Dialysis & Ultrafiltration Techniques

So, I’ve decided to dialyse the patient, what modes are available to me?

Intermittent hemodialysis is the most efficient – large amounts of fluid can be removed and electrolyte abnormalities can be rapidly corrected. However, this is not suitable in unstable patients: 20-30% of patients with ARF who are being hemodialysed become hypotensive, with huge associated osmotic shifts – disequilibrium syndrome. Many ICU patients are intolerant of such shifts. Moreover it appears that the hemodynamic changes that occur during hemodialysis (hypotension) may worsen the pre-existing renal injury by increasing the ischemic insult.

Peritoneal dialysis has the advantage of being simple and cost effective. The major disadvantages of PD are – poor solute clearance, poor uremic control, risk of peritoneal infection and mechanical obstruction of pulmonary and cardiovascular performance.

Continuous hemodiafiltration techniques were developed to overcome these deficiencies. In critical illness the phenomenon of capillary leak increases the interstitial volume and makes patients edematous. This makes the clearance of solute difficult to calculate and indeed to carry out. Continuous techniques lead to more effective urea clearance and more controlled fluid removal.

Please note: these tutorials are for personal study purposes only.  They are not currently peer reviewed, and no responsibility will be taken for mistakes or inaccuracies. Reproduction of information is forbidden. All material is copyrighted by the GasWorks Group.