When your clinical ends, mr. b is resting peacefully. his respiratory rate and heart rate are back to normal, his chest tube is not bubbling anymore, and his breath sounds are even on both sides. mrs. h is using her spirometer, and the respiratory tech says her vital capacity is a lot better than it was the first time he checked on her. the cns tells your prof you made a good save in noticing mr. b's tipped chest tube bottle. a great clinical all around! so you treat yourself to an after-class drink with a fellow student who spent her day in the nicu (neonatal intensive care unit). "you won't believe what happened to me today! the transport from er collapsed somebody's lung! " "it must be lung day. we have a preemie in the nicu with collapsed lungs as well." "wow, what happened? did it have a chest injury? do they put chest tubes in babies? " "no, she just never inflated them when she was born. the doctors keep talking about surfactant, but the mom didn't understand what that meant. she was so scared; i felt sorry for her. but i don't think i could explain it either! " you are on a roll today, so your friend come up with a clear explanation of what surfactant does. choose the best explanation?