Thoracic Park
What is the normal respiratory rate and CO2 range?
RR: 12 to 20 breaths/min, CO2: 35 to 45 mmHg
What is defined as the ease of lung distention?
Lung compliance
These 3 methods allow us to calculate FRC.
Nitrogen washout, helium dilution, and body plethysmography.
What gas law explains that a gas’s solubility in a liquid is proportional to its partial pressure?
Henry's Law
Where is the phrenic nerve on the spinal column? What muscle drives respiratory ventilation?
C3, C4, C5: Diaphragm
Which cell produces surfactant, and what is its purpose?
Type 2 alveolar. Surfactant reduces surface tension and stabilizes alveoli.
Where in the lungs will the aspired contents most likely settle? Why?
In the right middle lobe and the right lower lobe. The right mainstem is wider, and anatomically, the angle is more accessible. Gravity pulls particles down in the lung.
What does FVC stand for and measure?
Forced vital capacity- the maximum volume of gas exhaled as forcefully and rapidly as possible after full inspiration.
This type of gas exchange is limited only by the amount of blood flowing past the alveoli, not by the membrane.
Perfusion-limited gas exchange.
What is the name of the substance released from mast cells that causes bronchodilation and inflammation? Does it cause increased or decreased mucus secretions in the airways?
Histamine, Increased.
What are the 5 accessory muscles of inspiration? What clinical indication relies on these muscles rather than the diaphragm?
Sternocleidomastoid, scalene, pectoral major, trapezius, external intercostals. Emphysema (most commonly), but also COPD, asthma, restrictive diseases, and neuromuscular disorders: bilateral diaphragmatic paralysis.
Define Minute ventilation. If a patient has a VT of 500mL and RR of 14 breaths/min. Calculate minute ventilation. Lastly, what is this value used for clinically?
Minute Ventilation (VE) is the total volume of air breathed in or out of the lungs per minute
VE= 500 x 14= 7000mL/min or 7L/min
Clinically, the minute ventilation can help determine if a patient is hypo/hyperventilating, and or parameters for a mechanical ventilator, and can be used to calculate alveolar ventilation.
What is the FEV1/ FVC ratio, and what is it used for?
The FEV1/FVC ratio is calculated using incentive spirometry, allowing for the differentiation between obstructive and restrictive lung diseases.
When is a hyperbaric chamber used, and how does it work?
A hyperbaric chamber is used for patients with carbon monoxide poisoning, where it delivers high partial pressures of oxygen, which shortens the half-life of COHb.
This equation is for: X = VT/ (Pplat-PEEP)
Static Compliance
Describe how cAMP causes bronchodilation in the lungs.
Beta 2 receptors cause the release of cAMP, which leads to smooth muscle relaxation and bronchodilation in the lungs.
If PaCO2 is 40 mmHg and PECO2 is 30 mmHg, calculate the VD/VT ratio
VD/VT= (40-30)40 = 0.25
Given IRV=2800mL, VT=480mL, ERV=1200mL, RV=1150mL. Calculate the following IC, FRC, and TLC
IC= IRV+VT/ 2800+ 480= 3,280mL
FRC= ERV+RV/ 1200+ 1150= 2,350mL
TLC= IRV+ VT+ ERV+ RV/ 2800+ 480+ 1200+ 1150= 5,630mL
Name the first four layers that gas passes through ACM on the thin side
1.Surfactant/ Fluid layer
2. Alveolar epithelium
3. Fused alveolar capillary basement membrane
4. Endothelium
Define normal, hyperventilation, and hypoventilation based on PaCO2 values.
If a patient has a RR of 22, what is their diagnosis?
Normal PaCO2= 35 - 40mmHg
Hypoventilation PaCO2= >45mmHg
Hyperventilation PaCO2= <35mmHg
Tachypneic, cannot diagnose ventilation based on RR alone.
If a male patient is 6 '1 what is his ideal body weight (IBW) and why is this relevant in respiratory care?
106+(13 x 6)= 184 lbs. Calculating IBW is important because it helps calculate the anatomic dead space for a patient and tidal volume for ventilator settings.
According to Laplace’s law, what would happen to small alveoli if surfactant were absent?
Small alveoli would collapse into larger alveoli due to higher internal pressure.
Patient has the following PFTs
FVC= 67%
FEV= 80%
FEV1= 88%
What do the following PFTs indicate, and why?
Restrictive lung disease.
Normal values:
FVC: 81%
FEV: 89%
FEV1: 83%
What is the alveolar gas equation? What does each part mean? What is a normal RQ?
PAO2= (Pb-PH2O) x FiO2- PaCO2 ➗0.8
PAO2 = Partial pressure of oxygen in the alveoli (mmHg)
FiO2 = Fraction of inspired oxygen (e.g., 0.21 for room air)
PB = Barometric pressure (usually 760 mmHg at sea level)
PH2O = Water vapor pressure in the alveoli (~47 mmHg at body temperature)
PaCO2 = Partial pressure of carbon dioxide in arterial blood (mmHg)
Respiratory Quotient = 0.8
A patient presents with the following PFT
FVC- 83%
FEV- 67%
FEV1- 68%
What diagnosis could be given based on these values? And why?
Obstructive lung disease
Normal values:
FVC: 81%
FEV: 89%
FEV1: 83%