PLASMA BUPIVACAINE LEVELS AFTER FASCIA ILIACA COMPARTMENT BLOCK WITH AND WITHOUT ADRENALINE

Twenty children undergoing unilateral surgery on the thigh received a fascia iliaca compartment block using 2 mgkg(-1) of bupivacaine with ( Group A) or without (Group P) adrenaline 1/200 000. Venous blood sampl es were taken as 5, 10, 15, 20, 25, 30, 40, 50 and 60 min after inject ion and assayed for concentrations of bupivacaine. In all subjects an adequate block was produced. Plasma concentrations of bupivacaine in G roup P were significantly higher than those in Group A (P<0.05). The m edian maximum plasma concentration (C-max) was 1.1 mu g.ml(-1) (range 0.54-1.29 mu g.ml(-1)) in Group P and 0.35 mu g ml(-1) (range 0.17-0.9 6 mu g ml(-1)) in Group A. The median time taken to attain C-max (T-ma x) was 20 min (range 10-25 min) in Group P and 45 min (range 5-50 min) in Group A. The median time to first analgesia was 9.75 h (range 3-15 h) in Group P and 10.5 h (range 2.5-21h) in Group A. The study confir med the efficacy of the fascia iliaca compartment block in children an d showed that when performed with 2 mg kg(-1) of bupivacaine it is ass ociated with plasma concentrations of bupivacaine well within acceptab le limits. The addition of adrenaline 1/200 000 to the local anaesthet ic solution reduces the maximum plasma concentration reached.