“…The effect of fentanyl plasma concentrations on the respiratory system of this species therefore remains undetermined at this time. The pH at fentanyl target plasma concentrations of 8 ng mL )1 was lower than that seen at both 16 and 32 ng mL )1 , but the values obtained remain within a narrow range that is within published reference intervals for awake birds (Kollias & McLeish 1978;Neal et al 1981). The clinical significance of this finding, if any, remains unknown.…”