Acute renal failure in critical illness. Conventional dialysis versus acute continuous hemodiafiltration

Debate: Intermittent Hemodialysis versus Continuous Kidney Replacement Therapy in the Critically Ill Patient: The Choice Should Be Evidence Based

Kidney replacement therapy (KRT) plays a major role in the treatment of severe AKI. Intermittent hemodialysis (HD) and continuous KRT (CKRT) are the main modalities in critically ill patients with AKI. CKRT is the preferred modality in many countries because of its alleged superiority on both hemodynamic tolerance and on kidney function recovery. In fact, randomized controlled trials (RCTs) comparing the two modalities have not shown any actual benefit of one technique over the other on mortality, hemodynamics, or kidney function recovery. Those RCTs were conducted more than 15 years ago. Major progress was eventually made leading to much lower mortality rates in recent studies than in previous studies. In addition, those RCTs included a noticeable proportion of patients who could have recovered without ever receiving KRT, as demonstrated by several recent studies. In the absence of evidence of clinical superiority of one KRT modality, the choice must be addressed not only regarding clinical outcome but also resources and logistics. Conclusions of health technology assessments and study reports were heterogeneous and conflicting concerning cost-effectiveness of intermittent HD versus CKRT. All these considerations justify a reevaluation of the issue in new RCTs that take into account recent knowledge on KRT initiation and management. Pending results of such study, the choice should be guided mainly by organizational considerations in each unit and without condemning any modality in the absence of proof.

Changing Acute Renal Failure Treatment from Intermittent Hemodialysis to Continuous Hemofiltration: Impact on Azotemic Control

Background

Continuous renal replacement therapy is increasingly used in the management of acute renal failure in critically ill patients. The advantages of continuous renal replacement therapy (CRRT) over intermittent hemodialysis (IHD), however, are not yet fully documented. In particular, it is unknown whether continuous veno-venuous hemodiafiltration (CVVHDF) provides better control of azotemia than IHD.

Objectives

To study the effect on azotemic control of changing acute renal failure treatment from IHD to CVVHDF.

Settings

Tertiary intensive care unit.

Patients

Forty seven consecutive critically ill patients with multiorgan failure and acute renal failure treated with IHD and 47 similar patients treated with CVVHDF.

Methods

Analysis of daily morning urea and creatinine concentrations over the period of renal replacement therapy in the ICU. Statistical comparison of data.

Results

The two groups of patients were comparable for mean age (55 years for IHD vs. 60 years for CVVHDF; NS) and number of failing organs prior to therapy (mean of 4.2 for IHD vs. 3.7 for CVVHDF; NS). Severity of illness at admission as assessed by APACHE II score, however, was greater for patients receiving CVVHDF (29.4 vs 25.7; p<0.003). CVVHDF was associated with a significantly lower plasma urea (p< 0.0001) and serum creatinine (p<0.01) level at 24 hours of treatment despite similar levels at the start of therapy. Throughout the duration of therapy, mean urea levels (35.0 mmol/L for IHD vs 23.4 mmol/L for CVVHDF) and mean serum creatinine levels (513 micromoles/L for IHD and 263 micromoles/L for CVVHDF) showed significantly (p <0.0001) better control of uremia with CRRT.

Conclusions

Changing the form of renal replacement therapy from intermittent hemodialysis to continuous hemofiltration is associated with improved control of azotemia. The superior adequacy of small solute clearance achieved during CVVHDF provides additional support for its preferential use in the management of acute renal failure in the ICU.

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016

OBJECTIVE

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012."

DESIGN

A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.

RESULTS

The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.

CONCLUSIONS

Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016

OBJECTIVE

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012".

DESIGN

A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.

RESULTS

The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.

CONCLUSIONS

Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

Continuous Renal Replacement Therapy (CRRT) in the Intensive Care Unit

This review is specifically designed to address the topic of CRRT based on the needs and interests of intensivists. Some of the materials, concepts, and formulas presented in this review have been drawn from a previous chapter authored by myself and intended for individuals whose primary interest is specifically dialysis[1]. Since this previous chapter was authored in 1994, similar material presented in this review has been updated in order to present the most current information.

The Impact of Hemodialysis on Sexual Function in Male Patients using the International Index of Erectile Function Questionnaire (IIEF)

Introduction

Routine hemodialysis is one of the preferred treatment methods in patients with chronic kidney disease. It seems that routine hemodialysis can be effective in improving sexual function in these patients. This study aimed to determine the effect of routine dialysis sessions over a six-month period on the status of sexual function in men with chronic renal failure using the International Index of Erectile Function (IIEF) questionnaire.

Methods

The cross-sectional study was conducted from November 2015 to November 2016 on patients with chronic renal failure who were first-time candidates for routine hemodialysis and who were referred to Imam Reza Hospital of Mashhad. All of the patients completed the IIEF questionnaire before their first hemodialysis. Afterwards, all of the patients underwent routine dialysis sessions over a six-month period and completed the IIEF questionnaire again at the end of the sixth month. The prevalence of sexual dysfunction was assessed before and after hemodialysis. The scores on the two IIEF questionnaires were compared according to five domains, i.e., erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction. The comparisons were done before and after hemodialysis using the paired-samples t-test. Statistical analyses were performed using SPSS version 19.

Results

The study included 30 men with a mean age of 40.2 ± 8.2. The prevalence of sexual dysfunctions in the order of their frequency was as follows: intercourse satisfaction (100%), overall satisfaction (100%), sexual desire (96.7%), orgasmic function (93.3%), and erectile function (90%). After six months of treatment with hemodialysis, the ratings of all areas of sexual dysfunction were improved significantly (p-value = 0.00 for all domains).

Conclusion

According to the results of this study, it seems that a six-month course of hemodialysis can improve erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction in patients with chronic kidney disease.

Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012

OBJECTIVE

To provide an update to the "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," last published in 2008.

DESIGN

A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict of interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. A stand-alone meeting was held for all subgroup heads, co- and vice-chairs, and selected individuals. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations as strong (1) or weak (2). The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Some recommendations were ungraded (UG). Recommendations were classified into three groups: 1) those directly targeting severe sepsis; 2) those targeting general care of the critically ill patient and considered high priority in severe sepsis; and 3) pediatric considerations.

RESULTS

Key recommendations and suggestions, listed by category, include: early quantitative resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm a potential source of infection (UG); administration of broad-spectrum antimicrobials therapy within 1 hr of recognition of septic shock (1B) and severe sepsis without septic shock (1C) as the goal of therapy; reassessment of antimicrobial therapy daily for de-escalation, when appropriate (1B); infection source control with attention to the balance of risks and benefits of the chosen method within 12 hrs of diagnosis (1C); initial fluid resuscitation with crystalloid (1B) and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure (2C) and the avoidance of hetastarch formulations (1C); initial fluid challenge in patients with sepsis-induced tissue hypoperfusion and suspicion of hypovolemia to achieve a minimum of 30 mL/kg of crystalloids (more rapid administration and greater amounts of fluid may be needed in some patients) (1C); fluid challenge technique continued as long as hemodynamic improvement, as based on either dynamic or static variables (UG); norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥ 65 mm Hg (1B); epinephrine when an additional agent is needed to maintain adequate blood pressure (2B); vasopressin (0.03 U/min) can be added to norepinephrine to either raise mean arterial pressure to target or to decrease norepinephrine dose but should not be used as the initial vasopressor (UG); dopamine is not recommended except in highly selected circumstances (2C); dobutamine infusion administered or added to vasopressor in the presence of a) myocardial dysfunction as suggested by elevated cardiac filling pressures and low cardiac output, or b) ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure (1C); avoiding use of intravenous hydrocortisone in adult septic shock patients if adequate fluid resuscitation and vasopressor therapy are able to restore hemodynamic stability (2C); hemoglobin target of 7-9 g/dL in the absence of tissue hypoperfusion, ischemic coronary artery disease, or acute hemorrhage (1B); low tidal volume (1A) and limitation of inspiratory plateau pressure (1B) for acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure (PEEP) in ARDS (1B); higher rather than lower level of PEEP for patients with sepsis-induced moderate or severe ARDS (2C); recruitment maneuvers in sepsis patients with severe refractory hypoxemia due to ARDS (2C); prone positioning in sepsis-induced ARDS patients with a PaO2/FIO2 ratio of ≤ 100 mm Hg in facilities that have experience with such practices (2C); head-of-bed elevation in mechanically ventilated patients unless contraindicated (1B); a conservative fluid strategy for patients with established ARDS who do not have evidence of tissue hypoperfusion (1C); protocols for weaning and sedation (1A); minimizing use of either intermittent bolus sedation or continuous infusion sedation targeting specific titration endpoints (1B); avoidance of neuromuscular blockers if possible in the septic patient without ARDS (1C); a short course of neuromuscular blocker (no longer than 48 hrs) for patients with early ARDS and a Pao2/Fio2 < 150 mm Hg (2C); a protocolized approach to blood glucose management commencing insulin dosing when two consecutive blood glucose levels are > 180 mg/dL, targeting an upper blood glucose ≤ 180 mg/dL (1A); equivalency of continuous veno-venous hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1B); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding in patients with bleeding risk factors (1B); oral or enteral (if necessary) feedings, as tolerated, rather than either complete fasting or provision of only intravenous glucose within the first 48 hrs after a diagnosis of severe sepsis/septic shock (2C); and addressing goals of care, including treatment plans and end-of-life planning (as appropriate) (1B), as early as feasible, but within 72 hrs of intensive care unit admission (2C). Recommendations specific to pediatric severe sepsis include: therapy with face mask oxygen, high flow nasal cannula oxygen, or nasopharyngeal continuous PEEP in the presence of respiratory distress and hypoxemia (2C), use of physical examination therapeutic endpoints such as capillary refill (2C); for septic shock associated with hypovolemia, the use of crystalloids or albumin to deliver a bolus of 20 mL/kg of crystalloids (or albumin equivalent) over 5 to 10 mins (2C); more common use of inotropes and vasodilators for low cardiac output septic shock associated with elevated systemic vascular resistance (2C); and use of hydrocortisone only in children with suspected or proven "absolute"' adrenal insufficiency (2C).

CONCLUSIONS

Strong agreement existed among a large cohort of international experts regarding many level 1 recommendations for the best care of patients with severe sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for this important group of critically ill patients.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012

OBJECTIVE

To provide an update to the "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," last published in 2008.

DESIGN

A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict of interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. A stand-alone meeting was held for all subgroup heads, co- and vice-chairs, and selected individuals. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations as strong (1) or weak (2). The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Recommendations were classified into three groups: (1) those directly targeting severe sepsis; (2) those targeting general care of the critically ill patient and considered high priority in severe sepsis; and (3) pediatric considerations.

RESULTS

Key recommendations and suggestions, listed by category, include: early quantitative resuscitation of the septic patient during the first 6 h after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm a potential source of infection (UG); administration of broad-spectrum antimicrobials therapy within 1 h of the recognition of septic shock (1B) and severe sepsis without septic shock (1C) as the goal of therapy; reassessment of antimicrobial therapy daily for de-escalation, when appropriate (1B); infection source control with attention to the balance of risks and benefits of the chosen method within 12 h of diagnosis (1C); initial fluid resuscitation with crystalloid (1B) and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure (2C) and the avoidance of hetastarch formulations (1B); initial fluid challenge in patients with sepsis-induced tissue hypoperfusion and suspicion of hypovolemia to achieve a minimum of 30 mL/kg of crystalloids (more rapid administration and greater amounts of fluid may be needed in some patients (1C); fluid challenge technique continued as long as hemodynamic improvement is based on either dynamic or static variables (UG); norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥65 mmHg (1B); epinephrine when an additional agent is needed to maintain adequate blood pressure (2B); vasopressin (0.03 U/min) can be added to norepinephrine to either raise mean arterial pressure to target or to decrease norepinephrine dose but should not be used as the initial vasopressor (UG); dopamine is not recommended except in highly selected circumstances (2C); dobutamine infusion administered or added to vasopressor in the presence of (a) myocardial dysfunction as suggested by elevated cardiac filling pressures and low cardiac output, or (b) ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure (1C); avoiding use of intravenous hydrocortisone in adult septic shock patients if adequate fluid resuscitation and vasopressor therapy are able to restore hemodynamic stability (2C); hemoglobin target of 7-9 g/dL in the absence of tissue hypoperfusion, ischemic coronary artery disease, or acute hemorrhage (1B); low tidal volume (1A) and limitation of inspiratory plateau pressure (1B) for acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure (PEEP) in ARDS (1B); higher rather than lower level of PEEP for patients with sepsis-induced moderate or severe ARDS (2C); recruitment maneuvers in sepsis patients with severe refractory hypoxemia due to ARDS (2C); prone positioning in sepsis-induced ARDS patients with a PaO (2)/FiO (2) ratio of ≤100 mm Hg in facilities that have experience with such practices (2C); head-of-bed elevation in mechanically ventilated patients unless contraindicated (1B); a conservative fluid strategy for patients with established ARDS who do not have evidence of tissue hypoperfusion (1C); protocols for weaning and sedation (1A); minimizing use of either intermittent bolus sedation or continuous infusion sedation targeting specific titration endpoints (1B); avoidance of neuromuscular blockers if possible in the septic patient without ARDS (1C); a short course of neuromuscular blocker (no longer than 48 h) for patients with early ARDS and a PaO (2)/FI O (2) <150 mm Hg (2C); a protocolized approach to blood glucose management commencing insulin dosing when two consecutive blood glucose levels are >180 mg/dL, targeting an upper blood glucose ≤180 mg/dL (1A); equivalency of continuous veno-venous hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1B); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding in patients with bleeding risk factors (1B); oral or enteral (if necessary) feedings, as tolerated, rather than either complete fasting or provision of only intravenous glucose within the first 48 h after a diagnosis of severe sepsis/septic shock (2C); and addressing goals of care, including treatment plans and end-of-life planning (as appropriate) (1B), as early as feasible, but within 72 h of intensive care unit admission (2C). Recommendations specific to pediatric severe sepsis include: therapy with face mask oxygen, high flow nasal cannula oxygen, or nasopharyngeal continuous PEEP in the presence of respiratory distress and hypoxemia (2C), use of physical examination therapeutic endpoints such as capillary refill (2C); for septic shock associated with hypovolemia, the use of crystalloids or albumin to deliver a bolus of 20 mL/kg of crystalloids (or albumin equivalent) over 5-10 min (2C); more common use of inotropes and vasodilators for low cardiac output septic shock associated with elevated systemic vascular resistance (2C); and use of hydrocortisone only in children with suspected or proven "absolute"' adrenal insufficiency (2C).

CONCLUSIONS

Strong agreement existed among a large cohort of international experts regarding many level 1 recommendations for the best care of patients with severe sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for this important group of critically ill patients.

Clinical review: Optimal dose of continuous renal replacement therapy in acute kidney injury

Continuous renal replacement therapy (CRRT) is the preferred treatment for acute kidney injury in intensive care units (ICUs) throughout much of the world. Despite the widespread use of CRRT, controversy and center-specific practice variation in the clinical application of CRRT continue. In particular, whereas two single-center studies have suggested survival benefit from delivery of higher-intensity CRRT to patients with acute kidney injury in the ICU, other studies have been inconsistent in their results. Now, however, two large multi-center randomized controlled trials - the Veterans Affairs/National Institutes of Health Acute Renal Failure Trial Network (ATN) study and the Randomized Evaluation of Normal versus Augmented Level (RENAL) Replacement Therapy Study - have provided level 1 evidence that effluent flow rates above 25 mL/kg per hour do not improve outcomes in patients in the ICU. In this review, we discuss the concept of dose of CRRT, its relationship with clinical outcomes, and what target optimal dose of CRRT should be pursued in light of the high-quality evidence now available.

Intermittent versus continuous renal replacement therapy: a matter of controversy

BACKGROUND

Acute Renal Failure (ARF) requiring some form of replacement therapy is a frequent complication in the critically ill patient. Despite potential therapeutic advantages the expectation of an improvement in patient outcomes using Continuous Renal Replacement Therapy (CRRT) compared to conventional Intermittent Haemodialysis (IHD) remains controversial.

AIMS AND METHOD

This article will review the literature on the issues surrounding the use of IHD versus CRRT in the management of the critically ill patient. Articles were selected according to level of evidence with priority given to meta-analyses and randomised controlled trials.

DISCUSSION

Several operational features of CRRT allow this technique to be tolerated more easily in critical illness than IHD. The gradual removal of fluid reduces the incidence of hypotension and the risk of volume overload. Decreased variability in the concentration of solutes enables greater azotemia control. However, CRRT is required to operate uninterrupted to achieve a treatment dose that is equivalent to a conventional IHD treatment schedule. In the absence of definitive evidence to validate superior patient survival and return of renal function there is disagreement as to the most appropriate form of Renal Replacement Therapy (RRT) for the critically ill patient. The introduction of 'hybrid' therapies offers a further alternative treatment strategy, which combine favourable aspects of IHD and CRRT.

CONCLUSION

The decision to use IHD or CRRT should be guided by the therapeutic needs of the patient rather than the operational differences between the two techniques. The resources and expertise available at the organisation are also important in determining the mode best able to manage the critically ill patient at any stage and may change according to the severity of illness. The emergence of hybrid therapies provides a compromise option which encompasses many of the features of both systems, but does not embrace all options of either approach.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation (1) indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost) or clearly do not. Weak recommendations (2) indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for postoperative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B), targeting a blood glucose < 150 mg/dL after initial stabilization (2C); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); and a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSIONS

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the GRADE system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost), or clearly do not. Weak recommendations indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include: early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures prior to antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for post-operative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B) targeting a blood glucose < 150 mg/dL after initial stabilization ( 2C ); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper GI bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include: greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSION

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Continuous venovenous haemodiafiltration versus intermittent haemodialysis for acute renal failure in patients with multiple-organ dysfunction syndrome: a multicentre randomised trial

BACKGROUND

Whether continuous renal replacement therapy is better than intermittent haemodialysis for the treatment of acute renal failure in critically ill patients is controversial. In this study, we compare the effect of intermittent haemodialysis and continuous venovenous haemodiafiltration on survival rates in critically ill patients with acute renal failure as part of multiple-organ dysfunction syndrome.

METHODS

Our prospective, randomised, multicentre study took place between Oct 1, 1999, and March 3, 2003, in 21 medical or multidisciplinary intensive-care units from university or community hospitals in France. Guidelines were provided to achieve optimum haemodynamic tolerance and effectiveness of solute removal in both groups. The two groups were treated with the same polymer membrane and bicarbonate-based buffer. 360 patients were randomised, and the primary endpoint was 60-day survival based on an intention-to-treat analysis.

FINDINGS

Rate of survival at 60-days did not differ between the groups (32% in the intermittent haemodialysis group versus 33% in the continuous renal replacement therapy group [95 % CI -8.8 to 11.1,]), or at any other time.

INTERPRETATION

These data suggest that, provided strict guidelines to improve tolerance and metabolic control are used, almost all patients with acute renal failure as part of multiple-organ dysfunction syndrome can be treated with intermittent haemodialysis.

A Comparison of Continuous Renal Replacement Therapy to Intermittent Dialysis in the Management of Renal Insufficiency in the Acutely Ill Surgical Patient

Acute renal failure (ARF) occurs in 10 per cent to 23 per cent of intensive care unit patients with mortality ranging from 50 per cent to 90 per cent. ARF is characterized by an acute decline in renal function as measured by urine output (UOP), serum creatinine, and blood urea nitrogen (BUN). Causes may be prerenal, intrarenal, or postrenal. Treatment consists of renal replacement therapy (RRT), either intermittent (ID) or continuous (CRRT). Indications for initiation of dialysis include oliguria, acidemia, azotemia, hyperkalemia, uremic complications, or significant edema. Overall, the literature comparing CRRT to ID is poor. No studies of only surgical/trauma patients have been published. We hypothesize that renal function and hemodynamic stability in trauma/surgical critical care patients are better preserved by CRRT than by ID. We performed a retrospective review of trauma/surgical critical care patients requiring renal supportive therapy. Thirty patients received CRRT and 27 patients received ID. The study was controlled for severity of illness and demographics. Outcomes assessed were survival, renal function, acid-base balance, hemodynamic stability, and oxygenation/ventilation parameters. Populations were similar across demographics and severity of illness. Renal function, measured by creatinine clearance, was statistically greater with CRRT ( P = 0.035). There was better control of azotemia with CRRT: BUN was lower ( P = 0.000) and creatinine was lower ( P = 0.000). Mean arterial blood pressure was greater ( P = 0.021) with CRRT. No difference in oxygenation/ventilation parameters or pH was found between groups. CRRT results in an enhancement of renal function with improved creatinine clearance at the time of dialysis discontinuation. CRRT provides better control of azotemia while preserving hemodynamic stability in patients undergoing renal replacement therapy. Prospective randomized controlled studies and larger sample sizes are needed to further evaluate these modalities.

Adjunctive therapies in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for adjunctive therapies in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and to improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Glycemic control (maintenance of glucose <150 mg/dL) is recommended. The beneficial effect of glycemic control appears to be related control of glucose and not the administration of insulin. Glycemic control should be combined with a nutritional protocol. The dialysis dose is important in sepsis-induced acute renal failure. Continuous hemofiltration offers easier management of fluid balance in hemodynamically unstable septic patients but in the absence of hemodynamic instability is equivalent to intermittent hemodialysis. It is uncertain whether high-volume hemofiltration improves prognosis in sepsis. Bicarbonate therapy is not recommended for the purpose of improving hemodynamics or reducing vasopressor requirements in the presence of lactic academia and pH >7.15.

Dose of Dialysis in Acute Renal Failure

Acute renal failure (ARF) is a cause of significant morbidity and mortality. Despite advances in supportive care, outcomes in ARF have improved little over the past decades. The primary goals in management of patients with ARF are to optimize hemodynamic and volume status, minimize further renal injury, correct metabolic abnormalities, and permit adequate nutrition. Renal replacement therapy (RRT) is often required to achieve these goals while awaiting renal recovery, but the optimal dose of dialysis in patients with ARF is not known. Extrapolation of required dialysis dose from recommendations in chronic dialysis is unlikely to be appropriate because of the lack of a steady state and differences in distribution volume of urea that are intrinsic to ARF. The prescribed dialysis dose in ARF is often low, and actual delivered dose is often even less than prescribed. Delivery of dialysis in ARF is often hampered by the patient's hypercatabolic state, hemodynamic instability, and volume status, as well as suboptimal vascular access with temporary venous catheters. The impact of intermittent hemodialysis (IHD) versus continuous renal replacement therapy (CRRT) on outcomes in ARF is also not clear. Patient disease severity impacts more than dialysis modality in patient outcome, but when patients are stratified for equal disease severity, CRRT may have potential benefits over IHD in terms of patient survival, fluid and metabolic control, and renal recovery. Strategies associated with improved outcomes that have emerged thus far in ARF are to aim for a time-averaged blood urea nitrogen (BUN) of less than 60 mg/dl with IHD, varying IHD frequency as necessary, or to achieve a minimum ultrafiltration rate of 35 ml/kg/hr with CRRT.

Acute renal failure in the ICU: assessing the utility of continuous renal replacement

Acute renal failure (ARF) in the ICU patient still remains a common problem and is associated with increased morbidity, mortality, and cost. Potential advantages of continuous renal replacement (CRRT), compared with intermittent hemodialysis (IHD) include enhanced hemodynamic stability, increased solute removal, and greater ultrafiltration. Although it was hoped that CRRT would lead to improvement in patient outcomes, there are few prospective, randomized clinical studies comparing this modality with conventional hemodialysis in the treatment of patients with ARF. The difficulties associated with designing such prospective studies are the complex status of the medical patients and the ethical dilemma of randomizing patients to a certain dialysis modality. At this time, there is no evidence to support the assertion that CRRT improves clinical outcomes compared with IHD.

Predicting the outcome of renal replacement therapy in severe acute renal failure

Continuous renal replacement therapy (CRRT), such as continuous venovenous hemofiltration, has theoretical advantages over intermittent hemodialysis (IHD) that are related to cardiorespiratory stability, metabolic control, and fluid balance allowing nutritional supplementation. However, retrospective and controlled studies fail to show these advantages because of comorbidity associated with triage to CRRT. To compare outcomes using IHD versus CRRT, we applied published risk stratification models (Cleveland Clinic Foundation, Lohr index, and APACHE II) to the 349 patients with acute renal failure requiring renal replacement therapy at University of Michigan over the 2 year period including 1995 and 1996. The Cleveland Clinic Foundation model best predicted overall mortality, but our CRRT patients had excess, unpredicted mortality that was particularly prominent in the lower risk categories. The Lohr clinical score predicted mortality less accurately but also was associated with higher, unpredicted mortality at lower risk scores among the CRRT patients. APACHE II scores did not predict mortality very well among IHD, CRRT, or the combined group of patients. We conclude that the need for CRRT itself predicts mortality over and above that included in published risk models. Either CRRT is associated with some unidentified morbidity (e.g., treatment associated infection) or, more likely, triage to CRRT is associated with as yet unspecified comorbidity not detected in existing risk stratification schemes. It will be important to address these issues in any future studies evaluating outcome or comparing renal replacement therapy modalities among patients with severe acute renal failure.

Dialysis modalities in the intensive care unit

Acute renal failure in the ICU is a clinically diverse entity. Consequently, the indications for initiation of dialysis therapy are varied. In general, the indications are solute control, volume control, or both. A variety of dialysis modalities are available; however, there is no consensus as to the optimal modality for any particular group of patients. A careful understanding of the particular benefits, limitations, and potential complications of each modality coupled with a thorough assessment of the individual patient's need formulate the basis for dialysis modality selection. In certain circumstances, the more conventional intermittent therapies are sufficient, whereas in other settings, CRRT techniques are advantageous. The impact of modality selection on outcome remains an area of significant controversy. Future studies in which more uniformity within specific subgroups of patients with ARF is sought may shed light on the optimal modality for a particular patient group. Newer therapies aimed at more optimal and more specific blood purification may prove promising in the management of complex critically ill patients with ARF and other comorbid conditions.

A new method to control ultrafiltration in conventional continuous renal replacement therapy

Conventional continuous arteriovenous hemofiltration/hemodialysis (CAVH/D) and slow continuous ultrafiltration (SCUF) are types of continuous renal replacement therapy (CRRT) in which the ultrafiltrate (UF) volume is controlled imprecisely with a UF clamp, which is labor intensive, demanding frequent adjustment to preclude excessive fluid removal. We devised a simple method for precise control of the UF volume. Seven CRRTs in the form of CAVH, CAVHD, and SCUF were performed in four patients with massive edema. A standard circuit was created in each case using blood tubing sets and an HF 400 hemofilter obtained from MinnTech. Standard intravenous infusion tubing connected to an infusion pump (IMED, Gemini PC-2 volumetric pump/controller) with its proximal end inserted into the dialysate port at the venous end of the hemofilter, and the distal end draining into a plastic bag, was used to control the UF rate. Dialysis was added to the circuit using another pump connected to the dialysate port at the arterial end of the hemofilter. Treatment time ranged from 27 to 78 hours. Target fluid removal was achieved in all treatments, and the net UF rate required only once daily adjustment for total fluid intake. Mean time to reporting a problem by the intensive care nurse was 30 hours (range, 25-30 hours), and mean time to filter clotting was 38 hours (range, 27-40 hours). This set-up is less labor intensive, more cost effective, and is applicable in areas lacking automated machines. Future development of tubing for UF designed as above may further reduce cost.

A primer on continuous renal replacement therapy for critically ill patients

OBJECTIVES

To characterize the multiple continuous renal replacement therapy (CRRT) techniques available for the management of critically ill adults, and to review the indications for and complications of use, principles of drug removal during CRRT, drug dosage individualization guidelines, and the influence of CRRT on patient outcomes.

DATA SOURCES

MEDLINE (January 1981-December 1996) was searched for appropriate publications by using terms such as hemofiltration, ultrafiltration, hemodialysis, hemodiafiltration, medications, and pharmacokinetics; selected articles were cross-referenced.

STUDY SELECTION

References selected were those considered to enhance the reader's knowledge of the principles of CRRT, and to provide adequate therapies on drug disposition.

DATA SYNTHESIS

CRRTs use filtration/convection and in some cases diffusion to treat hemodynamically unstable patients with fluid overload and/or acute renal failure. Recent data suggest that positive outcomes may also be attained in patients with other medical conditions such as septic shock, multiple organ dysfunction syndrome, and hepatic failure. Age, ventilator support, inotropic support, reduced urine volume, and elevated serum bilirubin concentrations have been associated with poor outcomes. Complications associated with CRRT include bleeding due to excessive anticoagulation and line disconnections, fluid and electrolyte imbalance, and filter and venous clotting. CRRT can complicate the medication regimens of patients for whom it is important to maintain drug plasma concentrations within a narrow therapeutic range. Since the physicochemical characteristics of a drug and procedure-specific factors can alter drug removal, a thorough assessment of all factors needs to be considered before dosage regimens are revised. In addition, an algorithm for drug dosing considerations based on drug and CRRT characteristics, as well as standard pharmacokinetic equations, is proposed.

CONCLUSIONS

The use of CRRT has expanded to encompass the treatment of disease states other than just acute renal failure. Since there is great variability among treatment centers, it is premature to conclude that there is enhanced survival in CRRT-treated patients compared with those who received conventional hemodialysis. This primer may help clinicians understand the need to individualize these therapies and to prospectively optimize the pharmacotherapy of their patients receiving CRRT.

Management of acute renal failure in the pediatric patient: hemofiltration versus hemodialysis

Although outcome data for acute renal failure (ARF) in the adult population (analyzed by etiology of ARF, severity of illness, and modality of treatment) are readily available, few similar data exist for the pediatric population. Pediatric survival rate data vary widely, based upon era of analysis, age and size of child, and cause of ARF. Few comparative data are available that address impact by modality chosen to treat ARF. Comparison of 122 children who were treated by hemodialysis (HD; n = 58) versus hemofiltration (HF; n = 64) reveals a combined survival rate of 65%. Survival by modality was higher for HD (83%) than for HF (48%). The major diagnosis treated with HF was sepsis (29/64; 45%), with a survival rate of 31%, whereas the major diagnosis treated with HD (27/58; 46%) was primary renal failure, with a survival rate of 96%. Seventy-one percent of children undergoing HF required pressor support for hypotension, whereas only 24% of those receiving HD needed pressor support (P < 0.01). We conclude that the choice of renal replacement therapy (RRT) modality needs to be determined by the best treatment available. To adequately evaluate therapy measures, further analyses of outcome need to consider those factors that determine choice of RRT and those that affect survival independent of ARF.

Renal replacement therapy in the ICU: the Australian experience

The structure of health care drives medical practice in a powerful way, shaping choices of therapy and approaches, and influencing scientific evidence. The Australian experience with continuous renal replacement therapy (CRRT) confirms the importance of structure. A public health system like that of Australia's contains the following variables: well-developed intensive care tradition and expertise, a dominant "closed" intensive care unit (ICU) model, well-developed training of intensive care nurses with established one-to-one nurse-patient ratios, salaried medical practitioners, overworked general dialysis units with inadequate nursing resources, and lack of fee-for-service incentive for nephrologists to see ICU patients with acute renal failure. The likely outcome of such a system is for CRRT to be run by intensive care staff. As shown by a recent regional survey, this approach, although somewhat unique, is dominant and appears to work well with excellent clinical results and constant clinical research output.

Acute renal failure in infants, children and adults

Acute renal failure (ARF) occurs in many critically ill patients regardless of age. A combination of events often seen in critical care settings, including shock, sepsis, hypoxia, and the use of potentially nephrotoxic medications, combine to make ARF an ongoing and important management issue in critical care medicine. Since the events leading to the development of ARF differ in infants, children, adults, and the elderly, the pathophysiology, clinical features, and treatment modalities do indeed have remarkable similarities among the different age groups.

Should continuous renal replacement therapy be used for 'non-renal' indications in critically ill patients with shock?

Accumulating experience with the use of continuous renal replacement therapy (CRRT) in critically ill patients with acute renal failure suggests that these treatment modalities have distinct advantages relative to conventional dialysis in terms of solute clearances, fluid removal and hemodynamics, which may translate in improved renal and patient outcome. Recent data point to a possible beneficial effect of CRRT on the clinical course, independent from an impact on fluid balance, in critically ill patients with shock which is attributed to the continuous elimination of inflammatory mediators from the circulation. This has raised the question as to whether CRRT might be used for 'non-renal' indications such as the systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). In some animal models of experimental septic and non-septic shock, (short-term) hemodialysis and hemofiltration were found to improve hemodynamics and/or gas exchange. However, data were inconsistent and the clinical relevance questionable. Observations from both uncontrolled and controlled clinical studies (comprising only a small number of patients) support the hypothesis that CRRT may exert beneficial effects on the clinical course in critically ill patients with SIRS and MODS, independent from volume removal. Although several mediators known to play a role in the development of SIRS/MODS may pass hemofiltration membranes, quantitative data on the extent of its extracorporeal clearance relative to the production rate and endogenous clearance is often lacking. In addition, this aspecific elimination with CRRT may also effect levels of anti-mediators, which may be harmful. Ultrafiltrate properties include depression of cardiac performance, induction of proteolysis and immunosuppressive activity suggesting that water-soluble factors responsible for these deleterious effects are removed from the circulation by convection. However, no significant survival advantage has yet been shown for critically ill patients with SIRS/MODS when treated with CRRT as an adjunct to conventional therapy. Only prospective controlled studies of appropriate sample size, which requires a multicenter approach, might answer the question whether use of CRRT may alter the clinical course and outcome in critically ill patients with SIRS and MODS. Until such studies are performed, the rationale for the use of CRRT in the absence of conventional indications for dialytic support remains unproven.

A prospective study of continuous hemodiafiltration in the management of severe acute renal failure in critically ill surgical patients

Severe acute renal failure associated with surgical disease and a highly catabolic state poses a major therapeutic challenge. Treatment by conventional dialysis or arteriovenous hemofiltration suffers from serious shortcomings. The current study assesses the clinical and biochemical impact of a newer approach (continuous hemodiafiltration) in a cohort of 60 critically ill surgical patients with severe renal failure. All patients were studied prospectively and assessed for illness severity. Their biochemical response to therapy was analyzed and their clinical course to either death or hospital discharge documented. The use of continuous hemodiafiltration (CHD) permitted full control of azotemia in all patients (mean steady-state urea concentration: 19.8 mmol/L) and was associated with rapid control of acidemia (mean pretreatment pH: 7.27; mean ph after 24-h treatment: 7.35; p < .001). During the 15,696 h of therapy, there were no treatment-induced episodes of hypotension and/or hypoxemia. All patients were able to receive full-dose enteral (9) or parenteral (51) nutritional support with 1.5 to 2.5 g/kg/day of protein as tolerated. Despite their illness severity (mean APACHE II score: 28.9) and the need for vasopressor support and ventilation in 90% of cases, 21 patients (35%) survived to hospital discharge. We conclude that continuous hemodiafiltration is safe and effective in surgical critically ill patients with acute renal failure, and that it is associated with a low morbidity and an encouraging survival rate.

A review of continuous renal replacement therapy

Patients in the Intensive Care Unit commonly develop acute renal failure (ARF). The kidneys are rarely the only organs failing in these patients. Frequently ARF is part of multiple organ dysfunction syndrome. The choice of dialytic therapy should consider, not only the efficacy of the therapy, but also the undesirable effects such therapy may have on the other failing organs. Intermittent Haemodialysis and Peritoneal Dialysis were the conventional forms of dialysis available. Both are associated with complications which may make them unsuitable for use in the haemodynamically unstable, hypercatabolic patients, seen in the Intensive Care setting. Continuous Renal Replacement Therapy (CRRT) has been introduced in many Intensive Care Units to provide a more stable, flexible form of dialysis. The purpose of this article is to give an overview of the various forms of CRRT and to discuss the advantages of this form of therapy.

Acute renal failure in the critically ill: management by continuous veno-venous hemodiafiltration

The consequences of newer techniques of continuous renal replacement therapy in critically ill patients are not yet fully known. The clinical and biochemical impact of continuous veno-venous hemodiafiltration (CVVHD) was, therefore, prospectively studied in 60 critically ill patients with acute renal failure. Prospective clinical, biochemical, and hematological data were collected from patients receiving CVVHD. Over the initial 24 hours of therapy, CVVHD resulted in a decrease in mean plasma urea from 34.5 mmol/L (95% confidence interval [CI], 29.4 to 39.6) to 25 mmol/L (95% CI, 21.8 to 28.2). With continued CVVHD, the mean plasma urea reached a plateau level of 17.6 mmol/L (95% CI, 15.8 to 19.4) at 72 hours. This degree of azotemia control was achieved with ease and essentially without complications during 8,360 hours of therapy despite the presence of multi-organ failure and the aggressive administration of protein nitrogen (0.25 to 0.35 g/kg/day). No abnormalities of serum electrolytes developed during treatment. Survival to intensive care discharge was 46.6% and to hospital discharge 41.6%, despite a mean Acute Physiology and Chronic Health Evaluation (APACHE) II score at presentation of 27.7. Continuous veno-venous hemodiafiltration offers superior azotemia control and a safe approach to renal replacement therapy in critically ill patients. Its use is associated with a comparatively favorable outcome. CVVHD may be regarded as the treatment of choice in such patients.