  Several recent studies have determined that large quantities of neutral gas
are outflowing from the nuclei of almost all infrared-luminous galaxies. These
measurements show that winds in infrared-luminous galaxies play a significant
role in the evolution of galaxies and the intergalactic medium at redshifts z >
1, when infrared-luminous galaxies dominated the star formation rate of the
universe. These conclusions rely on moderate resolution spectra (FWHM > 65
km/s) of the NaI D absorption line and the assumption that there are no
unresolved, saturated velocity components. For the first time, we present high
resolution spectra (FWHM = 13 km/s) of massive, infrared-luminous galaxies. The
five galaxies in our sample are known to host outflows on the basis of previous
observations. With the present observations, all NaI D velocity components are
resolved with tau(NaI D1 5896 A) < 6. The column densities we measure are
consistent within the errors with those measured from moderate-resolution
observations. This confirms that the mass, momentum, and energy of outflowing
gas in infrared-luminous galaxies have been measured correctly by previous
studies.
