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160 Cards in this Set

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Define absolute risk (difference)
Also known as rate difference - typically defined as the incidence rate in the exposed minus the incidence rate in the unexposed.
What is the NULL value for absolute risk, and what does it mean in this case?
Null = 0; This indicates that the IR in exposed and IR in unexposed is the same.
What does it mean when RD (absolute risk difference) is less than 0? Is more than 0?
When RD < 0, the incidence rate is lower in the exposed group than the unexposed group.

When RD > 0, the incidence rate is higher in the exposed group than the unexposed group.
If the rate of cancer in people receiving drug X is 8.3 per 100 PY, and the rate in the general population is 6.2 per 100 PY, what is the RD?
Exposed group = 8.3, unexposed group = 6.2; 8.3-6.2 = 2.1;

So people receiving drug X will have 2.1 excess cases of cancer per 100 PY compared to those not receiving drug X.
Define relative risk (risk ratio)
Quantifies the association between a determinant (either a risk or preventive factor) and a health outcome.
What is the null value for RR (relative risk)?
Null value for RR = 1; This indicates that the rates are the same and there is no association between exposure and disease.
How is RR calculated? What are its units?
RR = IR in exposed / IR in the unexposed

Units cancel out
What does it mean if RR > 1?
If RR < 1?
RR > 1 = rate is higher in exposed;
RR < 1 = rate is lower in exposed;
If the incidence rate of colon cancer in men who eat red meat every day is 2.6 and incidence rate in men who eat red meat less than every day is 1.3, what is the RR?
RR = 2.6 / 1.3 = 2

The relative risk of colon cancer is 2x or 100% higher in men who eat red meat every day than those who eat it less.
How is hazard ratio difference from RR?
Hazard ratio tends to include other factors, while RR is a pretty simple estimate.
What does attributable risk ask?
How much of a health problem may arise from a known risk?
What is implied about attributable risk when there is no null value? What must be taken into account that could make the attributable risk less accurate?
No null value implies that the rates of the disease/outcome are different in the exposed and unexposed groups, and that there is an association.

There may be bias, confounding results, biological variability.
What is biological variability?
A variability that cannot be eliminated in most cases - intrinsic biological differences in human beings that cannot be measured because they are not known or poorly understood.
What are the three measures of central tendency, and define each.
Mean - sum of values / # of values
Median - level below which 50% of values lie, and above which 50% of values lie
Mode - most common value in the set
What are the four measures of variability or spread in a frequency distribution?
Standard deviation, percentiles, range, variance (standard deviation squared).
What are the characteristics of a normal/Gaussian curve?
It is symmetrical about its mean (mirror image), mean = median = mode, bell-shaped, and completely described by its mean and standard deviation.
How are mean and median related when the curve is skewed to the right? To the left?
Skewed to the right: mean > median;
Skewed to the left: mean < median;
When is the mean useful? Median?
The mean is most useful if there is a Gaussian distribution, a normal curve.
The median is more useful if there is not a Gaussian distribution, since the mean is more often affected by outliers/extremes, so the median is closer to the majority of values.
On each side of the Gaussian curve, what are the approximate percentages for standard deviations? What is the total percent on each side of the curve?
1st standard deviation - 34%;
2nd standard deviation - 13.5%;
3rd standard deviation - 2.5%
Total = 50%
Define probability
The quantitative expression of the likelihood that an event will occur.
What is the equation for probability (e.g. that event X will occur?)
Pr (A) = # of times that X actually occurs / # of times that X could potentially occur
Define conditional probability
The likelihood that A will occur given that B occurred.
How would you calculate a conditional probability?
Pr (A|B) = # of times that A and B occur together / # of times that B occurs
What is the multiplication rule of probability if A and B are independent?
Pr (A and B) = Pr (A) x Pr (B)
If A and B are mutually exclusive, what is Pr (A and B)?
Zero
State the additive rule of probability? (e.g. the odds of A and B occurring but not together?)
Pr (A and B) (but not both) = Pr (A) + Pr (B) - Pr (A and B)
If two people are taking drug X, which has a 10% chance of causing side effects, what are the odds they will both have side effects?
0.10 x 0.10 = 0.01 = 1% chance
If two people are taking drug X, which has a 30% chance of causing indigestion and a 10% chance of causing bleeding, what are the odds that one person will get indigestion and the other will get bleeding?
0.10 + 0.30 - (0.10 x 0.30 = 0.03) = 0.40 - 0.03 = 0.37 = 37% chance
What three conditions are necessary to justify a screening program?
The disease is an important cause of M/M

A proven and acceptable test exists to detect individuals at an early modifiable stage

There is safe and effective treatment available to treat the disease and its consequences
What is sensitivity, as far as screening tests?
The number of people who test positive and have the disease divided by the number who have the disease

Of those who have the disease, how many test positive?
What is specificity, as far as screening tests?
The number of people who test negative who do not have the disease divided by the number of people who do not have the disease

Of those who do not have the disease, how many test negative?
What is positive predictive value?
Among those who test positive, the percentage who have the disease
What is negative predictive value?
Among those who test negative, the percentage who do not have the disease
What is a true positive? True negative?
True positive - Person tests positive and HAS the disease

True negative - Person tests negative and does NOT have the disease
What is a false positive? False negative?
False positive - Person tests positive and does NOT have the disease

False negative - Person tests negative and DOES have the disease
What is sampling?
Assessment of information in a small group is used to make inferences about the population from which the individuals were selected.
What is bias?
Systematic deviation from the "truth"
What is random variability?
Some degree of variability in measurement is always to be expected - depends on the biological heterogeneity of the population and the sample size
What is random sampling? What kind of bias does it eliminate?
Random sampling is where every individual in a population has an equal chance of being selected to be in a sample group. Eliminates selection bias, ONLY.
What is a confidence limit or confidence interval?
A limit/interval created about a numerical value of interest (like hazard ratio, rate difference, etc) - the numerical value of interest is always within the confidence interval (bounded by an upper limit and a lower limit)
How can one interpret a 95% confidence interval?
If the study were repeated 100 times, and 100 estimates of a measure of interest and 100 confidence intervals were calculated, 95 of 100 CIs would contain the true value of the mean of interest.

95% confidence that the true value of the measurement of interest lies within the CI

95% confidence that the results are consistent with hypotheses that the true value of the measure lies within the CI

Confidence that the true value lies outside the measure of interest only 5% of the time
What information does the confidence interval give about bias or study validity?
None
What is "alpha" with regards to probability in a study?
The minimum probability that would be accepted as evidence that the differences are not likely to be due to random variability - must be determined in advance
By convention, what is the alpha value usually set at?
5% - if the probability is less than 5% that such a result would be obtained if the null is true, then the null hypothesis must be rejected and an alternate hypothesis must be considered true.
What is the null hypothesis?
All differences in the measures being compared are due solely to random variability
What is the difference between a simple comparison and a complex comparison?
SIMPLE comparison - one can look up the p-value in a table - each test statistic has its own table of corresponding p-values

COMPLEX comparison - the computer gives you the p-values in the printout
What constitutes "statistical significance"?
If the p-value is less than then alpha value, then the null hypothesis is rejected and results are said to be 'statistically significant' - as in, not due to random chance.

This is the only time in medical literature where the word "significant" is used
When the p-value is < 0.05, what does that mean for the confidence interval?
The 95% confidence interval DOES NOT CONTAIN the null value of the measurement and the results are statistically significant
What is the relationship between statistical significance and and clinical importance?
A difference in groups may be statistically significant, but not clinically important or relevant.

Clinical importance must be judged on other grounds.
How does statistical significance relate to sample size?
Larger samples are better, because sampling error is lower. Increases the ability to detect differences between groups.
What is a type I or alpha error?
When the null hypothesis is correct, but due to sampling errors the null is rejected

False conclusion of statistical significance.
What is a type II or beta error?
When the null hypothesis is false, but due to sampling errors the null is accepted.

False conclusion of statistical insignificance
What is study power?
Study power is the probability that the null hypothesis will be rejected when it is in fact false.

A function of the degree of difference between the study groups (increased difference = increased power)

Function of the level of alpha (as alpha increases power increases)

Function of sample size (sample size increases = power increases)
Why would study power be calculated?
To determine the necessary sample size for an accurate study
What lab tests are included in a Basic Metabolic Panel, also known as a Chem 7 or SMA 7?
Glucose
Calcium
Sodium
Potassium
Carbon Dioxide
Chloride
BUN
Creatinine
What lab tests are included in a Comprehensive Metabolic Panel, also known as a Chem 12, Chem 20?
The same tests as in the Chem 7 (Glucose, Sodium, Potassium, Carbon Dioxide, Chloride, Creatinine, BUN, Calcium)

Plus...
Albumin
Total Protein
Alkaline Phosphatase (ALP)
Alanine Aminotransferase (ALT/SGPT)
Aspartate Aminotransferase (AST/SGOT)
Bilirubin
What lab tests/information are included in a Complete Blood Count?
WBC
RBC
HGB
HCT
MCV
MCH
MCHC
PLT
RDW

Neutrophils, Eosinophils, Basophils, Lymphocytes, Monocytes
What is a "PT" blood test?
Prothrombin Time
What is a "PTT" blood test?
Partial Thromboplastin Time

May also be known as an aPTT or activated partial thromboplastin time
What lab tests are included in a Lipid Profile?
Total Cholesterol
HDL
LDL
Triglycerides
What color test tube top is used for CBC, ESR, Platelet Counts, Reticulocyte Counts?
Purple

*Note! Westengred Sedimentation Rate tests may also be drawn in a Blue Citrate or a long, thin black-topped glass test tube.
What additive is contained in a purple test tube?
EDTA
What color test tube top is used for Electrolyte tests? Glucose tests?
Red/Tiger/Gold top tube, without additive

*Fasting Glucose tests may be drawn in a Gray potassium oxalate/sodium fluoride-containing test tube and require adequate mixing!*
What color test tube top is used for LFTs, Albumin?
Green, containing Heparin
What color test tube top is used for BUN, Creatinine, Cardiac Enzyme tests?
Grey/Green tube containing sodium fluoride
What color test tube top is used for PT, (a)PTT, INR?
Light Blue tube containing Sodium Citrate
What color test tube top is used for toxicology screens, including THC, amphetamines, benzodiazepines, PCP, other narcotics?
Red/Tiger/Yellow tube containing no additives
What color test tube top is used for RA, ANA, autoimmune antibodies?
Red/Tiger/Yellow tube containing no additive
What color test tube top is used for TSH, T3, T4, FSH, Testosterone, Estrogen?
Red/Tiger/Yellow tube containing no additive
What additive is typically found in a light-blue top test tube?
Sodium Citrate
What additive is typically found in a green top test tube?
Heparin
What additive is typically found in a gray test tube?
Potassium Oxalate-Sodium Fluoride
What test tube(s) is/are used for a type and cross?
Red top (no additive)
Purple top (EDTA)
How is an ABG specimen obtained?
An ABG syringe on ice, containing Heparin
What information must be present on a blood specimen?
Patient Name
Date/Time of draw
Medical Record #
Room and Bed # if inpatient
Initials of Technician
For what kinds of studies must the test tube be filled all the way to the top?
Coagulation Studies - blue top tubes (sometimes the long thin black-topped tubes)
Are tourniquets required for arterial blood sticks?
No
What are some chief complaints that strongly indicate a respiratory component?
Chest pain
Dyspnea
Cough
Hemoptysis
Stridor
Wheezing
What is the goal of the HPI with regard to respiratory problems?
Try to determine which symptom is primary when more than one occurs concurrently, and to determine whether key constitutional components are present (fever, weight loss, night sweats)
What are some significant past medical history components to ask regarding respiratory problems?
General health
Chronic respiratory disease
Immunization against influenza
Pneumonia
Use of home oxygen
COPD
What previous surgical history components are relevant to the respiratory system?
Past thoracic trauma
Past thoracic surgery
What are some family history components that are relevant to the respiratory system?
Tuberculosis
Cystic fibrosis
Emphysema
Allergies
Smoking
Malignancy
Clotting disorder
What are some components of the social history that are relevant to the respiratory system?
Work related exposure - irritants, allergens, hazards
Environmental factors in home - heating, air conditioning, humidification
Illicit drug and alcohol
Tobacco
Travel
Exposure to respiratory infections
Hobbies
Weight loss
What systems in the review of systems are most telling for respiratory system problems?
Respiratory system (duh)
Constitutional system
Cardiovascular system
Others
What are the parts of the respiratory system?
Nasal cavity
Epiglottis
Pharynx
Larynx
Trachea
Bronchus
Left lung
Right lung
Diaphragm
Pleural cavity
What vertical lines are important for locating landmarks on the chest?
Right/left scapular line
Right/left posterior axillary line
Right/left midaxillary line
Right/left anterior axillary line
Right/left midclavicular line
Midsternal line
Vertebral line
What are the muscles of inspiration?
Sternocleidomastoid
Scalenes
External intercostales
Diaphragm
What are the muscles of expiration?
Internal intercostals
External oblique
Internal oblique
Rectus abdominis
Transverse abdominis
What are the general components of the focused respiratory exam?
General assessment
Vital signs
Focused exam with four techniques - inspection, palpation, percussion, auscultation
Modified ENT exam - nose, frontal and maxillary sinuses, lips and oral cavity
Describe the appearance of cyanosis?
Pulmonary dysfunction - mucous membrane of the conjunctivae, the lips, tongue are blue.

Upper extremities - cyanosis of the fingers, same significance as central cyanosis.
What are some important things to note if present when examining the neck?
Symmetry
Evidence of contraction of the sternocleidomastoid or scalene muscles
Trachea for midline placement
What is clubbing and with what is it associated?
A widening of the A-P and lateral diameter of the terminal portion of the fingers/toes

Intrathoracic malignancy primary and seconday lung, pleura, and mediastinal
Supprative lung disease- lung abscess, bronchiectasis, empyema
Diffuse interstitial fibrosis

Associated with other systemic disorders
What are some things to note about the anterior chest in inspection?
Chest wall deformities
Respirations - rate, rhythm, pattern, and respiratory effort
Observe for intercostal muscle retractions and the use of accessory muscles (sternocleidomastoid, scalene)
Note any audible sounds with respiration
What are some patterns of respiration?
Normal
Bradypnea
Tachypnea
Hyperventilation/Hyperpnea
Sighing
Air trapping
Cheyne-Stokes
Kussmaul
Biot
Ataxic
Describe the "sighing" pattern of respiration.
Frequently interspersed deeper breath
Describe the "hyperventilation" pattern of respiration compared to the "Tachypnea" pattern of respiration.
Hyperventilation - faster than 20 breaths per minute, deep breathing

Tachypnea - faster than 20 breaths per minute
Describe the "air trapping" pattern of respiration.
Increasing difficulty in getting breath out
Describe the "Cheyne-Stokes" pattern of respiration.
Varying periods of increasing depth interspersed with apnea
Describe the "Kussmaul" pattern of respiration.
Rapid, deep, labored
Describe the "Biot" pattern of respiration.
Irregularly, interspersed periods of apnea in a disorganized sequence of breaths.
Describe the "ataxic" pattern of respiration.
Significant disorganization with irregular and varying depths of respiration.
Where are the auscultation locations on the anterior chest?
on the left and the right, moving more lateral with each step down...
Above the 1st rib, clavicle
Between ribs 2 and 3
Between ribs 4 and 5
Between ribs 6 and 7
What should be noted in the inspection of the posterior chest?
Move to rear of patient and check for symmetry and deformities of posterior chest wall

Look for scars, rashes, or other chest wall skin abnormalities
What should be palpated on the posterior chest?
Skin, not over gown or clothing
Areas of tenderness or pain
Assess expansion and symmetry of chest (unliateral lung disease = asymmetry, global decrease = restrictive lung disease)
What is tactile fremitus?

When does this occur?
Palpable vibrations transmitted from the tracheobronchial air column through the pulmonary septa and pleura.

This occurs when the lung tissue is damaged, pleura is thickened, pleural surfaces are separated by air or fluid

Increased with tension in the lung septa, from consolidation of lung tissue in pneumonia, inflammation around a lung abscess.
What is vocal fremitus?
The vibratory sensation induced when a patient produces a noise through their vocal cords

May be absent with damaged vocal cords or blockage of the airway
What are some aspects of percussion and what they may indicate?
Flat - Pleural effusion
Dull - lobar pneumonia
Resonant - Normal lung
Hyperresonant - Empysema, Pneumothorax
Tympany - Gastic air bubble, Large pneumothorax
Where do you percuss on the posterior chest?
On both sides, between...
ribs 2 and 3
ribs 4 and 5
ribs 5 and 6
ribs 7 and 8
ribs 9 and 10
What are normal breath sounds?
Vesicular - high-pitched, breezy
Bronchovesicular - combination bronchial and vesicular, normal in some areas
Bronchial - coarse, loud
Tracheal
What are adventitious breath sounds?
Wheezes - whistling, high-pitched bronchus
Rhonchi - coarse, low-pitched, may clear with cough
Crackles - fine crackling, high-pitched
Rub - scratchy, high-pitched
Bronchial (not normal) - coarse, loud, heard with consolidation
What are the two kinds of crackles?
Fine crackles - short and high pitched sounds.
Coarse crackles - longer lasting low pitched sounds.
When might you hear crackles?
They usually occur with atelectasis and aveolar filling processes such as pulmonary edema and interstitial lung disease. They signify distention of fibrotic lung tissue or opening of collapsed aveoli.
List three transmitted voice sounds. what is indicated by these sounds?
Bronchophony
Egophony
Whispered pectoriloquy

They indicate consolidation
What is bronchophony?
Normally spoken syllables are indistinctly heard in the lungs. In the presence of pulmonary consolidation, syllables are heard distinctly and sound very close to the ear.
Describe the differences in percussion, fremitus, breath sounds, voice transmission, adventitious sounds in the following lung problems:

Consolidation/atelectasis - with patent airway
Consolidation/atelectasis - with blocked airway
Consolidation/atelectasis with patent airway - dull percussion, increased fremitus, bronchial sounds, bronchophony, whispered pectoriloquy, egophony, crackles

Consolidation/atelectasis with blocked airway - dull percussion, decreased fremitus and breath sounds, decreased voice transmission, absent adventitious breath sounds
Describe the percussion, fremitus, breath sounds, voice transmission and adventitious sounds in asthma.
Asthma - resonant, normal fremitus, vesicular breath sounds, normal voice transmission, wheezing
Describe the percussion, fremitus, breath sounds, voice transmission, and adventitious sounds in interstitial lung disease.
Interstitial lung disease - resonant, normal fremitus, vesicular breath sounds, normal voice transmission, crackles
Describe the percussion, fremitus, breath sounds, voice transmission and adventitious sounds in emphysema.
Emphysema - hyperresonant, decreased fremitus, breath sounds, and voice transmission, absent adventitious sounds or wheezing
Describe the percussion, fremitus, breath sounds, voice transmission and adventitious sounds in pneumothorax.
Pneumothorax - hyperresonant, decreased fremitus, breath sounds, voice transmission; absent adventitious sounds.
Describe the percussion, fremitus, breath sounds, voice transmission and adventitious sounds in pleural effusion.
Pleural effusion - dull percussion, decreased fremitus, breath sounds, voice transmission; absent adventitious sounds or pleural friction rub
What constitutes suffering?
Physical symptoms
Social threats
Effects on one’s appearance and abilities
Perception of one’s future
How do the goals of medical treatment differ between patient and physician (regarding pain/suffering)?
Physician more focused on curing/managing a disease

Patient more focused on relieving their suffering
What is the definition of suffering?
The state of severe distress associated with events that threaten the intactness of the person.
What is the modern perspective of rights and responsibilities?
As long as an individual does not violate the rights of others, his responsibility to society has been fulfilled.

Is that so much to ask?
What is the Jewish perspective on rights and responsibilities?
Live is not merely for enjoying - liberty, happiness, etc. - who the heck would want that?

Humans have obligations and responsibilities to protect life, extending to preserving the lives of other people.

[insert religion-fueled exceptions]
So, according to Jews, when does life start?
They can't agree (surprise)

According to the Talmud, from the time of conception.
However, while the fetus is a dependent parasite on the mother, it hasn't actualized its full potential.

Can only abort of the fetus is a homicidal maniac and trying to bring the mother down with it.
So, according to Jews, what is the job of the physician?
Well, apparently God is the one who heals everyone, so doctors don't do all THAT much - least of all heathens.

So when patients thank god for me, I should expect it.
What are the four stages in progression of epidemiological reasoning.
First - suspicion that a factor influences a disease from occurrence that arises from clinical practice, lab research, examining disease patterns by person place and time, and prior epidemiologic studies

Second - formulation of a specific hypothesis

Third - Conduct an epidemiologic study to determine the relationship between the exposure and the disease, with interpretation of results taking into consideration random variability, bias, or confounding

Fourth - judge whether association may be causal.
List the purposes of epidemiologic research.
Identify etiologies of disease
Identify factors that prevent disease
Identify effective, safe treatments for disease

It can be a bridge between basic science research and medical practice
What is the difference between experimental and observational studies?
Experimental - investigator assigns the "exposure" to individual subjects and follows subject to determine the outcome.

Observational - the exposure status is not determined by the investigator and can only be "observed" - such as a genetic factor (blood type), behavioral choice (smoking), or medical choice (OCP).
What are the defining characteristics of a case-control study?
An observational study - do not say "retrospective study"

Cases with disease and controls (who do not have the disease) are chosen and past exposure to a factor is determined.
What are the advantages and disadvantages to the case-control study design?
Advantages - efficient, less expensive - time element, smaller sample
Can study rare diseases
Can study multiple exposures
Can use existing records

Disadvantages - more potential for bias (disease has already occurred) - bias in how cases are chosen, how information is collected, subject and investigator bias
More potential for confounding
Data quality may be poor - existing records may be incomplete, memory of distant events may be poor
Cannot calculate incidence rates so relative risk must be approximated with the ODDS RATIO
What are the defining characteristics of a cohort study?
An observational study - do not say "prospective study"

Subjects are chosen based on exposure status and followed or traced to determine the outcome.
What are the advantages and disadvantages of a cohort study design?
Advantages - Can study rare exposures, multiple outcomes in relation to the exposures measured, can calculate incidence rates and directly calculate relative risk.

Prospective cohorts have no selection bias or recall bias, better data quality, can collect information on potential confounders.

Disadvantages - longer study duration, more expensive, requires large sample, risk of loss to follow up over time, can study relatively common diseases.

For retrospective cohorts, poor information on exposure and other variables of interest, more susceptible to bias.
What are the defining characteristics of an experimental study (clinical trial)?
An investigator assigns exposure among a certain group - there must be genuine confidence that a treatment may be worthwhile in order to administer it to some individuals. Also must be genuine reservations about the treatment in order to withhold it from others.

Ethical considerations are very important in planning and executing an experimental study. Only a valid study can justify the potential risks and the anticipated inconveniences that subjects will incur.

Lack of knowledge must exist (equipoise), control group may need the current standard of care (no placebo), statistical power to address the hypothesis and ideally to detect unidentified side effects. Minimization of bias and confounding is essential to ensure that the comparison is valid.
What are the advantages and disadvantages of an experimental study design?
Advantage - gold standard because of potential minimization of bias and confounding relative to observational studies.
Random assignment of exposure, controlled group, double blind - subjects and investigators don't know what's going on. Can study multiple outcomes in relation to the exposure. Can calculate incidence rates, relative risk and risk differences directly. No selection bias or recall bias. Better data quality. Can collect data on potential confounders.

Disadvantages - ethical considerations, longer study duration, very expensive, requires large sample, risk of loss to follow up over time, can only study relatively common diseases - statistical power to small in rarer diseases.
What are the characteristics of a cross-sectional study?
Usually a survey format

Subjects are not selected based on either exposure status or disease status

All subjects are asked about exposure status and disease status
What are the advantages and disadvantages of the cross-sectional study design?
Good for determining prevalence of disease in a specified population. May be useful for hypothesis generation. Cannot be used to test hypothesis (lack of appropriate temporal relationship)
List the five characteristics of a causal association.
Temporal relationship of the association (cause precedes effect)

Strength of the association (the higher the relative risk, the more likely it is to be caused)

Dose-response (increasing degree of exposure leads to increasing risk)

Consistency of the association (other studies in other populations have also found this association)

Coherence of the association - biological plausibility
What are some factors that determine what kind of study design you choose?
State of knowledge
Frequency of exposure and disease
Time, cost, and other feasibility considerations
What are the two kinds of cohort studies?
Prospective cohort - subjects free of the disease to be studied are selected at the inception of the study, disease has not yet occurred. Subjects must be followed forward in time to determine who develops disease.

Retrospective cohort - both exposure and disease have already happened. Exposed individuals are identified, suitable controls identified. Disease status determined by finding records of outcome. Database research is an exciting new application of this type of study.
What is a Meta-analysis?
Original research

A systematic search of the literature for relevant studies meeting criteria for methodology and validity
A formal combining of the results of the studies using statistical techniques that allow hypothesis testing - a measure of outcome is generated and p-values and/or confidence intervals are calculated.
What are some outpatient things that respiratory therapists manage?
Asthma/COPD - inhalers, nebulizers, peak flow meter, asthma action plan
Home oxygen therapy
Pulmonary function studies
Sleep apnea
What are some inpatient things that respiratory therapists manage?
Pulmonary hygiene - breathing exercises, chest percussion and clopping, suctioning secretions
Obtaining arterial blood gas
Delivery of medications related to respiratory care
Medical gas administration
Mechanical ventilation and airway management
Describe mechanical ventilation.
Pressure gradient result of increased pressure of the air source by mechanical ventilation.

Can be noninvasive, involving various face masks

Invasive - endotracheal intubation
When is mechanical ventilation indicated?
Clinical or laboratory signs that the patient cannot maintain an airway or adequate oxygenation or ventilation

Respiratory rate > 30/min
Arterial O2 Saturation < 90%
FIO2 > 0.60 and PCO2 > 50 mmHg with pH < 7.25
What are some respiratory conditions treated in the ICU?
Acute respiratory distress syndrome - sudden lung failure, caused by other illnesses like infections or serious injury

Status asthmaticus
COPD
Pneumonia
Respiratory distress syndrome - infants, with underdeveloped lungs
Sepsis
Trauma
What is peak airway pressure?
Total pressure needed to overcome the inspiratory flow resistance - resistive pressure. The elastic recoil of the lung and chest wall (elastic pressure) and the alveolar pressure at beginning of breath (PEEP)

Peak Airway Pressure = Resistive Pressure + Elastic Pressure + PEEP
What is resistive pressure?
The product of circuit resistance and airflow.
What is elastic pressure?
Product of the elastic recoil of the lungs and chest wall and the volume of gas delivered.
What are some modes of mechanical ventilation?
Volume or pressure cycled, both
Both directly linked by the pressure-volume curve
Any given volume will correspond to a specific pressure
Adjustable ventilator settings - respiratory rate, tidal volume, trigger sensitivity, flow rate, waveform, inspiratory/expiratory ratio
What is volume-cycled ventilation?
Ventilator delivers a set tidal volume
Resultant airway pressure is not fixed
Varies with the resistance and elastance of the respiratory system and with the flow rate selected
Assist control or synchronized intermittent mandatory ventilation
What is A/C ventilation (Assist/Control)?
Simplest and most effective means of providing full mechanical ventilation
Each inspiratory effort beyond the set sensitivity threshold triggers delivery of the fixed tidal volume
If the patient does not trigger the ventilator frequently enough, the ventilator initiates a breath, ensuring the desired minimum respiratory rate
What is SIMV (Synchronized Intermittent Mandatory Ventilation)?
Delivers breaths at a set rate and volume
Synchronized to the patient's efforts
Efforts above the set respiratory rate are unassisted
Popular although not as effective as A/C
What is pressure-cycled ventilation?
Pressure control ventilation (PCV) or pressure support ventilation (PSV)
Ventilator delivers a set inspiratory pressure
Tidal volume varies depending on the resistance and elastance of the respiratory system
Theoretically benefit patients with acute lung injury or acute respiratory distress syndrome
Pressure control ventilation is similar to A/C
Pressure support ventilation - a minimum rate is not set; all breaths are triggered by the patient
What is noninvasive positive pressure ventilation?
Delivery of positive pressure ventilation via a tight-fitting mask
Used in spontaneously breathing patients
Continuous positive airway pressure (CPAP) or Bilevel positive airway pressure (BIPAP)
What is CPAP?
Continuous positive airway pressure

Constant pressure is maintained throughout the respiratory cycle with no additional inspiratory support
What is BIPAP?
Bilevel positive airway pressure

Physician sets both the expiratory positive airway pressure (EPAP) and the inspiratory positive airway pressure (IPAP), with respirations triggered by the patient
What kind of sedation and comfort management is expected with mechanical ventilation?
Most patients require continuous IV administration of sedatives (eg, propofol, lorazepam, midazolam) and analgesics (eg, morphine, fentanyl)to minimize stress and anxiety.
Also reduce energy expenditure to some extent, thereby reducing CO2 production and O2 consumption
What are some osteopathic correlates with mechanical ventilation?
Lymphatic drainage - thoracic pump, pedal pump
Rib lesions
Doming of diaphragm
Cervical and thoracic lesions
Chapman points