Ramesh Venkataraman

Apollo Hospitals, Chennai, Tamil Nādu, India

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Publications (43)161.71 Total impact

  • Critical Care 03/2013; 17(2). · 4.93 Impact Factor
  • Ramesh Venkataraman, John A Kellum
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    ABSTRACT: Sepsis and septic shock are syndromes that overlap between several disciplines and subspecialties. Emerging evidence suggests that sepsis may be associated with short- and long-term adverse outcomes, even when the syndrome does not appear to be severe and is not managed in the intensive care unit. Hence, all practicing clinicians need to be familiar with the fundamental principles of diagnosis and management of sepsis. In this review, we have summarized the key components in the management of sepsis/septic shock, including early recognition, early resuscitation, principles of antibiotic therapy, organ support, and role of adjunctive therapies.
    Advances in chronic kidney disease 01/2013; 20(1):6-13. · 2.42 Impact Factor
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    ABSTRACT: On-pump coronary artery bypass graft (CABG) surgery has been traditionally associated with a higher magnitude of inflammatory response than off-pump CABG. However with the development of polymer-coated biocompatible extracorporeal circuits, we wanted to see if cardiopulmonary bypass still played an important role in triggering this inflammatory response. In this prospective observational study, 33 patients undergoing CABG surgeries (25 on-pump and 8 off-pump patients) were studied. Serial plasma cytokine (TNF IL-6, IL-10) and procalcitonin concentrations were measured at different time-points during and after the surgery. Demographic and baseline clinical data, intra-operative management details and post-operative complications were also collected from the patients' charts. Plasma levels of all 4 mediators increased during surgery and returned towards normal postoperatively. There were no differences between groups for any mediator at any time-point. We conclude that with the use of recent polymer-coated biocompatible extracorporeal circuits, the inflammatory response triggered by on-pump CABG becomes very similar in magnitude and pattern to that triggered by off-pump CABG. Thus, the surgical procedure contributes to most of the inflammatory response, with the extra-corporeal circuit having minimal to no effect on this response.
    The International journal of artificial organs 04/2010; 33(3):131-8. · 1.76 Impact Factor
  • Transplantation 01/2010; 90. · 3.78 Impact Factor
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    ABSTRACT: Brain death induces dramatic changes in hemodynamics. Ischemic injury and inflammation resulting from inadequate resuscitation might influence organ yield for transplantation. Using functional hemodynamic monitoring in brain-dead organ donors, we test the hypothesis that donor preload (fluid) responsiveness is associated with increased inflammatory response and lower organ yield for transplantation. Prospective, observational, pilot study. A large intensive care unit of a university hospital in the United States. Twenty-one brain-dead organ donors between July 2006 and April 2007. None. Following declaration of brain death, we collected data on donor demographics, mechanism of brain death, and number of organs procured and transplanted. Functional hemodynamics were monitored using pulse contour analysis technique. Plasma tumor necrosis factor, interleukin-6, and interleukin-10 concentrations were measured at study enrollment, after 4 hrs, and immediately before organ procurement for transplantation. Preload responsiveness (pulse pressure variation >13%) was observed in 48% of donors (mean +/- sd pulse pressure variation, 19.2% +/- 4.8%). Plasma interleukin-6 and tumor necrosis factor concentrations at study enrollment were greater in preload responsive donors: mean concentrations of interleukin-6 in preload responsive vs. unresponsive donors were 5420 +/- 9102 vs. 378 +/- 631 pg/mL (p = .009), and mean concentrations of tumor necrosis factor were 60.5 +/- 103.6 vs. 15.7 +/- 10.1 pg/mL (p = .048). Preload responsive compared with unresponsive donors had significantly increased interleukin-6 (p = .013) and tumor necrosis factor (p = .044) concentrations over time. Fewer organs were transplanted from preload responsive donors: mean organs transplanted from preload responsive vs. unresponsive donors were 1.8 +/- 0.9 vs. 3.7 +/- 2.5 (p = .034). In multivariable regression, older donor age (p = .028) and increased plasma interleukin-6 concentration (p = .035) were significantly associated with lower number of organs transplanted. Preload responsiveness is common in brain-dead organ donors and is associated with higher inflammatory response and lower organ yield. A controlled trial of preload optimization is warranted in brain-dead donors.
    Critical care medicine 07/2009; 37(8):2387-93. · 6.37 Impact Factor
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    ABSTRACT: Brain death induces a massive inflammatory response. However, the influence of this inflammatory response on organ procurement, transplantation, and recipient outcome is unknown. We describe the inflammatory response characteristics in brain-dead organ donors and examine associations with organ transplantation and recipient survival. We test the hypothesis that increased inflammatory response is associated with fewer organs transplanted and decreased recipient survival. Prospective, observational, cohort study. Two large intensive care units of tertiary care university hospitals in the United States. We recruited 30 consecutive brain-dead organ donors and 78 recipients between April 11, 2004, and November 23, 2004; recipients were followed through May 2005. Following declaration of brain death, we collected data on donor demographics, mechanism of brain death, number of organs procured and transplanted, and recipient characteristics. Plasma cytokines (tumor necrosis factor, interleukin-6, interleukin-10) were measured in donors at baseline following study enrollment, every hour for the first 4 hrs, and immediately before organ procurement for transplantation. None. We examined the relationships among clinical characteristics, demographics, and cytokine response in donors and their influence on organ procurement and transplantation using multivariable regression and recipient's 6-month hospital-free survival using a Cox proportional hazards regression. One hundred-eighteen organs were procured from 30 donors, and 91 (77%) were transplanted (mean of three organs transplanted per donor). All cytokines were increased following brain death. Older age in donors was significantly associated with lower number of organs transplanted (p < .001). Higher plasma interleukin-6 concentrations in donors before organ procurement was significantly associated with lower 6-month hospital-free survival in recipients (hazard ratio 1.77; 95% confidence interval, 1.17-2.69, p < .007). Among brain-dead organ donors, older age donors contribute fewer organs for transplantation, and increased donor interleukin-6 level before organ procurement is associated with lower recipient six-month hospital-free survival.
    Critical care medicine 06/2008; 36(6):1810-6. · 6.37 Impact Factor
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    Ramesh Venkataraman
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    ABSTRACT: To review the literature on prevention of acute kidney injury (AKI). MEDLINE- and PubMed-based review of literature published from 1965 to 2007. 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.
    Critical care medicine 05/2008; 36(4 Suppl):S166-71. · 6.37 Impact Factor
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    John A Kellum, Martine Leblanc, Ramesh Venkataraman
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    ABSTRACT: Acute renal failure is characterised by abrupt and sustained decline in glomerular filtration rate, which leads to accumulation of urea and other chemicals in the blood. The term acute kidney injury has been recently introduced to encompass a wide spectrum of acute alterations in kidney function from very mild to severe. Acute renal failure/acute kidney injury is classified according to the RIFLE criteria where a change from baseline serum creatinine or urine output determines the level of renal dysfunction. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent acute renal failure in people at high risk? What are the effects of treatments for critically ill people with acute renal failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 77 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: albumin supplementation plus loop diuretics (intravenous), aminoglycosides, aminophylline, amphotericin B, calcium channel blockers, contrast media, dialysis membranes, dopamine, fenoldopam, loop diuretics, mannitol, N-acetylcysteine, natriuretic peptides, renal replacement therapy, sodium bicarbonate-based fluids, sodium chloride-based fluids, and theophylline.
    Clinical evidence 02/2008; 2008.
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    ABSTRACT: Inflammatory cytokines occur in the circulation and in the tissues after brain death and have been associated with dysfunction of donor organs before and after transplantation. To determine the feasibility of removing cytokines using a hemoadsorption device. Two-center, randomized, open-label, feasibility study in which brain-dead subjects were randomized to two treatment groups. Two U.S. academic hospitals. Eight brain-dead subjects deemed unsuitable for organ donation by respective organ procurement organizations. After obtaining consent from families, subjects were treated with hemoadsorption for 4 hrs using CytoSorb. Effects on cytokines (tumor necrosis factor, interleukin [IL]-6, and IL-10) were assessed both across the device and in the plasma over time. Feasibility for cytokine removal was assessed using objective criteria. Cytokine removal across the CytoSorb device ranged from 4% to 30% and was not significantly different from 1 hr to 4 hrs. Overall removal was greatest for IL-6, 28% (p = .006), and least for tumor necrosis factor, 8.5% (p = .13). Plasma concentrations of both IL-6 and tumor necrosis factor, but not IL-10, were significantly reduced after the first hour of therapy; mean differences were -13% +/- 7% for IL-6 (p = .039), -23% +/- 9% for tumor necrosis factor (p = .02), and -2% +/- 7% of IL-10 (p = 23). However, plasma concentrations for all three cytokines increased over time and were above baseline by the end of the intervention. No adverse effects of therapy were observed. However, removal of cortisol and triiodothyronine was similar to removal of cytokines. Hemoadsorption for removal of cytokines in brain-dead subjects is feasible. Evaluation of possible clinical benefit will require controlled trials in actual donors. However, the significant capacity for cytokine removal and absence of adverse events suggest that such trials are warranted.
    Critical care medicine 02/2008; 36(1):268-72. · 6.37 Impact Factor
  • John Kellum, Martine Leblanc, Ramesh Venkataraman
    American family physician 09/2007; 76(3):418-22. · 1.61 Impact Factor
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    ABSTRACT: Standard coronary artery bypass grafting (CABG) surgery involves cardiopulmonary bypass (CPB) but given concerns over neurological and inflammatory complications related to CPB, many patients receive so-called off-pump procedures (OPCABG). Our objective is to determine if the recent improvements in the biocompatibility of CPB circuitry have improved post-operative outcomes at the community hospital level, particularly in terms of hospital length of stay (LOS), stroke and post-operative infection. We analyzed hospital LOS, incidence of stroke, infection, and mortality along with several clinical variables in 209 patients (38% underwent OPCABG) at a single, non academic community hospital. We constructed a series of forward, stepwise, multiple-variable regression models using mediastinal infection, hospital LOS, and stroke as dependant variables. OPCABG was associated with a shorter median hospital LOS (3 days vs. 4 days; p=0.0001) and a reduced occurrence of stroke (0% vs. 7.6%; p=0.03). However, mediastinal infections occurred more commonly in OPCABG cases (10% vs. 2.2%; p=0.02). CABG and pre-existing renal disease were predictors of increased hospital LOS (p< 0.0001) whereas CABG was the only factor associated with decreased risk of mediastinal infection (OR=0.21 (0.05-0.80); p=0.02). At the community level, OPCABG appears to be superior in terms of LOS and incidence of stroke. Paradoxically, CABG surgery demonstrates a reduced rate of mediastinal infection.
    The International journal of artificial organs 05/2007; 30(4):338-44. · 1.76 Impact Factor
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    Ramesh Venkataraman, John A Kellum
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    ABSTRACT: 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.
    Chest 02/2007; 131(1):300-8. · 5.85 Impact Factor
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    Alan C Heffner, Eric B Milbrandt, Ramesh Venkataraman
    Critical care (London, England) 02/2007; 11(1):305. · 4.72 Impact Factor
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    Asjad Khan, Eric B Milbrandt, Ramesh Venkataraman
    Critical care (London, England) 02/2007; 11(5):314. · 4.72 Impact Factor
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    Ramesh Venkataraman, John A Kellum
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    ABSTRACT: Acute renal failure is common among critically ill patients and carries significant morbidity and mortality. The reported incidence and the attributed morbidity and mortality of acute renal failure vary widely, largely owing to the use of a wide variety of definitions for acute renal failure. Until recently, no consensus existed about how to best define, characterize, and study acute renal failure. This lack of a standard definition has been a major impediment to the progress of clinical and basic research in this field. This review outlines some of the physiologic principles that may help us better understand and define acute renal failure and describes the RIFLE criteria (an acronym comprising Risk, Injury, and Failure; and Loss, and End-stage kidney disease), a recent consensus method of defining and stratifying acute renal failure. Also discussed are many of the challenges and controversies associated with achieving consensus and developing a classification for acute renal dysfunction.
    Journal of Intensive Care Medicine 01/2007; 22(4):187-93.
  • M. Raghavan, R. Venkataraman, J. A. Kellum
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    ABSTRACT: Development of acute renal failure during sepsis syndrome is common and portends a poor outcome. The interplay between systemic host responses, local insults in the kidney, vascular bed, and immune system, all play a role in the development of sepsis-induced acute renal failure. Despite advances in critical care, mortality rates have remained high for sepsis-associated acute renal failure. This may be, in part, a function of our poor understanding of the mechanisms of sepsis-induced acute renal failure, leading to misguided management strategies for acute renal failure. Improved understanding of various emerging mechanisms of sepsis-induced acute renal failure such as epithelial barrier dysfunction, apoptosis, and cytokine-mediated injury, should open newer avenues of therapeutic targets in this field. As has often been the case in the study of sepsis, simple universal mechanisms such as tissue perfusion, have failed to explain the diverse and complex clinical response, and therapeutic strategies aimed at single mechanisms have not been successful. The pathophysiologic mechanisms now understood to be operative in sepsis-induced acute renal failure overlap and interact at many levels. Therefore, therapeutic strategies to prevent acute renal failure or to facilitate recovery will likely need to be multifaceted.
    12/2006: pages 393-405;
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    Ramesh Venkataraman
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    ABSTRACT: To review the literature on perioperative cardiac management of patients who are scheduled to undergo vascular surgery. MEDLINE- and PubMed-based review of literature published from 1965 to 2005. Perioperative cardiac events (myocardial infarction, heart failure) remain the leading cause of morbidity and mortality in vascular surgery patients. Existing guidelines allow physicians to cost-effectively streamline preoperative cardiac risk assessment and stratification. Perioperative optimization of volume status and cardiac function and the routine use of perioperative beta-blockers can significantly improve outcomes after major vascular surgery. Perioperative addition of statins to beta-blockers in high-risk patients undergoing vascular surgery merits further evaluation. Preoperative coronary revascularization should be restricted to patients with unstable cardiac symptoms.
    Critical Care Medicine 10/2006; 34(9 Suppl):S200-7. · 6.12 Impact Factor
  • John Kellum, Martine Leblanc, Ramesh Venkataraman
    Clinical evidence 07/2006;
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    ABSTRACT: The lack of a standard definition for acute kidney injury has resulted in a large variation in the reported incidence and associated mortality. RIFLE, a newly developed international consensus classification for acute kidney injury, defines three grades of severity--risk (class R), injury (class I) and failure (class F)--but has not yet been evaluated in a clinical series. We performed a retrospective cohort study, in seven intensive care units in a single tertiary care academic center, on 5,383 patients admitted during a one year period (1 July 2000-30 June 2001). Acute kidney injury occurred in 67% of intensive care unit admissions, with maximum RIFLE class R, class I and class F in 12%, 27% and 28%, respectively. Of the 1,510 patients (28%) that reached a level of risk, 840 (56%) progressed. Patients with maximum RIFLE class R, class I and class F had hospital mortality rates of 8.8%, 11.4% and 26.3%, respectively, compared with 5.5% for patients without acute kidney injury. Additionally, acute kidney injury (hazard ratio, 1.7; 95% confidence interval, 1.28-2.13; P < 0.001) and maximum RIFLE class I (hazard ratio, 1.4; 95% confidence interval, 1.02-1.88; P = 0.037) and class F (hazard ratio, 2.7; 95% confidence interval, 2.03-3.55; P < 0.001) were associated with hospital mortality after adjusting for multiple covariates. In this general intensive care unit population, acute kidney 'risk, injury, failure', as defined by the newly developed RIFLE classification, is associated with increased hospital mortality and resource use. Patients with RIFLE class R are indeed at high risk of progression to class I or class F. Patients with RIFLE class I or class F incur a significantly increased length of stay and an increased risk of inhospital mortality compared with those who do not progress past class R or those who never develop acute kidney injury, even after adjusting for baseline severity of illness, case mix, race, gender and age.
    Critical care (London, England) 02/2006; 10(3):R73. · 4.72 Impact Factor
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    Critical Care 01/2006; 10. · 4.93 Impact Factor