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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/03/29 16:38:25」(JST)

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In medicine, hemofiltration, also haemofiltration, is a renal replacement therapy similar to hemodialysis which is used almost exclusively in the intensive care setting. Thus, it is almost always used for acute renal failure. It is a slow continuous therapy in which sessions usually last between 12 to 24 hours and are usually performed daily. During hemofiltration, a patient's blood is passed through a set of tubing (a filtration circuit) via a machine to a semipermeable membrane (the filter) where waste products and water are removed. Replacement fluid is added and the blood is returned to the patient.

1 The Principle of Hemofiltration
2 Replacement fluid composition
3 Hemodiafiltration
4 Intermittent vs. continuous modes of therapy
- 4.1 On-line intermittent hemofiltration (IHF) or hemodiafiltration (IHDF)
- 4.2 Continuous hemofiltration (CHF) or hemodiafiltration (CHDF)
5 Is on-line intermittent hemodiafiltration (IHDF) better than regular hemodialysis?
6 References
7 See also
8 External links

The Principle of Hemofiltration

As in dialysis, in hemofiltration one achieves movement of solutes across a semi-permeable membrane. However, solute movement with hemofiltration is governed by convection rather than by diffusion. With hemofiltration, dialysate is not used. Instead, a positive hydrostatic pressure drives water and solutes across the filter membrane from the blood compartment to the filtrate compartment, from which it is drained. Solutes, both small and large, get dragged through the membrane at a similar rate by the flow of water that has been engendered by the hydrostatic pressure. Thus convection overcomes the reduced removal rate of larger solutes (due to their slow speed of diffusion) seen in hemodialysis.

Replacement fluid composition

An isotonic replacement fluid is added to the blood to replace fluid volume and electrolytes. The replacement fluid must be of high purity, because it is infused directly into the blood line of the extracorporeal circuit. The replacement hemofiltration fluid usually contains lactate or acetate as a bicarbonate-generating base, or bicarbonate itself. Use of lactate can occasionally be problematic in patients with lactic acidosis or with severe liver disease, because in such cases the conversion of lactate to bicarbonate can be impaired. In such patients use of bicarbonate as a base is preferred.

Hemodiafiltration

Hemofiltration is sometimes used in combination with hemodialysis, when it is termed hemodiafiltration. Blood is pumped through the blood compartment of a high flux dialyzer, and a high rate of ultrafiltration is used, so there is a high rate of movement of water and solutes from blood to dialysate that must be replaced by substitution fluid that is infused directly into the blood line. However, dialysis solution is also run through the dialysate compartment of the dialyzer. The combination is theoretically useful because it results in good removal of both large and small molecular weight solutes..

Intermittent vs. continuous modes of therapy

These treatments can be given intermittently, or continuously. The latter is usually done in an intensive care unit setting.

On-line intermittent hemofiltration (IHF) or hemodiafiltration (IHDF)

Either of these treatments can be given in outpatient dialysis units, three or more times a week, usually 3-5 hours per treatment. IHDF is used almost exclusively, with only a few centers using IHF. With both IHF or IHDF, the substitution fluid is prepared on-line from dialysis solution by running dialysis solution through a set of two membranes to purify it before infusing it directly into the blood line. In the United States, regulatory agencies have not yet approved on-line creation of substitution fluid because of concerns about its purity. For this reason, hemodiafiltration is almost never used in an outpatient setting in the United States as of 2007. Use of sterile, pre-packaged substitution fluid would be cost-prohibitive in the current economic environment.

Continuous hemofiltration (CHF) or hemodiafiltration (CHDF)

Hemofiltration is most commonly used in an intensive care unit setting, where it is either given as 8-12 hours treatments, so called SLEF (slow extended hemofiltration), or as CHF (continuous hemofiltration also sometimes called continuous veno-venous hemofiltration (CVVH)) or Continuous Renal Replacement Therapy (CRRT). Hemodiafiltration (SLED-F or CHDF or CVVHDF) also is widely used in this fashion. In the United States, the substitution fluid used in CHF or CHDF is commercially prepared, prepackaged, and sterile (or sometimes is prepared in the local hospital pharmacy), avoiding regulatory issues of on-line creation of replacement fluid from dialysis solution.

With slow continuous therapies, the blood flow rates are usually in the range of 100-200 ml/min, and access is usually achieved through a central venous catheter placed in one of the large central veins. In such cases a blood pump is used to drive blood flow through the filter. Native access for hemodialysis (eg AV fistulas or grafts) are unsuitable for CHF because the prolonged residence of the access needles required might damage such accesses.

Is on-line intermittent hemodiafiltration (IHDF) better than regular hemodialysis?

There is controversy about whether intermittent on-line hemodiafiltration (IHDF) gives better results than hemodialysis in an outpatient setting. In Europe, several observational studies have compared outcomes in patients getting dialysis with those getting IHDF. These have suggested a lower mortality rate and other favorable outcomes in patients getting IHDF vs. those getting ordinary hemodialysis. ^[1] However, the issue is not settled at this time, because the required randomized controlled clinical trials have not been done. Another problem has been that in several of the trials done, IHDF was compared to dialysis using low-flux (small pore) membranes, and the benefit found may have been due more to the use of a high-flux membrane than to the addition of convective transport (filtration) to dialysis. A recent Cochrane database review ^[2] of available trials could not find a definite benefit of either IHF or IHDF vs. hemodialysis in terms of outcomes.

References

^ Canaud B, Bragg-Gresham JL, Marshall MR, Desmeules S, Gillespie BW, Depner T, Klassen P, Port FK. Mortality risk for patients receiving IHDF versus hemodialysis: European results from the DOPPS. Kidney Int. 2006 Jun;69(11):2087-93. PMID 16641921
^ Rabindranath KS, Strippoli GF, Daly C, Roderick PJ, Wallace S, MacLeod AM. Haemodiafiltration, haemofiltration and haemodialysis for end-stage kidney disease. Cochrane Database Syst Rev. 2006 Oct 18;(4):CD006258. Review. PMID 17054289

External links

http://vam.anest.ufl.edu/dialysis/ A free interactive simulation of a CVVH machine

UpToDate Contents

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1. 持続的腎代替療法：概要 continuous renal replacement therapies overview
2. 末期腎不全における他の腎代替療法 alternative renal replacement therapies in end stage renal disease
3. 急性腎障害（急性腎不全）における持続的腎代替療法 continuous renal replacement therapy in acute kidney injury acute renal failure
4. 毒物除去の強化 enhanced elimination of poisons
5. 持続的腎代替療法中の薬物除去 drug removal during continuous renal replacement therapy

English Journal

[From the coronary care unit to the intensive cardiac care unit: the evolution of the Cardiovascular Department of a tertiary center].

Ferri L, Farina A, Lenatti L, Malafronte C, Ruffa F, Piatti L, Maggiolini S, Lorenzi G, Gamba A, Catena E, Achilli F.AbstractBackground. Substantial changes have occurred over time in the diagnoses, procedures and characteristics of patients admitted to coronary care units (CCU). Following the introduction of cardiac surgery activity in our hospital in December 2009, the aim of this study was to evaluate the changes in activity, processes of care and outcomes of patients consecutively admitted to our CCU after the reorganization of the Cardiovascular Department.Methods. All 1674 consecutive patients admitted to the CCU from January 2009 to December 2010 were enrolled in this retrospective registry.Results. In 2010, the number of patients referred from other hospitals or wards significantly increased (from 17.2% to 28.3%; p<0.001). Significant was also the increase of patients with ST-elevation myocardial infarction (n=190 to n=230, p<0.001), shock (n=20 to n=50, p<0.001), pulmonary edema (n=47 to n=64, p<0.05), cardiac arrest (n=2 to n=8, p<0.05), aortic dissection (n=0 to n=12; p<0.001). Conversely, the number of patients admitted for acute coronary syndromes without ST-segment elevation and GRACE risk score <140 significantly decreased (n=169 to n=52, p<0.001). In parallel, a significant increase in the use of intra-aortic balloon pump (2.0% to 5.6%, p<0.001), continuous hemofiltration (0.3% to 3.1%, p>0.001), non-invasive ventilation (5.6% to 10.5%, p<0.001) and mechanical ventilation (0% to 4.1%, p<0.001) was observed. Intensive care devices were more frequently used in the subgroups affected by shock, acute coronary syndromes without ST-segment elevation and GRACE risk score >200, and heart failure. Interestingly, despite the increase in high-risk clinical conditions the intra-CCU mortality did not change (3.1 vs 2.9%). Conclusions. Patients admitted to the CCU have high-risk acute clinical conditions. A model based on the sharing of cardiological, cardiac anesthesiological and surgical expertise is effective in increasing admission appropriateness and improving standards of care in a short period of time.
Giornale italiano di cardiologia (2006).G Ital Cardiol (Rome).2012 Sep;13(9):607-14. doi: 10.1714/1133.12489.
Background. Substantial changes have occurred over time in the diagnoses, procedures and characteristics of patients admitted to coronary care units (CCU). Following the introduction of cardiac surgery activity in our hospital in December 2009, the aim of this study was to evaluate the changes in ac
PMID 22825346

Predictors of haemoglobin levels and resistance to erythropoiesis-stimulating agents in patients treated with low-flux haemodialysis, haemofiltration and haemodiafiltration: results of a multicentre randomized and controlled trial.

Locatelli F, Altieri P, Andrulli S, Sau G, Bolasco P, Pedrini LA, Basile C, David S, Feriani M, Nebiolo PE, Ferrara R, Casu D, Logias F, Tarchini R, Cadinu F, Passaghe M, Fundoni G, Villa G, Di Iorio BR, Zoccali C.SourceCorrespondence and offprint requests to: Francesco Locatelli; E-mail: f.locatelli@ospedale.lecco.it.
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association.Nephrol Dial Transplant.2012 Sep;27(9):3594-600. Epub 2012 May 23.
Background Predictors of haemoglobin (Hb) levels and resistance to erythropoiesis-stimulating agents (ESAs) in dialysis patients have not yet been clearly defined. Some mainly uncontrolled studies suggest that online haemodiafiltration (HDF) may have a beneficial effect on Hb, whereas no data are av
PMID 22622452