1. ¹Faculté de Médecine Pierre et Marie Curie, Service de biochimie médicale et biologie moléculaire, Paris, France
2. ²Institut de Médecine Aérospatiale du Service de Santé des Armées, Bretigny-sur-Orge, France
3. ³Institut National de la Santé et de la Recherche Médicale U666 (GRERCA), Centre de Recherche en Biomédecine de Strasbourg, Faculté de Médecine, Université de Strasbourg, and Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
4. ⁴Etablissement des Diaconesses, Centre Ambulatoire, Strasbourg, France
5. ⁵Département de Neurobiologie des Rythmes, Institut de Neurosciences Cellulaires et Intégratives, CNRS (UMR7168), Université L. Pasteur, Strasbourg, France

Correspondence: L Pain, (laurepain@aol.com)

Received 3 June 2008; Accepted 11 August 2008; Published online 17 September 2008.

Abstract

Anesthesia and surgery are associated with fatigue and sleep disorders, suggestive of disturbance of the circadian rest–activity rhythm. Previous studies on circadian rhythm disturbance were focused on patients undergoing general anesthesia associated with surgery. This does not permit one to draw valid conclusions about the effects of general anesthesia per se on circadian rhythms. Our study was set up to determine the impact of a hypnotic dose of propofol on the circadian rest–activity rhythm in humans under real-life conditions. Seventeen healthy subjects scheduled to receive light propofol anesthesia for ambulatory colonoscopy were investigated. Their rest–activity rhythms were assessed using actigraphic monitoring. Diurnal rest was increased, whereas nocturnal sleep was unchanged in the days following anesthesia. Nonparametric analyses showed a decrease in the strength of coupling of the rhythm to stable environmental zeitgebers and increase of fragmentation of the rhythm after anesthesia. Light general anesthesia itself impairs synchronization of the circadian rest–activity rhythm to local time in patients by acting directly on the circadian clock.