The effect of pH buffering on reducing the pain associated with subcutaneous infiltration of bupivicaine [published erratum appears in Am J Emerg Med 1991 Jul;9(4):410]
 The authors propose that pH buffering of bupivicaine with sodium bicarbonate reduces the pain associated with its local subcutaneous infiltration.
 In a double-blind, prospective study, 62 healthy adult volunteers received a 0.5 mL subcutaneous infiltration of 0.5% buffered bupivicaine into the dorsum of a randomly chosen hand.
 The pH was adjusted to 7.0 by adding 0.05 mL of sodium bicarbonate (1 mEq/L [corrected]) to 10 mL vials of commercially available bupivicaine (1:200 dilution).
 The control hand was injected with the same amount of unbuffered agent.
 Pain was scored after each infiltration using a nonsegmented visual analogue scale.
 Student's t-test for paired measurements was used to analyze intergroup pain score differences.
 Forty-three subjects (69%) reported less pain with buffered bupivicaine and only 17 (27%) noted a modest increase: two subjects (3%) reported no difference.
 The mean pain score for the buffered agent was 22 mm compared with 30 mm for the control.
 The mean difference (control-experimental) was 8 mm (t = 4.64, df = 61, P less than .001).
 The authors conclude that the addition of sodium bicarbonate to bupivicaine reduces the pain associated with its local infiltration.
