Anesthesia induced changes of respiratory mechanics in rats measured by impulse oscillometry

Aim: Because anesthesia is often required in respiratory research of rodent species, whose influence on respiratory mechanics should be investigated utilising the non invasive Impulse Oscillometry (IOS) test. Material and methods: Ketamine/medetomidine combination (study a), followed by urethane two weeks later (study b), were applied for anesthesia of ten female rats. IOS measurements were taken before and 30 minutes after drug application in each study. Results: Breathing frequency and tidal volume decreased significantly due to anesthetics in both studies. Results of spectral resistance (R) and reactance (X), all in kPa L -1 s, as well as level of significance are presented in table 1. Conclusion: Anesthesia in rats leads to changes of their breathing pattern and various impedance parameters as well. These investigations are only possible using a non-invasive and non-cooperative technique like the IOS. The authors appreciate the financial support of the German Federal Ministry of Economics (Berlin Germany, registration number IW 070139).