BJA Advance Access originally published online on December 9, 2008
British Journal of Anaesthesia 2009 102(2):234-239; doi:10.1093/bja/aen346
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Efficacy of intracarotid propofol infusion and impact of cerebral blood flow alteration
1 Department of Anaesthesiology, Xijing Hospital
2 Neuroscience Institute
3 Department of Anaesthesiology, Stomatological College, Fourth Military Medical University, Xi'an, Shaanxi Province 710032, People's Republic of China
* Corresponding author. E-mail: kqmzk{at}fmmu.edu.cn
Background: Intracarotid propofol infusion was studied in canines as an experimental basis for application of propofol in the Wada test.
Methods: First, efficacy and side-effects of propofol anaesthesia were studied in eight mongrel dogs that received intracarotid and i.v. propofol infusions for 30 min according to a cross-over design. Auditory evoked potentials were used to guide anaesthesia. Secondly, eight mongrel dogs received intracarotid propofol infusion during both normal and cerebral hyperperfusion states using nicardipine. Haemodynamics and clinical endpoints were compared between the two infusion conditions.
Results: We required 33 (7.6) mg propofol intracarotically vs 113 (17) mg propofol i.v. to achieve an anaesthetic state. The mean arterial pressure (MAP) decreased about 15–27% from the baseline during i.v. infusion. However, no obvious decrease of MAP was observed after intracarotid infusion. Administration of nicardipine increased the blood flow in the internal carotid artery by 17%. Then, the propofol dosage for achieving the anaesthetic effect increased from 7.7 (0.9) mg in the normal control to 11.3 (0.8) mg in the nicardipine group. The onset time of anaesthetic effect was prolonged and the recovery time was shortened during intracarotid infusion during cerebral hyperperfusion.
Conclusions: Compared with i.v. propofol infusion, intracarotid infusion could reach and maintain the target anaesthetic depth with less dosage and without affecting MAP. In addition, increase of cerebral blood flow requires a higher propofol dose, prolongs onset, and shortens recovery time during intracarotid propofol anaesthesia, indicating that patients with a cerebral hyperperfusion state may need higher dose of anaesthetics during the Wada test.
Keywords: anaesthetics i.v., propofol; brain, blood flow; drug delivery, infusion; monitoring, depth of anaesthesia
This work was conducted in the laboratory of the Department of Anaesthesiology, Stomatological College, Fourth Military Medical University, Xi'an, Shannxi, People's Republic of China.