Flashcards in Biostat Deck (43):
what is sensitivity?
probability that person with disease has a positive test. if negative rule out disease
what is specificity?
probability that person without disease has a negative test. if positive, rule in disease
what is precision testing and what reduces precision?
reliability. random variation reduces precision.
what is accuracy testing and what reduces accuracy?
validity. systematic error (bias) decreases accuracy
increase in precision affects what 2 values?
increase power, decrease std deviation
odd ratio calculated in what observational study?
case control (looks at endpoint (disease) and than tries to determine risk factors)
relative risk calculated in what observation study?
cohort (has a risk factor and looks back to see who developed disease with risk factor)
when does OR=RR?
when outcome is uncommon in a population
what helps control confounding variables?
matching such that both groups have similar distribution (eg age, race) in accordance with those variables
biases pose a threat to what of the study?
methods to decrease confounding bias?
matching, restriction, randomization
relative risk and incidence can only be calculated from what?
prospective or experimental trials (ex prospective cohort)
what values significant for OR and RR?
any value besides 1
odds ration can be calculated for what?
retrospective (ex case control)
another name for prevelance surgery?
what is an epidemic?
observed incidence greatly exceeds expected incidence
define and give an example for nominal, ordinal, and continuous types of data and type of test it is associated with?
nominal-no numeric value (eg day of week)
ordinal-ranking but no quantification (eg class rank does not specify how far number 1 is ahead of you)
chi squared (nominal or ordinal), t-test or anova (continuous)
that the data were obtained by random error or chance
what correlates to chance of making type 1 error?
p-value because it claims that an effect or difference is presence when none really exists. so if p is 4%, there is less than 4% chance making type I error
what is type II error?
saying there is no difference (null hypothesis accepted) when one actually exists
what is power and how do you increase?
probability of rejecting null hypothesis when it is actually false. increase sample size
how do you know if you have a confounding variable?
it affects both the independent (manipulated) and dependent (outcome) variables
what is admission rate bias?
hospital A and B compared for mortality for MI. A is greater than B, but acutally they have tougher admission criteria and take sicker so they will have greater mortality
what is unacceptability bias?
ppl do not admit to embarassing behavior, claim to exercise more or claim to take experimental drugs and spit them out
test needed for caustic ingestion?
generally alkaline. need upper GI endoscopy within 24 hours to access extent of injury
cyanide poisoning management options for dermal, ingested, and all exposure?
dermal-remove clothing, skin decontamination
1) hydroxocobalamin 2) sodium thosulfate 3) nitrites followed by thiosulfate if not first two
best initial step vs best tx for organophosphate?
best initial step-remove all clothes and washing of skin to prevent more pesticide absorption
tx diphenydramine poisoning?
anticholingergic/antihistaminic properties (Dry as a bone, red as a beet, blind as a bat, hot as a hare, full as a flask, mad as a hatter,
tx iron poisoning
whole bowel irrigation, deforoxamine
best predictor intox for opioid?
differentiate opioid vs benzo intox?
degree of resp depression and miosis in opioid (vs normal pupils in benzo)
when do you give activated charcoal for acetaminophen?
greater than 7.5 g or greater than 150 mg/kg for kid in less than 4 hours ingested
nahco3- antidote for what and what does it help do?
TCA poisoning and alleviates cardiac toxicity of QRS widening and possible ventricular arrhythmia as Na+ competes for TCA spots increasing gradient across cardiac cells
exertional vs nonexertional heat stroke?
exertional-problem with heat dissipation due to thermoregulation failure
nonexertional-underlying impaired thermoregulation due to meds and underlying illness
central scotoma, decreased afferent pupillary reflex, visual blurring, and altered mentation
flank pain, hematuria, oliguria, CN palsy, and tetany
cns depression, disconjugate gaze, and absent ciliary reflex intox?
isopropyl alcohol ingestion
tx otitis externa
topical ofloxacin, neomycin, polymyxin B
cause and tx infections myringitis?
Mycoplasma or S pneumoniae. macrolides