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Neesh Pannu

Publications and source records attributed to Neesh Pannu.

12 recordsLinked to original sources
PubMed2006

Prophylaxis strategies for contrast-induced nephropathy.

CONTEXT: Contrast-induced nephropathy is associated with significant economic and clinical consequences, including prolonged hospitalization, the requirement for dialysis, and an increased risk of death. OBJECTIVES: To summarize the current state of evidence for prophylaxis of contrast-induced nephropathy, provide evidence-based recommendations regarding management of high-risk patients undergoing angiographic procedures, and identify new avenues for research. DATA SOURCES: Systematic searches of peer-reviewed publications were performed in MEDLINE, EMBASE, and the Cochrane database from 1966 to January 2006. Search terms included radio contrast nephropathy, contrast media, acetylcysteine, theophylline, sodium bicarbonate, HMG Co-A reductase inhibitors, ascorbic acid, kidney diseases, renal insufficiency, kidney failure, nephropathy, fenoldopam, diuretics, and saline or half saline. STUDY SELECTION: Observational studies of risk factors and randomized controlled trials of prophylaxis strategies for contrast-induced nephropathy that specified a definition of contrast-induced nephropathy or postprocedure creatinine level as an outcome measure. Evidence Synthesis Important patient-related risk factors for contrast-induced nephropathy include chronic kidney disease, diabetes mellitus, heart failure, older age, anemia, and left ventricular systolic dysfunction. Non-patient-related risk factors include high-osmolar contrast, ionic contrast, contrast viscosity, and contrast volume. Practice guidelines recommend obtaining preprocedural serum creatinine levels among patients with renal disease, diabetes, proteinuria, hypertension, gout, or congestive heart failure. Available evidence, largely based on small- to medium-sized trials, supports the use of hydration, bicarbonate, and low volumes of iso- or low-osmolar contrast in patients at risk. N-acetylcysteine or ascorbic acid may be of value in very high-risk patients. CONCLUSIONS: While several risk factors for contrast-induced nephropathy have been identified, the development of an effective prophylaxis strategy for contrast-induced nephropathy has been limited by our poor understanding of the pathophysiology and the clinical significance of this condition. Future research should focus on correctly identifying higher-risk patients and testing therapies in the setting of large well-powered clinical trials.

Contrast Media↗
PubMed2006

Cost-effectiveness of hemofiltration to prevent contrast nephropathy in patients with chronic kidney disease.

OBJECTIVE: Prophylactic hemofiltration has been reported, in one study, to reduce renal complications and death but necessitates additional up-front health care resource deployment in a critical care setting. We sought to explore the potential scope and cost-effectiveness of this strategy. DESIGN: Economic evaluation using decision analysis. SETTING: Tertiary or quaternary care hospital. PATIENTS: Subjects undergoing angiography at risk for developing contrast nephropathy. INTERVENTION: Prophylactic hemofiltration was compared with intravenous saline. Secondary models incorporated sodium bicarbonate and N-acetylcysteine as comparators. MEASUREMENT AND MAIN RESULTS: The cost per quality-adjusted life year (QALY) gained with hemofiltration compared with intravenous saline in high-risk subjects (mean serum creatinine, 265 micromol/L) was 3,900 US dollars. This finding was sensitive to variations in several important variables. For instance, the cost-effectiveness ratio became less attractive (i.e., >50,000 US dollars/QALY) when hemofiltration was used in lower-risk subjects (serum creatinine, <265 micromol/L). The cost-effectiveness remained <50,000 US dollars/QALY provided that the relative risk of hemofiltration compared with saline alone was below 0.65 (reported relative risk, 0.10). Although based on indirect comparison of clinical efficacy, when N-acetylcysteine or sodium bicarbonate was used as the comparator, the cost per QALY gained for hemofiltration became markedly less attractive (50,100 US dollars and >1,000,000 US dollars), although the relative effectiveness of these three strategies strongly influenced the results. CONCLUSIONS: Use of prophylactic hemofiltration in patients at high risk for contrast nephropathy may be potentially cost-effective only if certain conditions are satisfied, and its attractiveness is materially diminished when compared to other strategies. As this invasive therapy would entail certain immediate resource outlay, before considering its implementation it is crucial to confirm the clinical effectiveness and health care resource consequences of hemofiltration relative to current standards of care in future studies.

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PubMed2006

Strategies to reduce the risk of contrast nephropathy: an evidence-based approach.

PURPOSE OF REVIEW: Contrast nephropathy is a common complication associated with angiographic procedures that carries significant morbidity and mortality. Recent clinical trials of prophylactic strategies have reported contradictory results. This review presents recent insights into the pathophysiology of contrast nephropathy and reviews trial results in this context. RECENT FINDINGS: A prediction rule has been developed to better identify patients at risk of developing contrast nephropathy. Factors other than osmolality play a significant role in the pathogenesis of contrast nephropathy, at least for agents with osmolalities of 800 mOsm/kg or less. New randomized trial data do not support a role for N-acetylcysteine in contrast nephropathy prophylaxis and there is additional evidence that fenoldopam is ineffective. Pooled analyses of theophylline prophylaxis trials are inconclusive. Theoretical and clinical data suggest that ascorbic acid may be renoprotective, but this requires further study. SUMMARY: The overall incidence of contrast nephropathy remains low. Available evidence supports the use of hydration and low volumes of iso-osmolar or low-osmolar contrast in patients at risk of developing contrast nephropathy. Heterogeneity has affected interpretability of interventional trials of N-acetylcysteine or theophylline prophylaxis strategies. Future clinical trials must identify and target moderate-risk to high-risk patients and ensure that proven therapies are included in trial protocols.

Acetylcysteine↗
PubMed2005

Access flow in arteriovenous accesses by optodilutional and ultrasound dilution methods.

BACKGROUND: Most large studies evaluating the diagnostic properties of access blood flow (Qa) in arteriovenous (AV) accesses have used the Transonic HD01 (Transonic Systems Inc, Ithaca, NY) device, and recommended thresholds for angiography are based on data from these studies. There has been little exploration of how the use of other devices might affect the feasibility or performance of screening in AV accesses. METHODS: We compared 2 devices for measuring Qa: the Transonic HD01 and the Crit-Line TQA III (Hemametrics, Salt Lake City, UT). We studied 124 adults with end-stage renal disease and a functioning AV access (fistula or graft). Qa was measured with both devices in immediate succession during a single dialysis treatment. The primary outcome was the technical feasibility of the Qa measurement. We also compared mean Qa values measured by the Crit-Line III and Transonic devices. RESULTS: Qa measurements were less likely to be technically feasible when the Crit-Line III device was used compared with the Transonic device (86.3% versus 100%; P < 0.001). In patients with valid measurements, mean Qa measured using the Crit-Line III was significantly less than that measured using the Transonic HD01 device (886 +/- 557 versus 1,148 +/- 685 mL/min; P < 0.001). The mean difference was 261 mL/min (95% confidence interval [CI], 117 to 405) and was greater at higher levels of Qa. On average, Qa measured by means of the Crit-Line III device was 73% as high as that measured using the Transonic device (95% CI, 63 to 84). There was poor agreement between devices about whether criteria for angiography were met (kappa < 0.1). The proportion of patients for whom angiography was indicated (based on results from the Crit-Line device) was significantly greater than when only results from the Transonic device were considered (40.3% versus 7.3%; P < 0.001). CONCLUSION: Consideration should be given to device-specific Qa thresholds for angiography or, alternatively, standardization of Qa results between manufacturers. Clinicians should be aware that Qa results cannot be compared directly between different devices, and access monitoring should be performed using a single technique in any given patient. Additional studies are required before the Crit-Line TQA device can be recommended for widespread use.

Absorptiometry, Photon↗
PubMed2004

Effect of mechanical ventilation on the kidney.

Mechanical ventilation is a standard component of intensive care unit management of critically ill patients and is widely used for respiratory support. Recent animal and clinical studies have shown that positive pressure ventilation can worsen pre-existing lung injury and produce ventilator-induced lung injury, which has been linked with the development of systemic inflammation and multi-system organ dysfunction, including renal failure. Although the physiological consequences of mechanical ventilation on pulmonary and cardiovascular function have been extensively studied, its effects on renal function are not as well defined. Previous experimental studies and few clinical reports have shown a significant effect of mechanical ventilation on renal function. Interestingly, recent data are emerging which suggest that renal dysfunction also has a direct, adverse effect on pulmonary function. This chapter reviews the information in these areas and provides a framework for future investigation in this field.

Animals↗
PubMed2004

Systematic review of the impact of N-acetylcysteine on contrast nephropathy.

BACKGROUND: The efficacy of N-acetylcysteine (NAC) for preventing contrast nephropathy is uncertain. We performed a systematic review and meta-analysis to assess the efficacy of NAC for preventing contrast nephropathy after administration of intravenous contrast media. METHODS: Data were obtained from searching MEDLINE (1969-2003) and EMBASE (1988-2003), Cochrane Controlled Clinical Trial Registry (2002, Volume 3), and conference proceedings. We considered all randomized studies that compared changes in renal function between groups that received and did not receive NAC. Studies in which the control group also received active therapy were excluded, although co-intervention directed at both groups was permitted. Two reviewers independently extracted quantitative and qualitative data. Disagreements were resolved by consensus with the aid of a third party. RESULTS: Fifteen studies with a total of 1776 patients satisfied inclusion and exclusion criteria. Contrast nephropathy was typically defined by an increase in serum creatinine of 0.5 mg/dL within 24 to 48 hours of contrast administration. The pooled random effect relative risk was 0.65 (0.43-1.00, P= 0.049), indicating that NAC significantly reduced the incidence of contrast nephropathy. However, the effect of NAC was not statistically significant in several prespecified subgroup analyses, and the results were not robust to the addition of hypothetical new or unidentified randomized trials. There was evidence of significant heterogeneity in NAC effect across studies (Q = 26.3, P= 0.02). Random effects meta-regression did not implicate identified differences in participant or study characteristics as responsible for the observed heterogeneity. CONCLUSION: NAC may reduce the incidence of acutely increased serum creatinine after administration of intravenous contrast, but this finding was of borderline statistical significance, and there was significant heterogeneity between trials. Before NAC becomes the standard of care for all patients receiving intravenous contrast, new randomized trials evaluating its effect on clinically relevant outcomes are required.

Acetylcysteine↗
PubMed2002

Mechanical ventilation and renal function: an area for concern?

Mechanical ventilation is a standard component of intensive care unit management of critically ill patients and widely used for respiratory support. Patients requiring ventilation often have renal dysfunction that can occur as a consequence of the underlying disease or be related to the therapy. Although the physiological consequences of mechanical ventilation on pulmonary and cardiovascular function have been extensively studied, its effects on renal function are not as well defined. Previous experimental studies and few clinical reports have shown a significant effect of mechanical ventilation on renal function. This review compiles the information in this area and provides a framework for future investigation in this field.

Animals↗
PubMedDate not supplied

Optimizing dialysis delivery in tunneled dialysis catheters.

Long-term dialysis is often delivered through tunneled central venous catheters (CVC) despite their associated morbidity and mortality rates. Because poor solute clearance might contribute to this risk, we examined the relation between blood pump speed (QB), access recirculation (AR), and dialysis delivery in patients with CVC. We conducted a prospective study on 102 patients receiving long-term hemodialysis with CVC. QB was systematically varied, and AR was measured by saline dilution with the blood supply lines in both the straight and the reversed positions during each of two dialysis sessions. During a third session, we measured ionic dialysance (EID) in patients with AR>0% and those in whom dialysis was usually delivered with catheters in the reversed position.Approximately one third (34.3%) of patients were usually run in the reversed position. Clinically significant AR (>10%) was infrequent (3%) in the straight position but common in the reversed position (86%). QB and EID were linearly correlated for both the straight and reversed positions. Approximately half (48.6%) of patients who were generally treated with their lines reversed were able to receive dialysis with the lines in the straight position within acceptable pressure limits when blood lines were switched part way through the run. In these patients, solute clearance was equivalent (EID straight 204 ml/min vs. reversed 196 ml/min, p=0.58) with lines in the straight configuration despite lower achieved QB (straight 354 ml/min vs. reversed 404 ml/min, p=0.04). Maximization of prescribed QB in CVC increased AR when blood line position was reversed but improved small solute clearance regardless of line position. This suggests that QB in CVC should be set as high as circuit pressure limits will allow, regardless of the potential for AR, and that reversal of line position confers no benefit with respect to solute clearance.

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