Veterinary Surgical Nursing

PRINCIPLES of ASEPSIS

Veterinary Surgical Nursing

PRINCIPLES OF ASEPSIS


Asepsis

• A-sepsis– To be “without infection”– But not necessarily without presence of all

infectious organisms– Doing enough to prevent routine infections


Varying degrees of asepsis

• Antiseptic– Degree of kill achieved on living biological surfaces

• Povidone iodine• Chlorhexidine

• Disinfectant – Degree of kill achieved on inanimate surfaces (floors, walls,

equipment)• Bleach• Quaternary ammonium compounds

• Sterilising agent– Full kill achieved with sterilising agent (if properly used)

• Steam heat• Dry heat• Ionising radiation• Ethylene oxide • Glutaraldehyde


Introduction

• Wounds of all types are prone to contamination and the eventual development of sepsis or infection.

• Nowadays, most people expect to survive surgery, however until this century the mortality rate for even simple procedures was high due to wound infections and shock.


Antisepsis

• Antisepsis means the killing of micro-organisms within living tissue. (eg treating a contaminated wound).

• In 1865 the surgeon, Lister, introduced the concept of antisepsis by applying a mild solution of carbolic acid (phenol) to wounds and dressings circumventing, in many cases, the need to amputate limbs because of infection.


1865

• Joseph Lister– Reduced surgical mortality rates

from 50% to 15% – Sprayed carbolic acid around operating

theatres and onto wounds


Aseptic technique

• Aseptic technique means establishing conditions that prevent the contamination of surgical wounds. As a veterinary nurse you play a crucial role in its implementation and maintenance.

• In practice it is not possible to totally eliminate micro-organisms falling into the wound. However, there is a level of contamination which, when exceeded, will lead to infection. This level will vary between animals and is dependant on the competency of their immune system. This may be impaired by factors such as concurrent disease (eg renal failure, drugs, stress and tissue trauma at the site of the wound).


Sources of infection

• Environment (incl equipment)• Patient• Personnel


Environmental Sources

• Room and its contents • Atmosphere • Surgical equipment


Patient Sources

• Skin• Cavities

– Alimentary tract– Respiratory tract– Urogenital tract

• Patient-sourced infection may be– Direct (via contact) – Indirect (via blood or lymph stream)


Personnel Sources

• Clothing • Hands, Hair • Exhaled gases


‘Sterile Field’

• Any areas draped – e.g. anything green– But also paper/plastic drapes– Gowns– Also gloves, instruments, swabs, saline– Includes areas vertically above these fields


Wound contamination

Clean A surgical wound made under aseptic conditions. There is no break into a contaminated area such as the respiratory or gastrointestinal tract.

Clean-contaminated

Where a contaminated area is entered but without spillage or spread of contamination (i.e. respiratory, gastrointestinal or urogenital tract)

Contaminated Where there is spillage from a viscus or severe inflammation is encountered, but no infection present. Open fresh traumatic wounds e.g. HBC or animal bite.

Dirty Infection where there is pus present or viscus perforation spilling pus. Traumatic wound containing devitalised tissue or foreign bodies


GOLDEN RULESOF ASEPSIS


Confinement

• Surgical team members remain within sterile area– Movement out of the sterile area may

encourage cross contamination

• The entry of personnel into operating theatre greatly increases (x100) the number of air borne particles


Talking

• Talking is kept to a minimum– Talking releases moisture droplets laden

with bacteria


Movement

• Movement in the operating room or by personnel is kept to a minimum

• Only necessary personnel should enter the operating room– Movement may cause turbulent airflow and

result in cross contamination


Areas Over sterile field

• Non-scrubbed personnel do not reach anywhere over sterile fields– Dust, lint or other carriers of bacteria may

fall on sterile field


Face each other

• Scrubbed team members face each other and the sterile field at all times– A team members back is not considered

sterile even if wearing a wrap-around gown


Sterile equipment

• Equipment used during surgery must be sterilised– Unsterile instruments may be a source of

cross-contamination


Handling sterile equipment

• Only scrubbed personnel handle sterilised equipment– Risk of cross-contamination


Doubtful instrument sterility

• If sterility of an item is questioned it is considered contaminated


Table height

• Sterile tables are only considered sterile at table height– Items hanging over the table edge are

considered non-sterile because they are out of the surgeons vision


Gowns

• Gowns are sterile from mid chest to waist and from gloved hand to 5 cm above the elbow– Back of a gown not considered sterile even

if wrap-around


Moisture proof drapes

• Drapes covering instrument tables and patient should be moisture proof– Moisture carries bacteria from a non-sterile

surface to a sterile surface (“strike-through” contamination) – can happen within a minute


Packet edges

• If a sterile object touches the sealing edge of the pouch that holds it during opening, it is considered contaminated– Sealed edges are not sterile


Damaged or wet wrappers

• Sterile items within a damaged or wet wrapper are considered contaminated– Contamination by perforation or moisture

“strike through”


Body posture

• Do not fold hands into the axillary region or dangle on sides– Rather clasp hands in front of the body

above the waist


Seating

• If the surgical team begins surgery sitting then they should remain seated until surgery completion– Surgery field only sterile from table height

to chest; movement from sitting to standing may bring bacteria onto sterile field


Scheduling

• Schedule contaminated surgery last– Abscesses– Bite wounds– Dentals


More ideal principles

• Staff shower before surgery• Scrub suits used• Positive pressure ventilation of

theatre• Sterile air flows away from sterile

field


The End

Veterinary Surgical Nursing

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