What kind of pressure must be created in order to move air into the lungs
Negative
- diaphragm moves down, increasing volume
What are the factors that affect diffusion?
- Surface area
- Partial pressure gradient of O2
- Thickness of membrane
- Quality of O2 (molecular weight)
D = (SA x PO2) / (T x square root of molecular weight)
What is the average V/Q of lungs? is perfusion or ventilation higher or lower?
apex of lungs?
Base of lungs?
average = .8L ; perfusion Apex = 2.1L ; ventilation Base = .23:; perfusion
- less in base due to gravity
Why are accessory muscles of inspiration hypertrophied in patients with COPD?
Air trapping and hyper-inflation result in an increased AP diameter of the rib cage and flattening out of the diaphragm. These two changes decrease the efficiency of respiratory muscles as they are no longer in optimal position to aid in respiration.
Is lung perfusion higher at the apex or base? Why?
Perfusion is higher at the base because of gravity
What impact will perfusion have on a recumbent patient?
Recumbent (lying down) patients have decrease in perfusion, which can lead to orthopnea (SOB while lying down)
What are the accessory inspiratory muscles?
- Serratus posterior superior
- Serratus posterior inferior
- Sternocloidomastoid
- Latissimus Dorsi
- Pec Minor
- Pec Major
- Quadratus Lumborum
- Paraspinal(erector spinae)
- Serratus anterior
- Subclavius
What are the primary muscles of inspiration?
- Scalenes: increase intrathoracic volume
- Diaphragm: Primary action is contraction, Secondary action is to stabilize position of the dome of diaphragm
- external intercostals- Internal and external (parasternal fibers) elevate the ribs, increase intrathoracic volume, and stabilize intercostal spaces to prevent inward collapse of thoracic wall
What are the muscles of forced expiration?
- Rectus Abdominus
- External Obliques
- Internal Obliques
- Tranversus Thoracis/Triangularis Sterni
- Internal Intercostals
How is pulmonary emboli diagnosed?
V/Q ratio is messed up; it increases (ventilation > perfusion) and you find this out through the central line
What are the characteristics of an obstructive disease?
- Dyspnea
- increase in the amount of air that stays in the lungs after each breath
- cough with or without sputum
Volume in the lungs at max inflation; sum of VC and RV
Total Lung Capacity (TLC)
Volume of air moved into or out of the lugs during quiet breathing
Tidal Volume (VT)
Volume of air remaining in the lungs after maximal exhalation
Residual Volume (RV)
Max volume of air that can be exhaled from the end-expiratory position
Expiratory Reserve Volume (ERV)
Max volume that can be inhaled from the end-inspiratory position
Inspiratory Reserve Volume (IRV)
Sum of IRV and TV
Inspiratory capacity (IC)
Max volume of air inhaled from the point of max expiration
Inspiratory Vital Capacity (IVC)
Volume of air breathed out after the deepest inhalation
Vital Capacity (VC)
Volume in the lungs at the end-expiratory position
Functional residual capacity (FRC)
Can you explain why asthma and pneumonia are classified differently?
Asthma = caused by inflammation and increased reactivity of smooth muscle of the airways to various stimuli (obstructive) Pneumonia = caused by inflammatory response affecting the parenchyma of the lungs (restrictive)
What are central chemoreceptors sensitive to that will cause breathing?
pH, specifically H+ ions that cross the BBB
Why should a person with COPD be monitored if given supplemental O2?
A patient with COPD, the central breathing system’s chemoreceptors have been shut down. They rely on the peripheral breathing system to stimulate the vagal nerve for breathing. Peripheral breathing system chemoreceptors are sensitive to the PO2. If there is too much O2 in the blood, this results in the loss of respiratory control.
What is the normal partial pressures of O2, CO2, in gas exchange at the alveolar-capillary membrane?
- O2 = 104 mmHg
- CO2 = 40 mmHg
