[Clinical administration of muscle relaxants for intubation]

Muscle relaxants are used for tracheal intubation, surgical procedures and in the intensive care unit. This review describes muscle relaxants available in Germany, with special focus on their use in endotracheal intubation. We compare the advantages and disadvantages of succinylcholine (the only depolarising agent) with those of short- and intermediate-acting non-depolarising agents in an attempt to define the characteristics of the ideal muscle relaxant. The effective doses required to attain 95% neuromuscular block and maximum effect (onset time) are compared for adults and children. It is documented that, with non-depolarising agents, increasing the dose and using either the priming or timing principle possibly reduce the onset time of neuromuscular block during a rapid sequence induction. The advantages and disadvantages of using non-depolarising instead of depolarising agents are discussed using data from our studies and those of other research groups. Possible side-effects due to the chemical structure and the necessary dosage for intubation of different agents are also discussed. Two points are emphasized: firstly, the use of non-depolarising agents for intubation requires the possibility of safe ventilation of the patient via mask, and, secondly, it is important that procedures be performed by an experienced anaesthetist.