EFFECTS OF SMOKING ON ROCURONIUM NEUROMUS CULAR BLOCKADE

Citation
F. Latorre et al., EFFECTS OF SMOKING ON ROCURONIUM NEUROMUS CULAR BLOCKADE, Anasthesist, 46(6), 1997, pp. 493-495
Citations number
12
Categorie Soggetti
Anesthesiology
Journal title
ISSN journal
00032417
Volume
46
Issue
6
Year of publication
1997
Pages
493 - 495
Database
ISI
SICI code
0003-2417(1997)46:6<493:EOSORN>2.0.ZU;2-8
Abstract
Recent studies have shown different results concerning the effects of smoking on neuromuscular blocking agents. Some reports indicate that s mokers need higher doses of vecuronium, but are more sensitive to atra curium. The aim of this study was to evaluate the effects of smoking o n onset and recovery time after a single 0.6 mg/kg intubating dose of rocuronium an analog of vecuronium. Methods: Following institutional a pproval and informed consent, 20 smokers (>10 cigarettes/day) and 20 n onsmokers were included in the study. Following oxazepam premedication and induction with fentanyl and thiopental, single-twitch stimulation of the ulnar nerve was performed every 10 s. Following stabilisation of control responses, patients received rocuronium 0.6 mg/kg for intub ation. Anaesthesia was maintained with enflurane less than or equal to 0.8 vol.% (end-tidal) and 65% nitrous oxide in oxygen. Onset time and recovery to 25% and 75% of the twitch control values were recorded. R esults: Onset and recovery times were not different between smokers an d nonsmokers. Conclusions: The results of the present study suggest th at chronic nicotine exposure does not change onset time or duration of rocuronium neuromuscular blockade. A previous study found a greater n eed for vecuronium in smokers and discussed stimulation of the neuromu scular junction and enhanced biotransformation due to the enzyme-induc ing properties of nicotine. The differences in our results could be pa rtly due to a longer period of refraining from smoking in our patients , leading to very low nicotine blood concentrations without the propos ed receptor-stimulating effect. Another cause for different behaviour of the two analogs could be different elimination pathways. Recent inv estigations suggest that rocuronium may not be eliminated principally by the liver. Therefore, enhanced nicotine-induced biotransformation, as suggested for vecuronium, would not occur with rocuronium.