ISSN:
1619-7089
Keywords:
Ventilated anaesthetised baboon model
;
Technetium-99m hexamethylpropylene amine oxime single-photon emission tomography
;
Drug-induced cerebral blood flow changes
;
Lidocaine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The baboon under general anaesthesia as a model to assess drug-induced cerebral blood flow changes (Δ CBF) using single-photon emission tomography (SPET) offers great in vivo possibilities but has to comply with demands on control of anaesthesia-related influencing factors, such as P aCO2 changes. The model sought in this study and described here allows control of P aCO2, in the baboon under thiopentone anaesthesia by ventilation, and was evaluated for the functional dependence of Δ CBF vs Δ P aCO2, using SPET technetium-99m hexamethylpropylene amine oxime (HMPAO) and the split-dose method together with controlled ventilation. During the experiment the model was validated for normal reactivity to P aCO2 changes, and subsequently applied to investigate the mechanisms (still uncertain) of CBF increase known to follow administration of the local anaesthetic lidocaine. Six baboons received 6 mg/kg lidocaine intravenously. CBF was measured between two consecutive SPET acquisitions (split-dose method) respectively relating to HM-PAO distributions in the brain before and after the injection of lidocaine. Meanwhile the animals were maintained at constant respiratory rate and volume. The results indicate that the correlation between Δ CBF and the ensuing fall in PaCO2 deviated from the baseline pattern from the model and confirmed a cerebrovascular contribution to the lidocaine-induced CBF increase. This agreed well with mean and systolic blood pressure changes and heart rate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00173489
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