Effects of anesthesia on efferent phrenic activity in neonatal swine

The effects of two levels of Saffan anesthesia (standard recording level: 2–4 mg/kg/min, and 10x recording level) and a single level of pentobarbital (5 mg/kg) on the power spectral density of efferent phrenic discharge were investigated in piglets aged from1day to50days. The phrenic high frequency oscillation (HFO) was present in decerebrate, unanesthetized piglets and in piglets anesthetized with Saffan, albeit reduced at 10 times recording level, but was absent under pentobarbital. The results indicate that Saffan does not have a significantly depressant effect on the phrenic HFO in developing swine.