Randomised comparison of spinal anaesthesia with bupivacaine or levobupivacaine for hip surgery in elderly subjects.

Background: Bupivacaine and levobupivacaine have similar pharmacokinetic and pharmacodynamic characteristics, and are used regularly in spinal anaesthesia. Whether potential differences in their haemodynamic and anaesthetic profiles could determine differential risk of complications in elderly subjects is controversial. 

Objectives: To compare intrathecally administered levobupivacaine versus racemic bupivacaine through regional cerebral O2 saturation, anaesthetic parameters,  postoperative cognitive status and neurological complications. 

Methods: The trial was approved by the Ethics Committee (CEIC Corporació Sanitaria ParcTaulí, Sabadell) and the Spanish Agency on Medicines and Medical Devices, and in accordance with the Helsinki Declaration of 1975, as revised in 1983. The study was registered at the European Union Clinical Trials Register (EudraCT 2013-000846 -20) on April 9th, 2013 and at ClinicalTrials.gov (NCT01960543) on September 23rd, 2013
The trial included 58 patients aged 70 or older undergoing surgery for hip fracture and requiring spinal anaethesia, who were randomized to receive bupivacaine or bupivacaine. The primary outcome was the proportion of intraoperative time with regional cerebral desaturation (≥20% reduction from baseline), as monitored by near –infrared spectroscopy. Secondary end points included hemodynamic parameters, level of sensitive and motor block, changes in Short Portable Mental Status Questionnaire, and neurological complications.

Results: No significant differences for regional cerebral oxygen saturation or other hemodynamic parameters were observed. Levobupivacaine showed significantly lower sensitive block at the start of surgery and motor block at 15 minutes. No differences in intellectual function were observed after surgery, but neurological complications were more frequent with bupivacaine (50% vs 21.4%, p=0.05). Lower baseline regional oxygenation of right hemisphere and minimum mean blood pressure increased risk for desaturation.

Conclusions: Bupivacaine and levobupivacaine differed in sensitive and motor block levels at the start of surgery, but not in hemodynamic parameters. Neurological complications were more frequent with bupivacaine. Avoiding low intraoperatory mean blood pressure is important to preserve cerebral oxygenation, specially in subjects with low regional oxygenation of right hemisphere.