Thursday, February 13, 2014

Dialysis Technology: Application of dialysis in acute renal failure !

Our kidneys are destined to perform excretory as well as regulatory function to maintain a state of homoeostasis in our body. Acute renal failure (ARF) is a syndrome defined as sudden or rapid loss of renal function (kidney function) leading to accumulation of urea and creatinine (nitrogenous waste compounds). If hyperbolic relationship between plasma creatinine or urea and glomerular filtration rate (GFR) is observed after investigations, the diagnosis is established as ARF. The early clinical signs of ARF/uremia are anorexia, nausea, vomiting, and sometimes pericarditis also. The ARF is an implication of loss of more than 50% of renal function. Dialysis should be instituted whenever early signs of uremia (elevated levels of urea in the blood) are present. Cases of metabolic acidosis as well as electrolyte and fluid imbalance also need dialysis for the reversal of hemodyanmics to normal.

Dialysis is a procedure for artificially purifying the blood of a patient through meticulous surgical intervention and electromechanical equipment. No specific elevated value of plasma creatinine or urea could be regarded as critical. The fluid intake and nutritional requirements are taken into consideration for deciding the timing and mode of dialysis. Cases of ARF should be put on dialysis without much delay for the successful recovery of their renal function. However, cases of chronic renal failure (CRF) may be kept in waiting. The dialysis procedure is of two types: i)  Hemodialysis (where patient's blood is passed through artificial kidney in conjunction with dialysis solution) and ii)  Peritoneal dialysis (where dialysis fluid is passed through the abdominal peritoneal cavity of the patient). The technique of dialysis was established long back in USA by Dr. Alan P Kendal, who also patented a 'suitcase kidney' in 1978.

Conventional hemodialysis remains the preferred and the best mode of dialysis. The hemodialysis is ideal for non-hypotensive and hemodynamically stable patients. Peritoneal dialysis is probably less effective in patients with hypercatabolic disorder and/or with undiagnosed abdominal disease. Peritoneal dialysis should be avoided in patients with recent abdominal surgery. The surgical intervention for hemodialysis can be in the following ways: i)  Continuous arteriovenous hemofiltration (CAVH), ii)  Continuous arteriovenous hemofiltration with/without concomitant dialysis (CAVHD), iii)  Continuous veno-venous filtration (CVVHD). These hemodialysis techniques are simpler, safe and very effective. The biochemical recovery is monitored during the dialysis for needful correction of fluid and electrolytes. After successive dialysis sessions the patient would return to normal health.