Best Practices in Maintaining the Sterile Field
By Jennifer Schraag
Let’s face it, maintaining a sterile field is no easy task. The definition of “sterile” — the absence of all living microorganisms — is in itself about as far-reaching as it can get. But combine that with a room full of organism-laden people, surfaces, instruments, and machinery, and this tall order becomes an ever-increasing challenging demand for today’s surgical teams.
Have you heard the ongoing buzz over allowing a parent to accompany a child in the operating room (OR) while the child receives anesthesia? The caring parent — and often the surgical team — of course wants nothing more than to reduce the anxiety a child may feel in such situations, but at what price? The pros: the child may remain calmer. The cons: the parent — donned in street clothes — just entered a sterile field.
The number of people in the OR is a critical factor in maintaining a sterile field, according to Carol Petersen, RN, BSN, MAOM, CNOR, a perioperative nursing specialist at the Association of periOperative Registered Nurses’ (AORN) Center for Nursing Practice. Aside from the above-mentioned parental saga, Petersen says that even the surgical team should not be passing through the sterile field. “In other words the back table and the patient,” she explains. “They should be walking out around the periphery of the sterile field. You need to keep the number of people in the room to a minimum.”
Ramona Conner, RN, MSN, CNOR, a perioperative nursing specialist, also with AORN’s Center for Nursing Practice, says controlling the number of people in the room is a big challenge for a lot of organizations, particularly teaching organizations because there are a lot of people who want to observe the procedures. “Although we have an obligation to teach, we have a higher priority to protect the patient,” she asserts.
This aspect relates well to event related sterility (ERS). ERS means that once an item has been sterilized, it remains sterile until something occurs that contaminates it. If somebody touches it or an unsterile surface touches it or another vector comes in contact with the sterile item, it becomes contaminated, Conner explains. Air currents can contain airborne contaminants. “The more people in the room, the more likely you are going to have airborne contaminants because people are the most common cause of contamination in the environment,” she points out. “This is because we shed skin cells, we breathe and exhale bacteria. We’re just pretty dirty. So the item is sterile until something comes in contact with it to contaminate it.”
She continues, “People need to be aware that part of maintaining the sterile field includes maintaining the environment. People need to be aware that if they leave the OR doors open or frequently open them they are impeding the air exchange system in the OR. The HVAC system is designed to maintain a minimum of 15 air exchanges per hour in the OR. If they leave that door open or frequently open and close it, the system can’t maintain 15 air exchanges per hour. It also changes the directional air flow. The OR pressure is supposed to be maintained as positive pressure. When they open that door, that equalizes that pressure between the OR and the outside corridor and so they are allowing airborne contaminates potentially to enter the OR.”
Other environmental recommended practices (RPs) Conner offers involves movement techniques within and around the sterile field. “When somebody is passing a sterile field, you should always face it, not have your back to it. You do this so you can keep an eye on it and not accidentally brush up against it with your back.”
She says a common question AORN receives involves people sitting while in sterile attire. “You shouldn’t be below the level of the sterile field,” she answers. “When you sit, your hands are often on your lap or near your lap. We recommend that you only sit when the entire procedure is going to be performed in the sitting position.” Also, she warns, if there is a delay in the case, the person maintaining the sterile field should not sit while awaiting the procedure to begin.
According to Conner the first “commandment” in maintaining a sterile field is that before donning a sterile gown and gloves the surgical hand antisepsis should be performed — thoroughly. “Then they should be attired in sterile gowns and gloves,” she says, adding that OR personnel should don the sterile gowns and gloves away from the sterile field and away from the main instrument table. Moreover, gowns should fit appropriately so large areas of the back are not exposed and the gown is not bulging or sagging in any areas. Also, somebody who is bald needs to cover their entire head regardless of whether there is hair there or not.
Generally, the front of a sterile gown is considered sterile from the chest to the level of the sterile field. Conner explains that the sterile area of the gown extends from the area of the sterile field because scrub personnel work adjacent to the sterile field and table.
Gown sleeves are considered sterile from two inches above the elbow to the cuff. However, it is important that people understand that the neckline, shoulders, underarms and back of the gown are not considered sterile.
“Sleeve cuffs should be considered contaminated once the person’s hands pass beyond the cuff,” Conner shares. “It’s important to know so that people are aware so that when they are changing a contaminated glove, they need to change the glove either with the person assisting them or by the open glove method.”
If someone on the sterile team can not glove them once their hand has gone through that cuff, then they may need to change the gown as well, Petersen adds.
Sterile drapes need to be used to establish a sterile field and the sterile drapes need to cover an adequate area to prevent contamination from unsterile surfaces. Conner says the general rule of thumb is about 18 inches. “But there is no hard and fast rule,” she says. Varying sources mention anywhere between 12 inches to 24 inches to be the standard.
Petersen explains that one of the principals of this is to ensure no one is holding an unsterile arm or other body part such as your head over the sterile field. “If you are 18 inches away, you can’t do that,” she asserts.
Back to the discussion of having too many people in the room … Conner says one item that is new in the 2006 AORN Recommended Practices for Maintaining a Sterile Field is a section recommending only one patient at a time in the OR and that there should not be concurrent cases.
“There were some attempts to perform like surgeries on two different patients in the same room at the same time,” she explains. “We recommend against that practice. You wouldn’t think you would have to mention that, but yes, there is an effort in certain circles to increase OR productivity by doing two patients at the same time in the same room.”
If there is a delay on the case and a surgical team must hold a room, Petersen says many aspects must be seriously considered. “How long can a sterile field be held before you use it?,” she asks. “There is no time frame, but the room needs to be constantly monitored. We tell them, if they need to hold a room to take in several considerations: the kind of surgery being performed; the length of time the procedure will take; and the patient’s condition (i.e. immunocompromised).
“If it is going to be a long case, you probably do not want to hold that room for very long. Some facilities will set an arbitrary time frame of 30 minutes to an hour just so staff can have something to go by, if they choose. They really don’t have to because you still really have to make that clinical judgment. That’s the key.”
AORN does not recommend covering the sterile field in such cases, according to Conner. “That’s a touchy subject. If you do it right, you could do it, but we don’t recommend it because it is so difficult to do,” she explains. “The key thing that people need to be aware of is that sterility is event related and unless they have someone present, monitoring that sterile open field, they are not going to be able to be certain that no event occurred — such as a fly in the room, somebody accidentally coming in the room and contaminating it, something like that.
Unless they have someone in the room monitoring it, they are not going to be able to know that. We have to be able to provide the patient with assurance that the items that are being used on them are sterile.”
Such equipment as microscopes, C-arms, etc., must be draped if they are to be brought over the sterile field. They are to be draped away from the sterile field but not so far that the item can become contaminated. “It should be done close enough that a sterile person doesn’t have to walk across the room to get it, but not so close that the sterile person would contaminate because they can’t move around,” Petersen says, adding that this is what she calls “critical thinking.”
RPs regarding surgical instruments include closely inspecting the instruments and the packaging and pans they are presented in to the sterile field. AORN’s RPs says to inspect the package carefully prior to opening it to make sure there hasn’t been a compromise in the packaging.
Conner says another question she receives frequently concerns wet packs. “Particularly hard instrument cases that have moisture in them,” she says. “If there is moisture present, they should not be considered sterile.”
Petersen points out that with both individual packaging or a big pan of instruments, it is recommend that these items are opened on a separate table. “And then let the sterile person take them off of that. Check to make sure that a.) there is no wetness inside the pan; and b.) that there is an internal chemical indicator that has changed to show that it has gone through the sterilization cycle. As they lift it up, if it is a paper package, they need to make sure there is no hole on the inside that would compromise sterility; and if it is a pan of instruments, they are checking to make sure the filters are in place and working correctly.
“So once they’ve identified all of that, then they can take that pan of instruments and put it on the back table. If they just open them and put them in that back table immediately; if they find that the filter wasn’t right or there isn’t an internal indicator or that it was wet, then that whole table is contaminated and you have to start over. So, you need to use a separate table so you do not contaminate your whole back table if something is wrong.”
Conner adds that checking for debris such as bone chips or blood that is still on the instruments or in the channels of instruments after they have been processed and sterilized is critical.
“The chemical indicator will still change, but that blood and debris will obstruct that sterilization process,” she points out. “If there is blood and debris on the instruments, they should not be considered sterile.”
RPs involving fluids and medication delivery also has evolved. Petersen says that when pouring a bottle of saline, for example, you should pour the entire bottle and not just part of it to then go back and pour the rest later. “You need to empty the entire bottle so that you don’t have the little drips running down the exterior where it is unsterile and then going back and contaminating,” she asserts.
Conner adds that the use of multi-use containers can be confusing. “The RPs are very clear that you should pour the entire contents onto the sterile field or pour what you need and discard the rest, but you should not reuse the container,” she says.
Delivering medications to the sterile field also needs to be carefully thought through. “We get that question very frequently,” Conner says. “The old practice of removing the stopper from the medication vial and then pouring it onto the sterile field is not recommended. Use the sterile transfer devices (i.e. filter straws).”
Some people are actually trying to puncture through the metal to draw up the solution, according to Petersen. “I would just suggest that they pull that stopper or metal cap back just part way, wipe it off, then stick in the syringe and draw up the medication and then completely remove the syringe from the needle and leave the needle in the container,” she offers.
The prior use of a can opener (akin to those found in a common kitchen) to pop the stopper contaminates the sterile field. “The edge of the medication vial will be contaminated. It’s never clean. And we’ve all done it. But even an old dog like me can learn a new trick, and sterile dispensing products are best,” Conner reiterates.
Maintaining the sterile field requires constant vigilance from everyone on the surgical team — the circulator, the scrub person, the surgeon, the assistants, the anesthesiologist — everybody that is involved in that patient’s care needs to maintain constant vigilance and they need to function as a team in order to maintain it, Conner asserts. “And anybody that knows that a break in technique occurred should be able and feel perfectly free to point it out so that correction can be made immediately,” she adds.
Aseptic technique is one of the top priorities of a perioperative nurse, as Petersen points out. “It is a whole team that has to be part of that. Everyone needs to have what we call a ‘surgical conscious’ so that if they see a break in technique or if they do a break in technique themselves, they need to have the consciousness to say ‘I am not sure if I contaminated or not.’ And if there is any kind of a doubt, you need to throw it out, as the old adage goes. Either change your gloves or change your gown or whatever got contaminated if you think it may be contaminated, but if you don’t know for sure, you should always consider it contaminated. Maintaining a good aseptic technique is critical to patient safety.”
What’s New In AORN’Ss 200 Guidelines For Aseptic Technique?
Bonnie G. Denholm, RN, MS, CNOR, a perioperative nursing specialist with the Association of periOperative Registered Nurses (AORN)’s Center for Nursing Practice, says several AORN recommended practices that pertain to aseptic technique were updated for the 2006 Standards, Recommended Practices, and Guidelines.
The changes made to the “Recommended Practices for Maintaining a Sterile Field” include:
- specifications for gowns (eg, liquid barrier performance, adequate size to close completely in the back, sleeve length adequate to prevent cuff exposure outside the glove)
- clarification that ear, nose, throat, and hemorrhoidectomy procedures should be performed using sterile instruments
- sterile transfer devices should be used when delivering medications to the sterile field
The “AORN Recommended Practices for Traffic Patterns in the Perioperative Practice Setting” has also been updated to include parameters for positive air pressure in the OR. There are also extensive updates to the “Recommended Practice for Surgical Tissue Banking.”
The “AORN Guidance Statement: Reuse of Single-Use Devices” was also revised for the 2006 Standards, Recommended Practices, and Guidelines. Although it is not new this year, the perioperative nurse consultants in the Center for Nursing Practice have been reinforcing the content in the “AORN Guidance Statement: Fire Prevention in the Operating Room” because more alcohol-based solutions are being used for skin preps.
Denholm says healthcare facilities should abide by the AORN Standards, Recommended Practices, and Guidelines as a basis for developing policies and procedures in aseptic technique. Nurse educators can also use the Perioperative Nursing Data Set, Perioperative Nursing Vocabulary (PNDS) as a resource for establishing education programs throughout the facility. She adds, “One of the patient outcomes included in this nursing vocabulary states, ‘The patient is free from signs and symptoms of infection.’ The potential nursing diagnoses, nursing interventions, and nursing activities that apply to this outcome are also presented to facilitate nursing care planning throughout a facility.”
AORN works closely with the Centers for Disease Control and Prevention (CDC) and the Association for Professionals in Infection Control and Epidemiology (APIC) as well as other professional associations to review and develop the recommended practices and guidance statements.