Comprehensive Study Notes on Asepsis and Infection Control
Introduction to Asepsis and Infection Control
Role of Nurses: Nurses are directly involved in providing a biologically safe environment for patients.
Distribution of Microorganisms: Microorganisms are ubiquitous and exist everywhere, including:
Water and soil.
Body surfaces: Skin and the intestinal tract.
Areas open to the outside: Mouth, upper respiratory tract, vagina, and the lower urinary tract.
Communicable Disease: An illness caused by an infectious agent or its toxins. It occurs through direct or indirect transmission from:
An infected individual or their products.
An animal or vector.
The inanimate environment to a susceptible animal or human host.
Virulence: Refers to the severity or harmfulness of a disease. It is a quantitative measure, colloquially referred to as "Vagsik ng sakit."
Key Definitions in Infection and Asepsis
Infection: The implantation and successful replication of an organism in the tissue of a host, which results in signs and symptoms.
Infectious Agent (Etiologic Agent): The microorganism responsible for the infection.
Pathogenicity: The ability of an organism to produce a disease.
Pathogen: A microorganism that causes disease.
True Pathogen: An infectious agent that causes disease in virtually any susceptible host.
Opportunistic Pathogens: Potentially infectious agents that rarely cause disease in individuals with healthy immune systems.
Asepsis: Freedom from disease-causing microorganisms.
Medical Asepsis: Known as "Clean Technique." These are practices intended to confine or reduce the number of microorganisms.
Surgical Asepsis: Known as "Sterile Technique." These are practices that keep an area or object free of ALL microorganisms.
Sepsis: A condition in which acute organ dysfunction occurs secondary to infection.
Bacteremia: A condition where a culture of an individual’s blood reveals the presence of microorganisms.
Septicemia: Occurs when bacteremia results in a systemic infection.
Categories and Classifications of Microorganisms
Bacteria: The most common infection-causing microorganisms; they are unicellular.
Viruses: Consist of nucleic acid and must enter living cells in order to reproduced.
Fungi: Includes yeasts and molds.
Parasites: Microorganisms that live on other living organisms, such as protozoa, helminths, and arthropods.
Colonization: The process by which strains of microorganisms become resident flora. In this state, they may grow and multiply but do not cause disease.
Types of Infection based on Location and Duration:
Local Infection: Limited to the specific part of the body where the microorganisms remain.
Systemic Infection: Occurs when the infection spreads to different parts of the body.
Acute Infection: Generally appears suddenly or lasts a short time.
Chronic Infection: May occur slowly over a long period and may last for months or years.
Healthcare-Associated Infections (HAIs)
Nosocomial Infections: Infections acquired in a hospital or healthcare facility.
Iatrogenic Infections: Infections that are the direct result of diagnostic or therapeutic procedures (e.g., bacteremia resulting from an intravascular infusion line).
Common HAIs and Prevention Strategies:
CLABSI (Central IV Line-Associated Bloodstream Infection):
Causes: Improper tubing and site care technique; inadequate hand hygiene.
Prevention: Hand hygiene prior to insertion, maximal barrier precautions, chlorhexidine skin antisepsis, optimal site selection, and daily review of the necessity of the line.
CAUTI (Catheter-Associated Urinary Tract Infection):
Causes: Improper catheterization technique, contamination of closed drainage systems, and inadequate hand hygiene.
Prevention: Use urinary catheters only when needed, use sterile equipment, maintain a closed sterile drainage system, and remove the catheter as soon as it is no longer needed.
SSI (Surgical Site Infections):
Causes: Improper dressing changes and inadequate hand hygiene.
Prevention: Parenteral antibiotic prophylaxis, washing patients with soap or an antiseptic agent the night prior to surgery, avoiding hair removal (using electric clippers if necessary), assessing blood glucose, and maintaining intraoperative glycemic control at < 200\,mg/dL.
VAP (Ventilator-Associated Pneumonia):
Causes: Improper suctioning and inadequate hand hygiene.
Prevention: Elevate the head of the bed between and , perform daily oral care with chlorhexidine, and conduct a daily assessment of the patient's readiness to extubate.
Hand Hygiene Standards and Safety Goals
2019 Joint Commission National Patient Safety Goal 7: Reduce the risk of healthcare-associated infections.
Comply with current CDC or WHO hand hygiene guidelines.
Implement evidence-based practices to prevent HAIs due to multidrug-resistant organisms, CLABSI, CAUTI, and SSI.
Handwashing Protocols:
Routine Care: Vigorous washing under a stream of water for to seconds using soap at the start of a shift, when hands are visibly soiled, and after using the toilet (WHO, 2009).
Alcohol-Based Rubs: The CDC recommends the use of antiseptic hand rubs (rinses, gels, or foams) before and after each direct client contact following the initial soap and water wash.
The Chain of Infection and Mitigation
1. Etiologic Agent: Any microbe capable of producing disease (bacteria, virus, fungi, parasite).
Breaking the Chain: Clean and disinfect articles before use; educate clients on cleaning and disinfection.
2. Reservoir: Where organisms survive and multiply (people, animals, food, water, soil).
Carrier: A human or animal reservoir.
Breaking the Chain: Change soiled dressings, maintain skin and oral hygiene, dispose of feces/urine in proper receptacles, and keep suction/drainage bottles covered and emptied per shift.
3. Portal of Exit from Reservoir:
Example: M. Tuberculosis (Respiratory tract) exits via the nose or mouth by sneezing or coughing.
Breaking the Chain: Cover the mouth and nose when sneezing.
4. Method of Transmission:
Direct Transmission: Touching, biting, kissing, sexual intercourse.
Droplet Transmission: A form of direct transmission occurring within () through sneezing, coughing, spitting, singing, or talking.
Indirect Transmission:
Airborne Transmission: Involves Droplet Nuclei (residue of evaporated droplets) that remain in the air for long periods.
Vehicle-borne Transmission: Via Fomites (inanimate materials or objects).
Vector-borne Transmission: Via Vectors (animal or flying/crawling insects).
Breaking the Chain: Handwashing, wearing gloves for secretions, wearing gowns to prevent clothing soilage, holding bedpans steadily, and wearing masks/eye protection for droplet contact.
5. Portal of Entry to Susceptible Host: Mouth, nose, eyes, or cuts in the skin.
Breaking the Chain: Use aseptic technique for invasive procedures (foley catheterization, injections, wound care), place needles in puncture-resistant containers, provide personal care items to clients, and wear PPE.
6. Susceptible Host: Individuals at risk, such as the very young, very old, those receiving immune suppression (cancer treatment, organ transplant), chronic illness, or immune deficiency.
Breaking the Chain: Maintain skin integrity, ensure a well-balanced diet, provide immunizations, encourage deep breathing and movement, and manage stress.
Body Defenses Against Infection
Non-Specific Defenses (Protects against ALL microorganisms):
Anatomic and Physiologic Barriers:
Intact skin and mucous membranes.
Nasal passages (Cilia).
Lungs (Large phagocytes).
Saliva ("Laway"): Lactoferrin, Lysozyme, IgA.
Eyes (Tears).
Stomach: High acidity.
Vagina: to .
Urine flow.
Inflammatory Response: A defense against bacteria, viruses, and other agents.
Specific Defenses:
Antibody-mediated immunity.
Cell-mediated immunity (T cells):
Helper T cells: Support immune system functions.
Cytotoxic T cells: Attack and kill microorganisms and sometimes the body's own cells.
Suppressor T cells: Suppress the functions of helper and cytotoxic T cells.
The Three Stages of Inflammation
Stage 1: Vascular and Cellular Response:
Initiated by injurious agents (physical, chemical, or microorganisms).
Blood vessels at the injury site constrict, then dilate (Histamine release) causing Hyperemia.
Increased vascular permeability causes fluids, proteins, and leukocytes to leak into interstitial spaces (Swelling).
Signs: Redness (Rubor), Heat (Calor), Swelling (Tumor), Pain (Dolor) from pressure on nerve endings, and Loss of Function.
Leukocytosis: Increase in white blood cell production.
Stage 2: Exudate Production:
The injurious agent is overcome and exudate is cleared via lymphatic drainage.
Types of Exudates:
Serous: Chiefly serum (e.g., blister from a burn).
Purulent: Thicker, contains Pus.
Sanguineous (Hemorrhagic): Large amounts of Red Blood Cells (e.g., wounds).
Serosanguineous: Clear and blood-tinged (e.g., surgical incisions).
Purosanguineous: Consists of pus and blood (e.g., infected new wound).
Bright Sanguineous: Fresh bleeding.
Dark Sanguineous: Older bleeding.
Stage 3: Reparative Phase:
Regeneration: Replacement of destroyed tissue by cells identical or similar in structure and function.
Granulation Tissue: Fragile, gelatinous pink or red tissue with many newly formed capillaries.
Cicatrix (Scar): Formed when the tissue shrinks and collagen fibers contract.
Isolation and Infection Control Measures
Disinfection: Elimination of pathogenic microorganisms EXCEPT spores.
Concurrent: Done while the individual is still the source of infection.
Terminal: Done when the patient is no longer the source of infection.
Sterilization: Complete elimination of ALL forms of microbial life.
Isolation Categories:
Strict Isolation: For highly contagious/virulent infections (private room, PPE).
Contact Isolation: For infections spread by direct contact.
Respiratory Isolation: Prevents transmission over short distances through the air.
Enteric Isolation: Prevents spread through direct contact with feces.
Precautions:
Standard/Universal Precautions: Used for ALL clients. Applies to blood, body fluids, excretions, secretions (except sweat), non-intact skin, and mucous membranes. Includes hand hygiene, gloves, masks, eye protection, and sharps safety.
Transmission-Based Precautions:
Airborne: For Measles (Rubeola), Chickenpox (Varicella), Tuberculosis. Requires AIIR (negative pressure room), N95 respirator mask, and surgical mask on client during transport.
Droplet: For Diphtheria, Pertussis, Mumps, Pneumonia. Requires private room and mask if within ().
Contact: For C.Diff. Requires gloves, gown (if incontinent/drainage), and dedicated equipment.
Personal Protective Equipment (PPE) and Waste Management
PPE Levels:
Level A: Self-rebreathing apparatus with encapsulated chemical suit (highest protection).
Level B: Positive pressure with non-encapsulated chemical suit.
Level C: Air-purifying respirator.
Level D: Standard work clothes (no respirator).
Specific PPE Guidelines:
Masks: Must fit tightly over nose and mouth. Lose effectiveness if wet, worn too long, or not changed between clients.
Gowns: Worn if clothing is likely to be soiled; single-use only.
Caps and Shoe Covers: Shield hair and body parts from accidental exposure.
Waste Classification:
Infectious Waste: Blood, lab specimens/cultures, contaminated equipment, diapers.
Injurious Waste: Sharps (needles, scalpels, lancets, broken glass).
Hazardous Waste: Radioactive materials, chemotherapy solutions, caustic chemicals.
Levels of Preventive Care
Primary Prevention: "True prevention" applied to healthy clients (e.g., health education, immunization, nutrition).
Secondary Prevention: Focuses on ill individuals or those at risk of complications. Directed toward diagnosis and intervention (e.g., screenings, surgery, medications).
Tertiary Prevention: Focuses on permanent or irreversible disability. Aims to minimize long-term effects (e.g., Rehabilitation/Physical Therapy).