Use of dopamine in acute renal failure: a meta-analysis

Postoperative renal failure

Acute renal failure (ARF) or acute kidney injury (AKI) is a common problem occurring in about 1% to 5% of all hospitalized patients. It leads to poor quality of life and increased length of stay (LOS), cost of care, morbidity, and mortality. The survival rate for ARF has not drastically changed over the past 4 decades because of the aging population and presence of multiple comorbid conditions. About 200 patients per million population develop severe ARF each year. Approximately one-third of these patients require ICU care. Recent studies have shown that even milder forms of renal dysfunction are associated with increased LOS and mortality.

Management of acute kidney injury in children: a guide for pediatricians

Acute kidney injury (AKI; previously called acute renal failure) is characterized by a usually reversible increase in the blood concentration of creatinine and nitrogenous waste products and by the inability of the kidney to appropriately regulate fluid and electrolyte homeostasis. The incidence of AKI in children appears to be increasing and the etiology of AKI over the past decades has shifted from primary renal disease to multifactorial causes, particularly in hospitalized children. Renal failure can be divided into prerenal failure, intrinsic renal disease including vascular insults, and obstructive uropathies. The history, physical examination, and laboratory studies including a urinalysis and radiographic studies can establish the likely cause(s) of AKI. Once intrinsic renal failure has become established, management of the metabolic complications of AKI requires meticulous attention to fluid balance, electrolyte status, acid-base balance, and nutrition. Many children with AKI will need renal replacement therapy to remove endogenous and exogenous toxins and to maintain fluid, electrolyte, and acid-base balance until renal function improves. Renal replacement therapy may be provided by peritoneal dialysis (PD), intermittent hemodialysis (HD), or hemofiltration with or without a dialysis circuit. Many factors--including the age and size of the child, the cause of renal failure, the degree of metabolic derangements, blood pressure, and nutritional needs--are considered in deciding when to initiate renal replacement therapy and which modality of therapy to use. The prognosis of AKI is highly dependent on the underlying etiology of the AKI. Children who have AKI as a component of multisystem failure have a much higher mortality rate than children with intrinsic renal disease. Recovery from intrinsic renal disease is also highly dependent on the underlying etiology of the AKI. Children who have experienced AKI from any cause are at risk for late development of renal failure long after the initial insult. Such children need life-long monitoring of their renal function, blood pressure, and urinalysis.

The prevention of acute kidney injury an in-depth narrative review: Part 2: Drugs in the prevention of acute kidney injury

The second part of this in-depth clinical review focuses on drugs used in the prevention of AKI in the patient at risk and/or in the management of the patient with incipient AKI. Among the drugs used to maintain a normal renal perfusion pressure, norepinephrine and vasopressin are most commonly used in hypotensive critically ill patients. The most recent RCT did not find a difference between low-dose vasopressin plus norepinephrine and norepinephrine alone in patients with septic shock, suggesting that either approach is reasonable. However, vasopressin may be beneficial in the less severe septic shock subgroup. Loop diuretics may convert an oliguric into a non-oliguric form of AKI that may allow easier fluid and/or nutritional support of the patient. Volume overload in AKI patients is common and diuretics may provide symptomatic benefit in that situation. However, loop diuretics are neither associated with improved survival, nor with better recovery of renal function in AKI. Among the renal vasodilating drugs, the routine administration of dopamine to patients for the prevention of AKI or incipient AKI is no longer justified. On the other hand, although additional studies may be warranted, fenoldopam may appear to be a likely candidate for the prevention of AKI, particularly in critically ill patients, if the positive results obtained in some recent studies are confirmed. Trials with natriuretic peptides were in general inconclusive but despite the fact that nesiritide is currently approved by the FDA only for the treatment of heart failure, this vasodilator may in the future play a role in the prevention of AKI, particularly in association with heart failure and cardiac surgery. The most recent trials seem to confirm a potential positive preventive effect of N-acetylcysteine (NAC), particularly in contrast-induced nephropathy (CIN), NAC alone should never take the place of IV hydration in patients at risk for CIN; fluids likely have a more substantiated benefit. At present, initiation of statin therapy for the prevention of CIN cannot be recommended, but these drugs should not be stopped before a radiological intervention in patients on chronic statin therapy. Rasburicase is very effective in the prevention of acute tumour lysis syndrome. Erythropoietin (EPO) has tissue-protective effects and prevents tissue damage during ischaemia and inflammation, and currently trials are performed with EPO in the prevention of AKI post-cardiac surgery, CIN and post-kidney transplantation. From this review it becomes clear that single-drug therapy will probably never be effective in the prevention of AKI and that multiple agents may be needed to improve outcomes. In addition, drugs should be administered early during the course of the disease.

Acute kidney injury in children

Acute kidney injury (AKI) (previously called acute renal failure) is characterized by a reversible increase in the blood concentration of creatinine and nitrogenous waste products and by the inability of the kidney to regulate fluid and electrolyte homeostasis appropriately. The incidence of AKI in children appears to be increasing, and the etiology of AKI over the past decades has shifted from primary renal disease to multifactorial causes, particularly in hospitalized children. Genetic factors may predispose some children to AKI. Renal injury can be divided into pre-renal failure, intrinsic renal disease including vascular insults, and obstructive uropathies. The pathophysiology of hypoxia/ischemia-induced AKI is not well understood, but significant progress in elucidating the cellular, biochemical and molecular events has been made over the past several years. The history, physical examination, and laboratory studies, including urinalysis and radiographic studies, can establish the likely cause(s) of AKI. Many interventions such as 'renal-dose dopamine' and diuretic therapy have been shown not to alter the course of AKI. The prognosis of AKI is highly dependent on the underlying etiology of the AKI. Children who have suffered AKI from any cause are at risk for late development of kidney disease several years after the initial insult. Therapeutic interventions in AKI have been largely disappointing, likely due to the complex nature of the pathophysiology of AKI, the fact that the serum creatinine concentration is an insensitive measure of kidney function, and because of co-morbid factors in treated patients. Improved understanding of the pathophysiology of AKI, early biomarkers of AKI, and better classification of AKI are needed for the development of successful therapeutic strategies for the treatment of AKI.

Sepsis: Clinical Approach, Evidence-Based at the Bedside

Sepsis is a common disease in intensive care medicine representing almost one third of patient admissions. Its incidence has substantially increased over the past decades and overall mortality has declined during this period of time. It was reported that sepsis incidence increased from 82.7 to 240.4 per 100,000 population between 1979–2000. At the same time, sepsis global mortality decreased from 27.8 to 17.9% [1–3]. However, the absolute number of deaths significantly increased from 21.9 to 43.9 per 100,000 population. Male gender, some chronic diseases like diabetes, immunosuppressive states, human immunodeficiency virus infections, and malignancies are factors that increase the risk for sepsis. Some particular conditions like progressive number of organ dysfunctions, in-hospital-acquired infections and increasing age are associated with higher risk of death [1,4]. On the other hand, septic shock mortality only diminished from 61.6 to 53.1% [5]. This slight decline in mortality observed during recent decades could be attributable to improvements in supportive care and/or avoidance of iatrogenic complications. For example, the instrumentation of early goal resuscitation protocols not aiming at supranormal targets for cardiac output and oxygen delivery, and the use of lung protective strategies could explain at least in part this favorable change. Other strategies directed to treat the pathophysiological mechanisms involved in the septic process like recombinant human-activated protein-C (rhAPC), have also contributed to improve survival. However, mortality remains unacceptably high and further improvement in sepsis management is needed.

Hepatic and renal protection during cardiac surgery

Hepatic injury in cardiac surgery is a rare complication but is associated with significant morbidity and mortality. A high index of suspicion postoperatively will lead to earlier treatment directed at eliminating or minimizing ongoing hepatic injury while preventing additional metabolic stress from ischemia, hemorrhage, or sepsis. The evidence-basis for perioperative renal risk factors remains hampered by the inconsistent definitions for renal injury. Although acute kidney injury (as defined by the Risk, Injury, Failure, Loss, End-stage criteria) has become accepted, it does not address pathogenesis and bears little relevance to cardiac surgery. Although acute renal failure requiring renal replacement therapy after cardiac surgery is rare, it has a devastating impact on morbidity and mortality, and further studies on protective strategies are essential.

Nephrotoxicity as a cause of acute kidney injury in children

Many different drugs and agents may cause nephrotoxic acute kidney injury (AKI) in children. Predisposing factors such as age, pharmacogenetics, underlying disease, the dosage of the toxin, and concomitant medication determine and influence the severity of nephrotoxic insult. In childhood AKI, incidence, prevalence, and etiology are not well defined. Pediatric retrospective studies have reported incidences of AKI in pediatric intensive care units (PICU) of between 8% and 30%. It is widely recognized that neonates have higher rates of AKI, especially following cardiac surgery, severe asphyxia, or premature birth. The only two prospective studies in children found incidence rates of 4.5% and 2.5% of AKI in children admitted to PICU, respectively. Nephrotoxic drugs account for about 16% of all AKIs most commonly associated with AKI in older children and adolescents. Nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, amphotericin B, antiviral agents, angiotensin-converting enzyme (ACE) inhibitors, calcineurin inhibitors, radiocontrast media, and cytostatics are the most important drugs to indicate AKI as significant risk factor in children. Direct pathophysiological mechanisms of nephrotoxicity include constriction of intrarenal vessels, acute tubular necrosis, acute interstitial nephritis, and-more infrequently-tubular obstruction. Furthermore, AKI may also be caused indirectly by rhabdomyolysis. Frequent therapeutic measures consist of avoiding dehydration and concomitant nephrotoxic medication, especially in children with preexisting impaired renal function.

Perioperative renal protection

Acute kidney injury (AKI) is a significant cause of perioperative patient morbidity and mortality. The definition of AKI has recently changed and further research is underway to identify clinically relevant biomarkers to aid in the diagnosis of the syndrome. AKI is often multi-factorial in origin and patients with certain preoperative risk factors are at elevated risk of perioperative AKI. An anesthesiologist's main objective for perioperative renal protection is prevention by maintenance of euvolemia, preservation of adequate renal perfusion, and avoidance of nephrotoxins. This review will address the definition and diagnosis of AKI, identify patients at risk of AKI, and critically appraise management options for perioperative renal protection.

Effects of human atrial natriuretic peptide on renal function in patients undergoing abdominal aortic aneurysm repair

OBJECTIVE

Ischemia-reperfusion injury is an important cause of renal dysfunction after abdominal aortic aneurysm repair. Human atrial natriuretic peptide (hANP) is a potent endogenous natriuretic, diuretic, and vasorelaxant peptide. The objective of the present study was to evaluate the effects of hANP on renal function in patients undergoing abdominal aortic aneurysm repair.

DESIGN

A prospective, randomized, placebo-controlled study

SETTING

Intensive care unit of a university hospital.

PATIENTS

Forty patients undergoing elective abdominal aortic aneurysm repair.

INTERVENTIONS

The patients were randomized to receive a continuous infusion of either hANP (0.01-0.05 microg/kg/min) (n = 20) or placebo (n = 20) immediately before aortic cross-clamping. The infusion of hANP or placebo continued for 48 hrs.

MEASUREMENTS AND MAIN RESULTS

Blood and urine samples were taken before surgery, at admission to the intensive care unit, and on days 1, 2, and 3 postoperatively, for measurement of serum concentrations of sodium, creatinine, and blood urea nitrogen and plasma concentrations of ANP and brain natriuretic peptide (BNP). Urine volume and urinary concentrations of N-acetyl-beta-D-glucosaminidase (NAG), sodium, and creatinine were also measured. The mean plasma concentration of ANP was significantly higher in the hANP group than in the placebo group. The mean plasma BNP concentration was significantly lower in the hANP group than in the placebo group. The mean serum concentrations of creatinine and blood urea nitrogen were significantly (p < .05) lower in the hANP group than in the placebo group. The mean urine volume and mean creatinine clearance were significantly (p < .05) higher in the hANP group than in the placebo group. The mean urinary NAG/creatinine ratio was significantly (p < .05) lower in the hANP group than in the placebo group.

CONCLUSIONS

The intraoperative and postoperative infusion of low-dose hANP preserved renal function in patients undergoing abdominal aortic aneurysm repair. Further studies are needed to assess the efficacy of prophylactic hANP infusion on perioperative renal outcome.

Can we prevent acute kidney injury?

OBJECTIVE

To review the literature on prevention of acute kidney injury (AKI).

DATA SOURCE

MEDLINE- and PubMed-based review of literature published from 1965 to 2007.

CONCLUSIONS

AKI is very common among critically ill patients. Even mild forms of AKI have significant attributable mortality. Hence, it is imperative that every effort to prevent AKI be made in clinical practice. However, there are very few interventions that have been shown to consistently prevent AKI. Measures such as adequate hydration, maintenance of adequate circulating blood volume and mean arterial pressure, and avoidance of nephrotoxins are still the mainstay of prevention. Loop diuretics and "renal-dose" dopamine have been clearly shown not to prevent AKI and may, in fact, do harm. Among the remaining pharmacologic options, N-acetylcysteine has the strongest evidence in prevention of AKI. Fenoldopam and theophylline need further investigation before being used to prevent septic AKI and contrast nephropathy, respectively. The role of prophylactic dialysis in preventing contrast nephropathy needs to be investigated further.

An overview of drug-induced acute kidney injury

The complex nature of critical illness often necessitates the use of multiple therapeutic agents, many of which may individually or in combination have the potential to cause renal injury. The use of nephrotoxic drugs has been implicated as a causative factor in up to 25% of all cases of severe acute renal failure in critically ill patients. Acute tubular necrosis is the most common form of renal injury from nephrotoxin exposure, although other types of renal failure may be seen. Given that this is a preventable cause of a potentially devastating complication, a comprehensive strategy should be used to avoid nephrotoxicity in critically ill patients including: accurate estimation of pre-existing renal function using serum creatinine-based glomerular filtration rates, avoidance of nephrotoxins if possible, ongoing monitoring of renal function, and immediate discontinuation of suspected nephrotoxins in the event of renal dysfunction.

Fenoldopam for acute kidney injury in children

We report two cases of children with severe cardiomyopathy requiring treatment with ventricular assist devices who developed acute kidney injury and were treated with fenoldopam. Therapy with fenoldopam appeared successful in one case in that renal replacement therapy was avoided with improvement in urine output and renal function. These are the first reported cases of fenoldopam use in children with acute kidney injury receiving mechanical circulatory support.

Recent developments in the diagnosis and management of severe sepsis

The last 5 years have brought dramatic changes to the care of patients with severe sepsis. While early diagnosis remains a challenge and, regrettably, a rapid, sensitive, and specific diagnostic test is still lacking, the methods to identify those critically ill patients who are likely to die have become clearer. The presence of multiple organ failure, vasopressor-dependent shock, and high values in formalized scoring methods such as the APACHE (acute physiology and chronic health evaluation) and sequential organ failure assessment systems all have some utility for outcome prediction for groups of patients. Refinements in long-used supportive practices such as lower tidal volume ventilation and enhanced glucose control have improved outcomes. A growing appreciation of the importance of timely provision of antimicrobial therapy, circulatory resuscitation, and activated protein C administration have also improved survival. Optimal treatment candidates for, and the timing and dose of some treatments (eg, corticosteroids) remain controversial and are undergoing additional study. Perhaps the most important change in the care of patients with severe sepsis is awareness that the syndrome is more common, lethal, and expensive, than previously appreciated, and as such it warrants an organized approach to care provided by experts. Although there is still much to learn, numerous studies now indicate that improvements in outcomes are possible when treatment protocols that incorporate all known beneficial therapies are applied in a timely fashion.

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.

Potential interventions in sepsis-related acute kidney injury

Sepsis is an important cause of morbidity and mortality. Acute kidney injury often complicates sepsis, leading to greater complexity, cost of care, and worsening prognosis. In recent years, a consensus definition of acute kidney injury has been developed, facilitating research into the pathophysiology and epidemiology of this disorder. New and emerging biomarkers to recognize kidney injury before functional abnormalities are manifest may allow early recognition and facilitate prevention or treatment. Furthermore, advances in the clinical management of sepsis may have secondary benefits with respect to renal outcomes. Existing and hybrid extracorporeal therapies are being investigated not only as means to replace lost kidney function but also to modulate the immune response to sepsis. For those who have more advanced forms of kidney injury, strategies to promote renal recovery are being sought to minimize the long-term consequences of impaired kidney function. This review provides an update on the current state of the science and a glimpse toward the future of intervention in sepsis-related acute kidney injury.

Severe Sepsis and Septic Shock

This chapter reviews the remarkable recent advances in the understanding of the molecular basis that underlies the pathophysiology of sepsis. This knowledge has improved diagnostic techniques and introduced new therapeutic agents into the standard management of patients with severe sepsis/septic shock. The current treatment regimens for sepsis are discussed, and the evidence to support each major treatment strategy is outlined in detail. Research priorities to further the optimal management of septic shock in the future are highlighted.

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.

Hemodynamic optimization of sepsis-induced tissue hypoperfusion

Sepsis is associated with cardiovascular changes that may lead to development of tissue hypoperfusion. Early recognition of sepsis and tissue hypoperfusion is critical to implement appropriate hemodynamic support and prevent irreversible organ damage. End points for resuscitation need to be defined and invasive hemodynamic monitoring is usually required. Targets for hemodynamic optimization should include intravascular volume, blood pressure, and cardiac output. Therapeutic interventions aimed at optimizing hemodynamics in patients with sepsis include aggressive fluid resuscitation, the use of vasopressor agents, inotropic agents and in selected cases transfusions of blood products. This review will cover the most important aspects of hemodynamic optimization for treatment of sepsis induced tissue-hypoperfusion.

The kidney in the critically ill

Acute kidney injury (AKI) is a common and serious complication in the intensive care setting. It seldom occurs in isolation, but is mostly part of a multiple organ dysfunction syndrome. The pathogenesis is frequently multifactorial, with sepsis contributing to 50% of the cases.The development of AKI in critically-ill patients is "bad news": patients with AKI have a high morbidity and mortality. In addition, AKI, even in its mildest from, is not only a marker of illness severity but appears to be independently associated with mortality. Prevention of AKI is therefore a major goal to improve outcome of critically-ill patients. Treatment of established AKI is largely supportive. The optimal modality for renal replacement therapy in critically-ill patients still remains a matter of debate). The majority of survivors recover renal function.

Low-dose dopamine in the intensive care unit

For much of the last four decades, low-dose dopamine has been considered the drug of choice to treat and prevent renal failure in the intensive care unit (ICU). The multifactorial etiology of renal failure in the ICU and the presence of coexisting multisystem organ dysfunction make the design and execution of clinical trials to study this problem difficult. However, in the last decade, several meta-analyses and one large randomized trial have all shown a lack of benefit of low-dose dopamine in improving renal function. There are multiple reasons for this lack of efficacy. While dopamine does cause a diuretic effect, it does very little to improve mortality, creatinine clearance, or the incidence of dialysis. Evidence is also growing of its adverse effects on the immune, endocrine, and respiratory systems. It may also potentially increase mortality in sepsis. It is the opinion of the authors that the practice of using low-dose dopamine should be abandoned. Other drugs and treatment modalities need to be explored to address the serious issue of renal failure in the ICU.

Cardiovascular pharmacotherapy update for the intensive care unit

Pharmacologic agents including vasodilators, inotropes, and vasopressors are frequently used in the critical care setting for management of the unstable cardiac patient. These medications are used to elicit varying effects on vascular resistance, myocardial contractility, and heart rate to help achieve desired hemodynamic and clinical endpoints. Therefore, it is important for the critical care nurse to have a practical understanding and working knowledge of cardiovascular pharmacotherapy in the intensive care unit setting. This article reviews the pharmacology and clinical utility of commonly used intravenous "vasoactive" medications encountered in the intensive care unit. We also highlight innovations in pharmacotherapy for this patient population, and provide practical considerations for the most appropriate and safe use of these medications.

Prevention of Acute Renal Failure

Acute renal failure (ARF) comprises a family of syndromes that is characterized by an abrupt and sustained decrease in the glomerular filtration rate. In the ICU, ARF is most often due to sepsis and other systemic inflammatory states. ARF is common among the critically ill and injured and significantly adds to morbidity and mortality of these patients. Despite many advances in medical technology, the mortality and morbidity of ARF in the ICU continue to remain high and have not improved significantly over the past 2 decades. Primary strategies to prevent ARF still include adequate hydration, maintenance of mean arterial pressure, and minimizing nephrotoxin exposure. Diuretics and dopamine have been shown to be ineffective in the prevention of ARF or improving outcomes once ARF occurs. Increasing insight into mechanisms leading to ARF and the importance of facilitating renal recovery has prompted investigators to evaluate the role of newer therapeutic agents in the prevention of ARF.

Beneficial Impact of Fenoldopam in Critically Ill Patients With or at Risk for Acute Renal Failure: A Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Acute kidney injury is common in critically ill patients. Fenoldopam mesylate is a potent dopamine A-1 receptor agonist that increases blood flow to the renal cortex and outer medulla. Because there is uncertainty about the benefits of fenoldopam in such a setting, we performed a systematic review of randomized controlled trials of intensive care unit patients or those undergoing major surgery.

METHODS

BioMedCentral, CENTRAL, PubMed, and conference proceedings were searched (updated October 2005). Investigators and external experts were contacted. Two unblinded reviewers selected randomized controlled trials that used fenoldopam in the prevention or treatment of acute kidney injury in postoperative or intensive care patients. Studies involving the prevention of contrast nephropathy or containing duplicate data were excluded from analysis. Two reviewers independently abstracted patient data, treatment characteristics, and outcomes.

RESULTS

A total of 1,290 patients from 16 randomized studies were included in the analysis. Pooled estimates showed that fenoldopam consistently and significantly reduced the risk for acute kidney injury (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.32 to 0.59; P < 0.001), need for renal replacement therapy (OR, 0.54; 95% CI, 0.34 to 0.84; P = 0.007), and in-hospital death (OR, 0.64; 95% CI, 0.45 to 0.91; P = 0.01). These benefits were associated with shorter intensive care unit stay (weighted mean difference, -0.61 days; 95% CI, -0.99 to -0.23; P = 0.002). Sensitivity analyses, tests for small-study bias, and heterogeneity assessment further confirmed the main analysis.

CONCLUSION

This analysis suggests that fenoldopam reduces the need for renal replacement and mortality in patients with acute kidney injury. A large, multicenter, appropriately powered trial will need to be performed to confirm these results.

Perioperative fluid management in renal transplantation: a narrative review of the literature

Adequate volume maintenance is essential to prevent acute renal failure during major surgery or to ensure graft function after renal transplantation. The various recommendations on the optimum fluid therapy are based, at best, on sparse evidence only from observational studies. This article reviews the literature on perioperative fluid management in renal transplantation. Crystalloid solutions not exerting any specific side-effects are the first choice for volume replacement in kidney transplantation. The use of colloids should be restricted to patients with severe intravascular volume deficits necessitating high volume restoration. The routine application of albumin, dopamine, and high dose diuretics is no longer warranted. Mannitol given immediately before removal of the vessel clamps reduces the requirement of post-transplant dialysis, but has no effects on graft function in the long term. There is insufficient evidence on the best use of dialysis, but it seems peritoneal dialysis pretransplant is associated with less delayed graft function, whereas the preference of dialysis post-transplant is not yet well-founded. This review article should provide better guidance for fluid management in kidney transplantation until best-evidence guidelines can be established based upon more research.

Lost in publication: Half of all renal practice evidence is published in non-renal journals

Physicians often scan a select number of journals to keep up to date with practice evidence for patients with kidney conditions. This raises the question of where relevant studies are published. We performed a bibliometric analysis using 195 renal systematic reviews. Each review used a comprehensive method to identify all primary studies for a focused clinical question relevant to patient care. We compiled all the primary studies included in these reviews, and considered where each study was published. Of the 2779 studies, 1351 (49%) were published in the top 20 journals. Predictably, this list included Transplantation Proceedings (5.9% of studies), Kidney International (5.3%), American Journal of Kidney Diseases (4.7%), Nephrology Dialysis Transplantation (4.3%), Transplantation (4.2%), and Journal of the American Society of Nephrology (2.4%). Ten non-renal journals were also on this list, including New England Journal of Medicine (2.4%), Lancet (2.3%), and Diabetes Care (2.2%). The remaining 1428 (51%) studies were published across other 446 journals. When the disciplines of all journals were considered, 59 were classified as renal or transplant journals (42% of articles). Other specialties included general and internal medicine (16%), endocrinology (diabetes) and metabolism (6.5%), surgery (6.2%), cardiovascular diseases (6.1%), pediatrics (4.3%), and radiology (3.3%). About half of all renal practice evidence is published in non-renal journals. Browsing the top journals is important. However, relevant studies are also scattered across a large range of journals that may not be routinely scanned by busy physicians, and keeping up with this literature requires other continuing education strategies.

[Diagnosis and therapy of sepsis. Guidelines of the German Sepsis Society Inc. and the German Interdisciplinary Society for Intensive and Emergency Medicine]

A recent survey conducted by the publicly funded Competence Network Sepsis (SepNet) reveals that severe sepsis and/or septic shock occurs in 75,000 inhabitants (110 out of 100,000) and sepsis in 79,000 inhabitants (116 out of 100,000) in Germany annually. This illness is responsible for approximately 60,000 deaths and ranges as the third most frequent cause of death after acute myocardial infarction. Direct costs for the intensive care of patients with severe sepsis alone amount to approximately 1.77 billion euros, which means that about 30% of the budget in intensive care is used to treat severe sepsis. However, until now German guidelines for the diagnosis and therapy of severe sepsis did not exist. Therefore, the German Sepsis Society initiated the development of guidelines which are based on international recommendations by the International Sepsis Forum (ISF) and the Surviving Sepsis Campaign (SSC) and take into account the structure and organization of the German health care system. Priority was given to the following guideline topics: a) diagnosis, b) prevention, c) causative therapy, d) supportive therapy, e) adjunctive therapy. The guidelines development process was carefully planned and strictly adhered to the requirements of the Working Group of Scientific Medical Societies (AWMF).

Management of sepsis during the early "golden hours"

Severe sepsis and septic shock are common causes of morbidity and mortality. Interventions directed at specific endpoints, when initiated early in the "golden hours" of patient arrival at the hospital, seem to be promising. Early hemodynamic optimization, administration of appropriate antimicrobial therapy, and effective source control of infection are the cornerstones of successful management. In patients with vasopressor-dependent septic shock, provision of physiologic doses of replacement steroids may result in improved survival. Administration of drotrecogin alfa (activated), (activated protein C) has been shown to improve survival in patients with severe sepsis and septic shock who have a high risk of mortality. In this article we review the multi-modality approach to early diagnosis and intervention in the therapy of patients with severe sepsis and septic shock.

Low-dose dopamine: a physiologically based review

BACKGROUND

In an attempt to prevent or alter the course of acute renal failure, many surgeons continue to use low-dose dopamine. This article critically reviews the physiologic reasons why low-dose dopamine is not clinically efficacious.

METHODS

A critical review of English language literature.

RESULTS

The effect of dopamine on renal blood flow remains controversial. If dopamine does increase renal blood flow, the vascular anatomy of the kidney would limit its effectiveness. Rather than improving renal function, dopamine has been shown to impair renal oxygen kinetics, inhibit feedback systems that protect the kidney from ischemia, and may worsen tubular injury. Dopamine has not been proven useful in the prevention or alteration of the course of acute renal failure as a result of heart failure, cardiac surgery, abdominal aortic surgery, sepsis, and transplantation. Dopamine has been associated with multiple complications involving the cardiovascular, pulmonary, gastrointestinal, endocrine, and immune systems.

CONCLUSIONS

Based on the anatomy and physiology of the kidney, low-dose dopamine would not be expected to improve renal failure and this has been demonstrated by the lack of efficacy in clinical trials.

[Diagnosis and therapy of sepsis]

A recent survey conducted by the publicly funded Competence Network Sepsis (Sep- Net) reveals that severe sepsis and/or septic shock occurs in 75,000 inhabitants (110 out of 100,000) and sepsis in 79,000 inhabitants (116 out of 100,000) in Germany annually. This illness is responsible for approx. 60,000 deaths and ranges as the third most frequent cause of death after acute myocardial infarction. Direct costs for the intensive care of patients with severe sepsis alone amount to approx. 1.77 billion euros, which means that about 30% of the budget in intensive care is used to treat severe sepsis. However, until now German guidelines for the diagnosis and therapy of severe sepsis did not exist. Therefore, the German Sepsis Society initiated the development of guidelines which are based on international recommendations by the International Sepsis Forum (ISF) and the Surviving Sepsis Campaign (SSC) and take into account the structure and organisation of the German health care system. Priority was given to the following guideline topics: a) diagnosis, b) prevention, c) causative therapy, d) supportive therapy, e) adjunctive therapy. The guidelines development process was carefully planned and strictly adhered to according to the requirements of the Working Group of Scientific Medical Societies (AWMF).

Effect of pre-treatment with catecholamines on cold preservation and ischemia/reperfusion-injury in rats

Treatment of organ donors with catecholamines reduces acute rejection episodes and improves long-term graft survival after renal transplantation. The aim of this study was to investigate the effect of catecholamine pre-treatment on ischemia/reperfusion (I/R)- and cold preservation injury in rat kidneys. I/R-injury was induced by clamping the left kidney vessels for 60 min along with a contralateral nephrectomy. Cold preservation injury was induced by storage of the kidneys for 24 h at +4 degrees Celsius in University of Wisconsin solution, followed by syngeneic transplantation. Rats were pre-treated with either dopamine (DA), dobutamine (DB), or norepinephrine (2, 5, and 10 microg/kg/min, each group) intravenously via an osmotic minipump for 24 h before I/R- and cold preservation injury. Pre-treatment with DA (2 or 5 microg/kg/min) and DB (5 microg/kg/min) improved recovery of renal function after I/R-injury and dose dependently reduced mononuclear and major histocompatibility complex class II-positive cells infiltrating the kidney after I/R-injury. One day after I/R-injury, upregulation of transforming growth factor (TGF)-beta 1 and 2 and phosphorylation of p42/p44 mitogen-activated protein kinases was observed in kidneys of animals treated with DA or DB. DA (5 microg/kg/min) and DB (5 microg/kg/min) pre-treatment reduced endothelial cell damage after 24 h of cold preservation. Only DA pre-treatment improved renal function and reduced renal inflammation after 24 h of cold preservation and syngeneic transplantation. Our results demonstrate a protective effect of pre-treatment with catecholamines on renal inflammation and function after I/R- or cold preservation injury. This could help to explain the potent organoprotective effects of catecholamine pre-treatment observed in human kidney transplantation.

Acute renal failure in the critically ill

PURPOSE OF REVIEW

Acute renal failure occurs frequently in hospitalized patients and is associated with significant morbidity and mortality. An effort to better understand the epidemiology and pathophysiology of this disease will hopefully lead to improvement in patient outcomes. Considerable effort has been expended to develop techniques to prevent acute renal failure or to facilitate its resolution. In this review we attempt to summarize some of these recent advances.

RECENT FINDINGS

Attempts have been made to clearly define acute renal failure. Among the available pharmacologic agents, current evidence suggests that with the possible exception of radio-contrast-induced acute renal failure, no drugs are capable of preventing the condition or hastening its recovery. Advances in techniques and understanding of how to best provide renal replacement therapy appear to have improved patient outcomes and several newer treatments are under preclinical evaluation and may hold promise for the future.

SUMMARY

Preventing acute renal failure, improving clinical outcomes of the condition and attempts to hasten renal recovery have all been very attractive but difficult propositions. Recent efforts to explore the underlying pathophysiology and insight into mechanisms leading to acute renal failure have triggered investigators to evaluate novel therapeutic agents and enhance existing dialytic techniques. These hold great promise for improving patient outcomes in the near future.

Primary prevention of acute renal failure in the critically ill

PURPOSE OF REVIEW

Acute renal failure is both common and highly lethal in the intensive care unit, with hospital mortality rates in excess of 50%. To date, no therapy apart from renal replacement therapy has been shown to improve survival or enhance recover. Thus, efforts to prevent acute renal failure are eagerly sought.

RECENT FINDINGS

Fluids and avoiding hypotension and nephrotoxins appear to be the most effective strategies to prevent acute renal failure. N-acetylcysteine has been shown to prevent the increase in serum creatinine in high risk patients given intravenous radiocontrast agents, although there is some evidence that N-acetylcysteine may reduce serum creatinine without increasing glomerular filtration.

SUMMARY

The best evidence suggests that nonpharmacologic strategies are more effective than drugs in reducing the risk of acute renal failure. Evidence also exists that strategies that improve survival in critically ill patients also reduce the incidence of organ failure, including acute renal failure.

Effectiveness of nesiritide on dialysis or all-cause mortality in patients undergoing cardiothoracic surgery

BACKGROUND

Natriuretic peptides have been shown to have favorable renal effects. However, recent evidence suggests potential renal side effects in patients with congestive heart failure.

HYPOTHESIS

This study examined the effect of nesiritide (human B-type natriuretic peptide) on hemodialysis or death in patients undergoing cardiothoracic surgery.

METHODS

This retrospective cohort study included patients (n = 940) undergoing nontransplant adult cardiothoracic surgery between July 2001 and February 2004. Patients receiving nesiritide within 3 days after and not before surgery (n = 151) were compared with those not given nesiritide (n = 789) for incidence of hemodialysis or in-hospital death by Day 21 (HD/death). Patients with preexisting dialysis and intraoperative deaths were excluded. Forward inclusion multiple logistic regression was used based on published risk factors for HD/death.

RESULTS

Of 940 patients (318 coronary artery bypass graft, 348 valve, and 274 thoracic aorta), 36 required dialysis and 60 patients died (HD/death; n = 77). Adjusted for significant confounders (gender, age, procedure, intra-aortic balloon, baseline serum creatinine mg/dl [SCr], 1 day % SCr increase), nesiritide showed a statistically nonsignificant HD/death reduction (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.29-1.17; p = 0.129) in the group as a whole. When stratified by baseline SCr, a significant benefit was noted in patients with SCr > 1.0 (OR, 0.35; 95% CI 0.14-0.87; p = 0.024), while no significant effect was found in patients with SCr < 1.0 (OR, 1.55; 95% CI 0.48-5.07, p = 0.465).

CONCLUSIONS

Nesiritide appears promising in reducing the risk of dialysis or death in patients with SCr > 1.0 undergoing cardiothoracic surgery; however, no effect was noted with SCr < 1.0. This study provides strong rationale for a randomized trial.

A comparison between fenoldopam and low-dose dopamine in early renal dysfunction of critically ill patients*

OBJECTIVE

Fenoldopam mesylate is a selective dopamine-1 agonist, with no effect on dopamine-2 and alpha1 receptors, producing a selective renal vasodilation. This may favor the kidney oxygen supply/demand ratio and prevent acute renal failure. The aim of the study was to investigate if fenoldopam can provide greater benefit than low-dose dopamine in early renal dysfunction of critically ill patients.

DESIGN

Prospective, multiple-center, randomized, controlled trial.

SETTING

University and city hospital intensive care units.

PATIENTS

One hundred adult critically ill patients with early renal dysfunction (intensive care unit stay<1 wk, hemodynamic stability, and urine output<or=0.5 mL/kg over a 6-hr period and/or serum creatinine concentration>or=1.5 mg/dL and<or= 3.5 mg/dL).

INTERVENTIONS

Patients were randomized to receive 2 microg/kg/min dopamine (group D) or 0.1 microg/kg/min fenoldopam mesylate (group F). Drugs were administered as continuous infusion over a 4-day period.

MEASUREMENTS AND MAIN RESULTS

Systemic hemodynamic and renal function variables were recorded daily. The two groups were well matched at enrollment for illness severity and hemodynamic and renal dysfunction. No differences in heart rate or systolic, diastolic, or mean arterial pressure were observed between groups. Fenoldopam produced a more significant reduction in creatinine values compared with dopamine after 2, 3, and 4 days of infusion (change from baseline at time 2, -0.32 vs. -0.03 mg/dL, p=.047; at time 3, -0.45 vs. -0.09 mg/dL, p=.047; and at time 4, -.041 vs. -0.09 mg/dL, p=.02, in groups F and D, respectively). The maximum decrease in creatinine compared with baseline was significantly greater in group F than group D (-0.53+/-0.47 vs. -0.34+/-0.38 mg/dL, p=.027). Moreover, 66% of patients in group F had a creatinine decrease>10% of the baseline value at the end of infusion, compared with only 46% in dopamine group (chi-square=4.06, p=.04). Total urinary output during drug infusion was not significantly different between groups. After 1 day, urinary output was lower in group F compared with group D (p<.05).

CONCLUSIONS

In critically ill patients, a continuous infusion of fenoldopam at 0.1 microg/kg/min does not cause any clinically significant hemodynamic impairment and improves renal function compared with renal dose dopamine. In the setting of acute early renal dysfunction, before severe renal failure has occurred, the attempt to reverse renal hypoperfusion with fenoldopam is more effective than with low-dose dopamine.