Surgical asepsis, often referred to as sterile technique, is the highest level of infection prevention employed in healthcare. This practice is defined by the complete elimination of all microorganisms, including bacterial spores, from an object or area. The goal is to create a sterile field that prevents the introduction of pathogens into susceptible body sites. Nurses use this technique in numerous invasive procedures.
Differentiating Aseptic Techniques
Aseptic techniques are broadly categorized into two types based on their goal: medical asepsis and surgical asepsis. Medical asepsis, also known as the clean technique, aims to reduce the number of microorganisms present and prevent their spread. Examples of medical asepsis include routine handwashing, wearing non-sterile gloves for general patient contact, and disinfecting environmental surfaces.
Surgical asepsis is a more stringent set of measures designed to achieve and maintain an environment completely free of microorganisms. It involves sterilization methods, such as using heat, chemicals, or radiation to destroy all microbes on instruments and equipment. Medical asepsis is suitable for general care, such as administering oral medications or performing non-invasive physical exams.
Surgical asepsis is mandatory for all invasive procedures where the skin barrier is intentionally broken or a normally sterile body cavity is entered. These procedures include surgeries, insertion of medical devices, and managing deep wounds. Eliminating all pathogens prevents serious complications, particularly healthcare-associated infections.
Core Principles of Maintaining Sterility
Maintaining a sterile field requires strict adherence to a specific set of rules, regardless of the procedure. The foundational principle is that a sterile object remains sterile only when touched by another sterile object. Contact with any non-sterile object, surface, or person renders the sterile item contaminated.
One fundamental rule is that any sterile object or field held or falling below the nurse’s waist level is considered non-sterile. Gravity causes fluid to flow downward, so the tips of sterile instruments must always be kept pointed down to prevent contamination from traveling up the shaft. Moisture is another recognized contaminant, as it allows microorganisms to “wick” or travel through the barrier material.
A one-inch border around the perimeter of any sterile drape or field is always considered non-sterile. Nurses must never turn their back on a sterile field or leave the room after setting it up, as the field must be constantly monitored. Air currents and movement near the area must be minimized, and non-sterile personnel must maintain a safe distance, usually one foot away, to prevent contamination.
The nurse must avoid reaching over the sterile field, as this risks dropping non-sterile particles onto the surface. If the sterility of any object becomes questionable (e.g., a tear in the packaging or an expiration date breach), it must be considered non-sterile and replaced. These rules form the framework for every procedure requiring sterile technique.
Key Clinical Examples of Surgical Asepsis
Indwelling Urinary Catheter Insertion
The insertion of an indwelling urinary catheter (Foley) requires strict surgical asepsis because it introduces a foreign object directly into the sterile bladder. The nurse begins by establishing a sterile field using the kit’s wrapping on a clean, dry surface above the waist. After donning sterile gloves, the nurse uses the sterile supplies to cleanse the patient’s meatus and surrounding area with an antiseptic solution.
For female patients, the nurse cleanses the area in a downward motion, using a new swab for each stroke to prevent reintroducing microbes. The nurse lubricates the catheter tip, taking care to keep the rest of the catheter sterile by coiling it in the hand. The catheter is inserted without touching any non-sterile surfaces, and the balloon is inflated with sterile water only once placement in the bladder is confirmed. This prevents the introduction of pathogens that could lead to a Catheter-Associated Urinary Tract Infection (CAUTI).
Central Line Dressing Change
Changing the dressing on a central venous catheter (CVC) demands surgical asepsis to prevent bloodstream infections. Both the nurse and the patient must wear masks to prevent respiratory droplets from contaminating the insertion site. The nurse removes the old dressing with clean gloves, performs hand hygiene, and then opens the specialized sterile dressing kit.
The nurse dons sterile gloves and uses the kit’s supplies to establish a sterile field around the CVC site. The insertion site is scrubbed with a chlorhexidine solution using a firm, back-and-forth motion for at least thirty seconds. Allowing the antiseptic to air dry completely for the recommended time, typically sixty seconds, is required to ensure its effectiveness. Finally, a new sterile antimicrobial patch and transparent dressing are applied to seal the site.
Sterile Field Setup for a Minor Procedure
A nurse preparing for a minor bedside procedure, such as a thoracentesis or complex wound dressing, utilizes surgical asepsis to create a controlled, sterile workspace. The nurse positions the sterile pack on a clean surface so that the outermost flap opens away from the body. The outer wrapper is unfolded, touching only the outer edges, to establish the initial sterile field.
Additional sterile supplies, such as instruments or gauze, are added to the field by peeling open their wrappers and allowing the contents to drop onto the sterile surface. The nurse ensures that hands and the outer wrapper do not pass over the sterile field during this process. If a sterile solution is required, the nurse pours it into a sterile receptacle on the field from a height of about six inches, avoiding splashing.