[Risk of secondary neuromuscular blockade after autotransfusion of blood drawn from the patient following curare administration].

A secondary neuromuscular blockade can occur after transfusion of autologous blood withdrawn after injection of muscle relaxants. In this study time course of muscle relaxation after transfusion of blood withdrawn before or after administration of atracurium (A) or vecuronium (V) was assessed. Forty adults undergoing haemorrhagic urologic surgery were included in the study. After induction of general anaesthesia and intubation of the trachea facilitated by local lidocaine, they were divided into 4 groups. In groups A1 and V1 the blood units were withdrawn before injection of atracurium 0.5 mg.kg-1 or vecuronium 0.1 mg.kg-1. In group A2 and V2 the blood units were withdrawn after administration of muscle relaxants. Haematocrit was decreased to 0.30. The last bolus of these muscle relaxant was injected 30 min before the end of surgical procedure. Autologous blood was transfused when train of four (T4R) recovered to 0.80. Electromyographic elicited responses to T4R stimulation were obtained every minute during the 4 first minutes after the beginning of transfusion (T1 to T4), thereafter every minute during the 5 first minutes after the end of transfusion (T5 to T9), and finally every 5 minutes for 10 minutes (T10 and T11). There was a secondary neuromuscular blockade in patients of groups A2 and V2. The intensity of blockade was more important after vecuronium than after atracurium (p < 0.01 from T2 to T11 between groups A2 and V2). In group A2, the T4R had not reached the control level at the end of the procedure (0.78 at T11 vs 0.80 at T0). These data emphasize the importance of withdrawing blood units before administration of muscle relaxants.(ABSTRACT TRUNCATED AT 250 WORDS)