Do we know the optimal dose for renal replacement therapy in the intensive care unit?

Increasing the dose of renal replacement therapy might increase survival in critically ill patients with acute renal failure. For continuous renal replacement therapy (CRRT), a single-center study suggests that increasing urea clearance from 20 ml/kg/h to 35-45 ml/kg/h might increase short-term survival. A further single-center study has now confirmed that the dose of CRRT might be a determinant of outcome. This issue is now being addressed by two large multicenter randomized controlled trials in the United States (the ATN study) and Australia and New Zealand (the RENAL study). The results of these two studies should be available in 2008. Before making any major changes to practice, it seems prudent to wait for the publication of the findings of these two pivotal trials.     

Does perioperative furosemide usage reduce the need for renal replacement therapy in cardiac surgery patients?

A best evidence topic was constructed according to a structured protocol. The question addressed was 'Does perioperative furosemide usage reduce the need for renal replacement therapy in cardiac surgery patients?' Forty-seven papers were found using the reported search, of which 10 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Current best available evidence to resolve the issue includes a systematic review and nine randomized controlled trials (RCTs). The systematic review of seven RCTs and one observational study has demonstrated that in patients who have undergone cardiac surgery, a more consistent and sustained diuresis is produced by a continuous infusion of furosemide compared with intermittent bolus doses of furosemide. However, there does not appear to be a significant difference in the total urine output or a change in serum electrolyte levels when furosemide is administered as a continuous infusion compared with intermittent bolus doses. Three RCTs recruiting neonatal and paediatric patients after open heart surgery also validated the safety and efficacy of furosemide infusion as well as intermittent bolus doses. Two of the five RCTS in adult cardiac surgery patients showed that furosemide infusion was associated with a reduced need for renal replacement therapy (RRT), while two RCTs failed to show any benefit and one reported an increased incidence of renal impairment. We conclude that continuous furosemide infusion in the perioperative period promotes a gentle and sustained diuresis in cardiac surgery patients. The evidence supporting the benefit of this strategy in terms of reducing the need for RRT is weak. At the same time, current best available evidence, albeit from small RCTs, suggests that the timely introduction of continuous furosemide infusion does not increase the incidence of renal impairment after cardiac surgery.     

Is the loss of health-related quality of life during renal replacement therapy lower in elderly patients than in younger patients?

BACKGROUND: Previous studies have reported that elderly (aged 65 years or over) end-stage renal disease (ESRD) patients have poorer health-related quality of life (HRQOL) than both younger patients and healthy subjects of the same age. The aim of present study was to evaluate the effect of ESRD and its treatment on the HRQOL, and to determine the effects of age and gender. METHODS: A cross-sectional multicentric study was carried out with 485 haemodialysis and renal-transplant patients, using the SF-36 Health Survey to evaluate their HRQOL. SF-36 scores were standardized by age and gender using Spanish normative data. Karnofsky scale score (KS), socio-demographic, and clinical data were also collected. RESULTS: In renal-replacement therapy (RRT), chronic haemodialysis, and renal-transplant patients, SF-36 standardized scores of elderly patients were higher than in younger patients. Therefore the reduction in HRQOL of elderly patients, in relationship with that of the general population of the same age and gender, was lower than in younger patients. In the case of renal-transplant patients, standardized scores in elderly patients were higher than in the general population for all parameters. CONCLUSIONS: Using standardized scores, elderly patients on renal replacement therapy (haemodialysis and kidney transplant) had relatively better HRQOL than younger patients, and in the case of transplant patients, they had even better HRQOL than in the general population of the same age and gender.     

Growth in children on renal replacement therapy: a shrinking problem?

Growth failure has been almost inextricably linked with chronic kidney disease (CKD) and end-stage renal disease (ESRD) since initial reports of renal dwarfism dating back to the turn of the twentieth century. Growth failure in CKD has been associated with both increased morbidity and mortality. Growth failure in the setting of kidney disease is multifactorial and is related to poor nutritional status as well as comorbidities, such as anemia, bone and mineral disorders, and alterations in hormonal responses, as well as to aspects of treatment such as steroid exposure. In this issue of Pediatric Nephrology, Franke et al. report on the gains made in growth and maturation in pediatric patients with ESRD in recent decades, particularly in Germany. Through advances in the care of CKD and ESRD over recent decades, the prevalence of growth failure appears to be decreasing. These findings, along with a recent report demonstrating decreases in mortality in childhood ESRD in the United States Renal Data System (USRDS), suggest overall improvements in the outcomes of care, perhaps reflecting improvements in the quality of care for children with kidney disease worldwide.     

Neonatal extracorporeal renal replacement therapy—a routine renal support modality?

Peritoneal dialysis (PD) is generally considered the preferred extracorporeal therapy for neonates with acute kidney injury (AKI). However, there are situations when PD is not suitable, such as in patients with previous abdominal surgery, hyperammonemia and significant ascites or anasarca. Additionally, with a need to start PD soon after catheter placement, there is increased risk of PD catheter leak and infection. Extracorporeal continuous renal replacement therapy (CRRT) is challenging in severely ill neonates as it requires obtaining adequately sized central venous access to accommodate adequate blood flow rates and also adaptation of a CRRT machine meant for older children and adults. In addition, ultrafiltration often cannot be set in sufficiently small increments to be suitable for neonates. Although CRRT practices can be modified to fit the needs of infants and neonates, there is a need for a device designed specifically for this population. Until that becomes available, providing the highest level of care for neonates with AKI is dependent on the shared experiences of members of the pediatric nephrology community.     

Can antiosteoporotic therapy reduce mortality in MRI-proved acute osteoporotic vertebral fractures?

Patients with MRI-proved acute painful vertebral fractures in whom conservative pain management fails are frequently referred for vertebroplasty. This study investigated the effects of treating osteoporosis on the mortality rate of patients with MRI-proved acute osteoporosis-related vertebral fractures who had undergone vertebroplasty. We retrospectively reviewed the cases of osteoporosis patients with MRI-proved acute vertebral fractures who had been treated with vertebroplasty from January 2001 to December 2007. The long-term outcomes of the patients who received antiosteoporotic therapy were compared with those of patients who received no therapy. A total of 304 patients (247 female patients and 57 male patients; mean age, 74.1 ± 7.7 years) were enrolled in the study. The patients who received antiosteoporotic therapy had a significantly lower mortality rate than did patients who did not receive antiosteoporotic therapy (P = 0.001; hazard ratio, 0.396, 95 % confidence interval, 0.273–0.575). At the end of the study, 183 patients were alive, and 121 had died. Effective treatment for osteoporosis may improve survival in patients with osteoporosis-related vertebral fractures after vertebroplasty.     

Can anesthesia improve the outcome in high risk obstertric patients?

Obstetric anesthetists should have an infrastructure that allows for referral and assessment of high risk patients. Management plans should be agreed well before delivery. This information must be available to other members of the team. Protocol for common high risk problems should be agreed and introduced. Promoting regional blockade for Cesarean section will reduce maternal anesthetic mortality. Epidural anesthesia preserves fetal biochemistry better than other forms of anesthesia.     

Should nitrous oxide ever be used in oncology patients receiving methotrexate therapy?

Nitrous oxide (N₂O) is frequently used for short anesthesia/analgesia in children undergoing painful or repetitive procedures. Children with acute lymphoblastic leukemia (ALL) require repeated lumbar punctures with direct instillation of intrathecal chemotherapy, usually the anti‐folate agent methotrexate, during their treatment. These procedures are frequently performed under anesthesia. Concerns have been intermittently raised about a drug interaction between methotrexate and N₂O that may potentiate the undesirable side effects of methotrexate, including neurotoxicity. However, the clinical evidence consists mainly of isolated case reports leading to a lack of consensus among pediatric anesthetists about the relative risk benefits of using N₂O in children with ALL. In this article, we review the biochemical basis and scientific observations that suggest a significant interaction between N₂O and methotrexate due to their dual inhibition of the key enzyme methionine synthase. The possible role of this interaction in potentiating neurotoxicity in children with cancer is discussed, and arguments and counterarguments about the clinical significance of this largely theoretical relationship are explored. Following comprehensive review of all the available data, we make the case for the circumstantial evidence being sufficiently compelling to prompt a review of practice by pediatric anesthetists and call for a precautionary approach by avoiding the use of N₂O in children receiving concurrent methotrexate.     

Can we avoid surgery in elderly patients with renal masses by using the Charlson comorbidity index?

OBJECTIVE

To determine the safety of surveillance for localized contrast‐enhancing renal masses in elderly patients whose comorbidities precluded invasive management; to provide an insight into the natural history of small enhancing renal masses; and to aid the clinician in identifying those patients who are most suitable for a non‐interventional approach.

PATIENTS AND METHODS

We conducted a retrospective chart review of 26 consecutive patients (16 men and 10 women), who were followed for ≥1 year, with localized solid enhancing renal masses between 1998 and 2006. These patients were unfit or unwilling to undergo radical or partial nephrectomy. None had their tumours surgically removed. Study variables included age, presentation, tumour size, growth rate, Charlson comorbidity index (CMI) and available pathological data.

RESULTS

The mean (range) patient age was 78.14 (63–89) year, with a mean follow‐up of 28.1 (12–72) months. The mean tumour size was 4.25 (2.5–8.7) cm at diagnosis. The tumour growth rate was 0.44 cm/year; among smaller masses (T1a) it was 0.15 cm/year, vs 0.64 cm/year in the larger masses (T1b and T2). The mean CMI was 2.96. There were 11 deaths overall; 10 patients died from unrelated illnesses. One death was directly attributable to metastatic renal cancer; this patient had an initial tumour diameter of 5.4 cm and a CMI of 6. All patients who died had a CMI of ≥3.

CONCLUSIONS

Elderly patients with small renal tumours (T1a) and comorbidity scores of ≥3 were more likely to die as a result of their comorbidities rather than the renal tumour. Surveillance of small renal masses appears to be a safe alternative in elderly patients who are poor surgical candidates, where the overall growth rate appears to be slow.