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Articles covered in this SG

Homework

Risk factors for CVD

  • Family history
  • BP
  • Cholesterol
  • Smoking
  • Obesity
  • Past history of disease
  • Diabetes
  • Chronic Kidney Disease
  • Decreased physical activity
  • Diet
  • Sex
  • Age
  • Demographic
  • Alcohol
  • Heart rate
  • Medications
  • Psychosocial

Think about which ones of these fit in the categories

  • Biological
  • Demographic
  • Medical
  • Lifestyle

ECG

  • Records electrical activity of the heart by setting up an electrical potential through the limbs
    • Can measure the rate and regularity of the heart and the size and position of its chambers
  • Procedure:
    • Lie down, electrode attached (12)
    • Still, hold breath (to eliminate disturbance)
    • Stress test, same, under exercise
    • Inferior leads, lateral leads, septal leads, anterior leads
  • Pqrstu-waves
    • u wave is the repolarisation of the papillary muscles

Smoking and Fitness

  • Carbon monoxide
    • Binds preferentially to haemoglobin, therefore decreases amount of oxygen in the blood
    • Has a biological half life of 8 hours, stays around for a while
  • Smoke
    • Causes a 2-3x increase in the movement of air in and out of the lungs
  • Decreased lung capacity
  • Tar – reduces elasticity of alveoli
    • Therefore there is a lowered lung capacity
    • Cilia – are a cleansing mechanism for the lungs, are destroyed by tar
  • Mucus is produced, this causes coughing – smoker’s cough
  • Emphysema – reduction of lung tissue available
  • The heart works harder because of less oxygen available
    • Thus, can have abnormal heart rhythms and chest tightness
  • Nicotine – can cause an increased blood pressure/ heart rate due to vasoconstriction

Blood pressure

  • BP – the force exerted by circulating blood on blood vessels
    • Decreases as it goes through the vessels
  • Measured using:
    • Sphygmomanometer
    • Anaesthesiologist in hospital
      • Arterial line inserted using a cannula needle
  • Recorded in:
    • Kilopascals (mmHg)
    • Systolic, diastolic
  • Variations due to stress, during the day
  • High blood pressure – normally no symptoms
    • If it remains high, can cause heart attacks, heart failure, kidney failure
  • Low blood pressure – not as bad
    • Reduces further, there is a chance of coronary heart disease/stroke
  • Influences – physical/physiological
  • Critically low blood pressure = shock

Obesity

  • causes decreased physical fitness and pulmonary function
    • due to excessive weight on the chest wall, can’t take as deep breaths
  • Increase in risk for CVD, the work load on the heart is increased
  • Blood sugar levels are increased
  • Higher risk of decompression sickness
    • Because nitrogen is very soluble in adipose tissue

Decompression sickness

  • The bends
    • The body is unable to adapt to a rapid decrease in pressure o Inert gases therefore come out of solution and form bubbles
      • Esp: nitrogen, causes itches in the skin, paralysis
  • 4 types:
    • bends – joint pain
    • neurological – headaches, visual disturbances
    • chokes – burning/pain in chest, shortness of breath o skin – itching, feeling of insects on skin
  • treatment
    • recompression in a hyperbaric chamber

Cholesterol

  • Waxy body fat
  • Made by the liver and in most cells
  • Carried around the body by lipoproteins
  • Used to make adrenaline, estrogen, testosterone
  • Aids metabolism
  • Types:
    • Very low density lipoproteins – bad o Low density lipoproteins – bad
      • Contain triglycerides
      • Increase risk of CVD
      • Enter the blood stream and clog arteries
    • High density lipoproteins – good
      • HDL removes LDL, takes it back to the liver for processing
  • Too much bad cholesterol = an increased risk of CVD
  • To stay health – reduce saturated fat intake
    • Cholesterol is an indicator of fitness
    • Smoke can cause cholesterol to stick to arteries

Family History

  • If there is a family history, ECG and stress tests should be performed regularly once over 40
  • History of asthma should be tested with spirometry

Age and Fitness

  • Physical requirements for diving
    • 45kg, 150cm, can handle equipment, can enter and exit the water easily
  • children complications:
    • different growth rates, maturity, growth plates
  • injury
    • growth plates, decompression sickness, bone/joint injry, cold stress
  • OLD issues:
    • Level of fitness
    • Chronological age vs physiological age
    • Health, agility, strength, HR, oxygen capacity, lung capacity
  • Risks in the younger
    • Pulmonary oedema
    • Myocardial infarction
    • rescue
  • Fitness vs maturity

Echocardiogram

3D Echocardiogram

wikipedia:Echocardiogram

  • Sonography of the heart
  • Ultrasound can create 2D images, now can make 3D images
    • Used to look at:
      • Size, shape, capacity, location, damage of the heart
      • Heart valve diseases
  • Blood flow patterning, esp. regurgitation
      • Function of the left ventricle, diameter of t he chamber during systole and diastole
      • Flow – Doppler
      • Blood pressure in the pulmonary artery (pulmonary circulation)
  • Advantages:
    • Noninvasive
  • Types:
    • Transthoracic echo, through the chest wall
      • looks at the chambers, epicardium and the aorta
    • trans-oesophageal echo – probe, ultrasound transducer, clearer because doesn’t need to go through skin, fat and ribs
      • looks at the aorta, pulmonary artery, atria, valves
      • disadvantages – invasive, discomfort, risk of perforation

Blood carrying capacity

  • Haemoglobin
    • Made up of 4 subunits with Haem molecules
    • Allows haemoglobin to carry 4 oxygen molecules
  • Attachment of oxygen is reversible
    • Hb + O2
      • HbO2
      • If pO2 in the lungs is high, conc of O2 in the blood increases
      • If pO2 in the viscera is low, conc of O2 in the blood drops and gives O2 to the organs
  • Saturation, 4/4 = 100%
  • Measurement
    • Pulse oximetry
      • Passes infrared + red light through the finger and is detected by a photodetector
      • Detects any colour change
        • oxygen, there is lots, infrared is absorbed, and appears red o arterial blood-gas analysis
      • taken from the radial artery

HR + fitness

  • number of heart beats /minute
  • average is 70(m), 75 (f)
  • pulse – Aorta stretches and creates a pressure wave
    • this increases in velocity the further it gets away
    • can be felt anywhere the pulse can be compressed against an underlying structure
  • more accurate methods – auscultation of the apex, ECG
  • Normal, 60-100
  • Exercise can cause an increase in the LV muscle mass, wall thickness, chamber size
    • In fit people, the SV increases, and therefore there is a slower heart rate


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