Diaphragmatic pressures in piglets: transvenous versus direct phrenic nerve stimulation.

We examined transdiaphragmatic pressure (Pdi) generation during both direct (DPNS) and transvenous (TVPNS) modes of phrenic nerve stimulation in anesthetized piglets of varying postnatal age. Pdi measurements during TVPNS were not statistically different from those obtained during DPNS (p greater than 0.10). Furthermore, a good correlation (r = 0.98, p less than 0.001) was obtained when the mean Pdi measurements obtained by both methods were compared. We conclude that TVPNS can be used in lieu of DPNS to generate Pdi. Furthermore, our data suggest that this technique can be used to study the effects of various experimental manipulations on diaphragmatic force output within a developmental context.