Evaluation of Clinical and Machine Data of Critically Ill Adult COVID Patients with Acute Kidney Injury Exposed to Enhanced Hemoadsorption during CRRT.

INTRODUCTION: The FDA authorized the emergency use of enhanced hemoadsorption with oXiris in critically ill adult COVID patients with respiratory failure or severe disease to reduce inflammation. In this study, we evaluated critically ill adult COVID patients with acute kidney injury (AKI) who were exposed versus not exposed to enhanced hemoadsorption with oXiris during continuous renal replacement therapy (CRRT). METHODS: Retrospective cohort study of critically ill adult COVID patients with AKI requiring CRRT. Exposure to oXiris was defined as receiving oXiris for >12 cumulative hours and more than one-third of the time within the first 72 h of CRRT. Study outcomes included filter-specific performance metrics and clinical outcomes such as ventilator requirement, mortality, and dialysis dependence. Inverse probability treatment weighting was used to balance potential confounders in weighted regression models. RESULTS: 14,043 h of CRRT corresponding to 85 critically ill adult patients were analyzed. Among these, 2,736 h corresponded to oXiris exposure (n = 25 patients) and 11,307 h to a standard CRRT filter (n = 60 patients). Transmembrane pressures (TMPs) increased rapidly and were overall higher with oXiris versus standard filter, but filter life (median of 36.3 vs. 33.1 h, p = 0.913, respectively) and filter/clotting alarms remained similar in both groups. In adjusted models, oXiris exposure was not independently associated with the composite of hospital mortality and dialysis dependence at discharge (OR 2.13, 95% CI: 0.98-4.82, p = 0.06), but it was associated with fewer ventilator (ß = -15.02, 95% CI: -29.23 to -0.82, p = 0.04) and intensive care unit days (ß = -14.74, 95% CI: -28.54 to -0.95, p = 0.04) in survivors. DISCUSSION/CONCLUSION: In critically ill adult COVID patients with AKI requiring CRRT, oXiris filters exhibited higher levels of TMP when compared to a standard CRRT filter, but no differences in filter life and filter/clotting alarm profiles were observed. The use of oXiris was not associated with improvement in clinical outcomes such as hospital mortality or dialysis dependence at discharge.

Acute kidney injury in neurocritical care.

Approximately 20% of patients with acute brain injury (ABI) also experience acute kidney injury (AKI), which worsens their outcomes. The metabolic and inflammatory changes associated with AKI likely contribute to prolonged brain injury and edema. As a result, recognizing its presence is important for effectively managing ABI and its sequelae. This review discusses the occurrence and effects of AKI in critically ill adults with neurological conditions, outlines potential mechanisms connecting AKI and ABI progression, and highlights AKI management principles. Tailored approaches include optimizing blood pressure, managing intracranial pressure, adjusting medication dosages, and assessing the type of administered fluids. Preventive measures include avoiding nephrotoxic drugs, improving hemodynamic and fluid balance, and addressing coexisting AKI syndromes. ABI patients undergoing renal replacement therapy (RRT) are more susceptible to neurological complications. RRT can negatively impact cerebral blood flow, intracranial pressure, and brain tissue oxygenation, with effects tied to specific RRT methods. Continuous RRT is favored for better hemodynamic stability and lower risk of dialysis disequilibrium syndrome. Potential RRT modifications for ABI patients include adjusted dialysate and blood flow rates, osmotherapy, and alternate anticoagulation methods. Future research should explore whether these strategies enhance outcomes and if using novel AKI biomarkers can mitigate AKI-related complications in ABI patients.

Fluid Responsiveness in the Critically Ill Patient.

Accurate assessment of intravascular volume status in critically ill patients remains a very challenging task. Recent data have shown adverse outcomes in critically ill patients with either inadequate or overaggressive fluid therapy. Understanding the tools and techniques available for accurate volume assessment is imperative. This article discusses the concept of fluid responsiveness and reviews methods for assessing fluid responsiveness in critically ill patients.

How To Prescribe And Troubleshoot Continuous Renal Replacement Therapy: A Case-Based Review.

Continuous RRT (CRRT) is the preferred dialysis modality for solute management, acid-base stability, and volume control in patients who are critically ill with AKI in the intensive care unit (ICU). CRRT offers multiple advantages over conventional hemodialysis in the critically ill population, such as greater hemodynamic stability, better fluid management, greater solute control, lower bleeding risk, and a more continuous (physiologic) approach of kidney support. Despite its frequent use, several aspects of CRRT delivery are still not fully standardized, or do not have solid evidence-based foundations. In this study, we provide a case-based review and recommendations of common scenarios and interventions encountered during the provision of CRRT to patients who are critically ill. Specific focus is on initial prescription, CRRT dosing, and adjustments related to severe hyponatremia management, concomitant extracorporeal membrane oxygenation support, dialysis catheter placement, use of regional citrate anticoagulation, and antibiotic dosing. This case-driven simulation is made as the clinical status of the patient evolves, and is on the basis of step-wise decisions made during the care of this patient, according to the specific patient's needs and the logistics available at the corresponding institution.

Timing of Renal Replacement Therapy for Acute Kidney Injury.

Acute kidney injury (AKI) is common in critically ill patients and associated with increased morbidity and mortality. With the increased use of renal replacement therapy (RRT) for severe AKI, the optimal time for initiation of RRT has become one of the most probed and debated topic in the field of nephrology and critical care. There appears to be an increased trend toward earlier initiation of RRT to avoid life-threatening complications associated with AKI. Despite the presence of a plethora of studies in this field, the lack of uniformity in study design, patient population types, definition of early and late initiation, modality of RRT, and results, the optimal time for starting RRT in AKI still remains unknown. The beneficial effects reported in observational studies have not been supported by clinical trials. Recently, 2 of the largest randomized control trials evaluating the timing of RRT in critically ill patients with AKI showed differing results. We provide an in-depth review of the available data on the timing of dialysis in patients with AKI.

A Monte Carlo Simulation Approach for Beta-Lactam Dosing in Critically Ill Patients Receiving Prolonged Intermittent Renal Replacement Therapy.

Cefepime, ceftazidime, and piperacillin/tazobactam are commonly used beta-lactam antibiotics in the critical care setting. For critically ill patients receiving prolonged intermittent renal replacement therapy (PIRRT), limited pharmacokinetic data are available to inform clinicians on the dosing of these agents. Monte Carlo simulations (MCS) can be used to guide drug dosing when pharmacokinetic trials are not feasible. For each antibiotic, MCS using previously published pharmacokinetic data derived from critically ill patients was used to evaluate multiple dosing regimens in 4 different prolonged intermittent renal replacement therapy effluent rates and prolonged intermittent renal replacement therapy duration combinations (4 L/h × 10 hours or 5 L/h × 8 hours in hemodialysis and hemofiltration modes). Antibiotic regimens were also modeled depending on whether drugs were administered during or well before prolonged intermittent renal replacement therapy therapy commenced. The probability of target attainment (PTA) was calculated using each antibiotic's pharmacodynamic target during the first 48 hours of therapy. Optimal doses were defined as the smallest daily dose achieving ≥90% probability of target attainment in all prolonged intermittent renal replacement therapy effluent and duration combinations. Cefepime 1 g every 6 hours following a 2 g loading dose, ceftazidime 2 g every 12 hours, and piperacillin/tazobactam 4.5 g every 6 hours attained the desired pharmacodynamic target in ≥90% of modeled prolonged intermittent renal replacement therapy patients. Alternatively, if an every 6-hours cefepime regimen is not desired, the cefepime 2 g pre-prolonged intermittent renal replacement therapy and 3 g post-prolonged intermittent renal replacement therapy regimen also met targets. For ceftazidime, 1 g every 6 hours or 3 g continuous infusion following a 2 g loading dose also met targets. These recommended doses provide simple regimens that are likely to achieve the pharmacodynamics target while yielding the least overall drug exposure, which should result in lower toxicity rates. These findings should be validated in the clinical setting.

Current state of the art for renal replacement therapy in critically ill patients with acute kidney injury.

Acute kidney injury (AKI) is associated with incremental risk for death and chronic kidney disease and represents a mounting clinical challenge for healthcare professionals. Renal replacement therapy (RRT) use in ICU settings is rising, likely in response to similar trends in AKI, taken together with an ageing population burdened by high prevalence of multi-morbidity and high illness acuity. Numerous features of RRT prescription and delivery are not standardized, nor are they supported from high-quality evidence derived from randomized trials. Despite the publication of rigorous clinical practice guidelines focused on RRT for AKI that are intended to optimize the quality and reliability of RRT in ICU settings, practice patterns and outcomes continue to show significant variability. In this concise review, we aim to summarize new knowledge and recent advances for the provision of RRT for critically ill patients with AKI.

Pharmacokinetics and Pharmacodynamics of Extended Infusion Versus Short Infusion Piperacillin-Tazobactam in Critically Ill Patients Undergoing CRRT.

BACKGROUND AND OBJECTIVES: Infection is the most common cause of death in severe AKI, but many patients receiving continuous RRT do not reach target antibiotic concentrations in plasma. Extended infusion of ß-lactams is associated with improved target attainment in critically ill patients; thus, we hypothesized that extended infusion piperacillin-tazobactam would improve piperacillin target attainment compared with short infusion in patients receiving continuous RRT. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted an institutional review board-approved observational cohort study of piperacillin-tazobactam pharmacokinetics and pharmacodynamics in critically ill patients receiving continuous venovenous hemodialysis and hemodiafiltration at three tertiary care hospitals between 2007 and 2015. Antibiotic concentrations in blood and/or dialysate samples were measured by liquid chromatography, and one- and two-compartment pharmacokinetic models were fitted to the data using nonlinear mixed effects regression. Target attainment for piperacillin was defined as achieving four times the minimum inhibitory concentration of 16 µg/ml for >50% of the dosing cycle. The probabilities of target attainment for a range of doses, frequencies, and infusion durations were estimated using a Monte Carlo simulation method. Target attainment was also examined as a function of patient weight and continuous RRT effluent rate. RESULTS: Sixty-eight participants had data for analysis. Regardless of infusion duration, 6 g/d piperacillin was associated with ≤45% target attainment, whereas 12 g/d was associated with ≥95% target attainment. For 8 and 9 g/d, target attainment ranged between 68% and 85%. The probability of target attainment was lower at higher effluent rates and patient weights. For all doses, frequencies, patient weights, and continuous RRT effluent rates, extended infusion was associated with higher probability of target attainment compared with short infusion. CONCLUSIONS: Extended infusions of piperacillin-tazobactam are associated with greater probability of target attainment in patients receiving continuous RRT.

A Multi-Center, Randomized, Controlled, Pivotal Study to Assess the Safety and Efficacy of a Selective Cytopheretic Device in Patients with Acute Kidney Injury.

OBJECTIVE: Acute kidney injury (AKI) is a highly morbid condition in critically ill patients that is associated with high mortality. Previous clinical studies have demonstrated the safety and efficacy of the Selective Cytopheretic Device (SCD) in the treatment of AKI requiring continuous renal replacement therapy in the intensive care unit (ICU). DESIGN, SETTING, PATIENTS: A randomized, controlled trial of 134 ICU patients with AKI, 69 received continuous renal replacement therapy (CRRT) alone and 65 received SCD therapy. RESULTS: No significant difference in 60-day mortality was observed between the treated (27/69; 39%) and control patients (21/59; 36%, with six patients lost to follow up) in the intention to treat (ITT) analysis. Of the 19 SCD subjects (CRRT+SCD) and 31 control subjects (CRRT alone) who maintained a post-filter ionized calcium (iCa) level in the protocol's recommended range (≤ 0.4 mmol/L) for greater or equal to 90% of the therapy time, 60-day mortality was 16% (3/19) in the SCD group compared to 41% (11/27) in the CRRT alone group (p = 0.11). Dialysis dependency showed a borderline statistically significant difference between the SCD treated versus control CRRT alone patients maintained for ≥ 90% of the treatment in the protocol's recommended (r) iCa target range of ≤ 0.4 mmol/L with values of, 0% (0/16) and 25% (4/16), respectively (P = 0.10). When the riCa treated and control subgroups were compared for a composite index of 60 day mortality and dialysis dependency, the percentage of SCD treated subjects was 16% versus 58% in the control subjects (p<0.01). The incidence of serious adverse events did not differ between the treated (45/69; 65%) and control groups (40/65; 63%; p = 0·86). CONCLUSION: SCD therapy may improve mortality and reduce dialysis dependency in a tightly controlled regional hypocalcaemic environment in the perfusion circuit. TRIAL REGISTRATION: ClinicalTrials.gov NCT01400893 http://clinicaltrials.gov/ct2/show/NCT01400893.

A Prospective International Multicenter Study of AKI in the Intensive Care Unit.

BACKGROUND AND OBJECTIVES: AKI is frequent and is associated with poor outcomes. There is limited information on the epidemiology of AKI worldwide. This study compared patients with AKI in emerging and developed countries to determine the association of clinical factors and processes of care with outcomes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This prospective observational study was conducted among intensive care unit patients from nine centers in developed countries and five centers in emerging countries. AKI was defined as an increase in creatinine of ≥0.3 mg/dl within 48 hours. RESULTS: Between 2008 and 2012, 6647 patients were screened, of whom 1275 (19.2%) developed AKI. A total of 745 (58% of those with AKI) agreed to participate and had complete data. Patients in developed countries had more sepsis (52.1% versus 38.0%) and higher Acute Physiology and Chronic Health Evaluation (APACHE) scores (mean±SD, 61.1±27.5 versus 51.1±25.2); those from emerging countries had more CKD (54.3% versus 38.3%), GN (6.3% versus 0.9%), and interstitial nephritis (7.0% versus 0.6%) (all P<0.05). Patients from developed countries were less often treated with dialysis (15.5% versus 30.2%; P<0.001) and started dialysis later after AKI diagnosis (2.0 [interquartile range, 0.75-5.0] days versus 0 [interquartile range, 0-5.0] days; P=0.02). Hospital mortality was 22.0%, and 13.3% of survivors were dialysis dependent at discharge. Independent risk factors associated with hospital mortality included older age, residence in an emerging country, use of vasopressors (emerging countries only), dialysis and mechanical ventilation, and higher APACHE score and cumulative fluid balance (developed countries only). A lower probability of renal recovery was associated with residence in an emerging country, higher APACHE score (emerging countries only) and dialysis, while mechanical ventilation was associated with renal recovery (developed countries only). CONCLUSIONS: This study contrasts the clinical features and management of AKI and demonstrates worse outcomes in emerging than in developed countries. Differences in variations in care may explain these findings and should be considered in future trials.

Levels of protein C and soluble thrombomodulin in critically ill patients with acute kidney injury: a multicenter prospective observational study.

Endothelial dysfunction contributes to the development of acute kidney injury (AKI) in animal models of ischemia reperfusion injury and sepsis. There are limited data on markers of endothelial dysfunction in human AKI. We hypothesized that Protein C (PC) and soluble thrombomodulin (sTM) levels could predict AKI. We conducted a multicenter prospective study in 80 patients to assess the relationship of PC and sTM levels to AKI, defined by the AKIN creatinine (AKI Scr) and urine output criteria (AKI UO). We measured marker levels for up to 10 days from intensive care unit admission. We used area under the curve (AUC) and time-dependent multivariable Cox proportional hazard model to predict AKI and logistic regression to predict mortality/non-renal recovery. Protein C and sTM were not different in patients with AKI UO only versus no AKI. On intensive care unit admission, as PC levels are usually lower with AKI Scr, the AUC to predict the absence of AKI was 0.63 (95%CI 0.44-0.78). The AUC using log10 sTM levels to predict AKI was 0.77 (95%CI 0.62-0.89), which predicted AKI Scr better than serum and urine neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C, urine kidney injury molecule-1 and liver-fatty acid-binding protein. In multivariable models, PC and urine NGAL levels independently predicted AKI (p=0.04 and 0.02) and PC levels independently predicted mortality/non-renal recovery (p=0.04). In our study, PC and sTM levels can predict AKI Scr but are not modified during AKI UO alone. PC levels could independently predict mortality/non-renal recovery. Additional larger studies are needed to define the relationship between markers of endothelial dysfunction and AKI.

Assessing continuous renal replacement therapy as a rescue strategy in cardiorenal syndrome 1.

BACKGROUND: Patients with acute decompensated heart failure (ADHF) and cardiorenal syndrome (CRS) 1 have poor outcomes. Ultrafiltration (UF) is used to mechanically remove salt and water in ADHF patients with diuretic resistance. However, little is known about the outcomes of ADHF patients on inotropes and/or vasopressors who require continuous renal replacement therapy (CRRT) for both UF and solute clearance in severe acute kidney injury. METHODS: We retrospectively analyzed 37 consecutive critically ill patients who were admitted for ADHF from 2005-13 and were on inotropes and/or vasopressors at the time of CRRT initiation. The primary outcome was in-hospital mortality. RESULTS: In-hospital mortality rate was 62%. Median survival was 15.5 days after CRRT initiation, and 10 months following hospital discharge. When comparing renal and cardiovascular variables for survivors and non-survivors at baseline, admission and CRRT initiation, survivors were less likely to need vasopressors. After controlling for multiple predictors, vasopressor use remained associated with time to death (HR 9.9; 95% CI 2.3-43.3; P = 0.002). Patients with isolated right ventricular dysfunction had an in-hospital mortality of 45% compared with 69% in those with left ventricular dysfunction (P = 0.27). Age of >70 years was associated with 100% in-hospital mortality. CONCLUSIONS: Rescue therapy using CRRT in refractory CRS1 was associated with high in-hospital mortality, especially when vasopressors were used and when patient age exceeded 70 years. Additionally, survivors had a poor long-term prognosis.

A continuous veno-venous hemofiltration protocol with anticoagulant citrate dextrose formula A and a calcium-containing replacement fluid.

INTRODUCTION: Regional citrate anticoagulation (RCA) is used as an anticoagulant for continuous renal replacement therapy (CRRT). A systemic calcium (Ca2+) infusion is required to replace Ca2+ lost in the effluent. The shortage of intravenous Ca2+ in the United States has limited RCA use. We describe a continuous veno-venous hemofiltration (CVVH) protocol with RCA using 2.2% anticoagulant citrate dextrose formula-A (ACD-A) and a commercial dialysate containing Ca2+ 1.5 mmol/l (N × Stage) as post-filter replacement fluid (RF), without need for Ca2+ infusion. METHODS: We prospectively evaluated five patients on CRRT who had at least three episodes of filter clotting within 24 h. Patients were switched to CVVH using ACD-A infused pre-blood pump and titrated to achieve a post-filter ionized calcium (iCa2+) level <0.5 mmol/l. The Ca2+ -containing dialysate was delivered post-filter as RF. RESULTS: Steady state mean serum chemistries were: Na+: 140.8 ± 2.3 meq/l, K+: 4.2 ± 0.4 meq/l, HCO3-: 30.9 ± 3.7 meq/l, pH: 7.42 ± 0.07, CO2: 47.9 ± 8.3 mmHg, total Ca2+: 8.08 ± 1.09 mg/dL. Post-filter iCa2+ ranged 0.27-0.36 mmol/l, and patient iCa2+ ranged 0.81-1.24 mmol/l. Mean post-filter RF rate: 3086 ± 164 ml/h, mean ACD-A rate: 298 ± 21 ml/h. Mean blood flow rate: 200 ± 17 ml/min, mean filtration fraction: 39.6 ± 7.2%. Mean effluent flow rate: 38.6 ± 6.7 ml/kg/h (range 28.7-55.8). Mean filter survival was 7 h without anticoagulation, compared to 42.6 h in the ACD-A group (p<0.0001). CONCLUSIONS: In this pilot study, CVVH using ACD-A for RCA and a Ca2+ -containing RF was safely and effectively used without a continuous Ca2+ infusion. This protocol is a promising solution for maintaining effective CRRT when intravenous calcium is in short supply.

A patient with AKI after cardiac surgery.

Up to 30% of patients undergoing cardiac surgery develop AKI, with 1% requiring RRT. AKI is an independent risk factor for morbidity and mortality. Postoperatively, even minimal changes in serum creatinine are associated with a substantial increase in mortality. No intervention has been definitely proven effective in reducing kidney injury. The successful prevention and management of AKI involves identifying patients at risk for AKI, recognizing subtle abnormalities in a timely manner, performing basic clinical assessments, and responding appropriately to data obtained. With that in mind, in this Attending Rounds, a woman with AKI in the setting of cardiac surgery is presented to highlight the use of history, physical exam, hemodynamic monitoring, laboratory data trends, and urine indices in establishing the correct diagnosis and appropriate management.

KDOQI US commentary on the 2012 KDIGO clinical practice guideline for acute kidney injury.

In response to the recently released 2012 KDIGO (Kidney Disease: Improving Global Outcomes) clinical practice guideline for acute kidney injury (AKI), the National Kidney Foundation organized a group of US experts in adult and pediatric AKI and critical care nephrology to review the recommendations and comment on their relevancy in the context of current US clinical practice and concerns. The first portion of the KDIGO guideline attempts to harmonize earlier consensus definitions and staging criteria for AKI. While the expert panel thought that the KDIGO definition and staging criteria are appropriate for defining the epidemiology of AKI and in the design of clinical trials, the panel concluded that there is insufficient evidence to support their widespread application to clinical care in the United States. The panel generally concurred with the remainder of the KDIGO guidelines that are focused on the prevention and pharmacologic and dialytic management of AKI, although noting the dearth of clinical trial evidence to provide strong evidence-based recommendations and the continued absence of effective therapies beyond hemodynamic optimization and avoidance of nephrotoxins for the prevention and treatment of AKI.

The effect of the selective cytopheretic device on acute kidney injury outcomes in the intensive care unit: a multicenter pilot study.

Acute kidney injury (AKI) is characterized by deterioration in kidney function resulting in multisystem abnormalities. Much of the morbidity and mortality associated with AKI result from a systemic inflammatory response syndrome (SIRS). This study described herein is a prospective, single-arm, multicenter US study designed to evaluate the safety and efficacy of the Selective Cytopheretic Device (SCD) treatment on AKI requiring continuous renal replacement therapy (CRRT) in the ICU. The study enrolled 35 subjects. The mean age was 56.3±15. With regard to race, 71.4% of the subjects were Caucasian, 22.9% were Black, and 5.7% were Hispanic. Average SOFA score was 11.3±3.6. Death from any cause at Day 60 was 31.4%. Renal recovery, defined as dialysis independence, was observed in all of the surviving subjects at Day 60. The results of this pilot study indicate the potential for a substantial improvement in patient outcomes over standard of care therapy, which is associated with a greater than 50% 60-day mortality in the literature. The SCD warrants further study in scientifically sound, pivotal trial to demonstrate reasonable assurance of safety and effectiveness.

Pharmacokinetics and pharmacodynamics of piperacillin-tazobactam in 42 patients treated with concomitant CRRT.

BACKGROUND AND OBJECTIVES: Current recommendations for piperacillin-tazobactam dosing in patients receiving continuous renal replacement therapy originate from studies with relatively few patients and lower continuous renal replacement therapy doses than commonly used today. This study measured the pharmacokinetic and pharmacodynamic characteristics of piperacillin-tazobactam in patients treated with continuous renal replacement therapy using contemporary equipment and prescriptions. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A multicenter prospective observational study in the intensive care units of two academic medical centers was performed, enrolling patients with AKI or ESRD receiving piperacillin-tazobactam while being treated with continuous renal replacement therapy. Pregnant women, children, and patients with end stage liver disease were excluded from enrollment. Plasma and continuous renal replacement therapy effluent samples were analyzed for piperacillin and tazobactam levels using HPLC. Pharmacokinetic and pharmacodynamic parameters were calculated using standard equations. Multivariate analyses were used to examine the association of patient and continuous renal replacement therapy characteristics with piperacillin pharmacokinetic parameters. RESULTS: Forty-two of fifty-five subjects enrolled had complete sampling. Volume of distribution (median=0.38 L/kg, intraquartile range=0.20 L/kg) and elimination rate constants (median=0.104 h(-1), intraquartile range=0.052 h(-1)) were highly variable, and clinical parameters could explain only a small fraction of the large variability in pharmacokinetic parameters. Probability of target attainment for piperacillin was 83% for total drug but only 77% when the unbound fraction was considered. CONCLUSIONS: There is significant patient to patient variability in pharmacokinetic/pharmacodynamic parameters in patients receiving continuous renal replacement therapy. Many patients did not achieve pharmacodynamic targets, suggesting that therapeutic drug monitoring might optimize therapy.

Critical care nephrology: management of acid-base disorders with CRRT.

Normal acid-base homeostasis is severely challenged in the intensive care setting. In this review, we address acid-base disturbances, with a special focus on the use of continuous (rather than intermittent) extracorporeal technologies in critical ill patients with acute kidney injury. We consider hypercapnic acidosis and lactic acidosis as examples in which continuous modalities may have different roles and indications than the traditional intermittent approaches to renal replacement therapy. Hypercapnic acidosis develops as a consequence of alveolar hypoventilation. In this condition, correction of pH above 7.2 is not currently recommended, and may even abrogate the beneficial effects of hypercapnic acidosis on overall outcomes. Extracorporeal technologies support lung protection while maintaining overall patient homeostasis. Similarly, in lactic acidosis, current evidence does not support bicarbonate infusions to correct acidosis. The management of lactic acidosis should correct the underlying causative disturbances. Most often, lactic acidosis is a biomarker denoting unfavorable outcomes, rather than an intrinsic pathogenetic mechanism. Extracorporeal procedures may assist in the removal of pathogenic drugs or toxins, as well as partially correcting acidemia. Whether or not these approaches will permit normalization of systemic pH, and the impact of these approaches on patient outcomes, needs to be addressed with prospective controlled trials.