Risk and preventative measures for postoperative acute renal failure [ARF]: a prospective controlled study

The extracorporeal circulation used during open heart surgery is associated with a significant decline in renal blood flow that can result in tubular injury. Although this complication is uncommon, it carries a poor prognosis. Although many experimental trials have highlighted the significant value of some pharmaceuticals in prevention of post ischaemic renal tubular injuries, few clinical trials are found. We aimed in this study to evaluate the efficacy of 4 drugs in the prevention of acute tubular necrosis [ATN] following open heart surgery. Patients received either diltiazem, captopreil, allopurinol or the antioxidant formula antox [n = 20 per agent], 20 control cases received placebo. Groups were matched in age, gender, type of cardiac disease, preoperative cardiac and kidney function and type of surgery. AII patients received the appointed agent for 1- week pre- and post- operative. Each group included 6 cases that underwent coronary bypass, 8 value replacements or repair and 6 total correction of congenital defects. In order to ascertain risk factors each case underwent a comprehensive history taking, clinical examination, 12 lead ECG, chest X-ray, echocardiography, arterial blood gas analysis, complete blood count, fasting and 2 hours post prandial [PP] blood sugar, coagulation profile, liver function tests, blood urea nitrogen [BUN], serum creatinine [Sc], creatinine clearance [CC], urine analysis and urine albumin/creatinine ratio [Alb/cr]. The total operation, total pump and ischaemic times were recorded for each case intra-operative as well as the use of any inotropes, vasopressors or diuretics and the occurrence of haematuria or haemoglobinuria. AII kidney function tests were repeated on the 1st, 4th and 7th post operative days. AII groups showed a postoperative significant increase in BUN, Sc, and Alb/cr and a significant decrease in CC; these changes were least with diltiazem. A highly significant correlation between preoperative Alb/cr and postoperative Sc was found for the population as whole [p<0.001]. ATN occurred only in coronary artery bypass graft, aortic valve, multiple valve and total correction of Fallot's IV patients. The incidence of ATN, duration of oliguria and need for dialysis were least with diltiazem, [P=0.05]. No single mortality was reported in either the diltiazem or allopurinol groups. In conclusion, prophylactic administration of diltiazem, to high risk patients help reduce mortality, incidence and duration of ATN, the need for dialysis and costs of hospital stay, Allopurinol is a good alternative in patients with poor left ventricular function

Bicarbonate versus acetate dialysate in long term haemodialysis: impact on acid-base status, delivered Kt/V and protein nutritional status. A prospective crossover study

We selected 40 cases of chronic renal failure [CRF] [25 males and 15 females] on thrice weekly haemodialysis [HD] using acetate for at least 1 year before study onset. All cases were allowed unrestricted protein intake starting one month before they were randomly divided into 2 groups matched for age, gender, body weight [BW] and socioeconomic status, Group 1 were shifted to bicarbonate dialysis while Group 2 patients were kept on acetate dialysis for 3 months then cross over was done for the following 3 months. Both biocarnonate and acetate were used at a fixed concentration of 36 mmol/L. Prescribed Kt/V was kept constant throughout the 6 months. Pre and post dialysis [Dx] blood pH and serum bicarbonate [Sbic].predialysis serum prealbumin [Spalb], and transferring [Stf], triceps skin fold thickness [TSF], mid arm muscle circumference [MAMC] as well as protein catabolic rate [PCR and nPCR] and urea reduction ratio [URR] were estimated at the onset and at the end of each 3 month period. Delivered kt/V was estimated from URR. Pre Dx Sbic and pH were significantly higher during bicarbonate dialysis compared to acetate dialysis [p<0.001]. Spalb increased significantly in Group 1 during bicarbonate and decreased significantly during acetate dialysis [p<0.00011 and 0.06,respectively] while in Group 2 it increased significantly in both periods [p<0.05 and 0.004.respectively]. Stf didn't show any significant change throughout the study. TSF, MAC and MAMC increased significantly in Group 1 during bicarhonate dialysis and decreased significantly during acetate dialysis [p<0.001,0.02.0.001,0.05,0.004 and 0.03,respectively for TSF, MAC and MAMC at 0,3 months and MAMC at 0,3 months and 6 months] while in Group 2 they did not change during acetate dialysis and increased significantly during bicarbonate dialysis [p<0.05,<0.002.>0.05, <0.03, >0.05 and <0.05, respectively]. nPCR increased significantly in Group 1 during bicarbonate dialysis and did not change during acetate dialysis [p<0.001 and >0.05, respectively] while in Group 2 nPCR did not change during acetate dialysis and increased significantly during bicarbonate dialysis [p>0.05 and >0.05, respectively]. Although prescribed Kt/V did not change throughout the study, delivered Kt/V increased significantly in Group 1 during bicarbonate dialysis and decreased significantly during acetate dialysis [p<0.001 and < 0.02, respectively]. In Group 2 delivered Kt/V did not change during acetate dialysis and increased significantly during bicarbonate dialysis [p>0.5 and <0.0001, respectively]. Conclusions: 1. Bicarbonate dialysis offers better blood pH and Sbic levels 2. Optimized serum pH and bicarbonate offers improvement in protein intake evidenced by increased nPCR associated with improved protein anabolism as evidenced by increased Spalb, TSF, MAC and MAMC. 3. Increased delivered Kt/V is likely due to better patient compliance during bicarbonate haemodialysis