British journal of anaesthesia
-
Letter Case Reports
Peripheral blocks of the lower limb for repair of fractured neck of femur.
-
Based on volume-flow relationships, CNS agents that are highly lipid soluble (log octanol-water partition coefficient > 2) are expected to have equilibration half-times (T1/2 kE0) that are proportional to brain solubility. Propofol, the most lipophilic anaesthetic in clinical use, has T1/2 kE0 values of 1.7 and 2.9 min in rats and humans, respectively, compared with an expected value of at least 8 min. ⋯ Brain:plasma and brain:blood partition coefficients were 8.2 (SD 1.6) and 3.0 (0.5), respectively. T1/2 kE0 predictions based on brain: blood partitioning in rats are more in agreement with the observed equilibration half-time, suggesting that drug bound to the formed elements of blood participates in the uptake and transfer of propofol to its effect site.
-
We describe a system for monitoring and controlling i.v. anaesthesia in rats using burst suppression ratio (BSR) detection in the extradural EEG. After bolus injection, peak BSR values of 95% were achieved with propofol 8 mg kg-1, etomidate 3.5 mg kg-1 and alphaxalone 4.5 mg kg-1. Thiopental 32 mg kg-1 produced a peak BSR of 70% (larger doses were not tolerated). ⋯ During these experiments the infusion rates were found to decrease with time, more so with etomidate (approximately 40%) than with propofol (approximately 20%). Recovery times were 2-3 times longer with etomidate than with propofol. This model demonstrated differences between i.v. anaesthetics and may be useful in screening new compounds in preclinical development.
-
Randomized Controlled Trial Clinical Trial
Influence of timing of morphine administration on postoperative pain and analgesic consumption.
We have investigated if a pre-emptive dose of morphine, given 30 min before skin incision, influenced postoperative pain and morphine consumption after hysterectomy. In a prospective, randomized, double-blind, placebo-controlled clinical study, patients received morphine 0.3 mg kg-1 at induction of anaesthesia or 30 min later at skin incision. The primary endpoint was defined as 24-h morphine consumption via patient-controlled analgesia. We could not demonstrate any difference between the two groups in morphine consumption or pain scores, and we conclude that there was no evidence of pre-emptive analgesia in this study.