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A Primer on Smoke Evacuation
Expert advice to help you clear the air in your OR.
Jenn Carbin
Publish Date: June 9, 2008   |  Tags:   Staff Safety
The inhalation of surgical smoke is a growing concern for surgical healthcare workers, and not a moment too soon: Significant research over the past two decades shows conclusively that smoke plumes generated by electrosurgical units and laser surgery are hazardous to the health of OR workers. It is widely understood that surgical smoke causes watery, burning eyes and nausea, and of more concern, respiratory problems and possible contamination by hazardous microbes. Al though an ever-growing number of surgeries performed these days use electrosurgical or laser technology, smoke evacuation has not become a standard practice in many facilities, particularly those that employ electrosurgery. In this article, experts will detail specific surgical-smoke concerns and recommend methods to control smoke in your ORs.

Understanding risks, overcoming resistance
Kay Ball, RN, is past president of the Association of periOperative Registered Nurses (AORN), and a perioperative consultant/educator and researcher in Lewis Center, Ohio. In a recent paper, she points to "physician and surgical team indifference" as one of the main reasons that surgical smoke is an ongoing problem. Says Ms. Ball, "The hazards have been proven??but it's so much harder to sell people on a health hazard than on a safety hazard. The health hazard is harder to determine, and develops over time."

Paula Graling is clinical nurse specialist of perioperative services and chair of AORN's Smoke Task Force. (The group is currently raising money for a study that would use the Harvard Nurses Study's data to compare the health outcomes of perioperative nurses with those of the general population of nurses. The results would be given to OSHA, which still hasn't specifically regulated surgical smoke.) Ms. Graling says that part of the reason for the indifference to smoke issues is the hard-to-trace, sometimes vague nature of smoke-related problems. "These [symptoms] are not the kinds of things you go to occupational health about; these are the things that you go to your primary-care doctor about??skin problems, asthma attacks, conjunctivitis, the colds that won't go away."

Safety issues are addressed more with laser surgery than with electrosurgery, perhaps because of the differences in the cultures of the times in which the technologies were developed. When laser technology was introduced in the more rights-oriented late 1960s, subsequent laser education and training stressed safety and the hazards of laser smoke. "It was always discussed," says Vince Mortimer of the National Institutes of Occupational Safety and Health (NIOSH). Electrosurgery, which came around in the 1920s, was not afforded the same concerns and discussions. Ms. Ball says that back then, "Everybody was amazed with electrosurgery; they weren't thinking about the smoke." It wasn't until 1985, that NIOSH published a Health Hazard Report stating that the smoke emanating from "electrocautery knives" presented a "potential health hazard."

Vigilance in evacuating ESU smoke is at least as necessary as evacuation during laser procedures. Ms. Ball says, in comparing electrosurgery to laser, that though "the plumes are very similar," studies "show that the cutting and coagulating in electrosurgery is more hazardous." She is quick to say though, that "the issue isn't which is more hazardous, it's that all smoke should be evacuated."

A 1989 study compared the hazards associated with laser and ESU smoke with the hazards of cigarette smoking. Researchers impacted one gram of tissue using a carbon dioxide laser, and collected the resulting smoke plume. An ESU was used to vaporize the same amount of tissue, and its plume was also collected. The laser plume had the same hazard potential as smoking three unfiltered cigarettes, the ESU plume, the same as six unfiltered cigarettes. Ms. Graling says, "We don't allow smoking in hospitals; we have smoke tents and ask people to go outside, yet every day my colleagues and I are exposed to what smoking cigarettes would expose us to."

Ms. Ball describes four areas of concern related to surgical smoke:

Odor. The noxious odor that accompanies smoke created when a hot tool is used to cut tissue is caused by destruction that produces chemical byproducts and toxins. Several toxic chemical byproducts have been identified in surgical smoke, including known carcinogens such as benzene, toluene, and formaldehyde.

Size of the particulate matter. The matter, which includes cellular material, tissue, and DNA, manifests in various sizes, according to Ms. Ball and other experts. A typical surgical mask filters matter as small as five microns if worn tightly around the face, but much of the matter in a smoke plume is small enough to pass through these masks; one study showed that 77 percent of a laser surgical plume contained matter smaller than 1.1 microns. Inhaling this mater may cause bronchitis, chronic irritation, or other complications.

Viability of the particulate matter. Many studies have shown the presence of viable, (i.e., alive and potentially disease-causing) particulate matter and viral DNA in surgical smoke generated by laser applications and electrosurgery; air samples taken during reduction mammoplasties have shown surgical smoke that contained mutagenic cells. But the question of whether this matter can transmit disease through inhalation has not yet been answered conclusively.

Endoscopic issues. In addition to visibility problems during flexible endoscopic biopsy or surgical excision with a laser or ESU, smoke plumes cause patient problems. Ms. Ball points to a 1993 study which shows that absorption of surgical smoke contributes to patient nausea and vomiting through increased methemoglobin and carboxyhemoglobin levels.

Ms. Ball's perspective on this sobering information: "We're facing a nursing shortage, and is it any wonder that nurses are leaving in record numbers when we don't take their health into consideration?"

Purchasing a smoke evacuation system
A smoke evacuator is basically a vacuum pump with one or more filters designed to evacuate surgical smoke and aerosol from the operative site, filter out essentially all of the contaminants, and return the filtered air to the OR. The main components of a smoke-evacuation system fit for a healthcare facility are:
  • a filter system, which traps smoke particulates and permits the return of filtered air to the operating room;
  • a vacuum source that pulls the air into a nozzle, through tubing, and through the filter;
  • a disposable hose and accessories that connect the unit to the surgical site;
  • an electronic control panel that controls unit operations, eliminates interference with other devices, and facilitates maintenance functions; and,
  • an activation device.

Regarding the control panel, Jim D'Alfonso, CNOR, director of education at HealthStream Education Design and a former manager of Rose Medical Center in Denver, Co., says that electronic panels facilitate rapid access and ease of use by allowing workers to easily read controls.

Smoke evacuators these days are more compact, more portable, and less noisy than their predecessors, he says. Keep in mind that how well a smoke evacuator works also depends on how well it's maintained by the personnel using it. What are the most important considerations in choosing a unit? Mr. D'Alfonso states it plainly: "Look for the most unobtrusive system you can get, and find the least noisy." Further, he suggests, managers should have their staffs test a few units out and help them decide.

Basically, the most important criteria to consider when choosing a smoke evacuation system are the following:

Determine whether the smoke evacuator is designed for use in open or closed procedures, or both. There are units designed to be used specifically for laparoscopic procedures.

Ms. Ball believes that chief on your list of considerations should be how much smoke is produced based on the procedures done in your facility or in given ORs, which will help you decide whether you want in-line filters, an individual smoke evacuator, or a centralized smoke-evacuation system. You may also choose a smoke evacuator with variable air-flow settings.
  • In-line filters. Ms. Ball suggests this system only for situations in which particularly small amounts of smoke are generated, such as that created during the removal of vocal cord polyps. The filter connects to an existing 1/4-inch wall suction line, and is positioned between the wall connection and the suction canister, which collects fluids while the filter purifies the air. In-line filters can be used without suction canisters in instances where a procedure will not produce fluids that need to be suctioned. The effectiveness of the filters decreases if they become wet, so care must be taken not to mistakenly suction fluids through them. Ms. Ball advises to never place the a filter between the patient and the suction (fluid) canister, but between the wall connection and the canister, to prevent the filter from absorbing fluid.

    Mr. D'Alfonso disagrees with the idea that in-line filters are ever good enough. He says that although, as a routine precaution to protect your central-vacuum (fluid-suctioning) system, you should always have an in-line filter in place between the wall connection and canister and you should never use an in-line filter in place of an actual smoke evacuator. "When OSHA regulates this and surveyors visit, he says, " do you think they'll accept different standards for smoke evacuation? I don't think they will."
  • Individual smoke evacuators. Smoke evacuators usually have a triple-filtration system that includes a pre-filter, a charcoal filter, and an ultra?low-penetration air (ULPA) filter. Charcoal is rated by the weight of the material it can capture. Ms. Ball explains that charcoal from activated virgin coconut shell is the most effective for absorbing and deactivating plume odor, and that "activated means that the charcoal has been treated using a heating process to expose its active absorption sites," and "virgin" means that the charcoal has not been reprocessed
  • Centralized smoke-evacuation systems. These are designed to provide evacuation for several ORs at the same time. The smoke tube is attached to a port located in the OR, and the smoke is conducted through the tubing to a central filtration area. Ms. Ball points out a few disadvantages, though she says that these systems are "quick" and provide easy accessibility. The cons are that the internal tubings need to be flushed regularly to prevent debris build-up, and if the central system breaks down, smoke evacuation is not available to several areas.

Filtration efficiency
Some experts suggest single-piece construction for filters to eliminate the need to order and handle contaminated prefilters. The argument for these is that the fewer the filters and the easier they are to change, the better the equipment will be maintained.

A system should include a filtration sensor that activates an indicator light, alerting the operator that the filter is full. This is a more dependable system than looking to OR personnel to notice the odor of surgical smoke or aerosol and judge it themselves. And by the way, make sure that your surgical team is using your system carefully, evacuating the majority of smoke, and practicing good upkeep by following the manufacturer's maintenance instructions. Says Mr. D'Alfonso, "If you can smell the smoke, if someone complains, if people are getting nauseous, you're not being effective. Make sure that you have the nozzle as close to the surgical site as possible. It should be able to capture a high percentage of the smoke right at the site."

Air flow capacity
The key to effective smoke evacuation is the movement of large quantities of air, which requires that the vacuum motor produce a high flow rate and intake velocity. Smoke evacuators with a capacity of providing at least 45 cfm of suction are sufficient for capturing plume at a distance of up to two inches (five cm). Because the constraints of some surgical procedures can prevent placement of the nozzle close to the tissue, smoke evacuators should capture smoke effectively at up to six inches (15 cm). An evacuator with 65 cfm airflow provides unsurpassed performance, according to HealthStream Education's web site, but Mr. D'Alfonso says the best bet is to "compare from manufacturer to manufacturer the capabilities and then follow the instructions, checking that the system is working properly on a basis decided by the manufacturer. Coordinate routine maintenance, such as formal testing and the changing of ULPA filters, with the facility's bio-medical department; nurses should just deal with the changing of disposable accessories," says Mr. D'Alfonso.

If the procedures for which the evacuation system will be used cover a broad range in terms of the amount of smoke generated, choose an evacuation system with variable air-flow settings. Most systems have a variable flow control that allows OR staff to fine-tune the vacuum motor to provide optimum evacuation with minimal noise.

Hose and accessory design
The nozzle and tubing are also important to the efficiency of the evacuation system. Premium corrugated tubing will not kink, say some industry insiders, but Ms. Ball recommends that smoke-evacuation tubes "should have a smooth inner lumen" because corrugated tubing produces a whistling sound as smoke is evacuated. She cautions that "surgical team members have tried to control costs by using anesthesia breathing circuit tubing that has a corrugated lumen," but this creates the distracting whistling noise.

There are generally two types of disposable accessories, those that attach to the hose or plug in on the end, and those where the actual delivery device attaches to the electrosurgery pencil and other instrumentation. There is also the device that exists within the cutting device itself, creating a vortex that surrounds the blade.

Special smoke-evacuation electrosurgical pencils remove smoke and odor, while apparently providing all the capabilities of a quality electrosurgical pencil. Arguments for these integrated devices include the following:
  • the vacuum is built in and so is turned on with the tool, which makes for easy use and is more comfortable;
  • they provide a sure grip even when wet because of their textured finishes;
  • they can be used in closer proximity to the wound site, ensuring that the evacuator is always where it is needed;
  • they conserve energy??staff doesn't have to remember to turn them off;
  • surgical-team members don't have to hold them for surgeons;
  • they are designed to be activated when the pencil is activated, so they're guaranteed to be used, and only when needed.

Mr. D'Alfonso is a fan. "We bought eight for Rose Medical Center, enough so that every OR would have its own smoke-evacuation system," he says. "The wise consumer should know what's on the market and really investigate these no-hassle systems and accessories."

Choose a smoke-evacuation pencil with a built-in channel that allows maximum air flow at the point of smoke generation, say Mr. D'Alfonso and colleagues.

Noise level
Of course, quiet systems provide a less stressful atmosphere for surgical staff and patients. "The more comfortable the accessory is the more likely that it will be used," Mr. D'Alfonso says firmly. "If it's obtrusive for your work, if its noisy and annoying, the doctor will ask that the evacuator be turned off, and the staff will start asking, ?Do we really have to put that on?'"

Smoke evacuation units with remote activation limit noise emission only to the instances where the ESU or laser is in use, as do foot-pedal systems and pencils that have smoke-evacuation nozzles attached to them. The latter two systems are turned on only as they are used, unlike a central system, which is on continuously.

Smoke evacuator noise at the appropriate flow rate should not exceed 70 dbA (a frequency-weighted measure of sound intensity in decibels), according to HealthStream Education Design. Levels above 70 dbA could interfere with communication or drown out the sound of other equipment or alarms.

There are a number of safety issues associated with the use of smoke evacuation systems. A safe system should:
  • Be fire resistant. Nozzles are made of plastics or petroleum, and can be fire-resistant or -retardant but can't be fire-proof. Mr. D'Alfonso suggests that OR managers consult National Fire Protection Agency requirements. ECRI has apparently found that nozzles of some devices glow when irradiated by carbon dioxide lasers, possibly damaging the nozzles. If a nozzle were to ignite from inadvertent contact with a laser beam, it could result in a fire and serious injury to the patient and/or surgical staff.
  • Prevent electrical malfunction. HealthStream says that the evacuator should carry the rating (and symbol) of an electrical-testing agency, and its web site refers to ECRI, which states that evacuators should be electrically grounded, with current leakage below 100 microamps, and that the evacuator should not be adversely affected by electromagnetic interference.
  • Withstand suctioning of unwanted materials. The nozzle should be designed to easily correct and withstand accidental trapping of tissue, foreign objects, or fluid. If tissue is accidentally suctioned and trapped at the nozzle, it has to be pulled from the evacuator or the evacuator must be turned off, which will interrupt the procedure. Nozzles with small openings (1/4 inch in diameter or so) may prevent tissue trapping, but their smaller diameter may significantly reduce the flow rate.
  • Be stable and portable. The unit should be tip-resistant and easy to move.
  • Be compact. The unit should be tall and thin (offer "vertical posture") or fit into the ESU cart so that it won't take up much space, which HealthStream points out will "facilitate safe traffic flow within already crowded OR rooms."
  • Prevent contact with contaminated filters. If the potentially contaminated filter is self-contained and easy to install and change, it protects personnel from potential harm and helps ensure that the equipment will be well maintained.

Though a few advisory bodies, such as NIOSH, recommend treating used filters and absorbers as potential biohazards, Ms. Ball says that "changing a contaminated filter is an occupational hazard, and staff should wear gloves...but the filter itself is not designated as an environmental hazard, so it does not need to be treated as biohazardous waste."

Mr. D'Alfonso, however, believes that you should err on the side of caution. "The literature has not defined all of the risks associated with the plume or the handling of accessories related to the plume," he says, and suggests that you "follow standard precautions" as you would for any biohazard.
  • Have an impervious surface. "Touchpads tend to be better," says Mr. D'Alfonso, as they are flat and tend to be covered with plastic and protected. Such a surface will reduce damage by fluids and the possibility of electrocution, as well as reduce downtime related to cleanup.

User friendliness
The unit should be easy to operate; look for a unit with a large, easy-to-read illuminated control panel. It should have a filter monitor that indicates when to change the filter through an indicator light. Appropriate filter usage should be measured in time used, say some, but Ms. Ball and Mr. D'Alfonso agree that systems that measure when filters should be changed based on smoke capacity (when they are full rather than by an internal clock determining when they "should" need to be changed) are more helpful, particularly if your system is one that is on continuously, as opposed to, say, turned on by foot pedal. Those with time-based indicators may go by all time that the unit is on, including time that smoke is not actually being suctioned, to indicate that you should change your filter.

Hoses and nozzles should be adaptable to different units and accessories. Managers and inventory control personnel should ensure that filters are accessible so that they are changed as often as needed.

Foot pedals can be used with systems to turn them on just when needed and decrease the operating time of the motor. There are also systems equipped with sensors that automatically turn them on when a hot cautery tool is also plugged into the same system.

  • Negotiate. The initial acquisition cost is only a fraction of the total cost of operation over the life of the unit, and prices of disposables vary enough to make cost comparisons worthwhile. Disposable filters, vacuum hoses and nozzles, and instrument adapters must all be purchased on a continuing basis. Frequency of replacement varies among vendors (and facilities) and depends on the type of procedure for which the unit is used. Mr. D'Alfonso says, "In this day and age of rising healthcare costs, it is imperative to make an informed decision." For large hospitals and facilities that are attached to big healthcare systems, he states that "the first order of business is to find out if the purchasing group has a contract with a manufacturer that sells a device." Mr. D'Alfonso says this may limit your deal-making ability, so you'll need to collaborate closely with purchasing personnel, possibly having them renegotiate or work out your going "off contract."

    If possible, negotiate for the stability of a price for disposables that continues over an extended period, before acquiring a system. Purchasing disposables in bulk can also save on costs.
  • Explore financial bundling opportunities. Some vendors offer an arrangement of selling disposables via an up-charge plan, whereby a small charge added to the purchase price of disposables enables the customer to spread payment for relatively expensive hardware over a period of one to five years. Customers able to make a down payment on the purchase can either reduce the disposables add-on expense or the term of the agreement.

    The evidence for addressing the problem of surgical smoke is overwhelming. If you are still not quite sure whether you want to invest in a smoke evacuator, consider the words of Mr D'Alfonso: "It saddens me to think that the people who are devoted to caring and advocating for patients are putting their own health at risk as they perform that care."