RE Chapter 26 Part 1 Flashcards
Which concha is most commonly injured during nasal intubation?
Inferior
What is choanal atresia?
A birth defect characterized by obstruction of the posterior nasal airway, may be life threaten ending in the obligate nose-breathing newborn.
The pharynx begins at the base of the skull and extends to ______
C6
The larynx extends from vertebrae _____ to _____
C3 to C6
The epiglottis is attached to the thyroid cartilage by the ______ ligament and to the base of the tongue by the ________
Thyroepiglottic ligament
Glossoepiglottic fold
The furrow between the glossoepiglottic fold and the base of the tongue is called the _______
Vallecula epiglottica
What are the 9 laryngeal cartilages of the larynx?
Epiglottis Thyroid Cricoid Aretynoids (2) Corniculates (2) Cuneiform (2)s
What is the narrowest portion of the airway in the adult? In children younger than 10?
Adult: vocal cords
Children: Cricoid cartilage
The Cricothyroid membrane lies between the ______ and _______ cartilages
Cricoid and thyroid
The true vocal cords are attached anteriorly to the ______ and posterior lay to the ______ in the larynx.
Anteriorly to the thyroid cartilage
Posterior lay to the arytenoids
Which muscles close the laryngeal inlet?
Aryepiglottic and oblique arytenoids muscles
What muscle opens the laryngeal inlet?
Thyroepiglottic muscle
What muscle opens the glottic opening?
Posterior cricoarytenoid muscle
What muscles close the glottic opening?
Transverse arytenoids and Lateral CricoArytenoid muscles (Let’s Close Airway)
What muscles lengthen the vocal cords?
CricoThyroid (Chords Tense)
What muscle shortens the vocal cords?
Thyroarytenoid muscles
Which nerve provides sensory innervation from the epiglottis to the vocal cords?
Internal SLN
Which nerve provides sensory innervation below the vocal cords?
RLN
Which nerve provides motor innervation to the Cricothyroid muscles?
External SLN
Which nerve provides motor innervation to all muscles of the airway except the Cricothyroid?
RLN
The ______ (right/left) RLN loops around the aortic arch and the ______ (right/left) RLN loops around the subclavian artery.
Left loops around aortic arch
Right loops around subclavian
Which arteries supply blood to the larynx?
- Superior thyroid artery (branch of external carotid)
- Inferior thyroid artery (branch of the thyrocervical trunk which arises from the subclavian artery)
What is the distance from the incisors to the carina?
26 cm
The right bronchus has an angle off the trachea of ______ degrees and is about ______ cm long.
25 degrees, 2 cm
The left mainstem bronchus takes off the trachea at ______ degrees and is about ______ cm long
45 degrees, 4 cm
How many bronchial segments exist before the alveoli?
20-25
By the seventh generation the diameter of the bronchioles are 2 mm and are referred to as ________
Small airways
These are the last structures perfused by bronchial circulation and are the end of the conducting airways. They are about 1 mm in diameter
Terminal bronchioles
With progression of airway divisions the number of airways and cross sectional area ________(increases/decreases) while the airflow velocity _______(increases/decreases)
Increases
Decreases
What is the closing volume?
The lung volume at which small airways tend to close
What happens to closing volume in those with obesity and COPD
It increases into the range of normal tidal breathing. Some airways close before the intended tidal volume has been expired
Which structures consist of the respiratory zone and what is it?
The respiratory bronchioles and alveolar ducts, sacs, and alveoli.
It is the area where gas exchange takes place.
All parts of the airway prior to the respiratory zone that are not involved with gas exchange are referred to as _______
The Conducting Zone
What are type I pneumocytes?
Structural cells
What are type II pneumocytes?
Produce surfactant to reduce alveolar collapse from surface tension
What are type III pneumocytes?
Macrophages
What is the total surface area available for gas exchange?
60 - 80 m²
What is the hilum?
The connection of the mediastinum to each lung. Structures inside include the mainstem bronchus, pulmonary/bronchial arteries/veins, lymph nodes, nerves, & pulmonary ligaments.
What does the parietal pleura line?
Chest wall, mediastinum, and diaphragm
What does the visceral pleura cover?
The lungs.
The left lung represents ____% of total lung capacity while the right represents _____%
Left lung = 45% of TLC
Right lung = 55% of TLC
Which nerve is the diaphragm innervated by? What does this nerve arise from?
The phrenic nerve that arises from C3, C4, C5
“C3, 4, 5 keep the diaphragm alive”
What type of block may cause paralysis of the phrenic nerve?
Interscalene
What is lung compliance?
The change in volume divided by the change in pressure (V/P)
True or False? Compliance is volume dependent.
True, lungs are less compliant at very high and very low lung volumes.
What is static compliance?
The pressure-volume relationship for a lung when air is not moving reflecting the compliance of the lung and chest wall alone.
Static effective compliance = tidal volume/(plateau pressure - PEEP)
What is a normal static effective compliance?
60 - 100 mL/cm H2O
What is dynamic compliance?
Compliance of the lung while air is moving
Dynamic compliance = tidal volume/(Peak insp. Pressure - PEEP)
What is Laplace’s law?
P = T/r
If surface tension (T) remains constant pressure (P) increases as the radius (r) decreases.
How does the presence of surfactant affect surface tension and the application of Laplace’s law on the alveoli?
As alveolar radius decreases, surface tension also decreases, so pressure remains constant.
When is surfactant produced in the fetus?
28-32 weeks gestation and not mature levels until 35 weeks.
What is transpulmonary pressure?
The difference between intraalveolar pressure and intrapleural pressure
What is the equation for Reynolds number?
Re=pvd/n
p = density v = velocity d = diameter of the vessel n = viscosity of fluid
What value of reynold’s number predicts laminar flow, turbulent flow, and transitional area
Laminar flow = <2000
Turbulent flow = >4000
Transitional area = 2000-4000
Where does laminar flow occur in the respiratory system?
Where does turbulent flow occur in the respiratory system?
Laminar flow - Smaller airways
Turbulent flow - large airways
What is Poiseuille’s law?
R = 8ln/r^4
Resistance to laminar airflow is directly proportional to the length of the tube and inversely proportional to the 4th power of the radius.
Why is net resistance to airflow low in small airways?
Because there is a massive number of parallel pathways.
Where is resistance to airflow the greatest?
Medium sized bronchi whose smooth muscle tone affects airway resistance.
What is a normal tidal volume for a 70kg male?
350-500 mL
What is minute volume?
Tidal volume x Respiratory rate
What is alveolar ventilation?
(Tidal volume - anatomic dead space) x respiratory rate
*anatomic dead space ~ 2mL per kg
Residual volume (RV)
Volume of air in lungs after maximal expiration
1200 mL
Expiratory reserve volume (ERV)
Maximum volume of air expired from resting end expiratory level
1100 mL
Inspiratory reserve volume (IRV)
Max volume of air inspired from resting end-inspiratory level
3000 mL
Total lung capacity (TLC)
Volume of air in lungs after maximum inspiration
IRV+VT+ERV+RV
5800 mL
Functional residual capacity (FRC)
Air remaining in the lungs at the end-expiratory level
RV+ERV
2300 mL
Inspiratory capacity (IC)
Max volume of air inspired from the end expiratory level
IRV + VT
3500 mL
Vital Capacity (VC)
Maximum volume of air expired from the maximum inspiration
IRV+VT+ERV
4500
Closing volume vs. closing capacity
Closing volume: The volume above residual volume where small airways close
Closing capacity: The absolute volume in the lung when small airways close (closing volume + residual volume)
Which conditions increase closing volume?
Supine positioning, pregnancy, obesity, COPD, CHF, and aging
What is physiologic dead space?
Anatomic dead space + alveolar dead space
What is the Bohr equation?
%VD = (PaCO2 - PECO2)/PaCO2
What is the respiratory quotient?
Amount of CO2 produced/O2 consumed
Normal: 200/250 = 0.8
What is the PO2 of inspired air 100% saturated with water vapor at body temp (PIO2)?
.21 X (760 mmHg - 47 mmHg) = 149 mmHg
**47mmHg is partial pressure of water vapor at body temp
How is alveolar PO2 (PAO2) calculated?
PAO2 = PIO2 - (PACO2/RQ)
Ex. When PACO2 is 40 mmHg and breathing atmospheric air
PAO2 = 149 -(40/0.8)
= 99 mmHg
Why is pulmonary vascular resistance about 1/8th of systemic vascular resistance
Pulmonary artery walls are less muscular & more distensible than the aorta and pulmonary vessels are much shorter (think poiseulle’s law)
What increases pulmonary vascular resistance?
Norepinephrine, serotonin, histamine, hypoxia, endothelium, leukotriene, thromboxane, prostaglandin, and hypercapnia
What decreases pulmonary vascular resistance?
Prostacyclin analogs (epoprostenol), endothelium receptor antagonists, posphodiesterase inhibitors (sildenafil), acetylcholine, and isoproterenol (minimally)
West Zone 1
Palv > Pcap
This region is ventilated but not perfused, this represents alveolar dead space
West Zone 2
Alveolar pressure related to respiration variably occludes capillary flow.
West Zone 3
Palv < Pcap
Greatest proportion of ventilation in the lung and perfusion is greatest here, no obstruction of blood flow.
West Zone 4
Compression of blood flow occurs from mechanical compression or interstitial fluid.
Which zone should a pulmonary artery catheter be placed?
West Zone 3
What is the normal ventilation-perfusion (V/Q) ratio
4 L/min / 5 L/min = 0.8
What is a shunt in relation to the V/Q ratio?
Alveoli that are perfused but not ventilated
V = 0 so the V/Q ratio is 0
What is dead space in relation to the V/Q ratio?
Alveoli that are ventilated but not perfused
Q = 0 so the V/Q ratio is infinity.
Shuntlike alveoli with a low V/Q have a ______(high/low) PO2 and a _______ (high/low) PCO2
Low PO2
High PCO2
Dead space-like alveoli with a high V/Q have a _______ (high/low) PO2 and a __________(high/low) PCO2
High PO2
Low PCO2
_____% of the O2 carried in blood is bound to hemoglobin
99.7%
With a PaO2 of 100 mmHg _____ mL of O2 is transported dissolved per 100 mL of plasma.
0.3
A hemoglobin of 10 g/100mL at 100% saturation carries _____ mL of O2 bound to Hgb per 100 mL of blood
1.36
Which conditions cause a left shift of the oxyhemoglobin dissociation curve?
Hypocapnea, hypothermia, decreased 2-3DPG.
*increased affinity of hemoglobin for oxygen (left latch)
Which conditions cause a right shift in the oxyhemoglobin dissociation curve?
Hyperthermia, hypercapnia, acidosis, increased 2,3-DPG
*decreased affinity of hemoglobin for O2 (right release)
What is the P50 on the oxyhemoglobin dissociation curve?
The portion where 50% of hemoglobin is saturated
Normal is 26-27 mmHg
A right shift of the oxyhemoglobin dissociation curve increases or decreases the P50?
Increases
A left shift decreases
What is the equation for arterial blood content (CaO2)?
(1.36 X Hgb x % arterial Hgb saturation) + (PaO2 x 0.003)
Normal is 20 mL per 100 mL of arterial blood
What is the equation for mixed venous blood o2 content?
(1.36 x Hgb x % mixed venous Hgb saturation) + (Pvo2 x 0.003)
Normal 15 mL per 100 mL of blood
(Where Hgb is 15 and Pvo2 is 40)
What is a normal arteriovenous O2 content difference?
What does a high or low value indicate?
Normal = 5mL/dL
High - low CO
Low- systemic arteriovenous shunts
How is CO2 carried in blood?
- In physical solution (5-10% of bloods total CO2 content)
- Chemically combined with amino acids (5-10% of total CO2 content)
- As bicarbonate ions (90% of bloods CO2 content)
In the presence of carbonic anhydrase CO2 and H2O yield ______.
Carbonic acid (H2CO3)
Carbonic acid dissociates to _____ and _____
H+ and HCO3-
What is the hamburger shift or chloride shift?
When HCO3- leaves blood cells, chloride ions enter to maintain electrical neutrality
When blood contains mainly oxygenated hemoglobin bloods capacity to hold CO2 increases or decreases? Which way does the CO2 dissociation curve shift?
Decreases, shift to the right.
When the blood contains mostly deoxyhemoglobin the capacity for blood to carry CO2 increases or decreases? Which way does the CO2 dissociation curve shift?
Increase, shift to left
What is the Haldane effect?
Deoxyhemoglbin more readily accepts H+ produced by the dissociation of carbonic acid which permits more CO2 to be carried in the form of bicarbonate ions.
What is the Bohr effect?
The association of H+ with the amino acids of hemoglobin lowers the affinity of Hgb for O2 at a low pH or high Pco2
An acute increase in PaCO2 of 10mmHg is associated with a decrease in pH of _______
0.08
A base increase of 10 mEq/L is associated with a pH change of _____
0.15
Should respiratory acidosis be treated with sodium bicarbonate? Why or why not?
No. The bicarbonate dissociates into more CO2, worsening the acidosis
Where is the respiratory center in the nervous system?
In the reticular formation of the medulla
How does hypoxemia effect the ventilatory response to CO2?
It potentiates the response
Are central and peripheral chemoreceptors stimulated by changes in PO2 or PCO2?
PCO2, they are not stimulated by hypoxia
What is the FEV1/FVC ratio?
It measures airway resistance, a normal value is 80% and decreases occur with increased airway resistance.
What is the FEF25%-75%?
The forced expiratory flow rate between 25% and 75% of the exhaled breath.
Normal is 4-5L/sec
Decreases indicate pulmonary disease, obstructive disease has sooner decreases than restrictive
What are 3 causes of a decrease in FEV1 in COPD?
- Decrease in the intrinsic size of bronchial lumina
- Increase in the collapsibility of bronchial walls
- Decrease in elastic recoil of the lungs
A low FEV1 and a low FEV1/FVC ratio is indicative of obstructive or restrictive lung disease?
Obstructive
A low FEV1 with a normal FEV1/FVC ratio is indicative of restrictive or obstructive lung disease?
Restrictive
