Statistics

Data consists of information coming from observations, counts, measurements or responses. and statistics is the science of collecting, organizing and analyzing and interpreting data in order to make decisions. 

How is a sample related to a population?

A SAMPLE is a subset, or part, of a population; whereas a population is the collection of all outcomes, responses, measurements, or counts that are of interest. 

Why is a sample used more often than a population?

Sample data is used to form conclusions about that population, it's used as a representative. Use appropriate method, such as random sampling. 

What is the difference between a parameter and a statistic?

Parameter is a numerical description of a population characteristic. A statistic is a numerical description of a sample characteristic. 

What are the main branches of statistics?

Descriptive statistic - involves organization, summarization and display of data.

Inferential statistic - using a sample to draw a conclusion about a population. A basic tool in the study of inferential statistic is a probability. 

Aortic Stenosis

Aortic Stenosis

is the narrowing of aortic valve due to calcification of valve leaflets or valvular damage!

it commonly occurs in an early age in patients with congenital bicuspid aortic valves. 

MOST COMMON cause is calcifications with age, 70's

also results  Rheumatic Fever ( more commonly causes Mitral Stenosis)

1. SYNCOPE
2. CHEST PAIN
3. DYSPNEA ON EXERTION
4. SUDDEN CARDIAC DEATH - when stenosis progresses rapidly

PATHOPHYSIOLOGY

Aortic stenosis is narrowing of the aortic valve due to calcification of the valve leaflets or valvular damage.

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• Aortic stenosis commonly occurs at an early age in patients with congenital bicuspid aortic valves.
• The most common cause of aortic stenosis is calcification of the valve leaflets with age, with the prevalence of aortic stenosis increasing rapidly beginning in the 7th decade.
• Aortic stenosis can also result from rheumatic fever. Though rheumatic fever is most strongly associated with mitral stenosis, other valves may also be affected.

Aortic stenosis is classically associated with syncope, chest pain and dyspnea on exertion. Aortic stenosis can progress rapidly, leading to sudden cardiac death.

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• Aortic stenosis can lead to left ventricular hypertrophy as the myocardium contracts against the narrowed valve opening. The myocardium outgrows its blood supply, leading to ischemia, progressively worsening chest pain, and dyspnea from pulmonary congestion.
• Since aortic stenosis leads to myocardial ischemia and a fixed cardiac output, symptoms initially present during exercise. As the disease progresses, however, symptoms begin to occur at rest.

Aortic stenosis causes a pansystolic crescendo-decrescendo murmur heard loudest in the second intercostal space at the right sternal border.

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• The murmur often radiates to the carotid arteries.
• The murmur decreases in intensity with decreased preload (such as in the Valsalva maneuver).
• Aortic stenosis is associated with an S4 heart sound as well as “pulsus parvus et tardus,” or peripheral pulses that occur weak and late relative to the heartbeat, due to the slow emptying of left ventricle to the systemic circulation.
• CXR shows left ventricular hypertrophy.
• Echocardiography shows a narrowed valve area with increased transvalvular pressure gradient. Other findings may include left atrial enlargement and left bundle branch block.The most accurate way to quantify the transvalvular pressure gradient is with cardiac catheterization.
• Microangiopathic hemolytic anemia with schistocytes → hemoglobinuria

  • Recall that intravascular hemolysis also leads to decreased haptoglobin as well.
• ECG will often show left ventricular hypertrophy (LVH), left atrial enlargement (LAE), and left bundle branch block (LBBB). Severe dilation of the left atrium can result in Atrial Fibrillation in late disease.

Aortic stenosis can result in insufficient supply of blood to the systemic circulation, due to the inability of the left ventricle to compensate for decreased aortic valve area, resulting first in cardiac insufficiency or syncope.

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• Cardiac insufficiency may result in ischemic heart disease and heart failure, which entails a poor prognosis.

Aortic stenosis is managed medically to control hypertension, until patients face significant morbidity with their disease, at which point surgical valve replacement is called for.

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• Aortic Valve replacement (AVR) is the only effective treatment for severe AS (symptomatic AS) as well as asymptomatic AS with EF<50%. Other indications for replacement:

  • Aortic valve area <0.6cm2
  • Mean gradient >60mmHg
  • Aortic jet >5m/s
  • Decrease of BP with exercise
• Medical management is used in asymptomatic patients and symptomatic patients who are not surgical candidates. It consists of medication to control HTN and instructing patients to avoid vigorous physical exercise. Avoid venodilators (nitrates) and negative inotropes (calcium channel blockers/beta blockers) in severe aortic stenosis.
• Intra-aortic balloon pump (IABP) is used for stabilization and bridge to surgery.
• Balloon aortic valvotomy (BAV) results in approximately 50% increase in valve area but 50% restenosis at 6-12mos.

Helpful strategies to cope with shift work

isolated night shifts

bright light (>10,000 lux ) for 2 hours after rising

regular exercise

anchor sleep and naps

shifts must be rotated in a CLOCKWISE MANNER each change to a later not earlier 

ideally with a month or more per rotation

sporadic shifts are less disruptive for than longer stretches of nights of circadian rhythms, Anchor sleep involves sleeping for the same 4-h period 

regardless of the shift worked

--
No one ever wins, no one finally loses, except the dead, under the sun, they rot together, with absolute biological equality.

Disaster Plan

Mechanism of activation

Assessment of the hospital's capacity

establishment of disaster command

communication

supplies

administrative and treatment areas

training and drills

immediate discharge of predisaster patients?-not contemplated

assessment of likely hazards

coorperation between the hospital and the community

--
No one ever wins, no one finally loses, except the dead, under the sun, they rot together, with absolute biological equality.

Anaerobes

Clindamycin -respiratory or above diaphragm

Metronidazole - GI anaerobes

Carbapenams

Cephalsporins cefoxitin and cefotetan

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Gram neg rods

Fluroquinolones
Aminoglycosides
Carbapenams
Astreoram
Ceftriaxam 3:4 gen cephalosporins
Pipercillin


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Marfan Syndrome

Connective tissue defect
Musculoskeletal cardiac ocular