Effects of propofol on oesophageal sphincters: a study on young and elderly volunteers using high-resolution solid-state manometry

Background and objective The oesophageal sphincters play an important role in protecting the airway. During manometric studies, administration of an anxiolytic agent is often required to make insertion of the catheter acceptable for the patient. The anxiolytic should not affect the results of the measurements. This study evaluates the effects of two different doses of propofol on the pressures in the oesophageal sphincters. The effect of increased abdominal pressure was also studied. Methods Twenty healthy volunteers, 10 young (mean age 25 years) and 10 elderly (mean age 71 years), were recruited. The effects of a low dose of propofol [0.3 mg kg(-1) intravenously (i.v.)] and a high dose of propofol (young group 0.9 mg kg(-1) i.v. and elderly group 0.6 mg kg(-1) i.v.) were studied with and without external abdominal pressure. Results There were no statistically significant changes in lower oesophageal sphincter (LOS) pressure after the low dose of propofol. After the high dose, there was an increase in LOS pressure, which was statistically significant in the young group (P < 0.05). The upper oesophageal sphincter (UOS) pressure decreased after both doses of propofol (P < 0.01 for the higher dose and P < 0.05 for the lower dose). Conclusion A low dose of propofol (0.3 mg kg(-1) i.v.) leaves the LOS unaffected in young and elderly volunteers and can be used safely as an anxiolytic agent during studies of the LOS without influencing the results. However, the UOS is more sensitive to the effects of propofol and we do not recommend the use of propofol as an anxiolytic agent during manometric studies of the UOS. Eur J Anaesthesiol 2011;28:273-278 Published online 30 November 2010