Does Sodium Bicarbonate Reduce the Pain of Lidocaine for Local Anesthesia in Percutaneous Breast Biopsies?

The purpose of this study is to determine the benefit, if any, of buffering lidocaine (adding sodium bicarbonate) when used for local anesthesia prior to percutaneous breast needle core biopsies. The medicine doctors use to reduce the pain of breast biopsies, lidocaine, can cause pain for approximately 15 seconds until the numbing effect begins. It is possible that this pain is caused because lidocaine is acidic. Some physicians believe that reducing the acidity of lidocaine by mixing it with sodium bicarbonate will reduce the initial pain of injecting the lidocaine. Both approaches - injecting 1% lidocaine alone and injecting 1% lidocaine mixed with sodium bicarbonate - are used as routine standard of care by radiologists today. The purpose of this study is to determine if either approach is more comfortable for patients having breast procedures.