One hundred fifty three sessions of SLED were performed in 43 haemodynamically unstable AKI patients admitted in ICU over one year of study period. The demographic and clinical va-riables of the study populations are summarized in table I.
All 43 patients completed at least two SLED sessions. After giving 2 SLED treatments, renal function of 1 patient improved and so, he did not require any RRT further. BP of another patient improved, and so, he was given intermittent HD assuming he would tolerate it. Remainingpatients (n=41) got 3rd session of SLED (i.e. total 3 sessions each). As 8 more patients became haemodynamically stable with improvement of BP after 3 SLED sessions, they were switched to intermittent HD.
Renal function improved in 3 patients in whom RRT was discontinued and 4 patients died. Final-ly, 26 patients got 4th session of SLED during the data collection period (total 7 days after initiation of SLED in each of remaining 26 pa-tients)(Figure. I).
Fourteen (32.55%) out of 43 patients had de novo AKI. Rest 29 patients (67.44%) had CKD prior to ICU admission with mean serum creati-nine 2.56 ± 0.62 mg/dl (ranged from 1.5 to 3.8 mg/dl).
All study patients tolerated SLED very well. Thirty one SLED sessions (20.26%) were asso-ciated with hypotension which was overcome by increasing the dose of inotrope. As there was no complication, SLED was not discontinued in any patient.
There was significant reduction of serum creati-nine, blood urea and serum K+ level with signifi-cant improvement of pH and HCO
level after SLED in all patientsregardless of their prior renal function(table II).
Table II: Comparison of post-SLED values with pre-SLED values of de novo AKI (Group 1, n=14) and AKI on CKD (Group II, n=29)
The following table (table III) demonstrates the relationship of outcome of the study patients with their age.
Thirtyout of 43 patients required inotrope support and 25 out of 43 study patients were on mechani-cal ventilator (MV) support.Relation of inotro-peand MV support with 28-day mortality have been shown in table IV and V respectively.
The cost of per session of SLED in BIRDEM Hospital was 8000 BDT (100 USD) during the study time. This cost was exclusive of daily ICU cost and medications. In this study, each patient had to pay same amount for each SLED session irrespective of duration of the session.
Renal replacement therapy for the AKI patients in ICU can be offered in several different for-mats. Among them, CRRT has been advocated in haemodynamically unstable patients as a means of mitigating the blood pressure that may occur with conventional intermittent HD. However, randomized controlled trials have not demon-strated superior survival in patients treated with CRRT.7,8
Moreover, implementation of a CRRT programme is expensive because of costs related to specialized machinery, filters, lines, and fil-trate replacement fluid. More recently, newer hybrid techniques i.e. SLED combining several advantages of CRRT and intermittent HD have been introduced into clinical practice across the world as a RRT for the critically ill patients. Cardiovascular tolerability associated with SLED is similar to that associated with CRRT, even in severely ill patients.9
Though solute and fluid removal are slower than conventional intermit-tent HD, but faster than CRRT; several prospec-tive controlled studies have shown that SLED clears small solutes with an efficacy comparable to that of intermittent HD and CRRT. At the same time it is less expensive than CRRT.10,11
So, SLED combines the therapeutic advantages of CRRT with the logistic and cost advantages of intermittent HD.
Epidemiologic studies have shown an increased incidence of AKI in men as compared with women; men constitute 59% to 64% of cases of severe AKI among critically ill pa-tients.12
Thisstudy also had male preponderance (67.4%). Similar gender distribution was ob-served in the SLED study by Schwenger13
(62.6% male), Carvalho1
(60% male) and Kilha-ra14
The mean APACHE II score of these critically ill patients were 26.88 ± 6.257 with 52.14% expected mortality. 30 (69.8%) of these critically ill patients required inotrope support and 25 (58.1%) mechanical ventilator sup-port.Prospective controlled studies13,15
have shown that SLED clears small solutes with an efficacy comparable to that of intermittent HD and CRRT, even when the latter employs high rates of fluid substitution. Metabolic changes were measured in terms of reduction in the levels of blood urea and serum creatinine, as well as normalization of serum potassium, pH and bicarbonate. Although it is beyond the scope of this study to provide a full measurement of solute clearance; good control of urea, creatinine, potassium, pH and bicarbonate was achieved with SLED as depicted in tableII.Nirmal Kumar16
in 2007 demonstrated normalization of blood urea, serum creatinine, potassium, pH and bicarbonate with SLED which resulted in earlier amelioration of uremic symptoms.
Carvalho demonstrated that 25.5% of their AKI patients recovered renal function after receiving SLED whereas 18.6% developed ESRD and 46.5% died.1
Almost similar result was found in thisstudy; AKI was resolved completely in 27.9%, and 32.6% patients expired. Mortality in ICU patients with AKI does not solely depend on renal function. Ninety five percent of patients were suffering from cardiogenic, or septic shock, or both.There is a wide range of mortality rates of AKI patients in ICU reported from 36% to 90%.17 The factors associated with mortality in AKI patients included the number of underlying diseases and on admission GCS and APACHE II score18
. As mentioned in table I, 69.8% of thestudy patients were on inotrope support, 58.1% needed positive pressure ventilation, andmean APACHE II score of all study patients was 26.88 ± 6.257 with expected mortality of 52.14% indicating that all the patients were truly very sick.
Some 40.0%patients in thestudy became dialysis dependant. This may be explained by the fact that 67.44% of our patients had pre-existing CKD. Significantly more patients having CKD prior to ICU admission became dialysis depen-dent than the patients who had normal renal function prior to admission (p <0.01) (figureII). This finding indicates that AKI places CKD patients at high risk for developing end stage renal disease (ESRD). Ishani also had similar finding when he did a study to see the development of ESRD after AKI.19
He found that episodes of AKI accelerated progression of renal disease in patients with previously diagnosed CKD.
The actual mortality in this study was 30.23% and the expected mortality was 52.14% calculated from APACHE II severity scoring system. Mortality rate was significantly higher in patients who had cardiogenic and/or septic shock and so were on inotrope support (p 0.017) compared to those who did not require inotrope (table IV). Otherwise, there wasno relation of 28-day mortality with age, prior renal function and mechanical ventilator requirement (p >0.05 in all) (table III and V).
An important aspect of use of SLED, especially in the developing countries, is the cost of care as well as availability. The conventional HD ma-chines are used for SLED with routine dialysate concentrate and inexpensive dialyzers. So, there is significantly lower cost of the circuit tubing, membranes and the machines used in SLED compared with those used in CRRT. In fact, all centeres across the world offering SLED use various conventional HD machines without adding or altering any software or hardware.20
In one study done in two major Philadelphia teaching hospitals, cost of CRRT and SLED were compared.9
The daily total cost of CRRT was 1061 USD and that of SLED was 426 USD if given for 12 hours and 797 USD if given for 24 hours. Theseincluded materials cost, pharmacy cost for solution and nursing cost.Another observational pilot study was done in auniversity hospital of Toronto, Canada.2
Daily cost of SLED was 238.5 USD when given for 8 hours. On the other hand, cost of 24 hours' CRRT was 372.45 USD if heparin was used, and 372.45 USD if citrate was used as anticoagulant. In ourICU, we used the same dialysis machine used for routine HD to give SLED. This resulted in substantial cost re-duction. The cost of intermittent HD in BIRDEM wasUSD 43.75 per session, and that of SLED was USD 100 per session. The cost of CRRT in the studycentre was about USD 1000 if given for 5 days. These expenditures included the cost of materials and pharmacy. Unfractionated or low molecular weight heparin wasused as anticoagulant here in intermittent HD, CRT and SLED. In Bangladesh, only 4 tertiary care hospitals in the capital city have CRRT facility. But HD facility is available in many districts of the country. As SLED can be given with HD machine, so any hospital with HD facility can offer SLED to theirhaemodynamically unstable patients. As a result, use of expensive CRRT can be substituted by use of SLED. This has a great economic and logistic impact for patients who cannot afford CRRT or where CRRT is not available.
Overall, SLED was tolerated well by the critically ill patients, and widely accepted by our ICU staff. Studies showed, 24% of respondents used SLED for AKI in ICU.21,22
Recent data demon-strate that neither the technique of RRT8,23
, nor the dose of RRT 24,25
had an impact on patient survival. In the light of markedly higher costs of CRRT, it was therefore suggested that, in the absence of a survival benefit of CRRT, slow continuous therapy like SLED should be the pre-ferred treatment modality for AKI in ICU.21,26,27
To increase the credibility of thestudy, compari-son with CRRT could be made. But CRRT is very expensive and the study patients could not afford it. Most of our patients refused CRRT due to financial constraints. As suchcomparison be-tween CRRT and SLED could not be made. Se-condly, as the sample size was small, the findings derived from study cannot be generalized to our reference population and the data should be interpreted with utmost caution.Thirdly, this study was carried out on adult population. So, outcome could not be applied on pediatric AKI patients.
This study concludes that SLED reduces blood urea, serum creatinine, and K+, and improves arterial pH and HCO3
-significantly. In the light of limited health care resources, SLED offers an attractive form of RRT for the AKI patients who are not able to tolerate intermittent hemodialysis. In a developing country like Bangladesh,the ju-dicious use of SLED is practical and cost-effective in the haemodynamically unstable pa-tients of ICU with AKI.
Authorswould like to express heartfelt gratitude to DrShakeraBinte Hassan and DrUmmeKulsum Chowdhury for their technical assistance in data collection.
- Carvalho C, Cabral R, Gaiao S, Martins P, Barbosa S, Honrado T, Paiva JA, Pestana M. Sustained low efficiency dialysis in the intensive care unit: a single centre experience. Port J NephrolHypert. 2009; 23(3): 257-60.
- Berbece AN, Richardson RMA. Sustained low-efficiency dialysis in the ICU: cost, anticoagulation, and solute removal. Kidney International. 2006; 70: 963-68.
- Kes P, Jukic NB. Acute kidney injury in the intensive care unit. Bosn J Basic Med Sci. 2010; 10(Suppl 1): S8-S12.
- O’Reily P, Tolwani A. Renal replacement therapy III: IHD, CRRT, SLED. Crit Care Clin. 2005; 21:367-78.
- Bellomo R, Ronco C, Kellum JA, Mehta RL, Pa-levsky P, and the ADQI workgroup. Acute renal failure- definition, outcome measures, animal models, fluid therapy & information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group. Crit Care. 2004; 8: R204-12.
- Levey AS, Coresh J, Balk E, Kausz AT, Leveen A, Steffes MW, Hogg RJ, Perrone RD, Lau J, Eknoyan G. National kidney foundation practice guidelines for chronic kidney disease: evaluation, classification and stratification. Ann Intern Med. 2003; 139: 137-47.
- Mehta RL, McDonald B, Gabbai FB, Pahl M, Pas-caul MTA, Farkas A, Kaplan RM. A randomized clinical trial of continuous versus intermittent dialysis for acute renal failure. Kidney International. 2001; 60(3): 1154-63.
- Lins RL, Elseviers MM, Niepen PVD, Hoste E, Malbrain ML, Damas P, Devriendt J. Intermittent versus continuous renal replacement therapy for acute kidney injury patients admitted to the intensive care unit: results of a randomized clinical trial. Nephrol Dial Transplant 2009; 24(2): 512-18.
- Salahudeen AK, Kumar V, Madan N, Xiao L, Lahoti A, Samuels J, Nates J, Price K. Sustained low ef-ficiency dialysis in the continuous mode (C-SLED): dialysis efficacy, clinical outcomes, and survival predictors in critically ill cancer patients. Clin J Am SocNephrol. 2009; 4: 1338-46.
- Liao Z. Kinetic comparison of different acute dialysis therapies. Artif Organs 2003; 27: 802-807.
- Ahmed Z, Gilibert S, Krevolin L. Cost analysis of continuous renal replacement therapy and extended hemodialysis. Dialysis and Transplantation. 2009; 38(12): 500-3.
- The VA/NIH acute renal failure trial network. Inten-sity of renal support in critically ill patients with acute kidney injury. N Engl J Med. 2008; 359(1):7-20.
- Schwenger V, Weigand MA, Hoffmann O, Dikow R, Kihm LP, Seckinger J, Miftari N, Schaier M, Ho-fer S, Haar C, Nawroth PP, Zeier M, Martin E, Mo-rath C. Sustained low efficiency dialysis using a sin-gle-pass batch system in acute kidney injury – a ran-domized interventional trial: the Renal Replacement Therapy Study in Intensive Care Unit Patients. Crit Care. 2012; 16: R140.
- Kilhara M, Iekada Y, Shibata K, et al. Slow hemo-dialysis performed during the day in managing renal failure in critically ill patients. Nephron. 1994; 67: 36-41.
- Marshall MR, Golper TA, Shaver MJ, Alam MG, Chatoth DK. Sustained low efficiency dialysis for critically ill patients requiring renal replacement therapy. Kidney International. 2001; 60: 777-85
- Kumar N, Ahlawat RS. Extended daily dialysis in acute renal failure: a new therapeutic approach. IJKD. 2007; 1: 63-72.
- Hoste EA, Lameire NH, Vanholder RC, et al. Acute renal failure in patients with sepsis in a surgical ICU: predictive factors, incidence, comorbidity, and outcome. J Am SocNephrol. 2003; 14(4): 1022-30.
- Samimagham HR, Kheirkhah S, Haghighi A, Najmi Z. Acute Kidney Injury in Intensive Care Unit: Inci-dence, Risk Factors and Mortality Rate. Saudi J Kidney Dis Transpl. 2011; 22(3): 464-70.
- Ishani A, Xue JL, Himmelfarb J,Eggers PW, Kimmel PL, Molitoris BA, Collins AJ. Acute kidney injury increases risk of ESRD among elderly. Am SocNephrol. 2009; 20: 223-28.
- Ellakany SA, Azab SH, Shehata OH, Deghady AA, Ali MA. Slow low efficiency extended hemodialysis in the management of refractory congestive heart failure and in critically ill patients. JMRI. 2006; 27(4): 303-13.
- Ronco C, Bellomo R. Dialysis in intensive care unit patients with acute kidney injury: continuous therapy is superior. Clin J Am SocNephrol. 2007; 2:597-600.
- Neuenfeldt T, Hopf HB. Sustained low efficiency dialysis in an interdisciplinary intensive care unit- a five year cost-benefit analysis. Rev ColombAneste-siol. 2013; 41(2): 88-96.
- Vinsonneau C, Camus C, Combes A, Beauregard MACd, Klarche K, Boulain T, Pallot JL, Chiche JD, Taupin P, Landais P, Dhainaut JF. Continuous ve-novenousdiafiltration versus intermittent hemodialy-sis for acute renal failure in patients with multiple-organ dysfunction syndrome: a multicentre rando-mized trial. Lancet. 2006; 368: 379-85.
- The Renal Replacement Therapy Study Investigators. Intensity of continuous renal-replacement therapy in critically ill patients. N Engl J Med. 2009 October 22; 361: 1627-38.
- Vesconi S, Cruz DN, Fumagalli R, Kindgen-Milles D, Monti G, Marinho A, Mariano F, Formica M, Marchesi M, Robert R, Livigni S, Ronco C for the Dose Response Multicentre International Collabora-tive Initiative. Delivered dose of renal replacement therapy and mortality in critically ill patients with acute kidney injury. Crit Care. 2009; 13(2): R57.
- Faulhaber-Walter R, Hafer C, Jahr N, Vahlbruch J, Hoy L, Holler H, Fliser D, Kielstein JT. The Han-nover Dialysis outcome study: comparison of stan-dard versus intensified extended dialysis for treatment of patients with acute kidney injury in the intensive care unit. Nephrol Dial Transplant. 2009; 24: 1-7.
- Fieghen HE, Friedrich JO, Burns KE, Nisenbaum R, Adhikan NK, Hladunewich MA, Lapinsky SE, Richardson RM, WaldR. The hemodynamic tolera-bility and feasibility of sustained low efficiency di-alysis in the management of critically ill patients with acute kidney injury. BMC Nephrology.2010;11:32.