24 patients randomly divided into two groups, one of the groups receiving atropine in addition to the planned anaesthesia. Skin conductance parameters to be compared between the two groups.

Skin conductance (SC), in terms of numbers of skin conduction fluctuations (NSCF), amplitude and mean skin conductance level, reflect the activity in the sympathetic postganglionic cholinergic fibers which innervate the palmar and plantar sweat glands. Skin conductance, especially numbers of skin conductance fluctuations, may be a promising tool to monitor anesthesia. Atropine, an anticholinergic agent, acts as an antagonist on the muscarinic receptors of the sweat glands and inhibits their secretion in a dose-dependent way. The aim of this study was to find out to what degree SC is influenced by i.v. administration of atropine.

Study hypothesis: SC is not influenced by i.v. administration of atropine.

Inclusion Criteria:

• Patients in ASA-group 1-2
• Operations (anal fissures, anal fistulas and haemorrhoids) lasting for less than one hour
• informed consent
• BMI <30

Exclusion Criteria:

• Patients using any medication known to influence the autonomous nervous system
• Patients with contraindications to atropine (e.i. fibrillation, glaucoma ect)
• BMI >30
• Pregnancy