The effect of low serum bicarbonate values on the onset of action of local anesthesia with vertical infraclavicular brachial plexus block in patients with end-stage renal failure.

Vertical infraclavicular brachial plexus block is utilized in patients with chronic renal failure at the time of creation of an arterio-venous fistula (AVF). The aim of this study is to test the effect of impaired renal function, with the resulting deranged serum electrolytes and blood gases, on the success rate and the onset of action of the local anesthetics used. In this prospective clinical study, we investigated the effect of the serum levels of sodium, potassium, urea, creatinine, pH, and bicarbonate on the onset of action of a mixture of lidocaine and bupivacaine administered to create infraclavicular brachial plexus block. A total of 31 patients were studied. The success rate of the block was 93.5 % (29 patients). The mean onset time for impaired or reduced sensation was found to be 8.9 +/- 4.7 mins and for complete loss of sensation, was 21.2 +/- 6.7 mins. There was no significant association with serum sodium, potassium, urea, creatinine or the blood pH level (P > 0.05). The bivariate correlation between serum bicarbonate level and the partial and complete sensory loss was -0.714 and -0.433 respectively, with significant correlation (P = 0.00, 0.019). Our study suggests that infraclavicular block in patients with chronic renal failure carries a high success rate; the onset of the block is delayed in patients with low serum bicarbonate levels.