DIALED IN Ergonomics are one consideration, but a lot of other factors also help determine which anesthesia machine is right for your facility.

Spend some time on an exhibit floor where anesthesia machine manufacturers are displaying their glistening wares, and you may start to feel as if you could use some oxygen. The range of features and the buzzwords flying around can be dizzying if you're not an expert.

Unfortunately, most people in charge of capital procurement aren't anesthesia machine experts, and they don't spend enough time with vendors to analyze and fully understand the key differences among machines. Instead they fall back on "comfort" features — the ergonomic components and other aspects that are easier to grasp: How big is the machine? What's the footprint? Does it have a shelf? Does it have a footrest? How's the lighting if the room is dark? Does it have nice wheels that make it easier to move? Can you mount it on the wall?

Potentially important considerations, granted. But the question of which anesthesia machine is best suited for a given facility requires a deeper understanding of the constantly evolving technology, a familiarity with the providers who'll be using the machines and a consideration of the kinds of patients they'll be used for. Let's take a look at what's out there and some of the factors you need to consider.

1. What types of patients are you working with? The bottom-line goal is to always keep patients breathing as normally as possible. But some patients are more challenging than others. Bariatric patients, for example, are more difficult to ventilate, because they're larger. The same is true with laparoscopic patients, because their bellies are blown up like basketballs, which restricts lung capacity. Patients in the steep Trendelenburg position are also difficult to ventilate. Patients like these require advanced methods of ventilation to reduce high pressures.

If, on the other hand, you're in an endoscopy setting where almost all procedures are TIVA (total intravenous anesthesia) with spontaneous ventilation, you can probably get by with a very simple machine. You just want to make sure you have a monitoring mode to eliminate false alarms when the patient is breathing on his own and you're simply monitoring that breath. Of course, clinicians in such a setting may not be planning a general anesthetic, but some still want to have a machine, in case the patient goes apneic and needs to be intubated and ventilated. A simple machine that provides ventilation and CO₂ absorption may be all you need.

EXPERT ADVICE Dr. Olympio talks to residents at Duke University about the features offered by various anesthesia machines.

2. How many cylinders do you need, and which ones? Assuming you have oxygen and air piped into the OR (which virtually all modern facilities have), the question is what sort of backup you need in the event of a medical gas failure or natural disaster. Most new machines have space for at least 2 cylinders. Since extra oxygen is a given for one, the question becomes what you want the second cylinder to be. Most facilities choose air, which is especially important if you're doing plastic surgery on and around the face, since oxygen buildup is a major fire hazard. The same consideration is warranted for neonates and some chemotherapy patients, both of whom are vulnerable to oxygen lung toxicity. But depending on your patient population, you might also choose to go with 2 oxygen cylinders. Nitrous oxide is also a possibility, but modern anesthetic agents are so short-acting that nitrous use has gone way down. One company does offer an optional third cylinder, which, instead of being hard-mounted, is connected to a hose and strapped onto the machine.

Of course, if there's a chance the machine will be used at a site that's not equipped with a medical gas pipeline, it will have to run off cylinders and you'll need to plan ahead as to what you'll need.

3. Anesthesia groups tend to have a personality. They may be dominated by established senior providers who are set in their ways, technically unsophisticated and resistant to change. Or they may be tech-savvy early adopters who love the newest gadgets. Note, by the way, that the folks who embrace new technology aren't necessarily just younger folks. Some senior providers are very tech savvy and love computerization.

But those in the first group tend to be rigid thinkers. Familiarity has a lot to do with safety, and they don't like surprises. They're likely to be extremely reluctant to give up old technology. They want the classic delivery method they were trained on. They want to be able to look at hoses and pipes and see which way the gas is flowing. They distrust invisible complexity and they've developed remarkable skill at troubleshooting technical problems. Some providers prefer standard needle valves that can be opened mechanically, as opposed to newer fresh-gas delivery systems that are operated by computer. Some may prefer conventional vaporizers, even though electronic vaporizers offer certain advantages, such as providing readouts that tell you how much gas you're consuming and how much money you're spending on different gases. Electronic vaporizers may also promise less maintenance.

4. Economic considerations at the purchase level. What sort of budget are you dealing with? Some hospitals may be in a position to sweep out all their old machines and replace them with brand new high-tech models. A smaller freestanding outpatient facility may have to consider a piecemeal approach. If you're going to be buying 2 machines a year, but ultimately want to replace the 10 you have, it makes sense to stay with the same company and same technology. Consider the expected lifespan of the machine and whether it will survive a long phase-in period. Machines break down, and that's a problem, whether the people who have to fix them are in-house or not. If they're not, you have to contract with machine-specific trained technicians to keep them operating. If you have in-house biomeds, similarly, you have to send them to training for every new kind of machine you buy. After all, somebody has to be certified to fix that machine, and those courses are very expensive.

5. Value after purchase. New machines range from about $35,000 to about $100,000, but spending more now may cost less in the long run. Machines that save money by allowing low fresh-gas flow and that let you manage your more difficult patients without having to swap out machines or borrow a ventilator from an ICU might pay for themselves faster. For example, some facilities might spend $200,000 a year on one type of anesthetic vapor. If you can save that much by dramatically reducing flows, the machine pays for itself.

One new highly efficient machine is engineered to flow gas when patients are inspiring, and shut it off when they're exhaling. Since the ratio of inspiration to exhalation is typically 1 to 2, that can theoretically reduce fresh gas flow by 67% — a strong selling point. The ability to save on gas flows by recirculating analyzed gas is another feature you might want to look for.

WHAT'S NEW? Younger anesthesiologists might be more inclined to embrace new technology, but don't assume all senior providers are technophobes.

6. Is the machine going to stay where it's planted or be moved around? Bolting the machine to the wall, as seen on Naval hospital ships, is the cleanest arrangement I've seen. The exposed gas hoses can be few or non-existent, or at least kept off the floor. But you may have surgeons who insist on moving things around. So the machine gets dragged over to the other wall. Or you may have to drag your machine to "safari" locations — dentistry one day, a cath lab the next and ECT the next. If so, you want a machine with a low center of gravity and nice wheels, so it rolls down the hallway easily and won't tip over. It also needs to be small enough that it can be handled by people who aren't big enough or strong enough to drag a 400-pound behemoth.

7. Case duration. Are you doing all 1-hour cases or are shorter case interspersed with 4- and 5-hour cases, as well? If some cases are longer, you might want to equip one OR with a bigger machine with cost-saving features related to duration of anesthetic, ventilation and gas conservation.

8. How green is your facility? How you handle CO₂ absorbent may be a consideration. Some machines have disposable cartridges. You snap them open, throw away the entire cartridge and simply snap on a new one. But if the idea of throwing the container away sounds wasteful, there are alternatives that let you simply dump out used absorbent and refill the container.

9. Are you doing a lot of plastic surgery on the upper body and face? Again, the concern here is the oxygen concentration, which creates a fire hazard if it's too high. You want to be able to meter the oxygen being delivered to a nasal cannula or facemask down to less than 30%, according to the Anesthesia Patient Safety Foundation. Some newer machines offer both air and oxygen inputs to the auxiliary flow meter and various methods to blend them. That allows you to still use the monitoring of the machine, while dialing in whatever gasses you want, including an anesthetic.

10. How much room do you have? As noted, some machines are very large. But they vary in size. We bought one that was tall and skinny for a cath lab, because there was no room for anything else.

FASTER ROI If you spend a significant amount of money on anesthetic vapor, more advanced machines can pay for themselves by allowing low fresh-gas flow.

11. Past experience with new equipment. How did your last phase-in of high-tech equipment go? Did everyone reject it, or did you have a bunch of grateful, happy people who loved the new additions? Did you mandate training? If so, did it go well or poorly? Remembering how people responded last time will give you some insight as to how far you can push the envelope.

12. Do you have anesthesiologists who are also ICU intensivists? ICU people are comfortable with silent ventilators and/or the kind where you don't see a bellows going up and down. Instead, they rely on artificial sound and movement, or no sound at all. But some providers aren't comfortable using the newer machines with their hidden pistons, spinning turbines and injected gasses.

13. Are you doing any training? If you're working with students, SRNAs, residents or anesthesia assistants, you can face a dilemma. On one hand, there's merit to having all the machines the same, to make learning easier and standardized. On the other, you may want some variation for teaching. When all machines are the same, students can learn quickly and instructors can learn to teach quickly. With multiple machines, they and their instructors may feel as if they're just pressing buttons without really understanding how the machines work.

Armed and less dangerous
Your anesthesia machine is one of the bigger purchases you'll make. Arming yourself with some background knowledge and the ability to ask the right questions can help you be confident you'll make the right choice.