Steve Stone Cold Austin's Stone Cold Respiratory Facts Flashcards
Conducting zone
large airways consist of nose, pharynx, larynx, trachea, and bronchi;
small airways consist of bronchioles and terminal bronchioles (large numbers in parallel leading to least airway resistance);
Warms, humidifies, and filters air but does not participate in gas exchange leading to anatomic dead space;
Cartilage and goblet cells extend to end of bronchi;
pseudostratified ciliated columnar cells (beat mucus up and out of lung) extend to beginning of terminal bronchioles, then transition to cuboidal cells;
airway smooth muscles extend to end of terminal bronchioles (sparse beyond this point)
Respiratory zone
Lung parenchyma;
consists of respiratory bronchioles, alveolar ducts, and alveoli;
participates in gas exchange;
mostly cuboidal cells in respiratory bronchioles, then simple squamous cells up to alveoli;
no cilia;
alveolar macrophages clear debris and participate in immune respone
type I pneumocyte
97% of alveolar surface;
line the alveoli;
squamous;
thin for optimal gas diffusion
Type II pneumocyte
secrete pulmonary surfactant causing decreased alveolar surface tension and prevention of alveolar collapse (atelectasis);
cuboidal and clustered;
also serve as precursors to type I cells and other type II cells;
Type II cells proliferate during lung damage
Club or Clara cells
Nonciliated; low-columnar/cuboidal with secretory granules; secrete component of surfactant; degrade toxins; act as reserve cell
Collapsing pressure equation
Collapsing pressure= 2(surface tension)/radius;
alveoli have the tendency to collapse during expiration as radius decreases (law of Laplace);
Surfactant
from type II pneumocytes;
mix of lecithins, the most important one being dipalmitoylphosphatidylcholine;
surfactant synthesis begins around week 26 of gestation, but mature levels not reached until week 35;
Lecithin to sphingomyelin ratio of >2 in amniotic fluid indicates fetal lung maturity
Aspirate a peanut, where will it go when you are standing and laying down
upright- lower portion of right inferior lobe;
supine- superior portion of right inferior lobe
Structures that perforate the diaphragm that are important
at T8= IVC;
at T10= esophagus, CN X;
at T12= aorta, thoracic duct, azygos vein (12 is red, white, and blue);
innervation of diaphragm
C3, 4, 5, innervate (phrenic);
pain from diaphragm can be referred to shoulder (C5), and the trapezius ridge (C3, 4)
determination of physiologic dead space
Vd= Vt x (PaCO2-PeCO2)/PaCO2
minute ventilation (Ve)
total amount of air entering the lung in one minute;
Ve=Vt x respiratory rate
Alveolar ventilation (Va)
Volume of gas per unit time that reaches the alveoli;
Va= (Vt-Vd) x RR
hemoglobin
2 alpha, 2 beta subunits;
T (Taut) form has low O2 affinity (unloads O2);
R (Relaxed) form has high O2 affinity (loads O2);
Fetal Hb has 2 alpha, 2 gamma with lower affinity for 2,3 BPG leading to increased O2 affinity
Methemoglobin
Oxidized form of Hb (ferric, Fe3+) that does not bind O2 as readily, but has increased affinity for cyanide;
iron in hemoglobin should be ferrous, Fe2+, or reduced state;
may present with cyanosis and chocolate-colored blood;
treat this with METHylene blue
how do you treat cyanide poisoning
give nitrites to turn Fe2+ into ferric Fe3+ because methemoglobin bind cyanide more readily;
give thiosulfate to bind this new cyanide forming thiocyanate, which is renally excreted;
Carboxyhemoglobin
form of Hb bound to CO in place of O2;
causes decreased Oxygen binding capacity with a left shift in the oxygen hemoglobin dissociation curve;
decreased O2 unloading in tissue;
Oxygen hemoglobin dissociation curve: what shifts it to the right
Right shift is a decrease in Hb’s affinity for O2 so we get unloading of O2;
Right shift is BAT ACE;
2,3 BPG, Altitude increase, Temperature increase, Acidic, CO2, Exercise;
how to calculate O2 content in blood
O2 content= (O2 binding capacity x % saturation) + dissolved O2
What are profusion limited gases
O2 in a healthy person, CO2, and N2O;
gas equilibrates early along the length of the capillary;
diffusion can be increased only if blood flow increases
What are diffusion limited gases
O2 in a emphysema or fibrosis patient), CO;
gas does not equilibrate by the time blood reaches the end of the capillary;
Equation for pulmonary vascular resistance
PVR= (Ppulm artery- Pleft atrium)/ cardiac output;
Pleft atrium= pulmonary wedge pressure
Alveolar gas equation
PAo2= PIo2 - (Paco2)/R; usually that means PAo2= 150- Paco2/0.8; PAo2= alveolar Po2; PIo2= Po2 in inspired air; Paco2= arterial Pco2; R= respiratory quotient= CO2 produced/O2 consumed; normal A-a gradient= 10-15; increased A-a gradient could mean hypoxia, causes include shunting, V/Q mismatch, fibrosis
hypoxemia
decreased Pao2;
With a normal A-a gradient look for high altitude or hypoventilation;
with an increased A-a gradient look for V/Q mismatch, diffusion limitation, R to L shunt
Hypoxia
decreased O2 delivery to tissue;
causes can be decreased cardiac output, hypoxemia, anemia, CO poisoning
Ischemia
loss of blood flow;
impeded arterial flow or decreased venous drainage
V/Q mismatch
V= ventilation (how much gas getting there);
Q= perfusion (how much blood is getting there);
base of lung= 0.6 (wasting perfusion);
apex of lung= 3 (wasting ventilation);
V/Q= 0 means airway obstruction;
V/Q= infinity means blood flow obstruction
Remember that V and Q are both highest at the base, but Q is just much higher at the base;
CO2 transport
3 forms: 1) HCO3- (90%), 2) carbaminohemoglobin or HbCO2 (5%) CO2 is bound to N-terminus of globin not the heme and favors taut Hb form, 3) Dissolved CO2 (5%)
When CO2 in a RBC is turned into HCO3- and is transported out of the RBC, what comes into the cell
HCO3- is pumped out while Cl- is pumped in
Bodies response to high altitude
decrease in atmospheric oxygen leads to decreased Pao2 causing increased ventilation and decreased Paco2;
get a chronic increase in ventilation;
increased EPO causing increased hematocrit and Hb;
increased 2,3BPG (increasing release of O2 from Hb);
increased mitochondria in cells;
Increased renal bicarb excretion to compensate for respiratory alkalosis (give acetazolamide if you need to stop this);
Chronic hypoxic pulmonary vasoconstriction can cause RVH;
Response to exercise
Increased CO2 production;
increased O2 consumption;
increased ventilation rate to meet O2 demand;
V/Q ratio from apex to base becomes more uniform;
increased pulmonary blood flow due to increased cardiac output;
decreased pH during strenuous exercise (secondary to lactic acidosis);
no change in Pao2 and Paco2, but increase in venous CO2 content and decrease in venous O2 content
Rhinosinusitis
obstruction of the sinus drainage into nasal cavity leading to inflammation and pain over affected area;
typically maxillary sinus in adults;
most common acute cause is viral URI;
may cause superimposed bacterial infection, most commonly S. pneumoniae, H. influenzae, and M. catarrhalis
Deep venous thrombosis
predisposed by Virchow triad (1. stasis 2. hyper-coagulability (e.g. factor V leiden) 3. endothelial damage (exposed collagen activates clotting cascade);
About 95% of PEs come from deep leg veins;
Homan sign- dorsiflexion of foot leading to calf pain;
Use heparin for prevention and acute management;
use warfarin for long-term prevention of DVT recurrence
Pulmonary emboli
V/Q mismatch leading to hypoxemia causing respiratory alkalosis;
sudden onset dyspnea, chest pain, tachypnea;
Types are: Fat, Air, Thrombus, Bacteria, Amniotic fluid, Tumor (FAT BAT);
If Fat you see long bone fractures or liposuction (also get triad of hypoxemia, neuro abnormalities, and petechial rash);
Amniotic fluid emboli can lead to DIC especially postpartum;
Gas emboli- nitrogen bubbles precipitate in ascending divers, treat with hyperbaric oxygen
Obstructive lung diseases
obstruction of air flow resulting in trapping air in the lungs;
airways close prematurely at high lung volumes;
increased RV and decreased FVC;
PFTs- greatly decreased FEV1, and decreased FVC causing a decreased FEV1/FVC ratio (hallmark), V/Q mismatch;
chronic, hypoxic pulmonary vasoconstriction can lead to cor pulmonale;
Chronic Bronchitis, Emphysema, Asthma, Bronchiectasis
Chronic bronchitis
blue bloaters;
a form of COPD along with emphysema;
hyperplasia of mucus secreting glands in the bronchi (Reid index > 50%;
productive cough > 3 months per year for >2 years;
disease of small airways;
findings: wheezing, crackles, cyanosis (early-onset hypoxemia due to shunting), late-onset dyspnea, CO2 retention