I had somewhere between 16-20 ultrasounds. I had a high risk pregnancy and they were keeping a close eye on the baby. Each ultrasound cost around $700 plus the costs from the doctor and lab for reading the results. Luckily our insurance picked up the cost after we paid $2500 out of pocket. Even with all that expense my daughter was totally worth it and is perfect.
Part of the difficulty in answering this question is that depth and cause of coma may vary, and memory is impaired during coma so people might hear but not be able to recall what they hear. In brief: Hard to know. It is hard to know if people in a coma can hear you.
A coma is a deep state of unconsciousness during which an individual is not able to react to their environment. Someone in a coma cannot respond to any form of stimulation whatsoever. Coma can be caused by an underlying illness, or it can result from head trauma. A comatose person is still very much alive, but he or she is not simply asleep. The brain wave activity in a comatose person is very different from that of a sleeping person; you can wake up a sleeping person, you can't wake a person in a coma. There are reports of people waking from a coma and recounting a classic near-death experience.