Module 8 - Respiration Flashcards
Describe the path that oxygen follows from inhalation to bining to hemoglobin
First inspiration:
- – contract intercostal muscles and diaphragm -> ribcage opens
- – creates under pressure in alveoli, overpressure mouth,, so air flows in
- – gas exchange happens in the alveoli
Describe anatomical deadspace and the types of physiological dead space
Anatomic dead space
- volume conducting airway segment with no alveoli
Physiological deadspace
- Shunt situation
- — There is perfusion but ventilation is zero. ventilation perfusion ratio is 0
- Dead space situation
- — There is ventilation but perfusion is zero, infinite ventilation perfusion ratio
Describe anatomical deadspace and the types of physiological dead space
Anatomic dead space
- volume conducting airway segment with no alveoli
Physiological deadspace
- Shunt situation
- — There is perfusion but ventilation is zero. ventilation perfusion ratio is 0
- Dead space situation
- — There is ventilation but perfusion is zero, infinite ventilation perfusion ratio
Mechanics of breathing with labels
Lungs are like a balloon. Connected to rib cage via pleural fluid
If the diaphragm contracts, and the intercostal muscles contract, then the lungs will open up.
Inspiration is an active process; contract intercostal muscles, and diaphragm
Expiration is a passive process; relaxation of the muscles leads to thorax falling back into place and breathing out
Sketch the pressures of the thorax as a function of time with correct axis
DRAW TABLET
Pressures; alveolar pressure and pleural pressure
Alveolar starts at 0 goes down a bit until halfway, then goes up again and to middle again
Pleural (thorax) pressure is always negative. Starts at -5 ish, goes down to -10 in the middle, and goes up to -5 again
In: cmH20
What is lung compliance?
The willingness of the lungs to distend, and elastance as the willingness to retugn to a resting position
ALSO:
Pulmonary volume change per unit pressure change
Draw pressure volume curve with correct axis and inhalation and exhalation
Give axis, eenheden. Also explain what you see
DRAW TABLET
Volume; tot 600 ml
Pressure van 5 cmH2O tot 30 cmH2O
When inhaling, overcome the lungs. Exhaling; overcome the airway resistance
DRAW TABLET
Draw the electrical analogue of lung compliance
resistance, capacitor, and circle arrow thing haha
Give the methods to measure lung compliance:
Super syringe method
- – step in volume and measure the pressure difference
- – you can use a balloon catheter for this
On ventilator
- – often used with mechanical ventilation
- – by stepping the pressure you measure changes in volume
Describe the most common lung diseases and if they are linked to increased or decreased compliance if you can
- Asthma (obstructive disease), increased compliance
- — inflammation of the airways, leads to swelling in airway lining. thorax increases because air is trapped in the lungs - COPD (obstructive disease), increased compliance
- —obstruction of small airways, difficult to exhale air
- – emphysema
- – bronchitis - Infectious lung diseases (destructive diseases), decreased compliance?
- — fluid in alveoli makes gas exchange and diffusion difficult - lung cancer (destructive disease), decreased compliance?
- — reduces the usable lung volume
Lasly there are also exchange problems; only influence exchange between the air sac and the capillary
for what do you use the water clock?
DRAWING ON TAB of waterclock
For tidal volume
Detect restrictive diseases; reduced lung volume
What is tidal volume?
the volume that one person breaths during regular in and exhalation
What three methods are there for residual volume?
Gas dilution tests; helium and nitrogen washout
Bodybox
Explain the nitrogen washout method, what is it used for?
DRAWING ON TABLET
To measure residual volume.
Need to make a full exhalation so that only residual volume is left in the lungs. then breathing pure oxygen until the exhaled air flow contains less than 2% nitrogen. Then all nitrogen is in the water clock, and the lungs only have oxygen.
Volume in lungs is then Vol in the spirometer * concentration of nitrogen, divided by nitrogen at the start
What is the helium gas dilution test used for and how does it work?
DRAWING ON TABLET
Measures residual volume
Helium is not going into the circulation so not through alveoli!
spirometer filled with helium. Start breathin through the closed system until there is no more change in helium. Then we know it is fully distributed over both lungs and the clock
What does the body box measure, and how does it work?
DRAWING ON TABLET
Body box also measures residual volume in the lungs.
As you enter the box you do not know the volume in the box anymore. Therefore need to calibrate the box with the shutter closed. Use a pump and apply low amount of volume and measure the pressure difference that occurs due to it. By P*V = constant you determine the volume in the box when the person is inside
Step 2: do forced breathing against a closed shutter. Then determine volume of the lungs by determining the volume, pressure changes in the box, and the initial volume of the box
Ways to establish dynamic flow volume measurement
- Pneumotachs
- Turbine
- Heated wire
- Fleish, Lilly, Variable orifice
- Turbine
- Heated wire
Explain what the Fleish type measures, and how it does it.
Fleish has the tubes. Measures pressure difference over known resistance (small tubes from which we can measure pressure difference)
Explain what the Lilly type measures, and how it does it
Pressure difference over screen (with known resistance)
Flow is determined by the pressure difference over the known resistance
Explain what the variable orifice type measures, and how it does it
and advantage and disadvantage
Changes the resistance if the flow gets higher -> the tube then opens
Better for patients since they do not feel pressure while breathing. However, difficult to calibrate
Name advantages and disadvantages of the pneumotachometers
They are easy, light and reliable (especially Fleish and Lilly)
Problems with humidity however
Differences in inspiration and expiration, since the gas mixture is changing and hence the temperature
Explain the turbine flowmeter.
Name advantages and disadvantages
It is a wind meter.
Turbine rotates. The faster the flow the faster the rotation. Counting the pulses to determine the flow
Adv.
not sensitive to turbulence and humidity
DisAdv.
Inertia of system is a downside
Explain the heated wire flowmeter
The more flow, the more cooling. From this determine what flow is corresponding to what temperature
Disadv.
- only local measurement, fragile
Adv.
- fast and low resistance
How does spirometry to flow-volume curve work?
You inhale and then exhale as fast as you can. You start at volume of 0L. Then start exhaling until you cannot anymore. THen you are asked to inhale again, getting the curve back to 0L
What are normal values in a flow volume curve? And how do you see the pathologies?
DRAW TABLET
NORMAL: Flow volume, x-axis: 4/5 Liters volume, y-axis: 8 L/s
RESTRICTIVE: x-axis 2 Liter volume, y-axis: below 0 =4 L/s, boven 8L/s
OBSTRUCTIVE: x-axis 2 liter volume, y-axis, 4 en 4
What is the single breath method?
Expire fully with 0.3% CO and 10% He from rseidual volume to the total lung capacity. Hold breath for 10 seconds. then exhale again to residual volume.
CO enters the circulation, He will not. At the beginning CO in the capillaries is 0.
