There have been a great many dramatized emergency room scenes on the big and small screens, but none of the fictionalized portrayals can match the raw, visceral power of the real thing one encounters in Ryan McGarry’s “Code Black.” McGarry served as a resident-in-training in the ER of the Los Angeles County General Hospital, where he served in the C-Booth (the cubicle where critical cases were treated), and paints—with the collaboration of cinematographer Nelson Hume and editor (as well as co-writer) Joshua Altman—a remarkable portrait of the intensity of the place and the dedication of the professionals working there, as well as they problems they confront.

One of those problems is indicated by the title. “Code Black” is the term the hospital uses when the ER is at or beyond capacity—something that happens frequently since, as a county establishment, it’s bound to provide treatment to everyone, regardless of ability to pay. As a result the waiting room is often filled to overflowing, and hard choices have to be made about who will be treated first. One of the doctors points out that this means that whether one supports what has come to be called Obamacare or not, the fact is that taxpayers ultimately pay the cost of indigent care in its absence.

Another difficulty for the doctors on call is that they sense an increasing lack of direct contact with patients from the beginning of treatment, largely as a result of the paperwork demands that take up so much of their time, but also—rather ironically—because of the completion of a new facility that offers more space but also creates a greater sense of distance between the physician and each patient. And as one senior administrator notes, as a county agency the hospital must jockey with others for support from the county itself.

A good deal of the film is made up of footage of the operation as a whole, including some wrenchingly graphic episodes of patients being treated by the intense C-Booth team and shots of individuals conversing with physicians about less urgent conditions; but there’s also considerable coverage of people waiting patiently, some in great pain, to be seen. On only a few occasions are patients themselves directly interviewed; toward the close, for example, there’s a tearful moment when an attorney whose practice has collapsed describes having to come for treatment of an injured foot after losing her private insurance.

The interview segments, however, are mostly with residents, nurses and administrators who express their dedication to serving the community despite the difficulties. In a few cases they describe their own pasts—one describes how as a youngster he was diagnosed with a potentially fatal disease and, having survived it, feels a drive to help others. What’s heard in these excerpts is barely a discouraging word; in fact, almost unanimously the interviewees express enthusiasm over the adrenaline rush they get from ER training, the sort of excitement that couldn’t be expected in any other form of practice. And they express pride that the L.A. facility has long served as a model where techniques of emergency treatment have been perfected and imitated elsewhere.

What comes across most powerfully in “Code Black” is the incredible idealism of the doctors engaged in work at County General, who not only strive to meet the needs of their patients but consistently discuss among themselves ways to improve the speed with which they can see to those needs and improve their level of interaction with patients. The emphasis on them, and the implication that they’re being hobbled, at least to some degree, by a system affected by political and economic constraints, gives the film an activist component, even if it’s not overt. Whatever your political viewpoint, however, this is a documentary that provides an incredibly intense, and genuinely moving, glimpse into the operation of one of the nation’s premier emergency medical facilities.