Aseptic technique can be divided into skin disinfection and sterile technique. Skin disinfection removes any microorganisms found on the skin and decreases potential contamination during the procedure. Sterile technique is performed for the same reason. There are different levels of aseptic technique, ranging from full aseptic technique (mask, gown, gloves, and drapes) to simple sterile gloves. The physician must use their judgment to determine which level is most appropriate to the task at hand.8
Disinfection involves the application and scrubbing of a disinfectant preparation onto the skin. Simple procedures, such as injections or venipunctures, may require little disinfection. Wipe the skin with gauze that has been impregnated with 70% isopropyl alcohol for simple procedures. The alcohol has an antibacterial effect. The mere force of wiping the skin reduces bacterial counts. No disinfection is used for simple venipunctures in some countries. More comprehensive skin preparation involves the use of a disinfectant agent such as povidone iodine or chlorhexidine solution.
Povidone iodine, 2% iodine tincture, and chlorhexidine are the most commonly used skin antiseptic solutions. Povidone iodine solution is highly germicidal for gram-positive and gram-negative bacteria, viruses, fungi, protozoa, and yeasts.7 It rapidly reduces bacterial counts on the skin surface and these effects last up to 3 hours.7,11 Allow the iodine solution to dry and then wipe it from the skin with 70% alcohol prior to beginning the procedure. The iodine solutions work by oxidation and cross-linking of sulfhydryl groups, killing bacteria as the solution dries. Isopropyl alcohol can be applied to the skin and scrubbed vigorously for 2 minutes to achieve disinfection, although this may cause skin irritation. Chlorhexidine or hexachlorophene preparations may be routinely used or as substitutes in iodine allergic or sensitive patients. These agents provide good bactericidal activity against gram-positive bacteria but somewhat less activity against gram-negative organisms.8
Chlorhexidine-based solutions are being used more commonly and are replacing the iodine-based solutions. Chlorhexidine provides much longer antimicrobial activity (up to 48 hours) and is more gentle on the skin than iodine.11–15 Chlorhexidine destroys cell membranes of gram-positive and gram-negative bacteria while precipitating the intracellular contents. Some preparations contain 70% isopropyl alcohol, further enhancing the antimicrobial activity.12–14 The use of chlorhexidine solutions is proving to be superior to iodine solutions.14,15
Use a skin disinfectant for procedures other than simple venipuncture. Place the disinfectant solution onto either a sterile sponge or sterile gauze if it is not supplied inside a single-use applicator. Historically, the application of disinfectant to the skin is in a circular motion, beginning with the central area of the procedure and working out toward the periphery of the sterile field (Figure 2-1). There is no evidence to support this application method. It has been suggested that scrubbing in a back-and-forth motion creates friction to dislodge microbes and may be preferable to the traditional circular application.9,10 The back-and-forth motion drives the disinfectant solution into skin crevices and deeper layers, thus killing more bacteria and hopefully preventing infections.
Preparation of the skin. Disinfectant solution is applied in a concentric circular pattern starting from the procedure site and working outward. Apply the disinfectant solution with sterile gauze held in a clamp (A), with sterile gauze held in a sterile gloved hand (B), or with a sponge on a stick (C).
Regardless of the disinfectant solution used, repeat the application process three or four times using a new sponge, gauze square, or applicator each time.8 This technique ensures that the central area where the procedure is to be performed is the most sterile area of the field. The area of disinfection must be much larger than the primary area of the procedure, as the number of organisms increases toward the periphery of the prepped area.
General sterile technique is described, followed by specific details for each step of the procedure. Strict sterile technique is virtually impossible in the ED. However, make every effort to maintain a sterile field in order to minimize infection. Assemble all equipment necessary and place it on a small procedure stand. Do not use the patient or their bed to set up supplies or equipment. Patient movement and their irregular body surfaces can result in items falling, breaking, becoming contaminated, or iatrogenic needle sticks. Avoid having different components scattered around the procedure area. Open all sterile items, using proper sterile protocol, so as to have them available once the physician has donned sterile gloves. Use anesthetic solution containers with removable caps. This allows the physician to draw up anesthetic without having an assistant and minimizes the risk of occupational needle exposure. Perform a thorough hand washing before the procedure.
Apply sterile gloves. Place sterile drapes or towels to form a field wide enough to allow for a comfortable work space. Drape the area near the patient closest to the bedside procedure table. This will minimize inadvertent contamination in moving from the table to the patient. Make a small flat sterile area near the procedure site to allow for placement of important items that must be immediately available. Open all caps, position stopcocks, and prepare all devices prior to starting the procedure. The likelihood of contamination increases if devices are not adequately prepared, thus requiring manipulation during the critical portion of a procedure. Adhere to universal precautions guidelines. Use eye and face protection during the procedure. This should be applied before donning gowns and gloves.
Always make sure that the outer wrapping is intact, the sterility expiration date has not passed, and the sterility indicator tape is the appropriate color before opening a sterile pack.2 Wash your hands and then remove the outer wrap if applicable. Remove the sterility indicator tape (Figure 2-2A). Place the sterile pack on a dry and level surface with the outermost flap facing away from you (Figure 2-2B). Grasp the corners of the outermost flap (Figure 2-2B). Hold your arms to the sides of the pack to avoid reaching over the sterile area. Lift the flap up and away from you (Figure 2-2B). Open the side flaps by grasping the folded corner with a thumb and index finger and pulling the flap to the side (Figure 2-2C). Open the bottom flap (Figure 2-2D). Grasp and open the bottom flap while stepping back to prevent contaminating the wrap on your clothing (Figure 2-2E). Make sure that your arms and clothes do not contaminate the contents of the pack when opening the flaps. Repeat the procedure if the pack has an inner wrap.
Opening a sterile pack. A. Remove the sterility indicator tape. B. Grasp the edges of the outermost flap and open it away from you. C. Open the side flaps. D. Open the remaining flap toward you. E. The open pack.
Placing Sterile Supplies on a Sterile Field
Sterile supplies are generally packaged in either a hard (hard pack) or a soft peel-back (soft pack) container. The general principle of opening these is the same, although there are subtle differences. Hold the hard peel-back container in the nondominant hand with the flap facing the sterile field (Figure 2-3A). Pull the flap toward you with the dominant hand so that the open end of the pack will be facing the field (Figure 2-3A). Hold the container 15 to 20 cm above the sterile field. This ensures that if the contents fall, it will be onto the sterile field where they are wanted. Drop the contents of the sterile pack onto the sterile field, taking care not to contaminate the field with the container itself (Figure 2-3B).
Opening a hard peel-back container. A. Grasp the container with the flap facing the sterile field. Remove the flap. B. Drop the contents of the hard container onto the sterile field.
Gloves and syringes are wrapped in soft packs. Grasp both sides of the unsealed edge of the soft pack and pull them apart slightly (Figure 2-4A). Hold the open end facing the sterile field (away from you). Continue to open the soft pack. Fold the sides of the sterile packing back and over your hands to keep the contents sterile (Figure 2-4B). Gently drop the contents of the soft pack onto the sterile field.
Opening a soft peel-back container. A. Grasp both sides of the unsealed edge and pull them apart. B. Face the pack toward the sterile field. Continue to open the edges until the contents fall onto the sterile field.
Surgical masks serve a dual role in the performance of aseptic technique. Masks have been shown to decrease contamination of the sterile field that may result from aerosolized droplets from the mouth and nose. Masks protect the caregiver's mucous membranes from exposure and possible splashing during the procedure. Wear a mask with an eye shield during high-risk procedures.
Apply the mask before donning gloves and other sterile equipment. Depending on the type and style of the mask, secure it by placing the elastic straps around the ears, placing the elastic straps around the head, or tying the mask securely to the face with ties around the head and neck. Pinch the metal nose clip securely to the bridge of the nose for a tighter fit and to minimize the gap between the mask and the nose.
A physician must thoroughly wash their hands despite the fact that sterile gloves are worn for all sterile procedures. Good hand washing technique should not be overlooked. A full surgical scrub is neither necessary nor feasible in the ED.
Rinse your hands in warm water prior to applying antiseptic soap. Apply soap, lather your hands, and rub them together vigorously for approximately 10 seconds. Wash each wrist with the opposite hand. Interlace the fingers of both hands and slide them back and forth to clean the web spaces. Clean around the nails with the fingertips and nails of the opposite hand. Completely rinse each hand from the fingers downward. Repeat the procedure a second time if your hands were grossly contaminated. Dry your hands with a disposable towel. Turn off the faucet, using the towel with which you dried your hands. Do not touch the faucet with clean hands. Otherwise they will become contaminated again.
Application of a Clean Gown
A clean (nonsterile) gown is often used as an additional barrier to contamination of both the field and the provider's clothing. Simply place your arms into the sleeves and pull on the gown with the opening toward the back. Secure the gown at the back of the neck and the lower back by tying the strings.
Application of a Sterile Gown
A sterile gown is worn for procedures requiring a stricter sterile technique (i.e., central venous access, diagnostic peritoneal lavage). To open a sterile gown, use the procedure previously described to open a sterile soft pack. Grasp and pick up the gown just below the neckline, touching only the inner surface of the gown. Hold the gown up and let it unfold with the inside facing you. Do not allow the gown to touch any nonsterile surfaces. Insert your arms into the sleeves until the gown is in place. Have an assistant grasp the back of the gown, pull it completely on, and tie the strings securely.
Application of Sterile Gloves
Wash your hands thoroughly before putting on sterile gloves. Apply a clean gown at this point if it will be worn during the procedure. Open the outer wrap of the sterile gloves and remove the inner wrap (Figure 2-5A). Place the inner wrap on a clean surface with the gloves' wrists facing toward you. Unfold the inner wrap, touching only the outside edges (Figure 2-5B). Open the inner wrap according to the procedure for opening a sterile pack (Figure 2-5C). Apply a sterile gown at this point if it will be worn during the procedure. Use the dominant hand to grab the opposite glove at the inner edge of its folded cuff (Figure 2-5D). Slip the nondominant hand into the glove, being careful not to touch the outer surface of the glove (Figure 2-5E). Pull the glove further onto the nondominant hand using the inner edge of the cuff (Figure 2-5F). Place the fingers of the gloved nondominant hand into the folded cuff of the other glove (Figure 2-5G). Slip the dominant hand into the glove (Figure 2-5H). Pull this glove over the dominant hand using the cuff (Figure 2-5I). Carefully unfold the cuff of each glove, taking care not to touch the fingers and palms of the gloves to nonsterile skin. Adjust each glove to ensure a snug fit over the fingers and hand.
Application of sterile gloves. A. Open the outer wrap and remove the inner wrap. B. Unfold the inner wrap. C. Completely open the inner wrap. D. Grasp the cuff of a glove. E. Slip the glove onto the hand. F. Pull the glove onto the hand. G. Slip the gloved hand into the folded cuff of the second glove. H. Slip the glove onto the hand. I. Pull the glove onto the hand.
Removal of Protective Clothing
Remove protective clothing in a systematic manner in order to protect yourself and others from the contaminants on your gown and gloves (Figure 2-6). Place all removed garments into appropriate waste containers. The first step is to untie the gown (Figure 2-6A). Have an assistant untie the neck strings of the gown or pull on both shoulders of the gown to break the neck strings. Untie the waist strings. Take off the gown by turning it inside out as it is removed (Figure 2-6B). Roll up the gown with the contaminated surface facing inward and away from you (Figure 2-6C). Dispose of the gown. Remove the gloves by turning them inside out, making sure that you do not touch the outside (contaminated) surface with your ungloved hands. Use the dominant hand to grasp the cuff of the glove on the nondominant hand (Figure 2-6D). Pull the glove inside out as you remove it and throw it away. Place the ungloved fingers of the nondominant hand into the inside edge of the gloved dominant hand and remove it by pulling the glove inside out (Figure 2-6E). Dispose of the glove. Remove the mask by untying its ties or removing the elastic straps from behind your ears. Dispose of the mask. Finally, wash your hands.
Removal of protective clothing. A. Untie the gown. B. Remove the gown by turning it inside out. C. Roll up the gown with the contaminated side facing inward. D. Remove the glove from the nondominant hand. E. Remove the glove from the dominant hand. Remove the face mask and wash your hands.