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 DEPARTMENT:  Pharmacy Services                        POLICY NO:   731-562

 TITLE:  Aseptic Technique                        SUBJECT:  Aseptic Technique



 To establish an educational training program on proper aseptic technique for Pharmacy Employees involved in the preparation of parenteral products.


 All pharmacy employees involved in the preparation of parenteral products shall be trained on utilizing proper aseptic technique.  Employees will be inserviced on aseptic technique annually.  Employees will demonstrate competency in aseptic technique procedures and knowledge.



 As the use of parenteral therapy continues to expand, the need for central­ized hospital intravenous admixture preparation has grown as well.  In addition, demand by practitioners for aseptic preparation of other compounded products, such as sterile irrigations and ophthalmic solutions, has also increased.  Recognizing this need, many hospital pharmacy departments have devoted increased resources to programs for aseptic preparation of sterile products.  In conjunction with the use of sterile equipment and supplies, an understanding of laminar air flow principles, the proper use of the laminar air flow hood, and development and maintenance of skillful manipulative technique by personnel are essential for the compounding of products that are free of microbial and particulate contamination.

 This program will review the clean room concept, including laminar air flow principles; proper use of the laminar air flow hood; appropriate attire and aseptic technique; use of syringes, needles, vials, and ampuls; and basic IV admixture compound­ing procedures.

              * * * *

By definition, sterile products are free of all living microorganisms.  In addition, parenteral solution must be relatively free of particles and free of pyrogens, which are usually bacterial toxins capable of causing a fever.  The goal of using specific clean room equipment and procedures in conjunction with proper aseptic tech­nique is to allow the manipulation of sterile products without contamination with microorganisms, pyrogens, or particles.

 Room air typically contains many thousands of suspended particles per cubic foot, most of which are too small to be seen with the naked eye, including contaminants such as dust, pollens, smoke, and bacteria.  To provide a safe environment for sterile dosage form preparation, there are several steps which should be taken to reduce the number of particles in the air.

 A sterile compounding area should be cleaned daily and segregated from normal pharmacy opera­tions, patient specimens, nonessential equipment, and other materials that produce particles.  For example, the introduction of cardboard into the clean environ­ment should be avoided whenever possible.  Traffic flow into a clean area should be minimized.  Other more sophisticated aspects of clean room design include special filtration or treatment systems for incoming air ultraviolet irradiation, air-lock entry portals, sticky mats to remove particulates from shoes, and positive room air pressure to reduce contami­nant entry from adjacent rooms or hallways.

 Sterile products should be prepared in a "Class 100" environment, containing no more than 100 particles per cubic foot that are 0.5 micron or larger in size.  Thus, laminar flow hoods are utilized in the hospital setting to achieve a "Class 100" environment.  Developed in the early 1960, laminar flow hoods are available in a variety of sizes and styles.  There are two common types of laminar flow hood, horizontal flow and vertical flow.

 Horizontal flow hoods operate, first, by drawing contaminated room air through a prefilter by means of an electrical blower within the food (Fig. 1).  The prefilter, similar to a furnace filter, removes only gross contaminants and should be cleaned or replaced on a regular basis.  Prefiltered air is then pressur­ized within a plenum to assure that a consistent distribution of air flow is presented to the final filtering apparatus.  Constituting the entire back portion of a hood's work area, this "high efficiency particulate air", or HEPA, filter removes 99.97% of particles that are 0.3 micron or larger, thereby eliminating airborne microorganisms.  The underlying principle of the laminar flow hood is that the constant flow of twice-filtered, laminar sheets or layers of "aseptic" air, at a rate of approximately 90 linear feet per minute across the work surface, physically sweeps the work area and prevents the entry of contaminated room air.

 Laminar flow hoods which utilize a vertical flow of filtered air are also avail­able.  In vertical flow hoods, HEPA filtered air emerges from the top and passes downward through the work area.  Because exposure to some antineoplastic (anticancer) drugs may be harmful, they are usually prepared in biological safety cabinets, which utilize vertical air flow, to maintain sterility and protect the operator.  The advan­tage of biological safety cabinets is that the risk of exposure to airborne drug is minimized by containing air flow within the hood.  For more information on biological safety cabinets, see the American Society of Hospital Pharmacists' videotape entitled "Safe Handling of Cytotoxic Drugs."

 The critical principle of laminar flow hood utilization is that nothing must interrupt the flow of air between the HEPA filter and a sterile object.  The introduc­tion of a foreign object between a sterile object and the HEPA filter presents the possibility that contaminants from the foreign object may be carried onto the sterile object.  To maintain sterility, nothing should pass behind a sterile object in a horizon­tal flow hood, or above a sterile object in a vertical flow hood.

 Furthermore, materials placed within the laminar flow hood disturb the patterned flow of air emanating from the HEPA filter.  This "zone of turbulence" created behind an object could potentially extend outside the hood, pulling or allowing contaminated room air into the aseptic working area (Fig. 2).  When laminar air flow is accessible to all sides of an object, the zone of turbulence extends approxi­mately 3X the diameter of that object.  When laminar air flow is not accessible to an object on all sides (for example, when placed adjacent to a vertical wall), a zone of turbu­lence is created that may extend 6x the diameter of the object (Fig. 3).  For these reasons it is advisable to place and work with objects as far into the hood as is practically feasible without blocking air vents, and to maintain unobstructed air flow between the HEPA filter and sterile objects.  Also, when working in the hood, the hands should be positioned so that air flow between the HEPA filter and sterile objects is not blocked.

 The following are general principles for proper laminar flow hood operation:

1.    All aseptic manipulations should be performed at least 6 inches within the hood to prevent the possibil­ity of reflected contamination from the worker's body or "backwash" contamination resulting from air patterns developing at the laminar flow hood-room air interface.

2.    A laminar flow hood should be left operating continuously.  If turned off, howev­er, the machine should not be used for a specified period of time when reactivat­ed, such as 30 min., depending on the hood manufacturer's recommendations.

3.    Before use, all interior working surfaces of the laminar flow hood should be cleaned with approved disinfectant such as cavicide and clean wipes.  Cleaning should be performed from back to front (away from the HEPA filter in horizontal flow hoods), so that contaminants are moved out of the hood.  The hood should be cleaned often through­out the compounding period.  Some materials are not soluble in alcohol and may initially require the use of water in order to be removed.  In addition, Plexi­glas sides, found on some types of laminar flow hoods, should be cleaned with warm soapy water or hydrogen peroxide as in the APreparing Parenteral Products@ to avoid damage.

4.    Nothing should be permitted to come in contact with the HEPA filter.  This in­cludes cleaning solutions, aspirate from syringes, or glass from ampuls, which should not be broken directly toward the filter.

5.    A laminar flow hood should be positioned away from excess traffic, doors, air vents, or anything that could produce air currents capable of introducing contami­nants into the hood.

6.    Jewelry should not be worn on the hands or wrists when working in the laminar flow hood since it may introduce bacteria or particles into the clean work area.

8.    Actions such as talking and coughing should be directed away from the laminar flow hood working area, and any unnecessary motion within the hood should be avoided to minimize the turbulence of air flow.

9.    Only those objects essential to product preparation should be placed in the laminar flow hood.  Do not put paper, pens, labels, or trays into the hood.

 10.       Laminar flow hoods should be tested by qualified personnel annually, whenev­er the hood is moved, or if filter damage is suspected.  Specific tests are employed to certify air flow velocity and HEPA filter integrity.

Although the laminar flow hood provides an aseptic environment, safe for the manipu­la­tion of sterile products, it is essential that strict aseptic technique be employed in conjunction with the proper hood operation.  It is important to remember that the use of the laminar flow hood alone, without the obser­vance of aseptic tech­nique, cannot insure product sterility.

 The first component of good aseptic technique concerns personal attire.  Clean garments, which are relatively particulate free, should be worn when preparing sterile products.  Clean room attire will depend on institutional needs and policies.  Many facilities provide clean scrub suits or gowns for this purpose.  Hair covers and shoe covers may also help reduce particulate or bacterial contamination, and some experts claim that the use of surgical masks and gloves is warranted as well.

 If used properly, the laminar flow hood removes nearly all airborne contaminants.  Thus, touch is the most common means of contaminating a sterile product.  Since the fingers harbor countless bacterial contami­nants, proper hand washing is extremely important.  The hands, nails, wrists, and forearms should be scrubbed thoroughly for at least 30 seconds with a brush, warm water, and appropriate bactericidal soap before performing aseptic manipulations.  Chlorhexidine gluconate in a detergent solution is preferred, as it has been shown to produce the greatest decrease in normal hand flora when compared to povidone-iodine or hexachlo­rophene.  Hand washing should be performed frequently, especially upon having left and returned to the compounding area, in order to reduce the possibility of touch contamina­tion.

 Alcohol gel may also be used to  resterilize hands.

 In addition to hand washing, another important factor in aseptic preparation of sterile products is the correct use of appropriate sterile equipment and supplies, including syringes and needles.

 Syringes are made of either glass or plastic.  Glass syringes are most often used when medication is to be stored in the syringe for an extended period of time, since most drugs are more stable in glass.  disposable plastic syringes are most frequently used in preparing the majority of sterile products, however, because they are cheaper and medications will only be in contact with the syringe for a short period of time.

 There are two basic parts of a syringe: the barrel and the plunger (Fig. 4). The plunger, which passes inside the barrel of the syringe, has a flat disc or lip for manipulation at one end and a cone-shaped rubber piston at the other.  The top collar of the syringe barrel helps prevent the syringe from slipping during manipulation, while the tip provides the point of attachment for a needle.  Many syringes have a locking mechanism at the tip, such as the Luer-lock, which secures the needle within a threaded ring.  Some, however, do not; and the needle is held on the syringe only by friction.

 Syringes are available in a variety of sizes, ranging from 0.5 ml to 50 ml.  Gradua­tion marks on syringes represent different increments, depending on the size of the syringe.  The larger the syringe capacity, usually the larger the interval between graduation lines.  For example, each line on a 10-ml syringe represents 0.2 ml; while on a 30-ml syringe, each line represents 1 ml.  When measuring with a syringe, the final edge (closest to the tip of the syringe) of the plunger piston which comes in contact with the syringe barrel should be lined up to the graduation mark on the barrel which corresponds to the volume desired.  To maintain sterility, two parts of a syringe may not be touched.  These are the syringe tip and the plunger.

 Syringes are sent from the manufacturer assembled and individually packaged in paper overwraps or plastic covers.  The sterility of the contents is guaranteed as long as the outer package remains intact.  Therefore, packages should be inspected, and any that are damaged should be discarded.  The syringe package should be opened within the laminar flow hood in order to maintain sterility.

 Most syringes are also packaged with a protector over the syringe tip.  The syringe tip protector should be left in place until ready for needle attachment.  When attaching needles to Luer-lock type syringes, a quarter-turn is usually sufficient to secure the needle to the syringe.

 Like syringes, needles are also available in a variety of sizes.  Needle size is designated by two numbers, measuring gauge and length.  The gauge of the needle corre­sponds to the diameter of the needle's bore and ranges from 27 (the finest), to 13 (the largest).  (Note that the larger the gauge, the smaller the bore of the needle.)  The length of a needle shaft is measured in inches and usually ranged from 3/8 to 3 2 inches.

 All needles consist of two parts:  the shaft and the hub (Fig. 5).  The hub is used to attach the needle to the syringe and is often color-coded to correspond to a specific gauge size.  The tip of the needle shaft is slanted to form a point, with the slant called the bevel and the point called the bevel tip.  The opposite end of the slant is termed the bevel heel.

 Needles are sent from the manufacturer individually packaged in paper and plastic overwraps.  The sterility of the contents is guaranteed as long as the package remains intact.  Therefore, packages that are damaged should be discarded.  To maintain sterili­ty, the needle package should be opened within the laminar flow hood.

 A needle shaft is usually metal and is lubricated with a sterile silicone coating.  For this reason, needles should never be swabbed with alcohol.  no part of the needle proper should be touched.  Needles should be manipulated by their protective covers only.  The protective cover should be left in place until the needle and/or syringe is to be used, for example, when withdrawing fluid from a vial or ampul.

 Injectable medications are usually supplied in vials or ampuls, each requiring different techniques for withdrawal of the medication.  A vial is a glass container with a rubber  stopper secured to its top by an aluminum band.  The rubber stopper is usually protected by a flip-top cap or aluminum cover.  Most protective caps do not guarantee sterility of the rubber closure.  Therefore, it is necessary, before entry, to spray or swab all vials with 70% isopropyl alcohol.  The correct swabbing technique is several firm strokes in the same direction over the rubber closure, always using a clean, unused portion of a swab on each item.  The swabbing is effective in two ways: first, the alcohol acts as a disinfecting agent; and second, the physical act of swabbing in one direction removes particles from the vial diaphragm.

 A problem to be avoided when using vials is the formation of cores, or pieces of the rubber closure which are carved out as the needle is inserted into the vial.  To prevent core formation, the needle should be inserted in such a way as to penetrate the rubber closure at the same point with both the tip and heel of the bevel.  This is accomplished by first piercing the rubber closure with the bevel tip and then applying lateral (toward the bevel) and downward pressure to insert the needle  (Fig. 6).

 Vials are closed-system containers, since air or fluid cannot pass freely in or out of them. For this reason, to prevent vacuum formation within a vial, it is usually necessary to replace with air the volume of fluid to be removed from a vial, so inject a quantity of air equal to the volume of fluid to be removed from the vial.

 If the drug within a vial is in powdered form, reconstitution must first be per­formed.  The desired volume of  diluent, such as sterile water for injection, is added to the vial containing the powdered drug. As the diluent is added, an equal volume of air must be removed in order to prevent a positive pressure from developing inside the vial.  This may be accomplished by allowing air to flow into the syringe before removing the needle from the vial.  Although most drugs dissolve rapidly when shaken, care must be taken to insure that the drug is completely dissolved before proceeding with further manipulations.

 Unlike vials, ampuls are composed entirely of glass, and once broken, become open-system containers.  Since air or fluid may now pass freely in and out of the container, it is not necessary to replace with air the volume of fluid to be withdrawn from an ampul.

 Ampuls often have a painted ring, representing either of two things.  A ring on the ampul neck indicates the point at which the ampul should break.  Most ampuls are weakened by the manufacturer at this point by physical or chemical means.  On the other hand, a ring painted higher on the ampul head indicates the point behind which fingers should be kept to avoid becoming cut when the ampul is broken.  Regardless of the location of the stripe, the ampul should always be broken open at the neck.

 To break an ampul properly, the ampul neck is cleansed with an alcohol swab and, leaving the swab in place, the ampul is grasped with one hand on each side of the neck, between the thumb and index finger.  A quick, firm, snapping motion is then exerted away from oneself, as if breaking a pencil.  Ampuls should not be opened toward the HEPA filter of the laminar flow hood or toward other sterile products within the hood.  If the ampul does not open easily, it should be rotated slightly so that pressure is exerted at a weaker point.

 To withdraw medication from an ampul, the ampul should be tilted and the bevel of the needle placed in the corner space near the opening.  Surface tension should keep the solution from spilling out of the ampul.  The syringe plunger is then pulled back to withdraw the solution.

 The possibility that glass or paint chips may fall into the solution when an ampul is broken requires the use of a filter in the preparation process.  Most often, a needle with a 5-micron filter in the hub is used, either as solution is pulled into or pushed out of the syringe.  Usually, the medication is withdrawn from the ampul with a regular needle and then the needle is changed to a filter needle before pushing drug out of the syringe.

 IV admixtures may be prepared in flexible plastic bags, glass bottles, or semirigid plastic containers.  Frequently, flexible plastic bags made of polyvinyl chloride (PVC) are used which allow easier storage and, compared to glass bottles, decreased breakage and elimination of the need to vent the container for fluid removal.

 PVC bags are available in several sizes, containing a variety of solutions.  They are supplied in plastic overwraps, which limit fluid loss.  The injection portal of a PVC bag, covered by a protective rubber tip, should be positioned toward the HEPA filter when preparing an IV admixture.

 Before compounding, all needed materials should be assembled and vials, ampuls, and IV solution containers visually inspected for signs of cloudiness, particulate matter, cracks or punctures, past expira­tion dates, or any other indications that the product may be defective.  Again, only materials necessary to the preparation process should be placed within the laminar flow hood.


Next, all injection surfaces should be disinfected, including the injection portal of the PVC bag.  Drug fluid is withdrawn from its container in the amount needed, using the syringe size closest to the volume to be injected.  To obtain as accurate a measure­ment as possible, air bubbles should be removed from the syringe after first pulling back slightly on the plunger to draw into the syringe barrel any fluid trapped in the needle.  Ampuls should not be opened toward the HEPA filter of the laminar flow hood or toward other sterile products within the hood.  If the ampul does not open easily, it should be rotated slightly so that pressure is exerted at a weaker point.

 The admixture of drug into a PVC bag is accomplished by inserting a needle into the injection portal and injecting the appropriate volume of drug fluid.  This injection portal has two diaphragms which must be pierced for fluid transfer into the IV solution (Fig. 7).  The first diaphragm is the tan, outside latex tip and is followed by another plastic diaphragm about 3/8 inch inside the injection portal.  Therefore, to assure fluid transfer into the IV bag, a needle longer than 3/8 inch should be used.

 The admixture of medication to a glass infusion container is accomplished by first removing the protective cap from the IV bottle.  A drug additive is then injected through the rubber stopper or latex diaphragm, either of which should be swabbed with alcohol before entry.  Needles should be inserted through rubber stoppers using the technique to avoid core formation, as previously described for vials.  Following admixture, a protective seal is placed over the stopper of a glass container before it is removed from the laminar flow hood.

 When using a polyolefin, semirigid container for admixture preparation, the protec­tive screw cap is removed and drug additions are made through the designated injection portal.  Disinfection of the portal and replacement of a protective cap are not neces­sary.

 Once an IV admixture or other sterile product is compounded, it should be properly labeled with the following information:

 1.          Patient name and room number

2.          Solution name and volume

3.          Additive name and quantity

4.          Date of preparation

5.          Expiration date and time

6.          Prescribed administration rate

7.          Ancillary precaution labels

8.          Storage instructions


A final inspection of the admixture for cores and particulates should be performed.  All drug and IV solution containers used in preparing the admixture should be checked to verify that the proper amount of the correct drug has been added to the correct IV solution.

 In summary, aseptic technique is a means of manipulating sterile products without contaminating them.  Proper use of the laminar flow hood and strict aseptic technique are the most important factors in preventing the contamination of sterile products.  Thorough training of personnel in the proper use of the laminar flow hood and strict aseptic technique, followed by the development of conscientious work habits, is of utmost importance to any sterile products program.


_________________________________________             ___________________

Director of Pharmacy              Date      


               TEST QUESTIONS

 To obtain continuing education credits, remove the answer sheet from the back of this study guide and follow the directions for completing the test and applying for credit.

 DIRECTIONS:  Blacken the letter on the answer sheet corresponding to the one best response for each of the following.

 1.       The most important requirement in the preparation of sterile products is:

                         a.       a properly functioning and certified laminar air flow hood.

b.       a "Class 100" environment with no more than 100 particles per cubic foot that are 0.5 micron or larger.

c.       the use of strict aseptic technique.

d.       a HEPA filter certified by qualified personnel.

 2.       The advantage of using a biological safety cabinet with vertical air flow for the preparation of antineo­plastic (anticancer) drugs is:

                         a.       the zone of turbulence created behind an object is minimized.

b.       the risk of reflected contamination from the operator's body or "backwash" is reduced.

c.       the operator is protected from exposure to radiation by a lead shield.

d.     contaminated air is not blown on the operator and into the room.

 3.       Sterile objects should be placed and manipulated at least 6 inches within the hood because:

                         a.     they are less likely to become contaminated if the operator coughs or sneezes.

b.     room air may contaminate sterile objects placed close to the front of the hood.

c.       air flow is faster deeper in the hood.

d.       air flow is more turbulent deeper in the hood.

 4.       The sterile parts of a syringe that may never be touched are:

                         a.       the barrel and plunger

b.       the barrel and tip

c.       the plunger and tip

d.       the barrel, plunger, and tip

 5.       Which of the following numbers represents a gauge size for a large bore needle?

                         a.       13

                        b.       27

                        c.          3/8

                        d.       3 2

 6.       Injection surfaces are swabbed with 70% isopropyl alcohol prior to needle insertion because:

a.       the alcohol acts as a disinfecting agent.

b.       the physical act of swabbing removes particles

c.       the evaporation of alcohol from the injection surface physically removes particles.

d.     both a and b are true.

 7.       A needle should be manipulated by its protective cover in order to:

                         a.     maintain sterility

b.     protect the operator from injury

c.     keep it from becoming dull

d.     keep the silicone coating intact

 8.       To equalize the pressure inside a vial when removing drug fluid, it is necessary to:

                         a.     inject a quantity of air equal to the volume of fluid to be removed.

b.     shake the vial.

c.     swab the top with 70% isopropyl alcohol.

d.     select the syringe size closest to the volume to be removed.

 9.       A filter must be used when preparing an admixture of a drug that comes in an ampul because:

                         a.     once the ampul is opened, it is an open-system container and can no longer be considered sterile.

b.     glass chips may fall into solution when the ampul is broken.

c.     drugs stored for extended periods in glass ampuls may contain impurities.

d.     drugs that come in ampuls may contain impurities because ampuls cannot be autoclaved.

 10.     After compounding, all drug and IV solution containers should be inspected:

                           a.       for cracks, punctures, haziness, cores, and particulates.

b.       to verify that the proper amount of the correct drug has been added to the correct IV solution.

c.       to verify that the label is accurate.

d.       all of the above are correct.