Intrathecal clonidine for postoperative analgesia in elderly patients: the influence of baricity on hemodynamic and analgesic effects.

Intrathecal (IT) clonidine is an effective analgesic, but it also produces hemodynamic depression and sedation which are likely to be related to IT clonidine's cephalad spread within the cerebrospinal fluid. We hypothesized that IT clonidine's side effects could be reduced without compromising the duration and quality of analgesia by injecting clonidine IT in a hyperbaric solution and elevating the patient's trunk. We prospectively randomized 30 elderly patients to receive IT 150 microg of either isobaric (ISO) or hyperbaric (HYPER) clonidine for postoperative analgesia after surgical repair of traumatic hip fracture.