Figure 3
Associations between electrocortical spectral changes and respiratory rate depression induced by fentanyl. (A) Comparisons of inspiratory duration, expiratory duration, respiratory rate, and the amplitude of diaphragm muscle activity between wakefulness, non-REM, REM sleep, and sedation by fentanyl (100 µg · kg−1) did not show significant differences. (B) Representative epochs showing electrocortical, spectrogram and diaphragm muscle activities showed some epochs did not present respiratory rate depression whereas others did. In the latter epoch, fentanyl also increased θ power. (C) Correlations between the magnitude of respiratory rate depression and changes in electrocortical band powers showed that respiratory rate depression was associated with increased θ power, and decreased δ, α, β1, and β2 powers. The association between respiratory rate depression and increased θ power was highly significantly and more pronounced than for the other powers. Dia, diaphragm. Data are presented as mean ± SEM.
