Right, so from what I've gathered, IV needles come in various gauges. If you're going to put a saline drip on someone (isn't that what patients are often given during and after surgery? If not, what is the clear liquid in the bag?), what gauge should you use and why? How do you know whether to go for 18 or 20, for instance? A couple of questions about anesthesia when a patient requires major brain surgery, gastrointestinal surgery (upper and lower GI), and amputation of an arm (including the shoulder) and both legs (including thighs): How long is it safe to keep a person under? For longer surgeries, is there a preference between inhalation and IV? If it's the IV option, is it one shot per every so and so many minutes / hours or do they use a constant, slower, well, drip or some such? Does the method of anesthesia (and its duration) differ if -it's one big, long process that takes hours upon hours from start to finish (do they ever change surgeons mid-surgery if it takes very long? Or would several surgeons work on the same patient at the same time to speed things up?) -the patient requires several surgeries done as soon as humanely possible to save their lives (is it common practice to allow the patient to wake up in the middle of the surgeries and recuperate a bit or do they just start the next one immediately after finishing the previous one?) What's the longest it's safe to keep a person under? I mean totally out, asleep. When do they opt for a medically induced coma? How safe / controllable is a barb coma? Are there other ways to pull it off besides barbs? And I'd also need to know how much carfentanil would it take to make a large grizzly (around 1100lbs) fall asleep / go unconscious (so it can be operated on)? How much saline should be used in the mix? Can it all fit in one dart syringe? In the scenario, carfentanil and saline are all the vet has at hand (a bit of an improv situation). How long would it be safe to keep the bear sedated? It seems carfentanil has a half-life of around 7,7hrs, but how soon would the bear start to wake up? Does the risk of complications like breathing problems rise the longer the animal is out? I know I'm asking for everything but the damn Moon from the sky but I'd really appreciate any input from those in the know Ball-park estimates are also ok if nobody knows the exact answers (thinking about the grizzly case since I don't know how many vets are here). ETA: Sorry, just one more question: why is it called a "peripheral" IV?