Hyperkalaemia associated with haemorrhagic shock in rabbits: modification by succinylcholine, vecuronium and blood...

In haemorrhagic patients, hyperkalaemia may occur after succinylcholine administration. We investigated in haemorrhagic rabbits whether vecuronium caused hyperkalaemia and if blood transfusion prevented succinylcholine-induced hyperkalaemia. Rabbits were lightly anaesthetized with halothane/N2O and 30-35 ml/kg blood were withdrawn to cause arterial pH to decrease to approximately 7.0-7.1. Group C (n = 12) received 3 ml saline, Group S (n = 13) received succinylcholine 1 mg/kg, Group V (n = 7) received vecuronium 0.25 mg/kg and Group T (n = 9) was transfused with 10 ml/kg blood 10 min prior to receiving succinylcholine 1 mg/kg. K+ analysis was repeated at 5 min, and at 10 min in most animals. Haemorrhage increased K+ (nmol.1-1, mean +/- SD): Group C, 3.4 +/- 0.3 to 6.8 +/- 1.8; Group S, 3.8 +/- 0.5 to 6.9 +/- 2.3; Group V, 3.8 +/- 0.3 to 7.1 +/- 1.9; Group T, 3.6 +/- 0.5 to 7.6 +/- 2.9. K+ decreased in Group T (to 5.4 +/- 1.8) after blood transfusion. K+ increased at 5 min in Group S (to 8.7 +/- 2.6) and at 10 min for Group C (to 8.4 +/- 1.7) and Group T (to 7.2 +/- 2.3). The K+ increase at 5 min for Group S (1.8 +/- 0.8) was significantly higher than those for Group C (1.0 +/- 0.6) or Group V (0.9 +/- 0.4), but was not different from that of Group T (1.5 +/- 0.7). We conclude that haemorrhage and succinylcholine cause hyperkalaemia in rabbits. Muscle relaxation itself does not appear to be a factor, but transfusion may lessen the hyperkalaemia.