  If massive stars form by disk accretion, then bipolar outflows should be
generated as in the case of low-mass star formation. High accretion rates lead
to high outflow rates and make the wind density very large near the protostar.
We therefore predict that massive protostars have very small, jet-like HII
regions confined by their outflows; we identify these HII regions with
"hypercompact" (<0.01 pc) HII regions. Their lifetime is approximately equal to
the accretion timescale (~10^5 yr), much longer than the sound-crossing and
dynamical timescales of the ionized region. We present an analytic description
of the density distribution of the outflow, relate the overall mass loss rate
to the accretion rate, and normalize to values appropriate to massive
protostars. For a given ionizing luminosity, we calculate the extent of the HII
region and its radio spectrum. A detailed comparison is made with observations
of radio source "I" in the Orion Hot Core. The spectra and morphologies of many
other sources are broadly consistent with this model. We argue that confinement
of ionization allows disk and equatorial accretion to continue up to high
masses, potentially overcoming a major difficulty of standard accretion models.
