Pulm Lectures; Exam II Flashcards
What happens if one side of the diaphragm is paralyzed?
Which lung is bigger and why?
-Heart sandwiched between the lungs
-Thorax contains the lungs and heart; consider this one sealed unit.
-If one side of the diaphragm is paralyzed, on inspiration the side that is not paralyzed will push down and the side that is paralyzed will be pushed upward
-R. lung is larger than the L. lung due to the space needed for the heart
-Lungs extend past rib 1, sometimes past the clavicle
How do the lungs move
Two sets of tissue that allow the lungs to move within the chest w/o friction
- Visceral pleura; outside of lungs
- Parietal pleura; stuck to visceral pleura, but on the side of the lungs
-On inspiration, lungs expand as the diaphragm contracts and pulls the lungs downward. This creates an even more negative pressure and causes air to be sucked in from the environment
Where is the diaphragm anchored?
-Anchored into the lumbar spine by two leaflets
What are we looking at here?
Inferior view of the diaphragm
- Caval canal; opening for the vena cava
- Esophageal aperture
- Aortic aperture
4.Central tendon; tendons are usually bone-bone. The central tendon is not connected to bone. Tendon in the middle of the diaphragm for the heart to sit on
What are we looking at here?
Anterior view of the diaphragm
- Esophageal aperture
- Caval aperture
- Central tendon
- Aortic Aperture
Phrenic nerves; run along the side of the neck, past the heart, and connect to the two sides of the diaphragm that they innervate
Only need one phrenic nerve to stay alive if we are completely healthy
Name the three sets of accessory muscles
What is being shown here?
Accessory muscles that help with ventilation during stress or exercise; scalene, intercostal, abdominal muscles
- Anterior Scalene; connect superiorly to C3-C6 and inferiorly to rib 1
- Middle Scalene; connect superiorly to C3-C7 and inferiorly to mid-rib 1
- Posterior Scalene; connect superiorly to C5-C7 and inferiorly to rib 2
Provide a platform to pull the ribcage up or pull the diaphragm down
In the circle is the top of the airway; the larynx. Contains the voicebox
1. Thyroid cartiledge
2. Cricoid cartiledge
3. R. Main stem
4. L. Mainstem
5. Tracheal bifurcation
6. Bronchioles continue to split until eventually becoming alveoli
24 generations of airways within the respiratory system
-Trachea is considered generation 0
-Should be 2cm in diameter
-mainstem bronchi are generation 1
-continue to split into bronchioles through generation 16
-This is the conducting zone; no ventilation happens here
-Generations 17-24 are our respirtatory/ventilation zone
-Respiratory bronchioles are transition zone; a small amount of gas exchange happens here due to a small number of alveoli (generations 17-19)
Alveoli have no cartiledge
- Normal
- Distress
- Not breathing
- Wheezing due to inflammation or tumor in airway
- Slow
- Fast
- Change in RR with position change
- Fast
- Ventilation that is occuring well in excess of metabolic demands
- Insufficient ventilation for metabolic demands
- Lungs that are larger than they should be. Ex; COPD. Connective tissue in lungs is lost, lungs expand too much
- DeoxyHgb >5gm/dL
- Decreased O2 at the level of the tissue
- Decreased O2 in the arterial system; systemic problem
- Excessive CO2 in arterial blood; hypercarbia
- Defiency of CO2 in arterial blood; hypocarbia
- O2 levels above normal at the tissue/organ level
- Collapse of functional lung units
- “P” 1mmHg = 1.36cmH2O
-using cmH2O gives us better resolution in the thoracic system - For our purposes; total O2 content of the blood = dissolved O2 and O2 attached to Hgb. How much gas content do we have in a sample?
- “a” PaO2
-“v” would be venous - “A” PAO2
- “V” how much air is moving in or out. Vt; tidal volume. Ve; expired volume of gas. Vi; gas going into the patient
- Volume of gas absorbed per minute; VO2; volume of O2 absorbed each minute. Indicated with a dot over the V
- Individual volumes of air
- Made up of individual volumes of air
- Stretch
- Inverse of compliance
-Total Lung Capacity: Sum total of volumes within the lung.
6L in a heathy adult, 3L per lung.
Total Lung Capacity contains the IRC, FRC, and the four volumes contained within those: **Inspiratory Capacity** 1. Inspiratory Reserve Volume (IRV): 2.5L. The volume of air that we can potentially inspire in addition to a normal Vt. 2. Tidal volume (Vt): 0.5L, volume of air moved during inspiration and expiration **Functional Residual Capacity** -(FRC) 3.0L. The volume of air remaining in the lungs after a normal, expired breath. Allows us to maintain stable blood gas levels, and prevents atelectasis in between breathes. 3. Expiratory Reserve Volume (ERV): 1.5L. The volume of air that we could push out of our lungs after expiration 4. Residual Volume (RV): 1.5L. Volume of air that we cannot expire from the lungs. Attempting to force this volume of air out would result in closing the airways.
-Vital Capacity (VC): 4.5L. The total amount of air that we can inspire and expire on maximal effort. Contains IRV, Vt, ERV
How do body position changes affect total lung capacity/pulmonary blood flow?
In a supine position; the weight from your abdomen will push your diaphragm upwards, causing air to be removed from the lungs.
Seated position: blood flow is still highest at the bottom
Supine: Blood flow is almost equal throughout, with flow being slightly higher at the apex. This is due to the apex of the lung being slightly head-down in this position
Normal Respiration
-This is a normal respiratory cycle that occurs over a period of four seconds
-Inspiratory and expiratory time are two seconds each
-One second in between breathes
-12 BPM is normal RR for this class
-Left side of graph is inspiration, right side is expiration
Vt, PIP, Air flow rate, and PA changes
Changes during inspiration
-In between breaths, our P IP is -5cmH2O
-During inspiration, the diaphragm pulls down on the lungs in a closed system, decreasing the P IP in order to suck air into the lungs.
-Vt steadily increases until the end of inspiration
-P IP decreases linearly over the course of two seconds during inspiration.
-At the end of inspiration, after we have inhaled our entire Vt, the P IP will decrease to -7.5cmH2O
-Air flow rate peaks halfway through inspiration (1 second) at 0.5L/sec. (The graph denotes inspired air as a negative number)
-Alveolar pressure is 0cmH2O in between breaths in comparison to the outside atmosphere (760cmH2O)
-During inspiration, the pressure surrounding the alveoli becomes more negative. (-5cmH2O –> -6cmH2) –> -7.5cmH2O)
-As this happens, the alveolar walls are being pulled open, causing the P A to decrease. This allows for air to be sucked into the lungs.
-As the air moves in, the pressure in alveoli begins to equilibrate with the environment. This is when inspiration ends
-Peak inspiration occurs when P A is at it’s lowest at -1cmH2O. This also corresponds to airflow rate being at it’s fastest.
Changes during expiration
-Vt decreases gradually through expiration
-P IP decreases linearly over the course of two seconds during expiration.
-P IP starts at -7.5cmH2O at the beginning of expiration
-Relaxing the diaphragm causes the P IP to go from -7.5cmH2O –> -6cmH2O –> -5cmH2O
-Air flow rate peaks halfway through expiration at 0.5L/sec (the graph denotes expiration as a positive number)
-Relaxing the diaphragm causes elastic recoil of the alveoli, making the P A to become more positive, and allowing for air to be pushed out of the lungs
-P A peaks halfway through expiration at +1cmH2O
-Pleural Pressure can be:
P IP or P PL
-Airflow rate will always be volume/time
-Transpulmonary Pressure: P TP
-Comparing pressures on two sides a wall (Delta P); pleural pressure vs alveolar pressure
West Perfusion Zones; Zone 1
- PA is greater than Pa & Pv
-Why does this happen? This is a continuous column of blood with a hydrostatic pressure gradient. The higher we move up the column, the higher the pressure becomes outside the capillaries, causing the alveolar capillaries to collapse.
- Compression of the capillaries
- Not seen under normal conditions in a healthy patient. Pa is just high enough to raise the blood to the top of the lungs
- When would this occur:
o Pa is reduced because of hemorrhage
o Positive pressure ventilation
West Perfusion Zones; Zone 2
- Pa is greater than PA, but PA is exceeding Pv
- Blood flow does not depend on the gradient (difference) between Pa and Pv at this point. Blood flow is dependent upon the gradient between Pa and PA.
o Why? Because the capillaries are collapsible. They collapse at the point where PA pressure exceeds Pv (start of the venous end of the capillaries)
o Often called the “waterfall effect” because the flow of a waterfall is not dependent upon the downstream pressure
- Why does this happen in this zone of the lung? Because Pa increases the further we move down the lung, but PA remains constant
Pulsatile blood flow
West Perfusion Zones; Zone 3
- Pa is increased even more, Pv is also increased because of the hydrostatic gradient, and PA now has the lowest pressure
- Capillaries are held open because of the increased Pa and Pv, and blood flow is determined with the usual formula. Pa-Pv
Continuous blood flow
Blood flow through the lungs is dependent upon what?
Gravity