Objective: To compare the duration of blockade with levobupivacaine and levobupivacaine with clonidine; to compare the duration of analgesia and the consumption of analgesics on the first post-operation day; the follow-up of the occurrence and severity of adverse effects of subarachnoidal anaesthesia (SAA) with levobupivacaine. Design: prospective, randomised, comparative. Setting: Dept. of Anaesthesiology and Intensive Care; Dept. of Orthopaedic Surgery. University Hospital, Brno-Bohunice. Patients and methods: Fifty-four patients were included in the study (mean age 66.5 years, weight 81.5 kg), undergoing total endoprosthesis of knee or hip joints. Surgery was performed in SAA. In group A, levobupivacaine was administered (3 ml), in group B levobupivacaine (3 ml) + 0,075 mg of clonidine (0,5 ml) was used. Subarachnoid puncture was performed at the intervertebral space L3/4 or L4/5 using the spinal needle 25G.Patients were monitored in the standard fashion during surgery. Anaesthesia was combined with 2–3 mg of midazolam. The time of subsidence of motor block as well as the time of administration of analgesics was documented after surgery and transfer to the orthopaedic ICU. Results: The average time of the onset of motor block (grade 2 according to the Bromage scale) was 6.3 min in both groups: motor block was complete in 47 patients, in 6 patients the block reached grade 2, in 1 patient grade 1. Adverse events: a hypotension with a mean arterial blood pressure drop > 25% occurred in 2 patients (and was corrected with ephedrine), bradycardia occurred in 1 patient (atropine was administered) in group A.A hypotension with a mean arterial pressure drop > 25% occurred in one patient, bradycardia in three in the group B. No other adverse effects were observed. The average duration of motor block was 212.04 min in group A and 309.26 min in group B, which means that the blockade was significantly (P<0.01) prolonged with clonidin by 97 min (45.9%) in group B. The average duration of analgesia was 292.22 min in group A and 432.04 min in group B – a significant (P<0.01) prolongation by 144 min (47.9%). The 2.18 doses of analgesics was administered in group A, comparing to 1.41 doses in group B on the first post-operation day – it represents a significant lowering of analgesics consumption by 35.3% (P<0.01). Conclusion: Clonidine administered intrathecally with levobupivacaine prolongs motor block duration and the duration of analgesia, thus diminishing the need for analgesics on the first post-operation day on the ICU. The 0.5% levobupivacaine ensures a high quality of anaesthesia with minimum adverse effects.

        Key words: levobupivacaine – subarachnoidal anaesthesia – postoperative analgesia – clonidin– endoprosthesis of joints