Fig. 2. Changes in the median (range) upper level of cold sensation blockade with time in patients receiving 10 mg of intrathecal isobaric (IB,  upper panel ) or hyperbaric (HB,  lower panel ) bupivacaine. Areas represent the range observed in each group (filled with horizontal bars for the 2-ml group; with diagonal bars for the 5-ml group, and grey for the 10-ml group). The time course and duration of cold sensation blockades were not modified by the volume of IB and HB bupivacaine. The duration of cold sensation block was longer with IB than with HB solutions.