Director: Okay, in this scene we're going to do the paddle thing.
Actor: What's my motivation?
Technical Consultant: You're in tachycardia.
Actor: I don't know how to emote tachycardia.
Technical Consultant: What do you know?
Actor: Asystole.
Director: Meh, that works for me.
Technical Consultant: But a defibrillator is useless for asystole!
Director: Shut your cakehole, poindexter.
Here the director crosses out "tachycardia" in the script and scribbles "He's flat lining!!!" in crayon.
We find this mistake in every film imaginable. Drama, comedy, action, romance. Major studio blockbusters and indie cult flicks. Academy award winners and direct-to-video stocking stuffers. Bonasera, Science mumbles to Hollywood whilst seated in a darkened office and stroking a lap cat. What have I ever done to make you treat me so disrespectfully?
Perhaps some explanation is in order. Read on.
Assuming you haven't been sacrificed to Kali or spent any time in grad school, you have a fist-sized organ in your chest (aka "heart") whose rhythmic contractions keep a steady flow of oxygenated blood flowing to your important bits. If we stick wires to you in the proper places, we can record an electrical waveform generated during these contractions known as the electrocardiogram or ECG (or EKG upon substitution of the Greek kardia for Latin cardio). The physics behind the ECG is quite fascinating -- it's not recording "waves" in the electromagnetic sense but rather a collection of quasi-static current dipoles in a volume conductor -- but that is a story for another time. The point for today is that the ECG of both the healthy and distressed heart has stereotypical features which makes it useful as a diagnostic tool. In short: the waveform tells you what's going on with the organ.
Here's an artist's rendition of the ECG produced by a heart in normal sinus rhythm:
"Sinus" refers to the sinoatrial node, a little nougat of hearty goodness that repeatedly triggers a sequence of events resulting in contraction (it puts the "bang" in whole shebang, we might say). These events need to proceed in an orderly fashion -- the various atriums and ventricles doing their squeezy thing at just the right time -- to get the job done. This cosmic dance can get discombobulated following trauma or disease, creating a condition known as tachycardia (from the Greek takhus kardia or "swift heart"). Here's an artist's rendition of the ECG during tachycardia:
Note the absence of rhythmic contraction. This is bad news for the owner of this lonely heart because a pump in tachycardia is no pump at all, and a loss of proper blood flow presents an immediate threat to life and limb.
Tachycardia is not the only thing that can leave you heart broken; your heart can also stop beating altogether. The medical term for this is asystole (from the Greek sustellein meaning "to contract"). Like tachycardia, asystole can result from any number of pathologies and is also bad news. (That being said, the heart is an amazingly tough bastard. A beating heart will continue to beat even after being removed from the chest. We demonstrate this routinely in undergraduate biology labs, albeit using frogs not undergraduates.)
An artist's rendition of asystole is a simple affair, even for artists who don't have fancy $1000 graphic tablets:
Note the absence of rhythmic contraction. Like tachycardia, a heart in asystole, too, is no pump at all and presents a clear and present danger. Yet, even a casual observer can see the difference between asystole and tachycardia. The former is a placid lake, silent as approaching death. The latter is two polecats fighting in a burlap sack. This has some bearing on what might be done to remedy the situation.
Both tachycardia and asystole call for immediate -- one might even call it savage -- medical intervention (diseases desperate grown by desperate appliance are relieved or not at all, Shakespeare teaches). The details I must leave vague for obvious legal reasons. However, as anyone with a merit badge knows, the proper first aid for asystole is CPR (and perhaps a shot of epinephrine through the sternum, which you should probably leave to the professionals). Alas, even if you collapse in the middle of a Boy Scout troop, things are probably not going to end well. I'm told by medical types that once CPR is required, survival rates drop to single digits. Furthermore, effective CPR is more brutal than most people realize, with tales of broken ribs post hoc not uncommon. Some Eagle Scout isn't simply going to press on your chest a few times and have you back on your feet in time for happy hour.
Conversely, the proper corrective measure for tachycardia is defibrillation. You put a paddle on either side of the misbehaving heart, press the trigger, and bam! With a little luck you reset the sinoatrial node with a jolt of current and normal sinus rhythm is restored. Assuming you have a defibrillator handy, that is. The good news is there's now easy-to-use units available in many grocery stores and airports and whatnot. Which is nice I guess, knowing somebody has my back, although having watched the average customer attempt to work a self-checkout machine, the prospect of them being the only thing that stands between me and the abyss should the need arise is cause for some misgivings.
Thus the take home: You do not fix asystole using a defibrillator. The proper response to asystole is CPR. On the other hand, CPR is not much help in tachycardia. Ergo, defibrillator. Perhaps this is best remembered by way of analogy. Tachycardia is a yappy poodle doing cartwheels and peeing on everything because someone rang the doorbell. Asystole is a dead whale rotting on the beach. Whereas smacking a yappy poodle with a rolled up newspaper might bring it back to its senses (in so much as a poodle has those), you can kick a dead whale down the beach all day and you will have nothing to show for it except sore feet.
Next time on LabKitty Watches Stuff, we'll have a look at why Post-Its are a bigger security hole than Kerberos, why you don't click the safety on a Glock, and why Penny wouldn't be able to afford a stylish one bedroom pad anywhere close enough to Los Angeles to be considered "living in LA" unless she was selling drugs in the Cheesecake Factory parking lot.
No comments:
Post a Comment