.19), lowest FB in first postnatal week (aOR 1.12, 95% CI 1.07-1.16), and FB on postnatal day 7 (aOR 1.10, 95% CI 1.06-1.13) were independently associated with MV on postnatal day 7. In a similar analysis, a negative FB at postnatal day 7 protected against the need for MV at postnatal day 7 (aOR 0.21, 95% CI 0.12-0.35). CONCLUSIONS: Positive peak FB during the first postnatal week and more positive FB on postnatal day 7 were independently associated with MV at postnatal day 7. Those with a negative FB at postnatal day 7 were less likely to require MV.

Cinacalcet for secondary hyperparathyroidism in end-stage renal disease patients below age 5 years
.

BACKGROUND: Management of chronic kidney disease mineral bone disorder (CKD-MBD) in pediatric patients with end-stage renal disease (ESRD) is challenging. While the use of calcimimetics is well-studied in adults on dialysis, few studies have been performed in pediatrics. Little is known about the use of cinacalcet in young children with ESRD. The aim of this study was to report the efficacy and safety of cinacalcet for treatment of secondary hyperparathyroidism in chronic dialysis patients younger than 5 years. MATERIALS AND METHODS: We included children aged < 5 years on chronic dialysis, either hemodialysis (HD) or peritoneal dialysis (PD), who were prescribed cinacalcet for more than 1 month. Retrospective chart review was performed to gather demographics, dialysis prescription, relevant mineral imbalance laboratory parameters, and medications. Data was collected for 6 consecutive months. RESULT: 18 patients (9 male), mean age at initiation of cinacalcet was 2.3 years; 13 PD and 5 HD. Average starting dose of cinacalcet: 6.2 mg daily, 0.55 mg/kg/day. Average time on dialysis was 14.4 months. Parathyroid hormone significantly decreased over the 1st month following initiation of cinacalcet from 929 (IQR 572 - 1,056) to 427 (IQR 256 - 778) pg/mL, p = 0.009. Three patients developed asymptomatic hypocalcemia (Ca < 9.4 mg/dL). Serum phosphorous decreased after initiation, and this was persistent at 6 months. Significant improvement in linear growth was observed while on cinacalcet and growth hormone (GH). CONCLUSION: Cinacalcet can be effectively used in young children on dialysis with minimal side effects. Good linear growth was seen in patients on cinacalcet and GH therapy. Long-term large scale data is necessary to confirm. Institution-based management algorithm incorporating cinacalcet would be helpful to maintain uniformity in role of cinacalcet for management of CKD-MBD.

Tumor-targeted 4-1BB agonists for combination with T cell bispecific antibodies as off-the-shelf therapy.

Endogenous costimulatory molecules on T cells such as 4-1BB (CD137) can be leveraged for cancer immunotherapy. Systemic administration of agonistic anti-4-1BB antibodies, although effective preclinically, has not advanced to phase 3 trials because they have been hampered by both dependency on Fcγ receptor-mediated hyperclustering and hepatotoxicity. To overcome these issues, we engineered proteins simultaneously targeting 4-1BB and a tumor stroma or tumor antigen: FAP-4-1BBL (RG7826) and CD19-4-1BBL. In the presence of a T cell receptor signal, they provide potent T cell costimulation strictly dependent on tumor antigen-mediated hyperclustering without systemic activation by FcγR binding. We could show targeting of FAP-4-1BBL to FAP-expressing tumor stroma and lymph nodes in a colorectal cancer-bearing rhesus monkey. Combination of FAP-4-1BBL with tumor antigen-targeted T cell bispecific (TCB) molecules in human tumor samples led to increased IFN-γ and granzyme B secretion. Further, combination of FAP- or CD19-4-1BBL with CEA-TCB (RG7802) or CD20-TCB (RG6026), respectively, resulted in tumor remission in mouse models, accompanied by intratumoral accumulation of activated effector CD8+ T cells. FAP- and CD19-4-1BBL thus represent an off-the-shelf combination immunotherapy without requiring genetic modification of effector cells for the treatment of solid and hematological malignancies.

The impact of fluid balance on outcomes in critically ill near-term/term neonates: a report from the AWAKEN study group.

BACKGROUND: In sick neonates admitted to the NICU, improper fluid balance can lead to fluid overload. We report the impact of fluid balance in the first postnatal week on outcomes in critically ill near-term/term neonates. METHODS: This analysis includes infants ≥36 weeks gestational age from the Assessment of Worldwide Acute Kidney injury Epidemiology in Neonates (AWAKEN) study (N = 645). Fluid balance: percent weight change from birthweight. PRIMARY OUTCOME: mechanical ventilation (MV) on postnatal day 7. RESULTS: The median peak fluid balance was 1.0% (IQR: -0.5, 4.6) and occurred on postnatal day 3 (IQR: 1, 5). Nine percent required MV at postnatal day 7. Multivariable models showed the peak fluid balance (aOR 1.12, 95%CI 1.08-1.17), lowest fluid balance in 1st postnatal week (aOR 1.14, 95%CI 1.07-1.22), fluid balance on postnatal day 7 (aOR 1.12, 95%CI 1.07-1.17), and negative fluid balance at postnatal day 7 (aOR 0.3, 95%CI 0.16-0.67) were independently associated with MV on postnatal day 7. CONCLUSIONS: We describe the impact of fluid balance in critically ill near-term/term neonates over the first postnatal week. Higher peak fluid balance during the first postnatal week and higher fluid balance on postnatal day 7 were independently associated with MV at postnatal day 7.

Structure of the malaria vaccine candidate antigen CyRPA and its complex with a parasite invasion inhibitory antibody.

Invasion of erythrocytes by Plasmodial merozoites is a composite process involving the interplay of several proteins. Among them, the Plasmodium falciparum Cysteine-Rich Protective Antigen (PfCyRPA) is a crucial component of a ternary complex, including Reticulocyte binding-like Homologous protein 5 (PfRH5) and the RH5-interacting protein (PfRipr), essential for erythrocyte invasion. Here, we present the crystal structures of PfCyRPA and its complex with the antigen-binding fragment of a parasite growth inhibitory antibody. PfCyRPA adopts a 6-bladed ß-propeller structure with similarity to the classic sialidase fold, but it has no sialidase activity and fulfills a purely non-enzymatic function. Characterization of the epitope recognized by protective antibodies may facilitate design of peptidomimetics to focus vaccine responses on protective epitopes. Both in vitro and in vivo anti-PfCyRPA and anti-PfRH5 antibodies showed more potent parasite growth inhibitory activity in combination than on their own, supporting a combined delivery of PfCyRPA and PfRH5 in vaccines.

Quadruple space-group ambiguity owing to rotational and translational noncrystallographic symmetry in human liver fructose-1,6-bisphosphatase.

Fructose-1,6-bisphosphatase (FBPase) is a key regulator of gluconeogenesis and a potential drug target for type 2 diabetes. FBPase is a homotetramer of 222 symmetry with a major and a minor dimer interface. The dimers connected via the minor interface can rotate with respect to each other, leading to the inactive T-state and active R-state conformations of FBPase. Here, the first crystal structure of human liver FBPase in the R-state conformation is presented, determined at a resolution of 2.2 Šin a tetragonal setting that exhibits an unusual arrangement of noncrystallographic symmetry (NCS) elements. Self-Patterson function analysis and various intensity statistics revealed the presence of pseudo-translation and the absence of twinning. The space group is P41212, but structure determination was also possible in space groups P43212, P4122 and P4322. All solutions have the same arrangement of three C2-symmetric dimers spaced by 1/3 along an NCS axis parallel to the c axis located at (1/4, 1/4, z), which is therefore invisible in a self-rotation function analysis. The solutions in the four space groups are related to one another and emulate a body-centred lattice. If all NCS elements were crystallographic, the space group would be I4122 with a c axis three times shorter and a single FBPase subunit in the asymmetric unit. I4122 is a minimal, non-isomorphic supergroup of the four primitive tetragonal space groups, explaining the space-group ambiguity for this crystal.

Proteinuria and hematuria in the neonate.

PURPOSE OF REVIEW: Neonatal proteinuria and hematuria while not common can have potentially devastating consequences if left undiagnosed and untreated. It is important to distinguish between inherited and acquired causes of proteinuria to initiate appropriate and timely treatment. With regards to hematuria, it is critical to identify true hematuria from pseudo-hematuria to balance between thorough investigation and unnecessary laboratory work up. This review provides an overview of the common causes of hematuria and proteinuria in a neonate. RECENT FINDINGS: The identification of genetic mutations in nephrotic syndrome has improved our understanding of the role of various proteins that play an important role in maintaining the glomerular filtration barrier. With the advancement in our ability to provide care for extreme premature neonates, the incidence of acute kidney injury has increased in these neonates along with proteinuria and hematuria. SUMMARY: Persistent proteinuria after neonatal acute kidney injury would be of interest in regards to the risk of developing future chronic kidney disease and hypertension.

Determination of protein-ligand binding constants of a cooperatively regulated tetrameric enzyme using electrospray mass spectrometry.

This study highlights the benefits of nano electrospray ionization mass spectrometry (nanoESI-MS) as a fast and label-free method not only for determination of dissociation constants (KD) of a cooperatively regulated enzyme but also to better understand the mechanism of enzymatic cooperativity of multimeric proteins. We present an approach to investigate the allosteric mechanism in the binding of inhibitors to the homotetrameric enzyme fructose 1,6-bisphosphatase (FBPase), a potential therapeutic target for glucose control in type 2 diabetes. A series of inhibitors binding at an allosteric site of FBPase were investigated to determine their KDs by nanoESI-MS. The KDs determined by ESI-MS correlate very well with IC50 values in solution. The Hill coefficients derived from nanoESI-MS suggest positive cooperativity. From single-point measurements we could obtain information on relative potency, stoichiometry, conformational changes, and mechanism of cooperativity. A new X-ray crystal structure of FBPase tetramer binding ligand 3 in a 4:4 stoichiometry is also reported. NanoESI-MS-based results match the current understanding of the investigated system and are in agreement with the X-ray structural data, but provide additional mechanistic insight on the ligand binding, due to the better dynamic resolution. This method offers a powerful approach for studying other proteins with allosteric binding sites, as well.

Glucocorticoids Reduce Renal NHE8 Expression.

The proximal tubule reabsorbs most of the filtered bicarbonate which is mediated in large part by Na+/H+ exchange (NHE). We have previously demonstrated that there is an isoform switch during postnatal maturation from NHE8 to NHE3 that is concordant with the postnatal increase in serum glucocorticoid levels. To examine if glucocorticoids may be responsible for this isoform switch, we administered dexamethasone daily to mice at 7-10 days of age, a time prior to the normal isoform switch. We show that compared to vehicle treated controls, dexamethasone caused a premature increase in renal NHE3 and decrease in NHE8 mRNA, total protein and brush border membrane protein abundance. To examine if there was a direct epithelial action of dexamethasone on NHE8, we studied NRK cells in vitro which express NHE8 on their apical membrane. Dexamethasone decreased NHE8 mRNA, total protein, and apical protein abundance. Dexamethasone also decreased Na+/H+ exchanger activity. These studies provide evidence that glucocorticoids may play a role in the developmental isoform switch from NHE8 to NHE3 and cause a decrease in NHE8 expression and activity.

Acute antibody-mediated rejection in pediatric kidney transplants: a single center experience.

aAMR is a potentially devastating complication of kidney transplantation. The incidence of aAMR in children, while thought to be rare, is not well defined, and there is a paucity of data on treatment regimens in children. We retrospectively reviewed the outcomes of our pediatric patients that were treated for aAMR between 2007 and 2009. Three adolescent Hispanic males were found to have aAMR. All three received deceased donor transplants, and all three verbalized non-adherence. Treatment consisted of rituximab, solumedrol, PE, and IVIgG in one patient, and PE, IVIgG, and bortezomib in two patients. The only side effect of therapy noted was mild hypotension with rituximab that resolved after decreasing the infusion rate. There were no reported infections two yr after treatment, and all of the viral monitoring in these patients remained negative.

Complement disorders and hemolytic uremic syndrome.

PURPOSE OF REVIEW: Complement mediated hemolytic uremic syndrome (aHUS) accounts for a significant proportion of non-shiga toxin HUS. The purpose of this review is to outline the pathophysiology, clinical features and therapeutic options for aHUS. RECENT FINDINGS: In the last decade, strides have been made in identifying several new disease-causing mutations in complement-regulating proteins. SUMMARY: Complement mediated HUS (aHUS) has a worse prognosis compared with shiga toxin mediated HUS, often resulting in end stage renal disease. Early identification of aHUS is crucial so that plasma therapy can be initiated. After renal transplantation, there is very high risk of disease recurrence and graft loss. Eculizumab and combined liver-kidney transplantation offer promise for improved prognosis.

Proximal tubule Na+/H+ exchanger activity in adult NHE8-/-, NHE3-/-, and NHE3-/-/NHE8-/- mice.

NHE3 is the predominant Na(+)/H(+) exchanger on the brush-border membrane (BBM) of the proximal tubule in adults. However, NHE3 null mice still have significant renal BBM Na(+)/H(+) activity. NHE8 has been localized to the BBM of proximal tubules and is more highly expressed in neonates than adult animals. The relative role of NHE8 in adult renal H(+) transport is unclear. This study examined whether there was compensation by NHE8 in NHE3(-/-) mice and by NHE3 in NHE8(-/-) mice. NHE3(-/-) mice had significant metabolic acidosis, and renal BBM NHE8 protein abundance was greater in NHE3(-/-) mice than control mice, indicating that there may be compensation by NHE8 in NHE3(-/-) mice. NHE8(-/-) mice had serum bicarbonate levels and pH that were not different from controls. NHE3 protein expression on the BBM was greater in NHE8(-/-) mice than in wild-type mice, indicating that there may be compensation by NHE3 in NHE8(-/-) mice. Both BBM NHE3 and NHE8 protein abundance increased in response to acidosis. Blood pressure and Na(+)/H(+) exchanger activity were comparable in NHE8(-/-) mice to that of controls, but both were significantly lower in NHE3(-/-) mice compared with control mice. Compared with NHE3(-/-) mice, NHE3(-/-)/NHE8(-/-) mice had lower blood pressures. While serum bicarbonate was comparable in NHE3(-/-) mice and NHE3(-/-)/NHE8(-/-) mice, proximal tubule Na(+)/H(+) exchange activity was less in NHE3(-/-)/NHE8(-/-) mice compared with NHE3(-/-) mice. In conclusion, NHE3 is the predominant Na(+)/H(+) exchanger in adult mice. NHE8 may play a compensatory role in renal acidification and blood pressure regulation in NHE3(-/-) mice.

Is there any benefit to adding intravenous ketamine to patient-controlled epidural analgesia after thoracic surgery? A randomized double-blind study.

OBJECTIVES: Thoracic surgery is associated with severe acute postoperative pain, leading to pulmonary complications and hyperalgesia-induced chronic pain. Thoracic patient-controlled epidural analgesia is also considered as the gold-standard postoperative analgesia. As previously described in major digestive surgery, combination with low-dose intravenous (i.v.) ketamine could potentiate epidural analgesia and facilitate pulmonary function recovery following thoracotomy. METHODS: In a randomized, double-blind trial, 60 patients scheduled to undergo thoracotomy were included. All patients received a thoracic epidural catheter placed before surgery, and standardized general anaesthesia. They were allocated to two groups to receive either an i.v. bolus of ketamine at induction, followed by a continuous infusion during surgery and the first 48 h postoperatively, or an i.v. placebo (a saline solution under the same infusion modalities). Cumulative epidural ropivacaine consumption, postoperative pain scores (patient self-rated numeric pain intensity scale), analgesic rescue consumption, residual pain, haemodynamics and respiratory recovery function were recorded from 12 h to 3 months. Data were expressed as mean ± standard deviation or median ± interquartile range (25-75%). The comparisons between ketamine and placebo groups were performed using χ(2) or Fisher's exact tests for frequencies, and Mann-Whitney tests for quantitative variables. RESULTS: Epidural ropivacaine consumption was similar between groups during the first 48 postoperative hours. Postoperative pain scores and spirometric parameters were not significantly different between groups. But the incidence of postoperative nausea was significantly increased in patients owning to the ketamine group. Finally, the incidence of residual pain was similar between groups at 1 and 3 months following thoracotomy. CONCLUSIONS: Adding i.v. ketamine did not potentiate epidural analgesia neither to reduce acute and chronic postoperative pain nor to improve pulmonary dysfunction following thoracic surgery. Pain scores were low in both groups, mainly because of an optimized analgesia provided by the patient-controlled epidural mode, and might explain this lack of benefit in adding i.v. ketamine.