Final Exam Flashcards
Infection definition
- the growth of pathogenic microorganisms in living tissue; it refers to the disease-producing process, not the routine multiplication of normal flora.
- can have MOs without infection
Review of Microbiology
- Pathogenic microorganisms are those that cause disease
- Sepsis: a severe, toxic, febrile condition resulting from infection with pathogenic microbes, usually pyogenic (pusforming)
- Bacterial infections most frequently cause “hospital-acquired” infections.
MRSA
- Aerobic
- Gram-positive Staphylococcus
- Methicillin Resistant Staph Aureus
- 20-30 % carry this
Group A Streptococcus
- Aerobic
- Gram positive streptococcus
- (may cause necrotozing fasciitis)
- not contagious
Mycobacterium Tuberculosis
- Aerobic bacteria
- A hardy bacillus- can live in soil for a long time
- Most common transmission route/infection site: airborne/lungs
- May be present as a “cyst” elsewhere in the body
- Escherichia coli
- Klebsiella sp.
- Proteus sp.
- Aerobic
- Gram-negative bacilli
- all normal flora of the GI tract
Clostridium difficile
- Anaerobic
- Gram-positive bacilli
- pseudomembranous colitis
- common nosocomial
- contact precautions
- antibiotics wipe out all the good bugs
Bacillus stearothermophilus
is used for testing autoclaves (AKA “Attest”)
*Bacteroides sp.
- Anaerobic
- Gram-negative bacilli
- normal flora of the gut
- cause gingivitis and periodontal disease
GRAM-NEGATIVE BACTERIA ARE THE PRIMARY CONTAMINANTS IN
NOSOCOMIAL INFECTIONS
Candida albicans
- Fungi
- AKA “thrush” (mouth), AKA “yeast” (vagina)
- can be normal flora of the mouth
Sources of Contamination
- Community-acquired infection:
- Spontaneous
- Traumatic
- Nosocomial
- Endogenous
- Exogenous
Community-acquired infection
- Spontaneous – Appendicitis, cholecystitis, peritonitis (kinda like endogenous)
- Traumatic – Compound fractures, penetrating wounds (kinda like exogenous)
Nosocomial Infections
- Endogenous:
- Develops from sources within the body
- This raises the issue of cross contamination, especially “bowel technique” (isolating, fix contaminations)
- Exogenous:
- Acquired from sources outside the body
- ex: healthcare worker didn’t wash hands
FACTS about nosocomial infections
- About 35% of all nosocomial infections develop in surgical patients
- The majority of these are related to instrumentation of the urinary tract and the respiratory tract.– isolate
Sepsis
- Definitions:
– A severe, toxic, febrile state resulting from infection.
– The presence of pathogenic microbes or their toxins in the blood or other tissues. - three stages:
– invasion
– localization
– either resolution leading to recovery, OR, spreading of the infection.
Development of Infection
- Cellulitis (invasion)- diffuse inflammatory response
- Abscess formation (localization):
- the result of tissue liquefaction with pus formation
- body attempts to wall off an abscess by means of a membrane that produces surrounding induration
- An abscess should be promptly drained.
Regional infection
- Occurs when localization does not contain the infection, and it spreads
- The spreading infection enters the lymphatic system, causing lymphangitis. lymphnodes can help
Systemic infection
-
Septicemia may develop if the lymph nodes fail to contain the infection
- Veins in the infected area form thrombophlebitis, which sloughs septic emboli into the circulatory system
- These emboli and pathogenic microbes seed abscess formation in remote tissues
- Bacterial septicemia is called “bacteremia”.
Septic Shock
- Exists in a state of widely disseminated infection, usually borne by the bloodstream, ie septicemia
- last stage before death
- Early symptoms of septic shock:
- Hypotension
- Tachycardia
- Rapid breathing
- Symptoms of Advanced septic shock:–decompensation– NOT GOOD
- Respiratory insufficiency
- Cardiac decompensation
- Diminished urinary output
- DIC
Clinical Factors contributing to infection:
- Pathogenic microbes
- Local factors
- Host Defense Mechanisms
Pathogenic microbes
- Must reach the host to cause infection
- The size and virulence of the inoculum is VERY important.
- can we stop it from reaching a new host?
Local factors
- Various body tissues have different powers of resistance
- The face, scalp, and chest are more resistant than the abdomen, thigh, calf, and buttocks
- Vascularity of the tissue is a major factor–more vascular= more able to fight off infection
Host Defense Mechanisms
- The general health of the patient is very important- how sick is your pt?
- The virulence of the infecting organism is very important
- Proper treatment plays a big part
Diabetes and host defense mechanisms
- The DIABETIC PATIENT DOESN’T HEAL WELL
- Compromised vascular system
- develop peripheral vascular disease
- loss of sensation (can’t feel the injury, then gets infected)
- Prone to infection
Adjuvant factors to infection
- Duration of pre-op hospitalization
- Contaminated wounds
- Procedures involving GI or GU tracts
- Duration of the procedure- the longer it goes, the more things could go wrong
- Surgical technique
- injured tissues– don’t retract super hard
- Implants
- Excessive use of electrocautery creates necrotic tissue
- Intravascular devices
- Catheters
- Drains- inspect
- Any Implantable device
Post-op Wound Infections
- Incisional :
- Infection occurs at the site of the incision
- Involves skin, subcutaneous fat, or muscle
- Deep :
- Infection occurs in the surgical area
- Involves tissues at or beneath the fascia
Intra-operative Complications
- Hemorrhage
- Friable Tissue
- Incidental Injury to other organs
Intra-operative Complications (Hemorrhage)
- Definitions:
- Shock: A state of inadequate blood perfusion to parts of the body (most likely intraoperatively) hypovolemic
- DIC: Disseminated Intravascular Coagulation – a condition in which the normal clotting mechanisms do not function (most likely postoperatively)
- Treatment of intra-op hemorrhage (larger vessel)
- Surgeon locates source and applies digital pressure
- Clamps put in place
- Vessel is then ligated or sutured
- Blood volume may need to be replaced with transfusion, or with “Cell Saver”
Friable Tissue
- AKA: “Readily crumbled”
- Tend not to hold suture well
- Can be lacerated by vigorous retracting
- Treat with chemical hemostatic agents
- NSAIDS break down tissue
- also radiation, smokers
-
Tumors (may be highly vascular): grow own blood supply
- Malignant tumors
- Hemangiomas
-
Friable Organs:
- Liver, spleen, kidney, pancreas, thyroid
Incidental Injury to other organs
- Friable organs
- Major Vessels
- Ureters
- Bowel
- Urinary Bladder
Incidental injury to Friable Organs
- Injuries may result from:
- Retractors- don’t retract hard
- Dissection- delicate, slow
- Sutures/ligatures- can tear through
Incidental Injury to Major Vessels
- Veins
- Thin; tear easily
- Difficult to suture effectively
- Arteries– clamp off well
- High pressure
Incidental injury to Ureters
- Anatomic relationship to pelvic structures
- Surgeon must identify the ureters to prevent accidental clamping, ligating, or cutting- check for peristalsis
- Ennervated smooth muscle; to identify, use a forceps, etc.
Incidental injury to Bowel
- May be cut during lysis of adhesions
- May be torn by pulling and tugging– we will be in charge of retracting
- Spillage of intestinal contents can cause infection & peritonitis (esp. large intest- colon)
Incidental injury to Urinary Bladder
- May be cut or torn, causing leakage of urine into the pelvic cavity, and bleeding
- thin walls-easy to cut/tear
- Hematuria: blood in the urine– check UDB
Foreign material left in the patient
- Sponges- worst thing-porous-MOs!
- Instruments and Needles
- Anything accidentally left in the patient must be removed!
- all scrub’s job
Post Operative Complications
- Hemorrhage
- Pain
- Scarring
- Keloids
- Adhesions
- Extravasation
- Wound Disruption
- Thrombosis
- Incisional Hernia
Post-op complications Hemorrhage
- May occur any time after the wound is closed
- Ties and hemoclips may slip off vessels
- Clots can become dislodged (from chemical hemostatic agents)
- Remember previous definitions
- DIC–bigger risk post-op
- Shock– more likely to happen intraoperatively
Post-op complication Pain
- Local Anesthetic-very acidic- burning sensation
- Must be injected
- General Anesthetic – many tradeoffs:
- Intra-op – If improperly administered, patient may sometimes feel pain, but can be unable to respond
- Post-op – nausea, vomiting, sore throat.
- Retractors – bruising of tissues, tearing of muscles
- Knives
Post-op complication: Scarring
- Keloids: hypertrophic skin scarring
- Adhesions:
- Develop in response to:
- Previous abdominal or pelvic surgery
- abrasion
- Appendicitis or peritonitis.
- Ischemia.
- most common cause of post-op intestinal obstruction.
- can cause infertility and chronic abdominal pain.
- Lysis of adhesions: a common surgical procedure.
- “Once Adhesions, Always Adhesions”
- Develop in response to:
Extravasation
- Definition:The passage of blood, serum, or lymph into tissues. (fluid outside a vessel)
- Edema: Abnormal accumulation of fluid in interstitial spaces of tissues. (plasma)
- Hematoma: A collection of extravasated blood in tissue. (blood)
Wound Disruption
- Definition: separation of wound edges.
- Occurs when:
- wound fails to heal, sometimes due to:
- suture material fails to secure wound
- Acute wound disruption most frequently follows abdominal laparotomy
- Wound Disruption is usually caused by distention (intra-abdominal pressure), or a sudden strain such as vomiting, coughing, or sneezing
Types of wound disruption
- Dehiscence: Splitting open of the layers of the wound.
- Evisceration: Protrusion of viscera completely through the abdominal incision.
Thrombosis
- Definition: the development of a thrombus
- Thrombus def: an aggregation (clump) of blood factors, especially platelets and fibrin; essentially, a “blood clot”
- Thrombophlebitis def : Inflammation of a vein, associated with thrombosis.
Venous Stasis
- Definition: stagnation of normal flow; ie static instead of dynamic
- The venous return of blood from the lower extremities can be slowed by:
- The effects of general or spinal anesthesia
- The position of the legs during prolonged surgical procedures.
Effects of Venous Stasis
- Thrombosis
- Thrombophlebitis
Deep Vein Thrombosis (DVT)
- The majority of thrombi occur in the deep veins of the legs and pelvis, (aka”Deep Vein Thrombosis“).
- These thrombi can become detached and be carried to the
- lungs (pulmonary embolism),
- heart (MI), or (heart attack)
- brain (CVA) (stroke)
Prevention of Thrombosis
- Anti-embolic stockings (TED hose)
- Elevation of legs
- Sequential Compression Devices- attach to a unit
Incisional Hernia
- After a surgical wound has completely healed, a weakness can develop in the fascia at the incision site.
- Segments of bowel can protrude through this weak spot, causing a hernia.
- This is usually the result of impaired healing of a previous surgical incision, usually a ventral midline abdominal incision.
- It must be surgically repaired .