40 Years of Continuous Renal Replacement Therapy. Группа авторов
Чтение книги онлайн.
Читать онлайн книгу 40 Years of Continuous Renal Replacement Therapy - Группа авторов страница 13
Название: 40 Years of Continuous Renal Replacement Therapy
Автор: Группа авторов
Издательство: Ingram
Жанр: Медицина
Серия: Contributions to Nephrology
isbn: 9783318063073
isbn:
Why Not Start CRRT?
CRRT can be associated with complications. CRRT necessitates central venous dialysis catheter insertion, exposure of blood to an extracorporeal circuit, and often use continuous anticoagulation to maintain circuit patency. CRRT, largely driven by ultrafiltration rate, has the potential to incite hemodynamic instability and contribute to delayed kidney recovery. CRRT also adds workload for bedside personnel, increases resource use, and is costly. As such, in the absence of high-quality data from rigorous clinical trials, there is a compelling argument for adopting a conservative approach for when to start CRRT. A number of clinical trials have not shown earlier that CRRT improves patients-centered outcomes when started in the absence of conventional indications or in response to AKI complications [7, 10, 11]. Accordingly, the theoretical and patient-specific benefit for earlier CRRT must be counterbalanced with the incremental resource implications and potential risk for delayed recovery or other complications related to CRRT (Table 2).
Table 2. Benefits and drawbacks of earlier RRT in the absence of conventional indications among critically ill patients with AKI (adapted from [22])
Current Recommendations from Clinical Practice Guidelines
A number of organizations have published practice guidelines that include statements on the timing of initiation of RRT in ICU settings (Table 3). In 2012, the Kidney Disease Improving Global Outcomes (KDIGO) group made 2 statements regarding the timing of RRT initiation in AKI, both of which were based on expert opinion and not graded by evidence [4]. The first was a straightforward recommendation to initiate RRT “emergently when life-threatening changes in fluid, electrolyte, and acid-base balance exist.” The second statement asked clinicians to consider the “broader clinical context, the presence of conditions that can be modified with RRT, and trends of laboratory tests – rather than single BUN and creatinine thresholds alone – when making the decision to start RRT. Though the latter statement may be viewed as imprecise by suggesting clinicians use relatively subjective indications in their decision-making, this would appear a reasonable portrayal of current clinical practice. In 2013, the National Institute for Health and Care Excellence in the United Kingdom published statements similar to those proposed by KDIGO [12]. The National Institute for Health and Care Excellence guidelines also highlighted the paucity of high-quality evidence to guide clinician decision-making on this issue. The guidelines further emphasized that clinicians need better tools, such as clinical risk prediction scores or novel point-of-care tests as decision-support that may help identify patients with a higher likelihood of having worsening AKI and those who may benefit from the earlier initiation. In 2015, the French Intensive Care Society also published statements for use of RRT in ICU settings [13]. All of these guideline statements acknowledged the limitations in current evidence with each of them declaring that additional high-quality clinical trials are needed to better inform clinical practice.
Table 3. Summary of clinical practice guidelines for starting RRT in critically ill patients with AKI
Can CRRT Improve Outcome?
There is controversy about whether CRRT itself may modify patient outcomes or whether, as a supportive therapy in the setting of high illness severity, it is largely a surrogate for the effect of critical illness on outcome. Observational data have shown that receiving any RRT per se may increase mortality risk among ICU patients with AKI [6, 14, 15]. These studies have compared outcomes among patients with AKI who received or did not receive RRT. While these data have methodological limitations common to observational studies, such as differences in populations studied (i.e., case-mix, illness severity), residual confounding by indication and uncontrolled bias (i.e., provider practice variation, information bias), an honest speculation does arise about whether, in selected circumstances, CRRT may contribute hazard to critically ill patients with AKI if not carefully selected or if perceived to have only marginal benefit [16]. Patient, provider, and institutional-level factors may interact to confound the observed association between RRT and outcome; however, these factors are often not accounted for in observational data. Similarly, many of these studies may have included patients in whom CRRT was never likely to improve outcome. For example, high utilization of CRRT for patients with very low survival probability (i.e., advanced chronic illness or severe acute illness) can represent an important source of bias, as these patients will shift effect estimates of risk of CRRT toward poor outcome [17]. Alternatively, inclusion of patients with less severe AKI and marginal indications for CRRT, where the likelihood of survival and kidney recovery was high regardless of CRRT, will also confound effect estimates of the hazards of CRRT [18]. In this circumstance, it is conceivable that the risk and/or harm associated with RRT per se could potentially outweigh benefit. Interestingly, additional observational data among critically ill patients with conventional indications for CRRT have shown starting RRT may improve survival [19, 20].
Recent Trials Examining RRT Initiation Strategies in AKI
Two high-profile trials of strategies for starting RRT in critically ill patients with severe AKI were reported. The Early Versus Late Initiation of RRT In Critically Ill Patients with Acute Kidney Injury (ELAIN) trial was a single-center randomized trial including 231 critically ill patients that evaluated whether early RRT, defined as starting RRT within 8 h of fulfilling KDIGO stage 2 AKI, would improve patient survival as compared to delayed RRT, defined as starting RRT within 12 h of developing KDIGO stage 3 AKI or upon an absolute indication ensuing (Table 4) [21]. All patients in the early group and 91% in the delayed group received RRT, with a median difference in time to initiate being 21 h (interquartile range 18–24). The early RRT intervention conferred a 15.4% absolute reduction in 90-day mortality compared with delayed RRT. Early RRT was found to have greater RRT independence, shorter duration of RRT, and reduced duration of hospitalization. Early RRT also showed an early reduction СКАЧАТЬ