Interaction between nondepolarizing neuromuscular blocking agents and inhalational anesthetics.

Although many studies have presented data based on administration of nondepolarizing neuromuscular blocking agents to patients given inhalation anesthesia for 30-45 min, no data exist on the interaction in a clinical situation where the relaxant is administered immediately after the start of anesthesia. We therefore studied the effect of the commonly used inhalation anesthetics, halothane and enflurane, on the clinical pharmacology of atracurium, vecuronium, pipecuronium, and pancuronium. No significant influence of the anesthetic technique on the onset time of the various neuromuscular blocking agents was observed. The duration of action of atracurium, pipecuronium, and pancuronium was significantly prolonged during enflurane anesthesia as compared with the other two anesthetic techniques. The duration of vecuronium blockade was not significantly influenced by enflurane. Halothane, in contrast to enflurane, did not significantly prolong the blockade induced by these agents. The prolongation of atracurium blockade was clinically irrelevant. A fact that is statistically significant but clinically irrelevant is that a cumulative effect with atracurium and vecuronium was only seen during enflurane anesthesia and after the fourth maintenance dose. We conclude that there is no clinical indication that the dosage of atracurium and vecuronium during inhalation anesthesia should be reduced, but the doses of pipecuronium and pancuronium should be reduced when prolonged paralysis is not desired.

Haemodynamic effects of vecuronium.

Three hundred and twenty adults (ASA grade I, both sexes), received diazepam 10 mg by mouth (50% received atropine 7 micrograms kg-1 in addition) i.m. 45 min before operation. Patients were then allocated randomly to undergo general anaesthesia with either a nitrous oxide-neurolept technique or nitrous oxide-halothane. Vecuronium was administered to 50% of the patients in each anaesthetic group and heart rate and arterial pressure were monitored. Vecuronium did not influence heart rate, or systolic or diastolic arterial pressures.

Interaction between pancuronium bromide and vecuronium bromide.

The interaction between two non-depolarizing neuromuscular blocking agents, pancuronium bromide and vecuronium bromide, has been studied at standardized levels of neuromuscular blockade and alternating the sequence of their administration, in 40 surgical patients. The drug administered first appeared invariably to play a dominant role in influencing both the dose requirements and the duration of action of the subsequent neuromuscular blocker. This resulted in reduced dose requirements and significant prolongation of action of vecuronium administered after pancuronium and increased dose requirements and shortening of neuromuscular blocking action of pancuronium given during vecuronium-induced partial neuromuscular blockade. Possible mechanisms of such interaction are discussed.

Three years' anaesthetic experience with the Groningen Nd YAG laser coagulation technique.

The use of the Neodymium YAG Laser technique in the palliative treatment of tracheo-bronchial tumors in 47 patients is described and the merits of the coagulation and anaesthetic techniques are discussed.