BPK 407 - Pulmonary Theory (p217-228)

What are the 5 parts of respiration?

- Pulmonary ventilation: movement of gases between the lungs and the environment

- Pulmonary Gas exchange: Movement of gas between lungs and the blood stream

- Gas transport: Movement of gases within the blood stream

- Tissue/blood gas exchange: Movement of gas between bloodstream and tissues

- Cellular respiration: Consumption of O2 and the production of CO2 by cells and organelles

How is a high concentration gradient ensured during gas diffusion in the lungs? (2)

- Movement low O2 and high CO2 conc blood to the lungs

- Pulmonary ventilation

where is the respiratory control centre located and what does it control?

- Located in medulla

- Depth and rate of breathing

What is the make up of dry air? (4)

- O2 = 20.93%

- CO2 = 0.03%

- N = 78.04%

- Trace gases = 1%

What is he gas fraction?

The percentage that a gas makes up of dry air

How do you calculate partial pressure?

Px = PB x Gas fraction

- PO2 = PB x 0.2093

What is Boyle's Law?

V is inversely proportionate to pressure

What is Charles Law?

Volume is proportionate to temperature

What are the two reference conditions used?

- STPD: Standard temperature and pressure Dry

- BTPS: Body temperature and pressure saturated

How do you correct for vapour pressure?

STPD factor = (PB - VP)/760- x 273(273+T)

What are the types of pulmonary function equipment? (4)

- Spirometers (water-seal vs Dry rolling-seal)

- Pneumotachographs

- Plethysmography (Whole-body vs Impedance)

- Volume Turbines

Explain how a Water-seal spirometer works

Collins 9 Liter Respirometer

- Collection of CO2 gas from subject through baralyme or soda lime canisters

- Baralyme pellets absorb CO2 from subjects expired air

Explain how a Dry rolling-seal spirometer works

Uses a piston in a cylinder that moves with expired air

- Movement activates electrical signal from potentiometer that is then analyzed

What is an example of a volume turbine?

Spirolab II pulmonary function testing device

Define Minute Ventilation (VE)

The volume of gas exchanged per minute at rest or during any stated activity.

- TV x # of respirations per min

Define Tidal volume (Tv)

The volume of air either inspired or expired with each breach at rest or during any stated activity

Define Vital capacity (VC)

The greatest volume of gas that can be expelled by voluntary effort after maximum inspiration. The should NOT expire air at a forceful effort

Define Inspiratory capacity (IC)

The max volume that can be inspire from the resting end-expiratory position

Define Expiratory Reserve Capacity (ERV)

The max volume that be exhaled from the resting end-expiratory position. The resting expiratory level is volume at which the inward recoil of the lungs is balanced by the outward recoil of the chest wall.

- Sum of IC and ERV

Define Functional Residual Capacity (FRC)

the volume of gas remaining in the lungs at the end of a quiet exhalation.

- ERV + Residual volume

Residual Volume (RV)

The volume of gas remaining in the lungs after a maximal expiration

Define Total lung capacity (TLC)

The Volume of fas in the lungs at the time of maximal inspiration.

- Sum of VC + RV

Explain the RV/TLC ration

expresses the percentage of the total lung capacity occupied by residual volume. as a fraction of TLC, RV increases from ~25% at 20 to ~40% at 70

Explain Maximum Breathing Capacity (MBC)

The max volume of repaired gas which may be breathed during max effort (exercise). Usually taken over a 12 sec period of hyperventilation

Explain Forced vital capacity (FVC)

After a max inspiration, the subject forcefully expired their air as fast as possible

Explain FEV 1

The volume of fas expired during the first one second of a FVC maneuver. Testing usually lasts 3-4s

Explain Mid-expiratory Flow Rate (MMFR)

the max flow rate fo air achieved one the middle 50% of the FVC maneuver. FEF25-75.

Explain Obstructive Pulmonary Disorders (5)

- Occurs with a blockage of the airways causing increases airway resistance.

- Bronchiolar obstruction can cause inflammation and edema, SM constriction, or bronchiolar secretion

- Decreases MMFR, FEV 1, Peak EFR, and max voluntary ventilation

- FEV1.0/FVC < 70%

- Can cause airway collapse during expiration and increases in RV, FRC, or TLC

List some examples of Obstructive Pulmonary Disorders (3)

- Asthma

- Bronchitis

- Emphysema

Explain Restrictive Pulmonary Disorders (3)

- Damage caused to lung tissue, resulting in decreased elasticity and decreased compliance. Making it more difficult to expand lung tissue

- Reduces ALL Lung volumes

- FEV1.0/FVC >90%

List some examples of Restrictive pulmonary disorders (2)

- Pulmonary fibrosis

- Pneumonia

What are normal PAco2 and PAo2?

- PAco2 = 40mmHg

- PAo2 = 95-100mmHg

What are breakpoint values after breathing room air for PAco2 and PAo2?

- PAco2 = 45-50mmHg

- PAo2 = 70-60mmHg

How does breathing in 100% O2 change PA values?

- PAo2 will be much higher (PIo2 = 150mmHg)

- PAco2 = 50-55mmHg before breakpoint

How does hyperventilation change PA values?

- PAco2 < 20mmHg

- PAco2 can climb back up to 40-45mmHg before breakpoint

- PAo2 < 50mmHg at breakpoint

What are some kinds of wearable technology for pulmonary function testing? (3)

- Acoustic sensors (monitors lungs)

- Acceleration Sensors (Captures breathing movements)

- Pulse Oximetry (Monitors )2 saturation on translucent body parts/areas)

Explain Pulse Oximetry (2)

- Transmission: Sensors at tissue locations transilluminates tissue with light (finger clip)

- Reflectance: Light source + Photodiodes on same side, can be used on less translucent areas (watch)

Limitations of pulse oximetry? (4)

- Only measures hemoglobin saturation and not pulmonary function

- Not as good as lab blood gas analysis (can't measure CO2, pH, HCO3-)

- Less accurate for obese or Low BP subjects

- Low sampling rate underestimates O2 saturation

What variables Can impact Pulmonary function testing? (4)

- Age

- Race

- Sex

- Height