Oesophageal contractility during total i.v. anaesthesia with and without glycopyrronium

Somatic movement and spontaneous and provoked oesophageal contractions were noted at time of incision in 51 patients receiving total i.v. anaesthesia with alfentanil and propofol. Probit analysis of the dose of propofol required to prevent spontaneous movement revealed an ED50 (95% confidence limits) of 2.5 (1.8-2.9) mg kg(-1) h(-1) and ED95 of 4.7 (4.0-7.5) mg kg(-1) h(-1). Corresponding venous blood concentrations gave an EC50 of 1.2 (0.4-1.6) micrograms ml(-1) and an EC95 of 4.0 (2.8-18.5) micrograms ml(-1). ED50 of propofol for preventing spontaneous oesophageal contraction was 3.0 (1.9-3.6) mg kg(-1) h(-1). ED95 was 6.9 (5.0-27.3) mg kg(-1) h(-1); EC50 for oesophageal contractions was 1.7 (0.7-2.3) micrograms ml(-1) and EC95 was 5.9 (3.7-70.6) micrograms ml(-1). Another group of 10 patients were given glycopyrronium 5 micrograms kg(-1) at induction; oesophageal contractility was significantly reduced in this group.