Abstract
Purpose
This study examined the bronchodilating effects of 0.6 MAC and 1, 1 MAC isoflurane (ISF) on respiratory system resistance (Rrs) following tracheal intubation and determined whether albuterol supplements that effect.
Methods
Sixty-seven adult patients were anaesthetized with 2 μg · kg−1 fentanyl and 5 mg · kg−1 thiopentone and their tracheas intubated following administration of 1 mg · kg−1 succinylcholine. Respiratory system resistance was measured following intubation and the patients then randomized to receive either 1. 1 MAC ISF in oxygen or 0.6 MAC ISF in 50% nitrous oxide and oxygen. Ten minutes later, Rrs was again measured. Patients were then further randomized to receive albuterol or a placebo using incremental doses of 2, 5, and 10 puffs (albuterol puff = 90 μg) delivered via a metered dose inhaler at ten minute intervals.
Results
Isoflurane at 1. 1 MAC decreased post-intubation Rrs by 23 ± 5% (mean ± sem) whereas the decrease was only 7 ± 5% for 0.6 MAC ISF (P < 0.01). Two puffs of albuterol resulted in a further decrease of 12 ± 3% (mean ± sem) in Rrs compared with a 2 ± 4% decrease in the placebo groups (P < 0.05). Additional puffs of albuterol resulted in no further changes in Rrs.
Conclusion
We conclude that following tracheal intubation the reduction in Rrs produced by ISF is highly concentration dependent. Albuterol results in a small further reduction in Rrs.
Résumé
Objectif
Étudier l’effet bronchodilatateur de l’isoflurane (ISF) à 0, 6 MAC et à 1. 1 MAC sur la résistance du système respiratoire (RTS) après l’intubation trachéale et déterminer si l’albutérol amplifie cet effet.
Méthodes
Soixante-sept adultes anesthésiés au fentanyl 2 μg · kg−1 et au thiopentone 5 mg · kg−1 ont été intubés après l’administration de succmylcholine 1 mg · kg−1. La résistance du système respiratoire a été mesurée après l’intubation et les patients ont été répartis aléatoirement pour recevoir soit ISF 1, 1 MAC ou ISF 0,6 MAC dans le protoxyde d’azote 50% en oxygène. Dix minutes plus tard, la RTS a été mesurée de nouveau. Les patients ont été de nouveau répartis aléatoirement pour recevoir de l’albutérol ou un placebo en dose fractionnées de 2, 5 et 10 bouffées (une bouffée d’albutérol = 90 μg) délivrées par un inhalateur gradué à dix minutes d’intervalles.
Résultats
L’ isoflurane à 1, 1 MAC diminue la RTS de 23 ± 5% (moyenne ± sem) alors que la diminution n’était que de 7 ± 5% avec l’isoflurane à 0,6 MAC (P < 0.01). Deux bouffées d’albutérol ont provoqué une nouvelle baisse de 12 ± 3% (moyenne ± sem) de la RTS comparativement à 2 ± 4% dans le groupe placebo (P < 0,05). Les bouffées additionnelles d’albutérol n’ont pas modifié davantage la RTS.
Conclusion
Après une intubation trachéale, la réduction de la RTS produite par l’isoflurane dépend fortement de sa concentration. L’albutérol provoque une petite réduction additionnelle.
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An erratum to this article is available at http://dx.doi.org/10.1007/BF03018860.
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Choi, JH., Rooke, G.A., Wu, SC. et al. Reduction in post-intubation respiratory resistance by isoflurane and albuterol. Can J Anaesth 44, 717–722 (1997). https://doi.org/10.1007/BF03013384
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DOI: https://doi.org/10.1007/BF03013384