A new practical technique to reduce allogeneic blood exposure and hospital costs while preserving clotting factors after cardiopulmonary bypass: the Hemobag®

Recent data independently linking allogeneic blood use to increased morbidity and mortality after cardiopulmonary bypass (CPB) warrants the study of new methods to employ unique and familiar technology to reduce allogeneic blood exposure. The Hemobag® allows the open-heart team to concentrate residual CPB circuit contents and return a high volume of autologous clotting factors and blood cells to the patient.

Fifty patients from all candidates were arbitrarily selected to receive the Hemobag® (HB) therapy. A retrospective control group of 50 non-Hemobag® (NHB) patients were matched to the HB group patient-by-patient for comparison according to surgeon, type of procedure, age, body surface area (BSA), body weight and CPB time. Many efforts to conserve blood (Cell Saver® and ANH) were employed in both groups. Post-CPB cell washing of circuit contents was additionally employed in the control group.

There were no significant differences between the HB and NHB groups in regard to patient morphology, pre-op cell concentrations, distribution of surgeon or procedures (41% valve, 16% valve/coronary artery bypass graft (CABG), balance CABG), pump and ischemic times and Bayes National Risk scores. The average volume returned to the patient from the HB was 8179/198 mL (1 SD). Average processing time was 11 min. The Hemobag®contained an average platelet count of 2309/80 K/mm3, fibrinogen concentration of 4139/171 mg/dl, total protein of 8.09/2.8 gm/dl, albumin of 4.49/1.2 gm/dl and hematocrit of 439/7%. Factor VII, IX and X levels in three HB contents averaged 259% greater than baseline. Substantial reductions were achieved in both allogeneic blood product avoidance and cost to the hospital with use of the HB.

Infusion of the Hemobag® concentrate appears to recover safely substantial proteins, clotting factor and cell concentration for all types of cardiac procedures, maintaining the security of a primed circuit.

[Mobile single-pass batch hemodialysis system in intensive care medicine. Reduction of costs and workload in renal replacement therapy]

This paper describes the introduction of a single-pass batch hemodialysis system for renal replacement therapy in a 14 bed intensive care unit. The goals were to reduce the workload of intensive care unit physicians using an alternative and simpler method compared to continuous veno-venous hemodiafiltration (CVVHDF) and to reduce the costs of hemofiltrate solutions (80,650 EUR per year in our clinic in 2005). We describe and evaluate the process of implementation of the system as well as the achieved and prospective savings. We conclude that a close cooperation of all participants (physicians, nurses, economists, technicians) of a hospital can achieve substantial benefits for patients and employees as well as reduce the economic burden of a hospital.

Sustained low-efficiency dialysis in the ICU: cost, anticoagulation, and solute removal

Hemodialysis (HD) for critically ill patients with acute renal failure has been provided as intermittent hemodialysis (IHD) or continuous renal replacement therapy (CRRT). IHD is often complicated by hypotension and inadequate fluid removal, and CRRT by high cost of solutions and problems with anticoagulation. Sustained low-efficiency daily dialysis (SLED) has been suggested as an alternative treatment. This is an observational, prospective pilot study describing the introduction of SLED at our institution. We compared SLED (23 patients, 165 treatments) with CRRT (11 patients, 209 days), focusing on cost, anticoagulation, and small solute removal. SLED consisted of 8 h of HD 6 days a week, with blood flow of 200 ml/min, dialysate flows of 350 ml/min, and hemofiltration with 1 l of saline/h. CRRT patients were anticoagulated with either heparin or citrate, and SLED patients with either heparin or saline flushes. The weekly costs to the hospital were $1431 for SLED, $2607 for CRRT with heparin, and $3089 for CRRT with citrate. Sixty-five percent of SLED treatments were heparin-free; filter clotting occurred in 18% of heparin treatments and 29% of heparin-free treatments (NS). Weekly Kt/V was significantly higher for SLED (8.4+/-1.8) and time-averaged serum creatinine was lower; equivalent renal clearance (EKRjc) was 29+/-6 ml/min for SLED, similar to that for CRRT. In summary, SLED may be routinely performed without anticoagulation; it provides solute removal equivalent to CRRT at significantly lower cost.

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.

Internal filtration-enhanced hemodialysis is a cost-effective treatment in view of solute removal

By modifying dialyzer module design, internal filtration (IF) within a dialyzer is enhanced to increase convective solute transport. Thus, it can be an alternative to hemodiafiltration with no requirement of substitution fluid or additional complex machines. Cost-effective analysis was conducted in three modes of therapy: high-flux hemodialysis, on-line hemodiafiltration and IF-enhanced hemodialysis. In IF-enhanced hemodialysis, cost-effectiveness of small solute removal is comparable with high-flux hemodialysis and that of beta(2)-microglobulin removal is the best. It is concluded that IF-enhanced hemodialysis is the most cost-effective therapy mode in comprehensive overall solute removal.

Citrate vs. heparin for anticoagulation in continuous venovenous hemofiltration: a prospective randomized study

OBJECTIVE

To compare the efficacy and safety of adjusted-dose unfractionated heparin with that of regional citrate anticoagulation in intensive care patients treated by continuous venovenous hemofiltration (CVVH).

DESIGN AND SETTING

Prospective, randomized, clinical trial in a 32-bed medical and surgical ICU in a university teaching hospital.

PATIENTS

ICU patients with acute renal failure requiring continuous renal replacement therapy, without cirrhosis, severe coagulopathy, or known sensitivity to heparin.

INTERVENTIONS

Before the first CVVH run patients were randomized to receive anticoagulation with heparin or trisodium citrate. Patients eligible for another CVVH run received the other study medication in a cross-over fashion until the fourth circuit.

MEASUREMENTS AND RESULTS

Forty-nine circuits (hemofilters) were analyzed: 23 with heparin and 26 with citrate. The median lifetime of hemofilters was 70 h (interquartile range 44-140) with citrate anticoagulation and 40 h (17-48) with heparin (p=0.0007). One major bleeding occurred during heparin anticoagulation and one metabolic alkalosis (pH=7.60) was noted with citrate after a protocol violation. Transfusion rates (units of red cells per day of CVVH) were, respectively, 0.2 (0.0-0.4) with citrate and 1.0 (0.0-2.0) with heparin (p=0.0008).

CONCLUSIONS

Regional citrate anticoagulation seems superior to heparin for the filter lifetime and transfusion requirements in ICU patients treated by continuous renal replacement therapy.

Cost analysis of blood purification in intensive care units: continuous versus intermittent hemodiafiltration

BACKGROUND

We implemented a program for continuous renal replacement therapies (CRRT) in intensive care units (ICU) based on the cooperative work of dialysis and ICU personnel. Our aim was to report the main details of this program and compare its cost with that of intermittent hemodiafiltration (IHDF).

METHODS

The study referred to 181 ICU patients with renal failure. We considered the costs of both technical devices and assisting personnel. CRRT was performed as continuous veno-venous hemodiafiltration (CVVHDF) (24 hr daily); dialysis and ICU nurses shared surveillance. Only dialysis nurses performed IHDF (as acetate-free biofiltration, 4 hr daily) in the ICU.

RESULTS

The daily cost of CRRT was Euro 276.70; of which 79% was for devices and 21% was for human resources. Nurse surveillance required 141 min per day, ICU nurses supplied 55% (77 min) and dialysis nurses 45% (64 min). On average, CRRT surveillance required less than 1 min/nurse/hr for both dialysis and ICU nurses. The daily cost of 4-hr IHDF sessions of was Euro 247.83, of which 44% was for technical devices and 56% was for human resources.

CONCLUSIONS

The cooperation between dialysis and ICUs improved the use of human resources and allowed us to supply CRRT to all critically ill patients with acute renal failure. The expenditure for CRRT was 12% higher than that for IHDF, due to the cost of technical devices.

Hemofiltration and peritoneal dialysis in infection-associated acute renal failure in Vietnam

BACKGROUND

In some parts of the world, peritoneal dialysis is widely used for renal replacement in acute renal failure. In resource-rich countries, it has been supplanted in recent years by hemodialysis and, most recently, by hemofiltration and associated techniques. The relative efficacy of peritoneal dialysis and hemofiltration is not known.

METHODS

We conducted an open, randomized comparison of pumped venovenous hemofiltration and peritoneal dialysis in patients with infection-associated acute renal failure in an infectious-disease referral hospital in Vietnam.

RESULTS

Seventy adult patients with severe falciparum malaria (48 patients) or sepsis (22 patients) were enrolled; 34 were assigned to hemofiltration and 36 to peritoneal dialysis. The mortality rate was 47 percent (17 patients) in the group assigned to peritoneal dialysis, as compared with 15 percent (5 patients) in the group assigned to hemofiltration (P=0.005). The rates of resolution of acidosis and of decline in the serum creatinine concentration in the group assigned to hemofiltration were more than twice those in the group assigned to peritoneal dialysis (P<0.005), and renal-replacement therapy was required for a significantly shorter period. In a multivariate analysis, the odds ratio for death was 5.1 (95 percent confidence interval, 1.6 to 16) and that for a need for future dialysis was 4.7 (95 percent confidence interval, 1.3 to 17) in the group assigned to peritoneal dialysis. The cost of hemofiltration per survivor was less than half that of peritoneal dialysis, and the cost per life saved was less than one third.

CONCLUSIONS

Hemofiltration is superior to peritoneal dialysis in the treatment of infection-associated acute renal failure.

Outcome in children receiving continuous venovenous hemofiltration

OBJECTIVE

Continuous venovenous hemofiltration (CVVH) alone or with dialysis (D) has become an important supportive therapy for critically ill children with acute renal failure. Previous reports of pediatric patient outcome either mix CVVH/D with other renal replacement modalities or do not examine severity of illness. The current study examines only outcomes of children receiving CVVH/D using Pediatric Risk of Mortality (PRISM) scores to control for severity of illness.

PATIENTS

Twenty-one patients (mean age: 8.8 +/- 6.3 years; mean weight: 28.3 +/- 20.8 kg) received 22 courses of CVVH/D.

OUTCOMES

Nine (42.8%) of 21 patients survived. Nine (75%) of 12 deaths occurred within 25 days of pediatric intensive care unit (PICU) admission. Mean PRISM score at PICU admission and CVVH initiation were 13.1 +/- 5.8 and 15.4 +/- 8.9, respectively. Mean patient weight, age, PRISM score at PICU admission and at CVVH/D initiation, maximum pressor number, estimated glomerular filtration rate at CVVH/D initiation and change in mean airway pressure did not differ between survivors and nonsurvivors. The degree of fluid overload at CVVH/D initiation was significantly lower in survivors (16.4% +/- 13.8%) compared with nonsurvivors (34.0% +/- 21.0%), even when controlled for severity of illness by PRISM score. Mean cost of providing CVVH/D accounted for only 1% of total PICU cost per patient.

CONCLUSIONS

The pattern of early multiorgan system failure and death, minimal relative cost of CVVH/D provision, and potential for improved outcome with initiation of CVVH/D at lesser degrees of fluid overload are factors that may support early initiation of CVVH/D in critically ill children with acute renal failure.

A controlled trial of low-molecular-weight heparin (dalteparin) versus unfractionated heparin as anticoagulant during continuous venovenous hemodialysis with filtration

OBJECTIVE

To compare the efficacy, safety, and cost of fixed-dose low-molecular-weight heparin (dalteparin) with adjusted-dose unfractionated heparin as anticoagulant for continuous hemofiltration.

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

University-affiliated adult intensive care unit

PATIENTS

All patients requiring continuous hemofiltration for acute renal failure or systemic inflammatory response syndrome (SIRS) were eligible. Fifty-seven patients were enrolled. Eleven were excluded, seven because of major protocol violations and four died before hemofiltration.

INTERVENTIONS

Patients received continuous venovenous hemodialysis with filtration with prefilter replacement at 500 mL/hr and countercurrent dialysate at 1000 mL/hr. Filters were primed with normal saline containing anticoagulant. Dalteparin-treated patients received a commencement bolus of 20 units/kg and a maintenance infusion at 10 units/kg/hr. Heparin-treated patients received a commencement bolus of 2000-5000 units and a maintenance infusion at 10 units/kg/hr, titrated to achieve an activated partial thromboplastin time in the patient of 70-80 secs.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure--time to failure of the hemofilter--was compared using survival analysis. Twenty-two patients (13 with acute renal failure and nine with SIRS; total, 41 filters) were randomized to heparin. Twenty-five patients (16 with acute renal failure and nine with SIRS; total, 41 filters) were randomized to dalteparin. Mean (SE) activated partial thromboplastin time in the heparin group was 79 (4.3) secs. Mean (SE) anti-factor-Xa activity in the six patients given dalteparin who were assayed was 0.49 (0.07). Mean (SE) prehemofiltration platelet count was 225 (35.5) x 10(9) for heparin and 178 (18.1) x 10(9) for dalteparin (p = .24, unpaired Student's t-test). Mean (SE) prehemofiltration hemoglobin was 11.4 (0.61) g/dL for heparin and 10.6 (0.38) g/dL for dalteparin (p = .31, unpaired Student's t-test).

PRIMARY OUTCOME

There was no significant difference in the time to failure between the two groups (p = .75, log rank test). For dalteparin, Kaplan-Meier (K-M) mean (SE) time to failure of the hemofilter was 46.8 (5.03) hrs. For heparin, K-M mean (SE) time to failure was 51.7 (7.51) hrs. The 95% CI for difference in mean time to failure was -13 to 23 hrs. The power of this study to detect a 50% change in filter life was >90%.

SECONDARY OUTCOMES

Mean (SE) reduction in platelet count during hemofiltration was 63 (25.8) x 10(9) for heparin and 41.8 (26.6) x 10(9) for dalteparin (p = .57, unpaired Student's t-test). Eight patients given dalteparin and four patients given heparin had screening for heparin-induced thrombocytopenia; three of the dalteparin patients and one of the heparin patients were positive (p = 1.0, Fisher's exact test). There were three episodes of trivial bleeding and two episodes of significant bleeding for dalteparin, and there were three episodes of trivial bleeding and four episodes of significant bleeding for heparin (p = .53, chi-square test). The mean (SE) decrease in hemoglobin concentration during hemofiltration was 0.51 (0.54) g/dL for heparin and 0.28 (0.49) g/dL for dalteparin (p = .75, unpaired Student's t-test). The mean (SE) packed-cell transfusion volume during hemofiltration was 309 (128) mL for heparin and 290 (87) mL for dalteparin (p = .90, unpaired Student's t-test). Daily costs, including coagulation assays, of hemofiltration were approximately 10% higher using dalteparin than with heparin.

CONCLUSIONS

Fixed-dose dalteparin provided identical filter life, comparable safety, but increased total daily cost compared with adjusted-dose heparin. Unfractionated heparin remains our anticoagulant of choice for continuous hemofiltration in intensive care.

Hemofiltration and double high flux dialysis: risks and benefits

Convective therapies such as hemofiltration, hemodiafiltration and double high flux dialysis have been shown to improve treatment delivered and treatment tolerance when compared to conventional dialysis therapies. The risk associated with these treatments is primarily in the quality of the substitution fluid. Technological advances now permit on-line produced substitution fluid, thereby significantly reducing the cost associated with hemofiltration and hemodiafiltration. The quality of the substitution fluid is only assured when the quality of the RO water used is within the guidelines set by the Association for the Advancement of Medical Instrumentation (AAMI). Therefore, the success of the application of this therapy is dependent on the water treatment protocols in the dialysis units. The success of this modality as a treatment for chronic renal failure is dependent on identifying those patient groups who will benefit most from this more efficient but more expensive treatment.

Impact of ultrafiltration on blood use for atrial septal defect closure in infants and children

BACKGROUND

Infants and children undergoing open cardiac operations have a high incidence of blood product transfusion. Ultrafiltration has been shown to reverse hemodilution and improve myocardial function and hemodynamics after cardiopulmonary bypass (CPB).

METHODS

The effect of ultrafiltration on the amount of blood transfusion and hospital charge in 39 consecutive patients who underwent elective atrial septal defect repair was examined. Patients in group I (n=26) had a conventional cardiopulmonary circuit prime with blood, whereas 13 patients had bloodless prime (group II). Ultrafiltration was used immediately after weaning from CPB in group II. The patients in group I received blood products after discontinuation of CPB to achieve a hematocrit of 30%. The amount of blood product used, hematocrit immediately after CPB and on arrival in intensive care unit, postoperative hemodynamics and saturations, total operating room charge, blood charge, hospital stay, and hospital charge were compared.

RESULTS

Mean body weight (15.8 kg in group I versus 17.5 kg in group II) and preoperative hematocrit values (35.6% in group I versus 34.2% in group II) were similar. Mean hematocrit immediately after CPB was 22% and 14% in group I and II, respectively (p < 0.0001). The mean hematocrit upon arrival to the intensive care unit was 34% in group I and 22% in group II (p < 0.0001). The amount of blood product transfusion was 32 mL/kg in group I and 3 mL/kg in group II patients (p < 0.0001). The patients in group II had significantly less blood bank charges; however, operating room charges and total hospital charges were similar between the two groups.

CONCLUSIONS

Elective atrial septal defect repair was performed with no blood product transfusion without increased morbidity or hospital stay. Ultrafiltration can be used to reverse hemodilution resulting from a bloodless CPB prime without an increase in hospital charge.

Continuous venovenous hemofiltration: a cost-effective therapy for the pediatric patient

The authors were surprised to discover that at Riley Hospital for Children the cost of continuous venovenous hemofiltration (CVVH) constitutes a small fraction of the total admission costs, even when it is performed for a large portion of inpatient stays. A reasonable treatment that gives critically ill children reasonable chances of surviving at reasonable costs, must be considered cost-effective. CVVH currently offers some pediatric patients an additional chance at survival without an extraordinary increase in total hospital bills. Further research regarding patient selection, timing of initiation of therapy, and improving outcomes is recommended.

Conventional haemofiltration during routine coronary bypass surgery

The use of conventional ultrafiltration during cardiopulmonary bypass (CPB) has been well recognized as an efficient modality of therapy to reverse the effects of deliberate haemodilution. Routine use of the haemofilter was prospectively studied on 60 patients undergoing coronary artery bypass surgery. Group A consisted of 30 patients on whom the ultrafiltrator was used and compared to group B who did not receive the ultrafiltration technique. The COBE 1200 ultrafiltration device was used. The results of the study demonstrated that, in group A, the mean total amount of ultrafiltrate collected during bypass was 2510 +/- 804 ml per patient. The mean 24-h postoperative blood loss was 440 +/- 192 ml in group A and 451 +/- 136 ml in group B. The average bank blood transfused was 0.6 +/- 1.3 units per patient in group A and 0.75 +/- 1.5 units per patient in group B. Postoperative weight gain in group A averaged 3.5 +/- 3.45 lb per patient, compared to 4.8 +/- 3.7 lb per patient in group B. Postoperative length of stay averaged 6.4 +/- 1.5 days per patient in group A and 6.4 +/- 2.1 days per patient in group B. Overall patient charges averaged $33,706 +/- 8348 per patient in group A and $33,041 +/- 7674 per patient in group B. It was concluded that routine use of ultrafiltration during routine coronary artery bypass surgery with CPB offers no improvement in the quality of care nor does it decrease the patient's overall charges.

Hemofiltration in a cardiac intensive care unit: time for a rational approach

The typical annual expenditure for patients requiring continuous hemofiltration (CHF) is high. To audit the benefit of this expensive treatment, the outcome of 48 consecutive patients (34 men, 14 women; mean age, 65 years) requiring hemofiltration for acute renal failure was analyzed during a period of 24 months. The operations performed were 26 CABG, 8 AVR, 3 AVR/MVR, 2 post infarction VSD repairs, and 1 thoracoabdominal aneurysmectomy. Indications for hemofiltration were oliguria and fluid overload in 69%, uremia in 56%, acidosis in 33%, and hyperkemia in 13%. Twenty five patients (52%) died while in the hospital, and 10 more died within 9 months of discharge. Of the remaining 13 survivors, 6 (46%) were classified as III or IV according to the New York Heart Association classification system. The mean ITU and hospital stay per patient requiring CHF was 15.3 days and 25.4 days, respectively. There were no statistically significant differences between patients who did and did not survive in the hospital in age, pre-operative renal function, ejection fraction, duration of cardiopulmonary bypass, or urine output before CHF. However, there were no survivors when the cardiac index was less than 1.7 L/m2 and adrenalin requirement was more than 30 micrograms/min before CHF (seven patients). These results suggest that the short- and long-term outcome in patients requiring CHF after cardiac surgery is poor. Considering the large demand on resources, the use of CHF should be rationalized, particularly in patients with persistent low cardiac output.

Membranes in artificial organs

Membrane processes by a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extra-corporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.

Renal considerations, dialysis, and ultrafiltration during cardiopulmonary bypass

Patients with preoperative renal insufficiency are more likely to develop postoperative renal failure than those with normal preoperative renal function. Both of these groups may benefit from optimizing intraoperative renal perfusion because not all preoperative renal risk factors are easily diagnosed. Patients with preoperative chronic renal failure who are unable to manage perioperative electrolyte levels, excess water, and uremic toxins may benefit from intraoperative dialysis. Ultrafiltration is valuable in removing excess plasma water during CPB. Modified ultrafiltration studies suggest that ultrafiltration post-CPB can improve postoperative patient outcomes and that the mechanism for these improvements involve more than excess water removal. Since there are no contraindications for ultrafiltration or dialysis during CPB, the decision to use these techniques depends on the perceived potential benefits and the cost of adding a component to the CPB circuit.

Predilution hemofiltration: a new technology applied to an old therapy

Postdilution hemofiltration (HF) as practised during the 80's is today associated with limitations of a medical, practical and economical nature. High blood flow rates are required to generate sufficient ultrafiltrate in order to achieve a clearance of small solutes comparable to hemodialysis within a reasonable time. High hematocrit and large body weight lead to extended treatment times. IV-quality solution is required in large volumes. This makes the use of bicarbonate difficult and has placed HF among the most expensive renal replacement therapies. These limitations can be resolved by performing HF in a predilution mode using an on-line prepared infusion solution. Diluting the blood before filtration increases the filtration fraction and the clearance of all solutes which are sieved by the membrane. Comparing pre- to postdilution at similar blood flow rates, the clearance may increase by 50% but three times as much infusion solution is required. To make predilution economically viable, the on-line preparation of the infusion solution is necessary, and this facilitates the use of bicarbonate. Compared to other dialysis therapies this new form of HF offers unequalled solute removal over a large molecular range.

Acute dialytic support for the critically ill: intermittent hemodialysis versus continuous arteriovenous hemodiafiltration

There is still debate about whether continuous renal replacement therapy is superior to intermittent hemodialysis (IHD) as dialytic support for the critically ill patient with acute renal failure, mainly because of lack of comparative data. We sought to address this issue by reviewing the medical records of such patients admitted to a single surgical intensive care unit treated with either continuous arteriovenous hemodiafiltration (CAVHD) or IHD between January 1, 1986, and August 31, 1993. Of 94 consecutive patients who received dialytic support for severe acute renal failure, 34 (36%) patients were treated with IHD and 60 (64%) patients with CAVHD. The patients were comparable in terms of age or gender and represented a similar case mix. Patients treated with CAVHD were more severely ill as manifested by a lower mean arterial pressure (75 +/- 3 vs. 86 +/- 5 mm Hg; p < 0.05), higher Apache II score (26.5 +/- 0.5 vs. 22.2 +/- 0.3; p < 0.05), and a higher number of organ system failures (3.4 +/ 0.2 vs. 2.6 +/- 0.3; p < 0.05). Despite greater illness severity and a higher probability of death (55 +/- 2.6 vs. 33 +/- 2.5%; p < 0.0001), in those treated with CAVHD, no difference in outcome was observed between groups: CAVHD 26/60 (43%) vs. IHD 20/34 (59%; NS). The mean Apache II score of patients treated with CAVHD who survived was similar to that of patients treated with IHD who died (24.5 +/- 0.3 vs. 24.2 +/- 0.4; NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal replacement therapies for critically ill pediatric patients

It could be a great challenge for a nephrologist to prescribe a renal replacement therapy for a critically ill, hemodynamically unstable pediatric patient. Intermittent hemodialysis and peritoneal dialysis frequently fall short of being an optimal renal replacement therapy for such a patient. Continuous hemofiltration is offering new alternatives that can deliver sufficient clearance to meet the needs of a critically ill child. High fluid intake required for total parenteral nutrition and medications can easily be fulfilled by these modalities without compromising the cardivascular system. Of these techniques, continuous veno-venous hemofiltration is superior to continuous arterio-venous hemofiltration because it delivers a consistent ultrafiltration rate dependent on pump-driven blood flow and does not require the insertion of a large-bore catheter into an artery. Thus, various modalities of hemofiltration can offer an alternative to the critically ill child with acute renal failure.

Collaborative development of a patient simulator for educating nurses in hemofiltration therapies

As the complexity and variety of the treatment modalities in critical care continue to expand, the clinician is faced with the task of providing a safe environment for the education of staff and the evaluation of these new modalities. The use of simulators, similar to the one described in this article, is one economical solution that can provide this education and evaluation. For instance, the major components of the hemofiltration simulator can be fabricated and purchased for under $1,000. This estimate excludes the medical cart, which retails for $437. The success of such a solution, however, necessitates that the simulator meet the defined clinical needs while meeting or exceeding the biomedical equipment standards set by AAMI or other regulatory agencies that might govern the use of such devices.

An experience of renal replacement therapy in a combined neonatal and paediatric intensive care unit of Hong Kong

Intensive care services are expensive. The experience of developing a combined paediatric and neonatal intensive care unit (ICU) in a regional hospital is reported with reference to the provision of renal support for the critically ill patients. The combined unit is staffed by a team of paediatric intensivists, each of whom has special interest in a subspecialty, including cardiology, respiratory medicine, nephrology and neonatology. In the past 7 years, renal replacement therapy (peritoneal dialysis and haemofiltration) was provided to 40 patients, with comparable mortality and complication rates to other reports. This arrangement has been feasible and might be more efficient than running separate paediatric and neonatal ICUs or combining the paediatric ICU with the adult ICU.

Continuous arteriovenous hemofiltration with dialysis (CAVH-D): an alternative to hemodialysis in the mass casualty situation

Renal failure is a common sequela of mass casualty, particularly when crush injury is involved. Traditional management of renal failure with hemodialysis equipment may be difficult or inaccessible due to lack of electricity and water supply or damage to existing equipment. Furthermore, a sudden new population of renal failure patients may overwhelm an existing dialysis program. The rapid mobilization of traditional hemodialysis equipment may be delayed due to limited supply, manufacturing delays, or inventory shortages. For these reasons, we propose the use of continuous arteriovenous hemofiltration with dialysis (CAVH-D) as an alternative renal support modality for the mass casualty situation.

Hemofilter reuse in maintenance hemofiltration

The practice of multiple use of hemofilter was examined on 16 patients in our dialysis center. The hemofilters were cleaned by reverse ultrafiltration using positive pressure in the blood and filtrate compartment of the hemofilter. Ten hemofilters used for continuous arteriovenous hemofiltration, 6 hemofilters used for pump-assisted acute hemofiltration and seventy hemofilters used for chronic maintenance hemofiltration were studied for the clearances of urea nitrogen and creatinine and sieving coefficients of albumin and electrolytes. Hemofilters were successfully reused in pump-assisted acute hemofiltration and chronic hemofiltration. In continuous arteriovenous hemofiltration, hemofilters could not be reused mainly because of clotting of fibers. The practice is safe, efficient and highly cost-saving.