Ragged yet frequently compelling: the experiences of Lydia Weber, a bright and experienced nurse in an intensive care unit (ICU) attached to the department of neurology and neurosurgery of a giant Manhattan teaching hospital by the East River. To Lydia, the ICU is an awesome factory of ""artificial animation"": above and around the comatose bodies (""you couldn't tell them apart until you really got to know them"") are the rhythms of a ""desperately loud life. . . whispers and honks, beeps, occasional bells."" And the round of long hours includes suctioning, adjusting, connecting and disconnecting, arranging lifeless limbs, and attending the staff conferences presided over by a brilliant but autocratic Chief. Then, however, the already-grim pressures escalate--when Lydia joins brain-chemistry specialist Dr. Sam Wheeler in an ambitious project: devising a system to predict outcome in comatose patients. Familiar questions about determining death and defining life proliferate. (""Who knows what might still be going on, deep in the sub-subcortex? Who the hell knows?"") Patients come and go; others linger on--pumped and drained by machines, arranged and anointed by nurses. Lydia has a tense, frustrating affair with married Sam--whose enthusiasm over a new chemical ""cocktail"" (to be used on some comatose patients to speed up brain transmission) is carrying him into dangerous, morally indefensible areas. And finally, after the tragic loss (in the ICU) of a friend and the collapse of the affair with Sam, Lydia vows to continue her fight for her unpopular but noble ethics. Blunt, in-the-field scrutiny of a hot medical topic--with an overload of preachment, perhaps, but also with exhaustive detail, authentic ambience (first-novelist Scherer is a research nurse), and relentless closeup realism.