Phosphate-containing dialysis solution prevents hypophosphatemia during continuous renal replacement therapy

ESPEN practical guideline on clinical nutrition in hospitalized patients with acute or chronic kidney disease

BACKGROUND AND AIMS

Hospitalized patients often have acute kidney disease (AKD) or chronic kidney disease (CKD), with important metabolic and nutritional consequences. Moreover, in case kidney replacement therapy (KRT) is started, the possible impact on nutritional requirements cannot be neglected. On this regard, the present guideline aims to provide evidence-based recommendations for clinical nutrition in hospitalized patients with KD.

METHODS

The standard operating procedure for ESPEN guidelines was used. Clinical questions were defined in both the PICO format, and organized in subtopics when needed, and in non-PICO questions for the more general topics. The literature search was from January 1st, 1999 until January 1st, 2020. Each question led to one or more recommendation/statement and related commentaries. Existing evidence was graded, as well as recommendations and statements were developed and agreed upon in a multistage consensus process.

RESULTS

The present guideline provides 32 evidence-based recommendations and 8 statements, defining how to assess nutritional status, how to define patients at risk, how to choose the route of feeding, and how to integrate nutrition with KRT. In the final online voting, a strong consensus was reached in 84% at least of recommendations and 100% of statements.

CONCLUSION

The presence of KD in hospitalized patients identifies a highly heterogeneous group of subjects with widely varying nutrient needs and intakes. Considering the high nutritional risk related with this clinical condition, an individualized approach consisting of nutritional status evaluation and monitoring, frequent evaluation of nutritional requirements, and careful integration with KRT should be planned to avoid both underfeeding and overfeeding. Practical recommendations and statements were developed, aiming at defining suggestions for everyday clinical practice in the individualization of nutritional support in this patient setting. Literature areas with scarce or without evidence were also identified, thus requiring further basic or clinical research.

Phosphate level predicts mortality in acute kidney injury patients undergoing continuous kidney replacement therapy and has a U-shaped association with mortality in patients with high disease severity: a multicenter retrospective study

BACKGROUND

This study investigated the association between serum phosphate level and mortality in acute kidney injury (AKI) patients undergoing continuous kidney replacement therapy (CKRT) and evaluated whether this association differed according to disease severity.

METHODS

Data from eight tertiary hospitals in Korea were retrospectively analyzed. The patients were classified into four groups (low, normal, high, and very high) based on their serum phosphate level at baseline. The association between serum phosphate level and mortality was then analyzed, with further subgroup analysis being conducted according to disease severity.

RESULTS

Among the 3,290 patients identified, 166, 955, 1,307, and 862 were in the low, normal, high, and very high phosphate groups, respectively. The 90-day mortality rate was 63.9% and was highest in the very high group (76.3%). Both the high and very high groups showed a significantly higher 90-day mortality rate than did the normal phosphate group (high: hazard ratio [HR], 1.35, 95% confidence interval [CI], 1.21-1.51, p < 0.001; very high: HR, 2.01, 95% CI, 1.78-2.27, p < 0.001). The low group also exhibited a higher 90-day mortality rate than did the normal group among those with high disease severity (HR, 1.47; 95% CI, 1.09-1.99; p = 0.01) but not among those with low disease severity.

CONCLUSION

High serum phosphate level predicted increased mortality in AKI patients undergoing CKRT, and low phosphate level was associated with increased mortality in patients with high disease severity. Therefore, serum phosphate levels should be carefully considered in critically ill patients with AKI.

Global Scientific Trends in Continuous Renal Replacement Therapy from 2000 to 2023: A Bibliometric and Visual Analysis

INTRODUCTION

Continuous renal replacement therapy (CRRT) is one of the most widely used blood purification and organ support methods in the ICU. However, the development process, the current status, hotspots, and future trends of CRRT remain unclear.

METHOD

The WoSCC database was used to analyze CRRT research evolution and theme trends. VOSviewer was used to construct coauthorship, co-occurrence, co-citation, and network visualizations. CiteSpace is used to detect bursts for co-occurrence items. Several important subtopics were reviewed and discussed in more detail.

RESULTS

Global publications increased from 56 in 2000 to 398 in 2023, a 710.71% increase. Blood Purification published the most manuscripts, followed by the International Journal of Artificial Organs. The USA, the San Bortolo Hospital, and Bellomo were the most productive and impactful institution, country, and author, respectively. Based on co-occurrence cluster analysis, five clusters emerged: (1) clinical applications and management of CRRT; (2) sepsis and CRRT; (3) CRRT anticoagulant management; (4) CRRT and antibiotic pharmacokinetics and pharmacodynamics; and (5) comparison of CRRT and intermittent hemodialysis. COVID-19, initiation, ECOMO, cefepime, guidelines, cardiogenic shock, biomarker, and outcome were the latest high-frequency keywords or strongest bursts, indicating the emerging frontiers of CRRT.

CONCLUSIONS

There has been widespread publication and citation of CRRT research in the past 2 decades. We provide an overview of current trends, global collaboration patterns, basic knowledge, research hotspots, and emerging frontiers.

Simplified regional citrate anticoagulation protocol for CVVH, CVVHDF and SLED focused on the prevention of KRT-related hypophosphatemia while optimizing acid-base balance

BACKGROUND

Hypophosphatemia is a common electrolyte disorder in critically ill patients undergoing prolonged kidney replacement therapy (KRT). We evaluated the efficacy and safety of a simplified regional citrate anticoagulation (RCA) protocol for continuous venovenous hemofiltration (CVVH), continuous venovenous hemodiafiltration (CVVHDF) and sustained low-efficiency dialysis filtration (SLED-f). We aimed at preventing KRT-related hypophosphatemia while optimizing acid-base equilibrium.

METHODS

KRT was performed by the Prismax system (Baxter) and polyacrylonitrile AN69 filters (ST 150, 1.5 m2, Baxter), combining a 18 mmol/L pre-dilution citrate solution (Regiocit 18/0, Baxter) with a phosphate-containing solution (HPO42- 1.0 mmol/L, HCO3- 22.0 mmol/L; Biphozyl, Baxter). When needed, phosphate loss was replaced with sodium glycerophosphate pentahydrate (Glycophos™ 20 mmol/20 mL, Fresenius Kabi Norge AS, Halden, Norway). Serum citrate measurements were scheduled during each treatment. We analyzed data from three consecutive daily 8-h SLED-f sessions, as well as single 72-h CVVH or 72-h CVVHDF sessions. We used analysis of variance (ANOVA) for repeated measures to evaluate differences in variables means (i.e. serum phosphate, citrate). Because some patients received phosphate supplementation, we performed analysis of covariance (ANCOVA) for repeated measures modelling phosphate supplementation as a covariate.

RESULTS

Forty-seven patients with acute kidney injury (AKI) or end stage kidney disease (ESKD) requiring KRT were included [11 CVVH, 11 CVVHDF and 25 SLED-f sessions; mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score 25 ± 7.0]. Interruptions for irreversible filter clotting were negligible. The overall incidence of hypophosphatemia (s-P levels <2.5 mg/dL) was 6.6%, and s-P levels were kept in the normality range irrespective of baseline values and the KRT modality. The acid-base balance was preserved, with no episode of citrate accumulation.

CONCLUSIONS

Our data obtained with a new simplified RCA protocol suggest that it is effective and safe for CVVH, CVVHDF and SLED, allowing to prevent KRT-related hypophosphatemia and maintain the acid-base balance without citrate accumulation.

TRIAL REGISTRATION

NCT03976440 (registered 6 June 2019).

Regional citrate anticoagulation (RCA) in critically ill patients undergoing renal replacement therapy (RRT): expert opinion from the SIAARTI-SIN joint commission

Renal replacement therapies (RRT) are essential to support critically ill patients with severe acute kidney injury (AKI), providing control of solutes, fluid balance and acid-base status. To maintain the patency of the extracorporeal circuit, minimizing downtime periods and blood losses due to filter clotting, an effective anticoagulation strategy is required.Regional citrate anticoagulation (RCA) has been introduced in clinical practice for continuous RRT (CRRT) in the early 1990s and has had a progressively wider acceptance in parallel to the development of simplified systems and safe protocols. Main guidelines on AKI support the use of RCA as the first line anticoagulation strategy during CRRT in patients without contraindications to citrate and regardless of the patient's bleeding risk.Experts from the SIAARTI-SIN joint commission have prepared this position statement which discusses the use of RCA in different RRT modalities also in combination with other extracorporeal organ support systems. Furthermore, advise is provided on potential limitations to the use of RCA in high-risk patients with particular attention to the need for a rigorous monitoring in complex clinical settings. Finally, the main findings about the prospective of optimization of RRT solutions aimed at preventing electrolyte derangements during RCA are discussed in detail.

Unapparent systemic effects of regional anticoagulation with citrate in continuous renal replacement therapy: a narrative review

The use of citrate, through reversible binding of calcium, has become the preferred choice for anticoagulation in continuous renal replacement therapy in the critically ill patient. Though generally considered as very efficacious in acute kidney injury, this type of anticoagulation can cause acid-base disorders as well as citrate accumulation and overload, phenomena which have been well described. The purpose of this narrative review is to provide an overview of some other, non-anticoagulation effects of citrate chelation during its use as anticoagulant. We highlight the effects seen on the calcium balance and hormonal status, phosphate and magnesium balance, as well as oxidative stress resulting from these unapparent effects. As most of these data on these non-anticoagulation effects have been obtained in small observational studies, new and larger studies documenting both short- and long-term effects should be undertaken. Subsequent future guidelines for citrate-based continuous renal replacement therapy should take not only the metabolic but also these unapparent effects into account.

Hypophosphatemia in critically ill patients undergoing Sustained Low-Efficiency Dialysis with standard dialysis solutions

BACKGROUND

In patients admitted to the Intensive Care Unit (ICU), Kidney Replacement Therapy (KRT) is an important risk factor for hypophosphataemia. However, studies addressing the development of hypophosphatemia during prolonged intermittent KRT modalities are lacking. Thus, we evaluated the incidence of hypophosphatemia during Sustained Low-Efficiency Dialysis (SLED) in ICU patients; we also examined the determinants of post-SLED serum phosphate level (s-P) and the relation between s-P and phosphate supplementation and ICU mortality.

METHODS

We conducted a retrospective analysis on a cohort of critically ill patients with severe renal failure and KRT need, who underwent at least three consecutive SLED sessions at 24-72 h time intervals with daily monitoring of s-P concentration. SLED with Regional Citrate Anticoagulation (RCA) was performed with either conventional dialysis machines or continuous-KRT monitors and standard dialysis solutions. When deemed necessary by the attending physician, intravenous phosphate supplementation was provided by sodium glycerophosphate pentahydrate. We used mixed-effect models to examine the determinants of s-P and Cox proportional hazards regression models with time-varying covariates to examine the adjusted relation between s-P, intravenous phosphate supplementation and ICU mortality.

RESULTS

We included 65 patients [mean age 68 years (SD 10.0); mean Acute Physiology and Chronic Health Evaluation II score 25 (range 9-40)] who underwent 195 SLED sessions. The mean s-P before the start of the first SLED session (baseline s-P) was 5.6 ± 2.1 mg/dL (range 1.5-12.3). Serum phosphate levels at the end of each SLED decreased with increasing age, SLED duration and number of SLED sessions (P < .05 for all). The frequency of hypophosphatemia increased after the first through the third SLED session (P = .012). Intravenous phosphate supplementation was scheduled after 12/45 (26.7%) SLED sessions complicated by hypophosphataemia. The overall ICU mortality was 23.1% (15/65). In Cox regression models, after adjusting for potential confounders and for current s-P, intravenous phosphate supplementation was associated with a decrease in ICU mortality [adjusted hazard ratio: 0.24 (95% confidence interval: 0.06 to 0.89; P = 0.033)].

CONCLUSIONS

Hypophosphatemia is a frequent complication in critically ill patients undergoing SLED with standard dialysis solutions, that worsens with increasing SLED treatment intensity. In patients undergoing daily SLED, phosphate supplementation is strongly associated with reduced ICU mortality.

Complications Associated with Continuous RRT

Continuous renal replacement therapy (CRRT) is a form of renal replacement therapy that is used in modern intensive care units (ICUs) to help manage acute kidney injury (AKI), end stage kidney disease (ESKD), poisonings, and some electrolyte disorders. CRRT has transformed the care of patients in the ICU over the past several decades. In this setting, it is important to recognize CRRT-associated complications but also up-to-date management of these complications. Some of these complications are minor, but others may be more significant and even life-threatening. Some CRRT complications may be related to dialysis factors and others to specific patient factors. Our overarching goal in this article is to review and discuss the most significant CRRT-related complications at the different stage of management of CRRT. With the advent of newer solutions, there have been newer complications as well.

Association of Phosphate-Containing versus Phosphate-Free Solutions on Ventilator Days in Patients Requiring Continuous Kidney Replacement Therapy

BACKGROUND AND OBJECTIVES

Hypophosphatemia is commonly observed in patients receiving continuous KRT. Patients who develop hypophosphatemia may be at risk of respiratory and neuromuscular dysfunction and therefore subject to prolongation of ventilator support. We evaluated the association of phosphate-containing versus phosphate-free continuous KRT solutions with ventilator dependence in critically ill patients receiving continuous KRT.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study was a single-center, retrospective, pre-post cohort study of adult patients receiving continuous KRT and mechanical ventilation during their intensive care unit stay. Zero-inflated negative binomial regression with and without propensity score matching was used to model our primary outcome: ventilator-free days at 28 days. Intensive care unit and hospital lengths of stay as well as hospital mortality were analyzed with a t test or a chi-squared test, as appropriate.

RESULTS

We identified 992 eligible patients, of whom 649 (65%) received phosphate-containing solutions and 343 (35%) received phosphate-free solutions. In multivariable models, patients receiving phosphate-containing continuous KRT solutions had 12% (95% confidence interval, 0.17 to 0.47) more ventilator-free days at 28 days. Patients exposed to phosphate-containing versus phosphate-free solutions had 17% (95% confidence interval, -0.08 to -0.30) fewer days in the intensive care unit and 20% (95% confidence interval, - 0.12 to -0.32) fewer days in the hospital. Concordant results were observed for ventilator-free days at 28 days in the propensity score matched analysis. There was no difference in hospital mortality between the groups.

CONCLUSIONS

The use of phosphate-containing versus phosphate-free continuous KRT solutions was independently associated with fewer ventilator days and shorter stay in the intensive care unit.

Acute Kidney Injury at the Neurocritical Care Unit

Neurocritical care has advanced substantially in recent decades, allowing doctors to treat patients with more complicated conditions who require a multidisciplinary approach to achieve better clinical outcomes. In neurocritical patients, nonneurological complications such as acute kidney injury (AKI) are independent predictors of worse clinical outcomes. Different research groups have reported an AKI incidence of 11.6% and an incidence of stage 3 AKI, according to the Kidney Disease: Improving Global Outcomes, that requires dialysis of 3% to 12% in neurocritical patients. These patients tend to be younger, have less comorbidity, and have a different risk profile, given the diagnostic and therapeutic procedures they undergo. Trauma-induced AKI, sepsis, sympathetic overstimulation, tubular epitheliopathy, hyperchloremia, use of nephrotoxic drugs, and renal hypoperfusion are some of the causes of AKI in neurocritical patients. AKI is the result of a sum of events, although the mechanisms underlying many of them remain uncertain; however, two important causes that merit mention are direct alteration of the physiological brain-kidney connection and exposure to injury as a result of the specific medical management and well-established therapies that neurocritical patients are subjected to. This review will focus on AKI in neurocritical care patients. Specifically, it will discuss its epidemiology, causes, associated mechanisms, and relationship to the brain-kidney axis. Additionally, the use and risks of extracorporeal therapies in this group of patients will be reviewed.

Impact of different hemodiafiltration solutions on ionemia in long-term CRRT

Critical patients with Acute Kidney Injury (AKI) requiring renal replacement therapy are in most cases eligible only for continuous modalities where the electrolyte balance control is a critical issue. The standard solutions used for hemodiafiltration, containing potassium at 2 mmol/L and no phosphorus, determines during the extended renal replacement therapy hypokalemia and hypophosphatemia. Therefore, solutions containing potassium and phosphate in physiological concentrations were formulated to avoid electrolyte imbalances and reduce ion alterations in prolonged treatments, these solutions are not routinely used in the standard clinical practice. To avoid electrolyte imbalances, we have first introduced in our practice two different solutions and then we have retrospectively analyzed the electrolyte balance upon these two solutions in order to identity the impact of these solutions on potassium and phosphate according to our clinical practice. We retrospectively analyzed 96 patients treated with Continuous Renal Replacement Therapy (CRRT) in the intensive care units (ICU) at Padua's University Hospital to evaluate the role on electrolyte balance of Phoxilium^® and Prismasol 2^® that differ in their composition and the need for electrolytes infusions. In the Phoxilium group the frequency of hypokalemia, hypophosphatemia, and the need of potassium and phosphate replacement were significantly reduced resulting in a reduction in complications, workload, and clinical risk associated with infusions of electrolytes. Our data demonstrated that the use of these two different hemodiafiltration solutions can reduce the occurrence of hypokalemia and hypophosphatemia during CRRT performing personalized treatments without the use of potassium and phosphate infusions.

Effect of Phoxilium on prognostic predictors in patients undergoing continuous venovenous hemodiafiltration

Background

Phosphorus-containing dialysis solution is used to prevent hypophosphatemia in patients undergoing continuous venovenous hemodiafiltration (CVVHDF). This study evaluated the effect of phosphorus-containing dialysis solution on mortality in patients undergoing CVVHDF based on changes in phosphorus and red cell distribution width-coefficient of variation (RDW-CV) levels.

Methods

We included 272 patients with acute kidney injury (AKI) who underwent CVVHDF at the medical intensive care unit from 2017 to 2019 and classified them according to Phoxilium (Baxter Healthcare Ltd.), as a phosphorus-containing dialysis solution, use within 48 hours after CVVHDF initiation. Clinical data were collected at baseline and 48 hours after CVVHDF initiation. The primary outcome was all-cause mortality during the follow-up period.

Results

The non-Phoxilium (NP) group had higher phosphorus and lower RDW-CV levels than the Phoxilium (P) group (phosphorus, 7.3 ± 4.3 vs. 5.0 ± 2.8 mg/dL; RDW-CV, 14.6 ± 1.9 vs. 15.7 ± 2.6%; all p < 0.001). In the multivariable Cox proportional hazard regression of the NP group, an increase in phosphorus and RDW-CV at 48 hours of CVVHDF was associated with mortality (delta phosphorus: median, >0 mg/dL vs. <-2.0 mg/dL; hazard ratio [HR], 8.62; 95% confidence interval [CI], 2.10-35.32; p = 0.003/delta RDW-CV: median, >0% vs. <-0.2%; HR, 4.34; 95% CI, 1.49-13.18; p = 0.008). Meanwhile, in the P group, an increase in delta RDW-CV was associated with mortality (delta RDW-CV: >0% vs. >-0.2% and <0%; HR, 2.65; 95% CI, 1.12-6.24; p = 0.03), while an increase in delta phosphorus was not.

Conclusion

In patients with AKI undergoing CVVHDF, the risk factors for all-cause mortality differed according to the initial phosphorus levels and use of Phoxilium.

Association of Phosphate Containing Solutions with Incident Hypophosphatemia in Critically Ill Patients Requiring Continuous Renal Replacement Therapy

BACKGROUND

Hypophosphatemia in critically ill patients is a common electrolyte disturbance associated with a myriad of adverse effects. Critically ill patients requiring continuous renal replacement therapy (CRRT) are at high risk of hypophosphatemia and often require phosphate supplementation during therapy. The aim of this study was to evaluate the association of phosphate versus non-phosphate containing CRRT solutions with incident hypophosphatemia in critically ill patients requiring CRRT.

MATERIALS AND METHODS

This is a single-center, retrospective, cohort study at a tertiary academic medical center of 1,396 adult patients requiring CRRT during their intensive care unit stay comprising 7,529 (phosphate containing) and 4,821 (non-phosphate containing) cumulative days of CRRT. Multivariable logistic regression was used to model the primary outcome of hypophosphatemia during CRRT according to exposure to phosphate versus non-phosphate containing CRRT solutions.

RESULTS

Incident hypophosphatemia during CRRT, serum phosphate <2.5 mg/dL or 0.81 mmol/L, was significantly higher in the non-phosphate versus phosphate containing solution group: 304/489 (62%) versus 175/853 (21%) (p < 0.001). Cumulative phosphate supplementation was also significantly higher in the non-phosphate versus phosphate containing solution group: 79 (IQR: 0-320) versus 0 (0-16) mmol (p < 0.001). Non-phosphate solutions were associated with an 8-fold increase in the incidence of hypophosphatemia (adjusted OR 8.05; 95% CI 5.77, 11.26; p < 0.001).

DISCUSSION/CONCLUSIONS

The use of phosphate containing CRRT solutions was independently associated with reduced risk of incident hypophosphatemia and decreased phosphate supplementation during CRRT. Interventional studies to confirm these findings are needed.

Low bicarbonate replacement fluid normalizes metabolic alkalosis during continuous veno-venous hemofiltration with regional citrate anticoagulation

Background

Metabolic alkalosis is a frequently occurring problem during continuous veno-venous hemofiltration (CVVH) with regional citrate anticoagulation (RCA). This study aimed to evaluate the effectiveness of switching from high to low bicarbonate (HCO₃⁻) replacement fluid in alkalotic critically ill patients with acute kidney injury treated by CVVH and RCA.

Methods

A retrospective-comparative study design was applied. Patients who underwent CVVH with RCA in the ICU between 09/2016 and 11/2017 were evaluated. Data were available from the clinical routine. A switch of the replacement fluid Phoxilium^® (30 mmol/l HCO₃⁻) to Biphozyl^® (22 mmol/l HCO₃⁻) was performed as blood HCO₃⁻ concentration persisted ≥ 26 mmol/l despite adjustments of citrate dose and blood flow. Data were collected from 72 h before the switch of the replacement solutions until 72 h afterwards.

Results

Of 153 patients treated with CVVH during that period, 45 patients were switched from Phoxilium^® to Biphozyl^®. Forty-two patients (42 circuits) were available for statistical analysis. After switching the replacement fluid from Phoxilium^® to Biphozyl^® the serum HCO₃⁻ concentration decreased significantly from 27.7 mmol/l (IQR 26.9–28.9) to 25.8 mmol/l (IQR 24.6–27.7) within 24 h (p < 0.001). Base excess (BE) decreased significantly from 4.0 mmol/l (IQR 3.1–5.1) to 1.8 mmol/l (IQR 0.2–3.4) within 24 h (p < 0.001). HCO₃⁻ and BE concentration remained stable from 24 h till the end of observation at 72 h after the replacement fluid change (p = 0.225). pH and PaCO₂ did not change significantly after the switch of the replacement fluid until 72 h.

Conclusions

This retrospective analysis suggests that for patients developing refractory metabolic alkalosis during CVVH with RCA the use of Biphozyl^® reduces external HCO₃⁻ load and sustainably corrects intracorporeal HCO₃⁻ and BE concentrations. Future studies have to prove whether correcting metabolic alkalosis during CVVH with RCA in critically ill patients is of relevance in terms of clinical outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00850-4.

ESPEN guideline on clinical nutrition in hospitalized patients with acute or chronic kidney disease

Acute kidney disease (AKD) - which includes acute kidney injury (AKI) - and chronic kidney disease (CKD) are highly prevalent among hospitalized patients, including those in nephrology and medicine wards, surgical wards, and intensive care units (ICU), and they have important metabolic and nutritional consequences. Moreover, in case kidney replacement therapy (KRT) is started, whatever is the modality used, the possible impact on nutritional profiles, substrate balance, and nutritional treatment processes cannot be neglected. The present guideline is aimed at providing evidence-based recommendations for clinical nutrition in hospitalized patients with AKD and CKD. Due to the significant heterogeneity of this patient population as well as the paucity of high-quality evidence data, the present guideline is to be intended as a basic framework of both evidence and - in most cases - expert opinions, aggregated in a structured consensus process, in order to update the two previous ESPEN Guidelines on Enteral (2006) and Parenteral (2009) Nutrition in Adult Renal Failure. Nutritional care for patients with stable CKD (i.e., controlled protein content diets/low protein diets with or without amino acid/ketoanalogue integration in outpatients up to CKD stages four and five), nutrition in kidney transplantation, and pediatric kidney disease will not be addressed in the present guideline.

Prevalence of hypophosphatemia in the ICU - Results of an international one-day point prevalence survey

BACKGROUND & AIMS

Hypophosphatemia (HypoP) is associated with organ dysfunction and mortality. Despite its potential severe consequences, HypoP remains poorly characterized in terms of real prevalence and timing of onset. The primary objective was to determine the prevalence of HypoP defined as blood phosphate <0.8 and < 0.65 mmol/l on one particular day at international level.

METHODS

One-day point prevalence survey conducted by the Section of Metabolism, Endocrinology and Nutrition (MEN) of the European Society of Intensive Care Medicine (ESICM) during week 11-2020.

RESULTS

In total, 56 adult and 4 paediatric ICUs, from 22 countries participated: 41 ICUs were mixed medico surgical, the 19 others being cardiac, medical or surgical. Phosphate measurements were performed daily in 21 ICUs, and 1-3 times per week in 39 ICUs. On D-Day 909 patients (883 adults) were present and 668/883 (75.7%) had serum/plasma phosphate determined, revealing a HypoP in 103 (15.4%) patients aged 62 [18 to 85] years. Of those, 49 patients presented phosphate <0.65 mmol/l: cases of hypophosphatemia were detected at any time of patient's ICU stay. No HypoP was observed in children. A treatment protocol existed only in 41.1% of adult ICUs, independently of ICU type, or size. Only 41/98 of the HypoP patients (29/41 of patients with phosphate <0.65 mmol/l) were receiving phosphate.

CONCLUSION

HypoP is present at least in 15.4% of ICU patients, and may occur at any time during the ICU stay. The absence of phosphate repletion protocols in 60% of participating ICUs is an unexpected finding, and confirms the necessity for the development of ICU phosphate protocols and guidelines.

CLINICALTRIALS IDENTIFIER

NCT04201899.

Hypophosphatemia in critically ill adults and children - A systematic review

BACKGROUND & AIMS

Phosphate is the main intracellular anion essential for numerous biological processes. Symptoms of hypophosphatemia are non-specific, yet potentially life-threatening. This systematic review process was initiated to gain a global insight into hypophosphatemia, associated morbidity and treatments.

METHODS

A systematic review was conducted (PROSPERO CRD42020163191). Nine clinically relevant questions were generated, seven for adult and two for pediatric critically ill patients, and prevalence of hypophosphatemia was assessed in both groups. We identified trials through systematic searches of Medline, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, and Web of Science. Quality assessment was performed using the Cochrane risk of bias tool for randomized controlled trials and the Newcastle-Ottawa Scale for observational studies.

RESULTS

For all research questions, we identified 2727 titles in total, assessed 399 full texts, and retained 82 full texts for evidence synthesis, with 20 of them identified for several research questions. Only 3 randomized controlled trials were identified with two of them published only in abstract form, as well as 28 prospective and 31 retrospective studies, and 20 case reports. Relevant risk of bias regarding selection and comparability was identified for most of the studies. No meta-analysis could be performed. The prevalence of hypophosphatemia varied substantially in critically ill adults and children, but no study assessed consecutive admissions to intensive care. In both critically ill adults and children, several studies report that hypophosphatemia is associated with worse outcome (prolonged length of stay and the need for respiratory support, and higher mortality). However, there was insufficient evidence regarding the optimal threshold upon which hypophosphatemia becomes critical and requires treatment. We found no studies regarding the optimal frequency of phosphate measurements, and regarding the time window to correct hypophosphatemia. In adults, nutrient restriction on top of phosphate repletion in patients with refeeding syndrome may improve survival, although evidence is weak.

CONCLUSIONS

Evidence on the definition, outcome and treatment of clinically relevant hypophosphatemia in critically ill adults and children is scarce and does not allow answering clinically relevant questions. High quality clinical research is crucial for the development of respective guidelines.

Impact of electrolyte-rich dialysate during continuous renal replacement therapy on serum phosphate and potassium in ICU patients

Background

Hypophosphatemia and hypokalemia occur frequently during continuous renal replacement therapy (CRRT). We evaluated serum phosphate and potassium levels in patients administered three different types of dialysis solution.

Methods

The study population consisted of 324 intensive care unit patients who underwent CRRT between January 2015 and December 2018. Patients were divided into three groups: group 1 (n = 105) received Hemosol B0 (no potassium or phosphate); group 2 (n = 78) received Hemosol B0 and potassium-containing solution (MultiBic); and group 3 (n = 141) received phosphate- and potassium-containing solution (Phoxilium), Hemosol B2, Prismasol 2, and Prismasol 4. A different protocol was followed in each group.

Results

The incidence rate of hypophosphatemia was 55% lower in group 3 compared to group 1 (incidence rate ratio (IRR) 0.45, 95% confidence interval (CI): 0.33 to 0.61) and 61% lower compared to group 2 (IRR 0.39, 95% CI: 0.29 to 0.53). Group 3 also had a 50% lower incidence rate of hypokalemia compared to group 1 (IRR 0.50, 95% CI: 0.29 to 0.88). The negative slope in phosphate level in group 3 was greater than that in group 1 (ß = 0.19, 95% CI: 0.02 to 0.37, p = 0.032), while the negative slope in the potassium level was greater in group 2 than in group 1(ß = 0.10, 95% CI: 0.03 to 0.17, p = 0.008). Additional intravenous calcium was not used in any case, and most cases of acid-base disturbances were well controlled.

Conclusions

The use of phosphate- and potassium-containing with a proper CRRT protocol prevented decreases in serum phosphate and potassium levels, thus also preventing hypophosphatemia and hypokalemia, and additional replacement during CRRT.

Determinants of Total/ionized Calcium in patients undergoing citrate CVVH: A retrospective observational study

PURPOSE

To identify potential determinants of the Total/ionized Ca ratio (T/iCa), a marker of citrate accumulation.

MATERIALS AND METHODS

Single-center retrospective observational study evaluating citrate dose, citrate target, albumin, phosphate, pH, lactate, and APACHE II score as potential determinants. Linear mixed models (LMM) using citrate dose and citrate target were developed describing associations with T/iCa.

RESULTS

From a dataset of 471 samples in 103 patients, an LMM in 379 complete samples (95 patients) sets revealed that citrate dose, pH, phosphate, albumin and APACHE were interactively related to T/iCa. A rising citrate dose was associated with a higher increase in T/iCa when phosphate was high, and less when phosphate was low. A rising albumin was associated with a higher increase in T/iCa when APACHE was high and phosphate was low and less when APACHE was low and phosphate high. In case of acidosis, a rising lactate was associated with a higher increase in T/iCa. In the LMM using citrate target, citrate target and pH were the main independent predictors of T/iCa with albumin, phosphate and APACHE score as modifiers.

CONCLUSIONS

Besides citrate dose, a high pH and high phosphate, albumin and APACHE are also associated with a rising T/iCa.

Intensity of Renal Replacement Therapy and Duration of Mechanical Ventilation: Secondary Analysis of the Acute Renal Failure Trial Network Study

BACKGROUND

Randomized clinical trials have failed to show benefit from increasing intensity of renal replacement therapy (RRT) for acute kidney injury, but continue to be frequently used. In addition, intensive RRT is associated with an increase in adverse events potentially secondary to small solute losses, such as phosphate. We hypothesized that, compared with less-intensive RRT, intensive RRT would lead to longer duration of mechanical ventilation.

RESEARCH QUESTION

Does more-intensive renal replacement therapy in critically ill patients with acute kidney injury increase time to extubation from mechanical ventilation when compared with less-intensive therapy?

STUDY DESIGN AND METHODS

The Acute Renal Failure Trial Network study was a randomized multicenter trial of more-intensive (hemodialysis or sustained low-efficiency dialysis six times per week or continuous venovenous hemodiafiltration at 35 mL/kg per hour) vs less-intensive (hemodialysis or sustained low-efficiency dialysis three times per week or continuous venovenous hemodiafiltration at 20 mL/kg per hour) RRT in critically ill patients with acute kidney injury. Of 1124 patients, 907 who were supported by mechanical ventilation on study initiation were included in this Cox-proportional hazards analysis. The primary outcome was the time to first successful extubation off mechanical ventilation.

RESULTS

Patients who were assigned randomly to more-intensive RRT had a 33.3% lower hazard rate of successful extubation (hazard ratio, 0.67; 95% CI, 0.52-0.88; P < .001) when compared with patients who were assigned to less-intensive RRT. Patients who were assigned to more-intensive RRT had, on average, 2.07 ventilator-free days, compared with 3.08 days in those who were assigned to less-intensive RRT (P < .001) over 14 days from start of the study.

INTERPRETATION

Critically ill mechanically ventilated patients who were assigned randomly to more-intensive RRT had longer duration of mechanical ventilation compared with those who were assigned to less-intensive RRT. The reasons for this, such as excessive phosphate loss from more-intensive RRT, deserve further study to optimize the safety and effectiveness of CRRT delivery. This was a post hoc analysis of the Acute Renal Failure Trial Network study; clinical trial registration of the original trial is NCT00076219.

Hypophosphatemia in critically ill patients with acute kidney injury on renal replacement therapies

Hypophosphatemia is a common but often underestimated electrolyte derangement among intensive care unit (ICU) patients. Low phosphate levels can lead to cellular dysfunction with potentially relevant clinical manifestations (e.g., muscle weakness, respiratory failure, lethargy, confusion, arrhythmias). In critically ill patients with severe acute kidney injury (AKI) renal replacement therapies (RRTs) represent a well-known risk factor for hypophosphatemia, especially if the most intensive and prolonged modalities of RRT, such as continuous RRT or prolonged intermittent RRT, are used. Currently, no evidence-based specific guidelines are available for the treatment of hypophosphatemia in the critically ill; however, considering the potentially negative impact of hypophosphatemia on morbidity and mortality, strategies aimed at reducing its incidence and severity should be timely implemented in the ICUs. In the clinical setting of critically ill patients on RRT, the most appropriate strategy could be to anticipate the onset of RRT-related hypophosphatemia by implementing the use of phosphate-containing solutions for RRT through specifically designed protocols. The present review is aimed at summarizing the most relevant evidence concerning epidemiology, prognostic impact, prevention and treatment of hypophosphatemia in critically ill patients with AKI on RRT, with a specific focus on RRT-induced hypophosphatemia.

Preparation times and costs for various solutions used for continuous renal replacement therapy

PURPOSE

Results of a study to determine time and cost requirements for final preparation of continuous renal replacement therapy (CRRT) products are reported.

METHODS

A 3-phase observational study was conducted at a tertiary care university hospital to evaluate costs associated with manual addition of phosphate and/or potassium to 3 commercial 5-L CRRT products. In the first phase of the study, pharmacy workflow processes for solution preparation were established; in the second phase, pharmacist and pharmacy technician time spent in the CRRT workflow and all materials used were observed and recorded. In the third phase, time and personnel requirements were analyzed in economic terms to estimate final preparation costs.

RESULTS

Through direct observation over 35 days, the CRRT workflow was observed and work times recorded for 511 bag preparations. The main cost contributors were the base CRRT solution and electrolyte additive prices. Technician compounding time differed substantially by solution brand and the need for electrolyte addition. Pharmacist verification time did not differ meaningfully by product.

CONCLUSION

Preparation and verification of premade CRRT solutions that contained physiological electrolyte concentrations required less technician and pharmacist time than solutions that needed addition of electrolytes in the pharmacy. Personnel costs, which were a small part of the total cost of dispensed CRRT bags, were higher for technicians than pharmacists. The baseline costs of the solutions and the electrolyte additives, if needed, were the main contributors to total cost.

Phosphate supplementation for hypophosphatemia during continuous renal replacement therapy in adults

Background: Hypophosphatemia is common during continuous renal replacement therapy (CRRT) in critically ill patients and can cause generalized muscle weakness, prolonged respiratory failure, and myocardial dysfunction. This study aimed to investigate the efficacy and safety of adding phosphate to the dialysate and replacement solutions to treat hypophosphatemia occurring in intensive CRRT in critically ill patients.

Methods: We retrospectively analyzed 73 patients treated with intensive CRRT (effluent flow ≥35 ml/kg/hr) in the intensive care unit. The control group (group 1, n = 22) received no phosphate supplementation. The treatment groups received dialysate and replacement solution phosphate supplementation at 2.0 mmol/L (group 2, n = 26) or 3.0 mmol/L (group 3, n = 25).

Results: The CRRT-induced hypophosphatemia incidence was 59.0%. Correction of hypophosphatemia with phosphate supplementation changed the mean serum phosphorus levels to 1.24 ± 0.37 and 1.44 ± 0.31 mmol/L in groups 2 and 3, respectively (p = .02). The time required for correction was 1.65 ± 0.80 and 1.39 ± 1.43 days for groups 2 and 3, respectively and was significantly longer in group 2 (p = .02). After supplementation, hypophosphatemia, and hyperphosphatemia both occurred in 7% of group 2. Group 3 developed no hypophosphatemia, but 20% developed hyperphosphatemia. The serum phosphate levels in hyperphosphatemia cases returned to normal within 2.0 days (group 2) and 1.0 day (group 3) after stopping phosphate supplementation.

Conclusion: Phosphate supplementation effectively corrected CRRT-induced hypophosphatemia in critically ill patients with an acute kidney injury. The use of 2 mmol/L phosphate is appropriate in patients with CRRT-induced hypophosphatemia, but a different concentration could be required to prevent hypophosphatemia at the start of CRRT.

Prevention of hypophosphatemia during continuous renal replacement therapy-An overlooked problem

Hypophosphatemia is a common and potentially serious complication occurring during continuous renal replacement therapy (CRRT). Phosphate supplementation is required in the vast majority of patients undergoing CRRT, particularly beyond the first 48 hours. Supplementation can be provided either as a standalone oral or parenteral treatment or as an additive to CRRT solutions. Each approach has advantages and disadvantages, and clinicians must weigh the individual factors most relevant in their practice setting. Currently there are no consensus protocols for phosphate replacement in CRRT, and many centers replete phosphate in response to hypophosphatemia as opposed to pre-emptively. Repletion protocols have also been challenged in recent years by shortages in injectable phosphate solutions. More recently a commercially available phosphate-containing CRRT solution was approved in the United States, but there has been limited clinical experience with this product. In this review, we present recommendations for phosphate repletion in CRRT to prevent hypophosphatemia, and describe our experience using phosphate-containing CRRT solutions.

Continuous Renal Replacement Therapy Update: An Emphasis on Safe and High-Quality Care

Continuous renal replacement therapy (CRRT) was introduced more than 40 years ago as a renal support option for critically ill patients who had contraindications to intermittent hemodialysis and peritoneal dialysis. Despite being the most common renal support therapy used in intensive care units today, the tremendous variability in CRRT management challenges the interpretation of findings from CRRT outcome studies. The lack of standardization in practice and training of clinicians along with the high risk of CRRT-related adverse events has been the impetus for the recent expert consensus work on identifying quality indicators for CRRT programs. This article summarizes the potential complications that establish CRRT as a high-risk therapy and also the recently published best-practice recommendations for providing high-quality CRRT.

The influence of hypophosphatemia on outcomes of low- and high-intensity continuous renal replacement therapy in critically ill patients with acute kidney injury

BACKGROUND

The purpose of this study was to assess the role of hypophosphatemia in major clinical outcomes of patients treated with low- or high-intensity continuous renal replacement therapy (CRRT).

METHODS

We performed a retrospective analysis of data collected from 492 patients. We divided patients into two CRRT groups based on treatment intensity (greater than or equal to or less than 40 mL/kg/hour of effluent generation) and measured serum phosphate level daily during CRRT.

RESULTS

We obtained a total of 1,440 phosphate measurements on days 0, 1, and 2 and identified 39 patients (7.9%), 74 patients (15.0%), and 114 patients (23.1%) with hypophosphatemia on each of these respective days. In patients treated with low-intensity CRRT, there were 23 episodes of hypophosphatemia/1,000 patient days, compared with 83 episodes/1,000 patient days in patients who received high-intensity CRRT (P < 0.01). Multiple Cox proportional hazards analysis showed that Acute Physiology and Chronic Health Evaluation (APACHE) III score, utilization of vasoactive drugs, and arterial pH on the second day of CRRT were significant predictors of mortality, while serum phosphate level was not a significant contributor to mortality.

CONCLUSION

APACHE score, use of vasoactive drugs, and arterial pH on the second CRRT day were identified as significant predictors of mortality. Hypophosphatemia might not be a major risk factor of increased mortality in patients treated with CRRT.

Hypophosphatemia in critically ill patients with acute kidney injury treated with hemodialysis is associated with adverse events

Background. Hypophosphatemia in critically ill patients may be exacerbated by renal replacement therapy (RRT). We aimed to identify risk factors and adverse outcomes associated with hypophosphatemia in intensive care patients treated with RRT for acute kidney injury (AKI).

Methods. This was a secondary analysis of data from a single-center prospective cohort study of medical and surgical intensive care patients with RRT for AKI between 18 December 2010 and 3 April 2013. Demographic, comorbidity, laboratory and RRT data were retrieved from patient case notes and electronic medical records. Outcomes assessed were hypophosphatemia (serum phosphate <0.94 mmol/L) during RRT, intensive care unit (ICU) mortality, and duration of mechanical ventilation and vasopressor support.

Results. Among 96 patients who received acute RRT, 25 (26.0%) developed hypophosphatemia. On multivariate logistic regression, serum phosphate at RRT initiation [adjusted odds ratio (OR) 0.29, 95% confidence interval (CI) (0.09, 0.91), P = 0.03] was independently associated with hypophosphatemia during acute RRT. Patients with hypophosphatemia during RRT required longer ventilatory support [median 12 (interquartile range: 8, 17) days versus 5 (3, 9) days, P < 0.001] and vasopressor support [5 (4, 15) days versus 2 (2, 6) days, P = 0.003] compared with those without hypophosphatemia but there was no significant difference in ICU mortality [5 patients (20.0%) versus 24 patients (33.8%), P = 0.20]. Hypophosphatemia during RRT was independently associated with prolonged mechanical ventilation (≥7 days) [adjusted OR 14.0, 95% CI (1.37, 143.90), P = 0.03].

Conclusion. Hypophosphatemia is common during acute RRT for critically ill patients and was associated with adverse clinical outcomes.

Experiences with Continuous Venovenous Hemofiltration using 18mmol/L predilution Citrate anticoagulation and a Phosphate Containing Replacement Solution

CONTEXT

Regional citrate anticoagulation for continuous renal replacement therapy is associated with a longer filter-life, less bleeding events and improved mortality. Problems associated with using Prismocitrate 10/2 solution in continuous renal replacement therapy, include hypomagnesemia, hypophosphatemia and the need for additional bicarbonate infusion.

AIMS

This study uses the new Prismocitrate 18/0 solution for improved buffer balance and Phoxilium solution for a more favourable electrolyte profile.

SETTINGS AND DESIGN

A retrospective analysis of patients who underwent continuous venovenous hemofiltration (CVVH) using Prismocitrate 18/0 and Phoxilium in our 21-bed ICU was conducted from March to July 2014.

METHODS AND MATERIAL

Continuous venovenous hemofiltration (CVVH) was performed at fixed rate by using Prismocitrate 18/0 predilution at 1250 ml/hour, a blood flow rate of 110 ml/min and post-replacement with Phoxilium at 1250 ml/hr. CVVH was run for 72 h or until filter clotting, transportation, or achievement of the clinical target.

STATISTICAL ANALYSIS USED

The results were displayed as the median with the interquartile range (IQR). The trend in pH, electrolytes, and base excess are shown using a standard box plot. All analyses were performed by the Statistical Package for Social Science for Windows, version 17 (SPSS, Chicago, IL, USA).

RESULTS

Forty-five CVVH episodes were analysed. The median circuit lifetime was 44 h (interquartile range, IQR 29-55). Metabolic alkalosis, hypophosphatemia and hypomagnesemia occurred in 8.3%, 3.5% and 40.2% of the blood samples, respectively. No patient developed hypokalemia or citrate toxicity.

CONCLUSIONS

This new CVVH regime is safe and easy to administer for critically ill patients.

Continuous Renal Replacement Therapy for the Management of Acid-Base and Electrolyte Imbalances in Acute Kidney Injury

Continuous renal replacement therapy (CRRT) is used to manage electrolyte and acid-base imbalances in critically ill patients with acute kidney injury. Although a standard solution and prescription is acceptable in most clinical circumstances, specific disorders may require a tailored approach such as adjusting fluid composition, regulating CRRT dose, and using separate intravenous infusions to mitigate and correct these disturbances. Errors in fluid prescription, compounding, or delivery can be rapidly fatal. This article provides an overview of the principles of acid-base and electrolyte management using CRRT.

Phoxilium(®) reduces hypophosphataemia and magnesium supplementation during continuous renal replacement therapy

Background

Although associated with severe clinical complications, phosphate remains a neglected ion. Additionally, phosphate balance during continuous renal replacement therapy (CRRT) is complex and multifunctional. The present retrospective study investigated the effects of phosphate-containing CRRT fluid on phosphate homeostasis.

Methods

We retrospectively analysed 112 patients treated with CRRT at Skåne University Hospital, Sweden. The control group was treated with Hemosol^® B0 (no phosphate; n = 36) as dialysis and replacement fluid, while the study group received Phoxilium^® (phosphate; n = 76) as dialysis fluid and Hemosol^® B0 as replacement fluid.

Results

Hypophosphataemia (<0.7 mM) occurred in 15% of the treatment days in the control group compared with 7% in the study group (P = 0.027). Magnesium substitution was reduced by 40% in the study group (P < 0.001). No differences in acid–base parameters were detected between the groups.

Conclusions

In this larger cohort, we could confirm that Phoxilium^® reduced the episodes of hypophosphataemia during CRRT. A beneficial effect on magnesium balance could also be observed.

Applying lean principles to continuous renal replacement therapy processes

PURPOSE

The application of lean principles to continuous renal replacement therapy (CRRT) processes in an academic medical center is described.

SUMMARY

A manual audit over six consecutive weeks revealed that 133 5-L bags of CRRT solution were discarded after being dispensed from pharmacy but before clinical use. Lean principles were used to examine the workflow for CRRT preparation and develop and implement an intervention. An educational program was developed to encourage and enhance direct communication between nursing and pharmacy about changes in a patient's condition or CRRT order. It was through this education program that the reordering workflow shifted from nurses to pharmacy technicians. The primary outcome was the number of CRRT solution bags delivered in the preintervention and postintervention periods. Nurses and pharmacy technicians were surveyed to determine their satisfaction with the workflow change. After implementation of lean principles, the mean number of CRRT solution bags dispensed per day of CRRT decreased substantially. Respondents' overall satisfaction with the CRRT solution preparation process increased during the postintervention period, and the satisfaction scores for each individual component of the workflow after implementation of lean principles. The decreased solution waste resulted in projected annual cost savings exceeding $70,000 in product alone.

CONCLUSION

The use of lean principles to identify medication waste in the CRRT workflow and implementation of an intervention to shift the workload from intensive care unit nurses to pharmacy technicians led to reduced CRRT solution waste, improved efficiency of CRRT workflow, and increased satisfaction among staff.

Reductions in red blood cell 2,3-diphosphoglycerate concentration during continuous renal replacment therapy

BACKGROUND AND OBJECTIVES

Hypophosphatemia is a frequent complication during continuous renal replacement therapy (CRRT), a dialytic technique used to treat AKI in critically ill patients. This study sought to confirm that phosphate depletion during CRRT may decrease red blood cell (RBC) concentration of 2,3-diphosphoglycerate (2,3-DPG), a crucial allosteric effector of hemoglobin's (Hgb's) affinity for oxygen, thereby leading to impaired oxygen delivery to peripheral tissues.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Phosphate mass balance studies were performed in 20 patients with severe AKI through collection of CRRT effluent. RBC concentrations of 2,3-DPG, venous blood gas pH, and oxygen partial pressure required for 50% hemoglobin saturation (P50) were measured at CRRT initiation and days 2, 4, and 7. Similar measurements were obtained on days 0 and 2 in a reference group of 10 postsurgical patients, most of whom did not have AKI. Associations of 2,3-DPG with laboratory parameters and clinical outcomes were examined using mixed-effects and Cox regression models.

RESULTS

Mean 2,3-DPG levels decreased from a mean (±SD) of 13.4±3.4 µmol/g Hgb to 11.0±3.1 µmol/g Hgb after 2 days of CRRT (P<0.001). Mean hemoglobin saturation P50 levels decreased from 29.7±4.4 mmHg to 26.7±4.0 mmHg (P<0.001). No significant change was seen in the reference group. 2,3-DPG levels after 2 days of CRRT were not significantly lower than those in the reference group on day 2. Among patients receiving CRRT, 2,3-DPG decreased by 0.53 µmol/g Hgb per 1 g phosphate removed (95% confidence interval 0.38 to 0.68 µmol/g Hgb; P<0.001). Greater reductions in 2,3-DPG were associated with higher risk for death (hazard ratio, 1.43; 95% confidence interval, 1.09 to 1.88; P=0.01).

CONCLUSIONS

CRRT-induced phosphate depletion is associated with measurable reductions in RBC 2,3-DPG concentration and a shift in the O2:Hgb affinity curve even in the absence of overt hypophosphatemia. 2,3-DPG reductions may be associated with higher risk for in-hospital death and represent a potentially avoidable complication of CRRT.

The use of hemodialysis in refractory hypercalcemia secondary to parathyroid carcinoma

Parathyroid carcinoma is a rare cause of hypercalcemia. Hypercalcemic crisis is a medical emergency. Hemodialysis is rarely needed to treat hypercalcaemia. We report a case of refractory hypercalcaemia secondary to parathyroid carcinoma requiring haemodialysis.

Continuous veno-venous hemofiltration using a phosphate-containing replacement fluid in the setting of regional citrate anticoagulation

PURPOSE

The need for prolonged anticoagulation and the occurrence of hypophosphatemia are well known drawbacks of continuous renal replacement therapies (CRRT). The aim was to evaluate the effects on acid-base status and serum phosphate of a regional citrate anticoagulation (RCA) protocol for continuous veno-venous hemofiltration (CVVH) combining the use of citrate with a phosphate-containing replacement fluid.

METHODS

In a small cohort of heart surgery patients undergoing CRRT for acute kidney injury, we adopted an RCA-CVVH protocol based on a commercially available citrate solution (18 mmol/l) combined with a recently introduced phosphate-containing replacement fluid (HCO3 -30 mmol/l, phosphate 1.2), aimed at preventing phosphate depletion.

RESULTS

In 10 high bleeding-risk patients, the RCA-CVVH protocol provided an adequate circuit lifetime (46.8 ± 30.3 h) despite the adoption of a low citrate dose and a higher than usual target circuit Ca2+ (≤0.5 mmol/l). Acid-base status was adequately maintained without the need for additional interventions on RCA-CVVH parameters and without indirect sign of citrate accumulation [(pH 7.43 (7.41-7.47), bicarbonate 24.4 mmol/l (23.2-25.6), BE 0 (-1.5 to 1.1), calcium ratio 1.97 (1.82-2.01); median (IQR)]. Serum phosphate was steadily maintained in a narrow range throughout RCA-CVVH days [1.1 mmol/l (0.9-1.4)]. A low amount of phosphorus supplementation (0.9 ± 2 g/day) was required in only 30% of patients.

CONCLUSIONS

Although needing further evaluation, the proposed RCA-CVVH protocol ensured a safe and effective RCA without electrolyte and/or acid-base derangements. CRRT-induced hypophosphatemia was prevented in most of the patients by the adoption of a phosphate-containing replacement solution, minimizing phosphate supplementation needs.

Continuous venovenous hemodiafiltration with a low citrate dose regional anticoagulation protocol and a phosphate-containing solution: effects on acid-base status and phosphate supplementation needs

BACKGROUND

Recent guidelines suggest the adoption of regional citrate anticoagulation (RCA) as first choice CRRT anticoagulation modality in patients without contraindications for citrate. Regardless of the anticoagulation protocol, hypophosphatemia represents a potential drawback of CRRT which could be prevented by the adoption of phosphate-containing CRRT solutions. The aim was to evaluate the effects on acid-base status and phosphate supplementation needs of a new RCA protocol for Continuous Venovenous Hemodiafiltration (CVVHDF) combining the use of citrate with a phosphate-containing CRRT solution.

METHODS

To refine our routine RCA-CVVH protocol (12 mmol/l citrate, HCO3- 32 mmol/l replacement fluid) (protocol A) and to prevent CRRT-related hypophosphatemia, we introduced a new RCA-CVVHDF protocol (protocol B) combining an 18 mmol/l citrate solution with a phosphate-containing dialysate/replacement fluid (HCO3- 30 mmol/l, Phosphate 1.2). A low citrate dose (2.5-3 mmol/l) and a higher than usual target circuit-Ca(2+) (≤ 0.5 mmol/l) have been adopted.

RESULTS

Two historical groups of heart surgery patients (n = 40) underwent RCA-CRRT with protocol A (n = 20, 102 circuits, total running time 5283 hours) or protocol B (n = 20, 138 circuits, total running time 7308 hours). Despite higher circuit-Ca(2+) in protocol B (0.37 vs 0.42 mmol/l, p < 0.001), circuit life was comparable (51.8 ± 36.5 vs 53 ± 32.6 hours). Protocol A required additional bicarbonate supplementation (6 ± 6.4 mmol/h) in 90% of patients while protocol B ensured appropriate acid-base balance without additional interventions: pH 7.43 (7.40-7.46), Bicarbonate 25.3 (23.8-26.6) mmol/l, BE 0.9 (-0.8 to +2.4); median (IQR). No episodes of clinically relevant metabolic alkalosis, requiring modifications of RCA-CRRT settings, were observed. Phosphate supplementation was needed in all group A patients (3.4 ± 2.4 g/day) and in only 30% of group B patients (0.5 ± 1.5 g/day). Hypophosphatemia developed in 75% and 30% of group A and group B patients, respectively. Serum phosphate was significantly higher in protocol B patients (P < 0.001) and, differently to protocol A, appeared to be steadily maintained in near normal range (0.97-1.45 mmol/l, IQR).

CONCLUSIONS

The proposed RCA-CVVHDF protocol ensured appropriate acid-base balance without additional interventions, providing prolonged filter life despite adoption of a higher target circuit-Ca(2+). The introduction of a phosphate-containing solution, in the setting of RCA, significantly reduced CRRT-related phosphate depletion.

Hypophosphatemia during continuous veno-venous hemofiltration is associated with mortality in critically ill patients with acute kidney injury

Introduction

The primary aim of this study was to determine whether hypophosphatemia during continuous veno-venous hemofiltration (CVVH) is associated with the global outcome of critically ill patients with acute kidney injury (AKI).

Methods

760 patients diagnosed with AKI and had received CVVH therapy were retrospectively recruited. Death during the 28-day period and survival at 28 days after initiation of CVVH were used as endpoints. Demographic and clinical data including serum phosphorus levels were recorded along with clinical outcome. Hypophosphatemia was defined according to the colorimetric method as serum phosphorus levels < 0.81 mmol/L (2.5 mg/dL), and severe hypophosphatemia was defined as serum phosphorus levels < 0.32 mmol/L (1 mg/dL). The ratio of CVVH therapy days with hypophosphatemia over total CVVH therapy days was calculated to reflect the persistence of hypophosphatemia.

Results

The Cox proportional hazard survival model analysis indicated that the incidence of hypophosphatemia or even severe hypophosphatemia was not associated with 28-day mortality independently (p = 0.700). Further analysis with the sub-cohort of patients who had developed hypophosphatemia during the CVVH therapy period indicated that the mean ratio of CVVH therapy days with hypophosphatemia over total CVVH therapy days was 0.58, and the ratio independently associated with the global outcome. Compared with the patients with low ratio (< 0.58), those with high ratio (≥ 0.58) conferred a 1.451-fold increase in 28-day mortality rate (95% CI 1.103–1.910, p = 0.008).

Conclusions

Hypophosphatemia during CVVH associated with the global clinical outcome of critically ill patients with AKI. The ratio of CVVH therapy days with hypophosphatemia over total CVVH therapy days was independently associated with the 28-day mortality, and high ratio conferred higher mortality rate.

[Nutrition and renal insufficiency]

Renal failure patients in the intensive care unit comprise a heterogeneous group of subjects with widely differing metabolic patterns and nutritional requirements. This group includes patients with acute kidney injury (AKI), acute-on-chronic renal failure, chronic kidney disease, and those on regular hemodialysis therapy. Renal failure is associated with a broad spectrum of specific metabolic alterations. In addition to these alterations and the often underrated impact of renal replacement therapy, the metabolism is also affected by the underlying disease process as well as associated organ failures and complications, especially infections. Nutritional support for renal failure is not fundamentally different from other disease processes, but in designing a nutrition regimen the variations in metabolism and nutrient requirements should be considered. Nutritional needs can differ widely between patients but also in the same patient during the course of disease. Thus, patients with renal failure require an individualized approach to nutritional support. Moreover, because of the altered metabolism of many nutrients and the intolerance of fluids and electrolytes, close monitoring of the nutritional therapy is mandatory in patients with renal failure.

Phoxilium vs Hemosol-B0 for continuous renal replacement therapy in acute kidney injury

PURPOSE

This study aimed to compare the biochemical effects of Phoxilium (containing phosphate at 1.2 mmol/L; Gambro Lundia AB, Lund, Sweden) and Hemosol-B0 (Gambro Lundia AB) as dialysate and/or replacement fluid during continuous renal replacement therapy (CRRT).

METHODS

We examined serum biochemistry in critically ill patients for 42 hours of Phoxilium administration for the prevention of hypophosphatemia during CRRT and compared them with corresponding results in random historical controls who received Hemosol-B0.

RESULTS

We studied 15 patients in each arm (Phoxilium vs Hemosol-B0). Respective median ages were 57 (49-68) and 64 (57-67) years. Baseline patient illness severity scores, prescribed CRRT effluent rates, and cumulative phosphate intakes were comparable. After 36 to 42 hours of Phoxilium administration, serum phosphate levels increased from 0.95 (0.81-1.13) to 1.44 (1.23-1.78) mmol/L, in contrast to the decline from 1.71 (1.09-2.00) to 0.83 (0.55-1.59) mmol/L with Hemosol-B0 (P=.0001). Serum ionized calcium levels decreased from 1.27 (1.22-1.37) to 1.12 (1.06-1.21) mmol/L with Phoxilium, compared with an increase from 1.09 (0.90-1.19) to 1.20 (1.16-1.25) mmol/L with Hemosol-B0 (P<.0001). Serum bicarbonate, base excess levels, and effective strong ion difference decreased with Phoxilium and were lower than those with Hemosol-B0 at 36 to 42 hours (P<.05).

CONCLUSION

Phoxilium effectively prevented hypophosphatemia during CRRT but was associated with relative metabolic acidosis and hypocalcemia compared with Hemosol-B0 use.

Optimizing healthy gestational weight gain in women at high risk of gestational diabetes: a randomized controlled trial

OBJECTIVE

Optimizing gestational weight gain (GWG) in early pregnancy is of clinical and public health importance, especially in higher risk pregnancies.

DESIGN AND METHODS

In a robustly designed, randomized controlled trial, 228 pregnant women at risk of developing gestational diabetes mellitus (GDM) were allocated to either control (written health information only) or intervention (four-session lifestyle program). All women received standard maternal care. Measures were completed at 12-15 and 26-28 weeks gestation. Measures included anthropometrics (weight and height), physical activity (pedometer and International Physical Activity Questionnaire), questionnaires (risk perception), and GDM screening.

RESULTS

The mean (SD) age [31.7 (4.5) and 32.4 (4.7) years] and body mass index [BMI; 30.3 (5.9) and 30.4 (5.6) kg/m(2) ] were similar between control and intervention groups, respectively. By 28 weeks, GWG was significantly different between control and intervention groups [6.9 (3.3) vs. 6.0 (2.8) kg, P < 0.05]. When stratified according to baseline BMI, overweight women in the control group gained significantly more weight compared to overweight women in the intervention group [7.8 (3.4) vs. 6.0 (2.2) kg, P < 0.05], yet in obese women, GWG was similar in both groups. Physical activity levels declined by 28 weeks gestation overall (P < 0.01); however, the intervention group retained a 20% higher step count compared to controls [5,203 (3,368) vs. 4,140 (2,420) steps/day, P < 0.05]. Overall, GDM prevalence was 22.8% [Corrected], with a trend toward less cases in the intervention group (P = 0.1).

CONCLUSIONS

Results indicate that a low-intensity lifestyle intervention, integrated with antenatal care, optimizes healthy GWG and attenuates physical activity decline in early pregnancy. Efficacy in limiting weight gain was greatest in overweight women and in high-risk ethnically diverse women.

Specialized nutritional support interventions in critically ill patients on renal replacement therapy

PURPOSE OF REVIEW

Optimal nutritional requirements and nutrient intake composition for patients with acute kidney injury remain a partially unresolved issue. Targeting nutritional support to the actual protein and energy needs improves the clinical outcome of critically ill patients, yet very few data are currently available on this topic in acute kidney injury. In this specific clinical condition the risk for underfeeding and overfeeding may be increased by factors interfering on nutrient need estimation, such as rapidly changing body weight due to fluid balance variations, nutrient losses and hidden calorie sources from renal replacement therapy. Moreover, as acute kidney injury is now considered a kidney-centered inflammatory syndrome, the renoprotective role of specific pharmaconutrients with anti-inflammatory properties remains to be fully defined. This review is aimed at discussing recently published results concerning quantitative and qualitative aspects of the nutritional approach to acute kidney injury in critically ill patients.

RECENT FINDINGS

Nutrient needs in patients with acute kidney injury can be difficult to estimate, and should be directly measured, especially in the ICU setting. In fact, recent findings suggest that hidden calorie sources not routinely taken into account - for example, calories from anticoagulants and replacement solutions for renal replacement therapy - could be quantitatively relevant in these patients. Moreover, recent experimental data indicate a possible role for some pharmaconutrients with anti-inflammatory effects (glutamine, and omega-3 fatty acids), in both the prevention of renal function worsening, and in the fostering of renal function recovery after an episode of acute kidney injury.

SUMMARY

Acute kidney injury includes a highly heterogeneous group of patients with widely varying nutrient needs and intakes. Nutritional requirements, in their quantitative and qualitative aspects, should be frequently assessed, individualized, and carefully integrated with renal replacement therapy, in order to avoid both underfeeding and overfeeding, as well as to exploit possible positive pharmacologic effects of specific nutrients.

Biochemical effects of phosphate-containing replacement fluid for continuous venovenous hemofiltration

AIMS

To examine biochemical effects of phosphate-containing replacement fluid (Phoxilium(®)) for continuous venovenous hemofiltration (CVVH).

METHODS

Retrospective comparison of respective serum biochemistry with sequential use of Accusol™ and Phoxilium, each over 48 h of CVVH.

RESULTS

We studied 15 critically ill patients. Accusol was switched to Phoxilium after 5 (4-8) days of CVVH. Respective serum biochemistry after 36-42 h of Accusol versus Phoxilium were: phosphate 1.02 (0.82-1.15) versus 1.44 (1.23-1.78) mmol/l, ionized calcium 1.28 (1.22-1.32) versus 1.12 (1.06-1.21) mmol/l, bicarbonate 24 (23-25) versus 20 (19-22) mmol/l, base excess 0 (-2 to 1) versus -4 (-6 to -3) mmol/l (p < 0.001). Cumulative phosphate intakes during respective periods were 69.6 (56.6-76.6) versus 67.2 (46.6-79.0) mmol (p = 0.45). Plasma strong ion differences were narrower with Phoxilium (p < 0.05), with similar strong ion gaps. No additional intravenous phosphate was given during Phoxilium use. Seven patients had serum phosphate >1.44 mmol/l.

CONCLUSIONS

Phoxilium versus Accusol use during CVVH effectively prevented hypophosphatemia but contributed to mild hyperphosphatemia, and is associated with relative hypocalcemia and metabolic acidosis.