immune 2 Flashcards
name the two reasons for antibiotic resistance
overprescribing and inappropriate use of current antibiotics
limited choice of ABX that manipulate only a narrow range of bacterial functions.
what disease was eradicated that is making a resurgence
TB
multidrug- resistant TB and
extremely drug resistant TB are a concern why?
resistant to previously effective antimicrobials
why are newer antibiotic developments slow
d/t regulations disincentives, market failures, lack of profitability
is there abs that are active against resistant gram negative pathogens
NO
SSI account for what percent of all nosocomial infections in hospitalized patients?
14-16%
following an SSI what % more likely are patients to spent time in the ICU?
how many more times likely to require readmission
how many more times likely to die
60%
5x more likely to readmit
2x more likely to die
in general dark terms…SSI is a major source of
morbidity and mortality
what percent of SSI for extrabdominal surgery
2-5%
what percent of SSI for intraabdominal surgery
20%
SSI affect how many people annually
500,000
what did the CMS and CDC implement in 2002
national surgical infection prevention project
list the three key measure for SSI
IV abs within 1 hours prior to incision (2hours vancomycin and fluroquinolones)
proportion of patients receiving prophylactic abs is consistent with published guidelines
proportion whose prophylactic abs is D/c’ed within 24 hours after surgery.
what is the predominate SSI
MRSA
SSI are divided into three layer sections-
superficial infections (skin and SQ)
deep infections (fascial, muscle layers)
organ & tissue spaces
SSI are attributed to (4)
bacterial resistance
increased implantation of prosthetics
foreign materials
poor immune status
increased proportion of SSI are caused by resistant pathogens and candida species- which may reflect what type of patients and their history
increasing number of severely ill patients
immunocompromised surgical patients
impact of wide use of broad spectrum ABX
SSI is affected by patient related factors
extremes of age poor nutritional status ASA physical status>2 diabetes mellitus smoking obesity co-existing infections colonization immunocompromise longer preoperative hospital stay
SSI microbial factors
enzyme production
polysaccharides capsule
ability to bind to fibronectin
biofil and slime formation
SSI wound related factors
devitalized tissue
dead space
hematoma
contaminated surgery
present of foreign material
when do SSI present themselves
30 days
name some S/s of SSI
localized inflammation at surgical site
evidence of poor wound healing
fever
malaise
what is the “gold standard” for documenting a wound infection
is to document the growth of organisms in an ascetically obtained culture specimen
what are the nonspecific indicators of SSI
elevated WBC
poor glucose control
elevated levels of inflammatory markers (CRP)
1/3 organism cultured are
staphylococci (aureus, epidermidis)
> 10% organisms cultured are
enterococcus
what makes up the bulk of the remainder of organisms
enterobacteriaceae
PREOP- patient shows signs of infection- what do you do?
what do you do if the infection is at the surgical site
fever, chills, malaise- assess to identify source of infection
aggressively treat acute infections before surgery
cancel surgery if localized area of infection is present at intended surgical site
what does smoking do for your infection risk?
how many weeks should they stop smoking before orthopedic surgery?
smoking increases incidence of respiratory tract infection and wound infection
stop 4-8 weeks before orthro surgery to decrease incidence of wound healing complications
what does alcohol do to your surgical risk
when should they stop drinking
significant preop alcohol consumption may result in general immunocompromise.
stop 1mo reduces post morbidity in alcohol users
hair clipping vs shaving?
hair clip
shaving gives tiny cuts- increased risk of infection
s. aureus most commonly implicated in SSI- can be found in the nares, what can we use ahead of time? what is the concern with treating it?
topical mupirocin to anterior nares as prophylactic but concern of developing resistant strain to s aureus
cachexia/obesity concerns with surgery
both extremes have increased peri-op infection- proper diet and or weight reduction can be beneficial
concern for DM patients and infection
DM is an independent risk factors for infection. optimize pre-op DM treatment may decrease periop infection
when are preop ABX stopped
regular surgery
cardiac surgery
24 hours after surgery
48 hours after cardiac surgery
how many doses of ABX are given in surgery
1 hour prior to surgery
give additional if surgery greater than 4 hours
infections associated with clean surges:
staphylococcal
infections associated with contaminated surgeries
polymicrobial and involve the flora of the viscus entered
what coverage do we use for small bowel entrance
gram negative coverage
what coverage is needed with large bowel and female genital tract surgeries
anaerobic organism
what drug is effective intraop
cephalosporins: ex. cefazolin
why is hypothermia a concern during surgery
can increase incidence of SSI
radiant heating to 38 degree celsius increases
sub q 02 tension and may be a mechanism for decreasing SSI risk
increasing concentration of inspired oxygen may help decrease surgical site infection although what is the concern with this method?
book says up to 80%
high inspired oxygen may cause pulmonary damage
how does treating surgical pain help decrease incidence of SSI
increases post op sq oxygen partial pressures at wound sites.
how does hypocapnia harm the patient under anthesia
vasoconstriciton
vasoconstriction that impairs perfusion to vital organs
how does making the patient slightly hypercapnia aid in healing
it causes vasodilation and increases skin perfusion
blood sugar should be maintained in normal range- what are the effects of high blood sugar on the body?
high blood sugar concentrations inhibit leukocyte function providing environment for bacterial growth
what is the effect of administration of glucose, insulin and potassium
stimulates lymphocytes to proliferate and attack pathogens
plays an important role in restoring immunocompetence to patients with immunocompromise
what is one of 10 leading causes of death in the us
community acquired pna
mycoplasma PNA, chamydia, legionella, adenovirus, and other microorganisms may cause atypical pna - are they common. do they respond to abx, are their symptoms normal?
not common pna and do not respond to common antibiotics and cause uncommon symptoms
what is the most frequent cause of bacterial pna in adults and cause typical pna
streptococcus pneumonia
aspiration PNA- most commonly from.
alcohol
drugs induced alteration of conscousness
head trauma
seizures and other neurologic disorders
administration of sedatives
other reasons for aspiration PNA
Abnormalities of swallowing/esophageal motility from NGT
Esophageal CA
Bowel obstruction
Repeated vomiting
Poor dental/ oral hygiene d/t
development of bacterial flora after aspiration
Induction and recovery from anesthesia
what can we give while walking to the OR do minimize our patients risk of aspiration(per hammon)
bicitra 30cc
the manifestations of aspiration pna depend on
nature and volume of aspirated material
aspiration of large volumes of acidic gastric fluid produces
fulminant (Sudden, great intensity or severity) PNA and arterial hypoxemia
aspiration of particulate materials result in
airway obstruction and smaller particles may produce atelectasis
which anaerobes are most likely cause of aspiration PNA
PCN sensitive anaerobes
what is different about hospital acquired pna
it alters the usual oropharyngeal flora, aspiration PNA in hospitalized patients often involve pathogens that are uncommon in community acquired pna
obesity, age greater than 70 and operations lasting longer than 2 hours have an increase risk of?
post op pna
chronic lungs disease increases the risk of post op pna how many fold?
3 fold
what percent of patients undergoing major thoracic, esophageal, upper abdominal surgery develop post op pna
20%
lung abscess may be seen in what three situations
after bacterial PNA
alcohol abuse and poor dental hygiene
septic PE- seen with Iv drug users
what are the characteristics of lung abscess?
air fluid level of CXR signifies rupture of abscess into bronchial tree
foul smelling sputum
treatment for lung abscess
abx
when is surgery indicated for a lung abscess
complications such as empyema
physical exam findings associated with worse outcomes of PNA
T: temp < 35 C or > 40 C R: Resp rate > 30 A: altered mental status S: Systolic BP < 90 mmHg H: HR > 125 bpm
lab findings associated poor prognosis
H: hypoxia PO2 < 60 mmHg or Sats < 90% on Room Air E: effusion A: anemia Hct < 30% R: renal BUN ? 29 mg/dL G: glucose > 250 mg/dL A: acidosis pH < 7.35 S: sodium < 130 mmol/L
if acute pna is present what do we do about surgery.
what is it usually associated with
Surgery should ideally be deferred if acute pneumonia is present
dehydration and renal insufficiency
what are the protective measures during general anesthesia for a patient with pna
vt 6-8ml/kg or ideal body mass
mean airway pressure and plateau pressure less than 30cmh20
pulmonary hygiene bronc if necessary
ett gives opportunity to obtain secretions for culture
concerns with fluid management for pna patient
over hydration can worsen gas exchange and morbidity
what is the most common nosocomial infection in the ICU and makes up 1/3 of all nosocomial infections
VAP
what is the definition of VAP
pna developing more than 48 hours after mechanical ventilation has been initiated via endotracheal tube or tracheostomy
map increases hospital stay by how many days
can increase hospital cost by
7-9 days
40,000 per patient
Between_________ of patients who have endotracheal tubes and undergo mechanical ventilation for longer than 48 hours acquire VAP, with mortality rates ranging from ______
10% and 20%
5%–50%.
Decrease occurrence of VAP
meticulous hand hygiene for all caregivers,
providing oral care
limiting patient sedation
positioning patients semi-upright
performing repeated aspiration of subglottic secretions
limiting intubation time if feasible
considering the appropriateness of noninvasive ventilatory support.
when is VAP usually suspected
VAP is usually suspected when a patient develops a new or progressive infiltrate on chest radiograph, together with leukocytosis and purulent tracheobronchial secretions
is VAP difficult to differentiate from other causes?
VAP is difficult to differentiate from other common causes of respiratory failure such as acute respiratory distress syndrome (ARDS) and pulmonary edema.
Treatment of VAP includes supportive care for respiratory failure plus antibiotics against the organism most likely to be implicated. The most common pathogens (2)
Pseudomonas aeruginosa and S. aureus.
Patients with VAP frequently require anesthesia for___
should major surgery commense
for tracheostomy- may be ill advised if the patient has minimal pulmonary reserve
major surgery should be deferred until the pna has resolved and respiratory function has improved
when transporting patients with VAP from the OR what must we use to keep their alveoli open
Because patients with respiratory failure may be positive end-expiratory pressure (PEEP) dependent, a PEEP valve should be used to decrease the likelihood of “de-recruitment” of alveoli during transport to the operating room. In the operating room, protective mechanical ventilation should be used.
what respiratory viruses may be associated with rampant courses, high virulence and high mortality
many death cases are in__
influence a
sars
h5n1- avian flu-subtype of a
young children
infection control precautions for SARS & H5N1 influenza A virus
Since primary transmission is via direct and indirect respiratory droplet spread, these viruses are highly contagious.
Contact precautions are also necessary because the viruses can be spread via fomites such as clothing, contaminated surfaces, and exposed skin
Barrier precautions include use of full-body disposable over-suits, double gloves, goggles, and powered air-purifying respirators with high-efficiency particulate air filters. If these are not available, N95 masks (which block 95% of particles) should be used rather than regular surgical masks.
intraoperative precaution for ears & h5n1 influenza A
Aerosolized particles may be generated during all invasive airway procedures, ventilation with noninvasive and positive pressure ventilator support modes, suctioning, sputum induction, high-flow oxygen delivery, aerosolized or nebulized medication delivery, and interventions that stimulate coughing
If mechanical ventilation is required, protective ventilation is indicated. Tidal volumes should be limited to 6–8 mL/kg lean body mass, and mean airway pressure should be less than 30 cm H2O.
Sudden cardiorespiratory compromise could indicate an expanding pneumothorax.
Drainage of pleural effusions may improve ventilation and gas exchange.
innate immunity:
rapid and nonspecific – it recognizes pathogen-associated molecular patterns (targets common to many pathogens) and requires no prior exposure to elicit an immune response.
is passed on to each generation, apparently to protect the species
adaptive immunity (also known as acquired immunity):
is a more mature system present only in vertebrates. Each individual must develop their own adaptive immunity.
what is the onset and memory of adaptive immunity
delayed onset of activation- capable of developing memory and very specific antigenic responses
adaptive immunity consists of {what} and is mediated by {what}
humoral component mediated by b lymphocytes that produce antibodies and a cellular component composed of T lymphocytes
what two subsets are t cells divided into
cytotoxic (tc) cells and helper modulatory (th) cells- and are distinguished by their different combinations of surface antigens
what cell responses are most important in mounting ineffective response to trauma ,infection, and tumorigenesis
t cell responses
