Large bolus dose vs. continuous infusion of cisatracurium during hypothermic cardiopulmonary bypass surgery.
OBJECTIVE
We investigated whether a high bolus dose of cisatracurium (8x ED95) given at induction can provide muscle relaxation for the major part of a cardiac procedure with hypothermic cardiopulmonary bypass, avoid important postoperative residual curarization and cause no waste of product.


METHODS
Twenty patients were randomly assigned either to Group 1 (n = 10) or Group 2 (n = 10). Those in Group 1 were given cisatracurium in a high bolus dose (0.4 mg kg(-1)). Those in Group 2 received cisatracurium 0.1 mg kg(-1) at induction followed after 30 min by a continuous infusion of cisatracurium. As an escape medication in case of patient movement, a bolus dose of cisatracurium 0.03 mg kg(-1) was given.


RESULTS
In Group 1 (large cisatracurium bolus dose), the clinical duration of effect (until T1/T0 = 25%) was 110 min. Six of 10 patients in Group 1 required additional boluses of cisatracurium intraoperatively. Four of these six had received an additional bolus near the end of surgery and had a train-of-four (TOF) ratio = 0 at the end. The other four patients in Group 1 had a final TOF ratio >0.9. In Group 2 (continuous cisatracurium infusion), only two patients had a TOF ratio >0.9 at the end of surgery, no patient moved and none received additional boluses. The total amount of cisatracurium used in the bolus and infusion Groups was 34.5 +/- 7.8 and 21.3 +/- 5.7 mg, respectively (P = 0.0004).


CONCLUSIONS
For continued neuromuscular block during hypothermic cardiac surgery, a high bolus dose of cisatracurium appears to be safe, although it is not an alternative to a continuous infusion, as its neuromuscular blockade does not cover the intraoperative period and a high incidence of movements occurs. In the patients who received a high bolus dose of cisatracurium, postoperative residual curarization appeared after additional boluses had been given. The consumption of cisatracurium by high bolus was significantly greater than with continuous infusion.
Cammu
G
G
O.L.V. Clinic, Department of Anaesthesia and Critical Care Medicine, Aalst, Belgium. Guy.Cammu@olvz-aalst.be
Boussemaere
V
V
Foubert
L
L
Hendrickx
J
J
Coddens
J
J
Deloof
T
T
D000368:Aged; D001279:Atracurium / Q000008:administration & dosage*; D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced; D007262:Infusions, Intravenous; D008297:Male; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage*; D011229:Preanesthetic Medication; D009435:Synaptic Transmission
D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium