Pulmonary Flashcards
when an endotracheal tube is placed, it must be 2-3 cm above what to ensure equal inflation in both lungs?
carina
what must be done after intubation & daily to ensure correct placement?
CXR
what is the parietal pleura?
membrane lining the chest wall
what is the visceral pleura?
membrane lining the lung parenchyma
what allows sliding back & forth whenever we are breathing?
2-3 tsp of fluid inside the parietal pleura & visceral pleura
what keeps the lungs from collapsing between the pleural space?
-5 cm H2o pressure (vacuum pressure)
why would there be a risk for damage related to the thinness of the alveoli wall?
too much positive pressure
what is the difference between type I & type II alveoli cells?
type I compose 90% of alveolar surface area & type II cells produce pulmonary surfactant
what is the importance of pulmonary surfactant? name 3 things
- decreases surface tension in the alveoli
- makes it easier to inflate alveoli during inspiration
- prevents collapse during expiration
what are connected from alveoli to alveoli that clean to maintain the sterility of the alveoli & lungs?
macrophages
what is ventilation & what is it often referred to?
movement of air in & out of the lungs (often referred to as external respiration) (movement of air between the atmosphere & alveoli)
what is perfusion & what does it focus on?
movement / flow of blood (focuses on alveolar capillary)
what is diffusion? it occurs from an area of _____ concentration to _____ concentration
movement of gases across the pulmonary membrane (occurs from an area of high concentration to low concentration)
which 4 things is alveolar diffusion affected by?
- decreased surface area
- thickness of alveolar capillary membrane
- partial pressure of gases (CO2 & O2)
- solubility of the gas (CO2 diffuses across alveolar capillary membrane 20 times faster than O2)
a patient will often become hypoxemic before becoming _____
hypercapnic
what does a shunt unit mean on a VQ scan?
- perfusion > ventilation
- blood passes alveolus w out gas exchange
EXs: pneumonia, atelectasis, tumor, mucus plugs
what does a deadspace unit mean on a VQ scan?
- ventilation > perfusion
- does not participate in gas exchange
EXs: PE or pulmonary infarction
20% shunt =
severe hypoxia
describe the two ways O2 is carried into the blood
- 97% bound to hemoglobin (SaO2)
- 3% dissolved in plasma (PaO2) (partial pressure of oxygen)
what does SaO2 measure?
saturation of arterial blood (O2 saturation of Hgb)
how is the PaO2 measured?
obtaining an ABG
list two ways the saturation of hemoglobin is measured
- ABGs (SaO2) (direct measurement; expensive & painful)
- pulse oximetry (SpO2) (indirect measurement & often times can get false readings)
name some signs & symptoms of hypoxemia
- tachypnea, hyperventilation, dyspnea
- use of accessory muscles / abdominal breathing
- cool, pale, clammy, skin (cyanosis)
- restlessness, agitation, irritability, confusion, personality changes, decreased LOC
- tachycardia, hypertension, palpitations, CP, dysrhythmias
which part of an ABG tells us the patient’s ventilation status?
PaCO2
what measures the adequacy of ventilation?
PaCO2
what does it mean if a patient’s PaCO2 is too high?
the patient is not moving enough air (decreased ventilation or hypoventilation) not breathing fast enough or not taking quality breaths
what does it mean if a patient’s PaCO2 is too low?
the patient is moving TOO MUCH air (hyperventilation) or breathing off too much CO2
which tool is noninvasive & measures the end tidal CO2 or the amount of CO2 being exhaled w each breath?
Capnography
what are some signs / symptoms of hypercapnia / hypercarbia?
same as hypoxemia
- drowsiness
- HA, decreased LOC, blurred vision, confusion, seizures
- flushed, clammy skin
what is a patient often placed on if they are hypercapnic?
CIPAP / BIPAP or intubation
what is the normal range for pH?
7.35 - 7.45
what is the normal range for PaO2?
80 - 100
what is the normal SaO2 range?
93% - 99%
what is the normal PaCO2 range?
35 - 45
what is the normal range for HCO3?
22 - 26
what is the difference between correction
& compensation?
correction: process by which the same system that is affected changes to bring pH back to normal
EX: not breathing fast enough so CO2 levels increase
compensation: process by which other system changes to attempt to bring the pH back to normal
EX: respiratory issue (being acidotic) & kidneys (metabolic parameter) correcting the acidosis caused by respiratory
if there is a PaO2 of 60, what will the SaO2 be?
90% or less
metabolic acidosis can cause decreased LOC that results in ______
respiratory acidosis (shallower breathing)
what is the goal of O2 therapy?
to deliver the least amount necessary
how much can a nasal cannula deliver & what is the percentage of inspired oxygen?
1-6 L/min
21-44% of FiO2
how much can a high flow nasal cannula deliver & what is the percentage of inspired oxygen?
1-60 L/min
21 - 100% FiO2
how much FiO2 do we breathe naturally?
20-21%
what type of situations is a nonrebreather often seen in?
emergent situations when transporting a patient from a floor to the ICU
describe the pathophysiology of acute respiratory failure & how it usually occurs
inadequate gas exchange; usually occurs secondary to another disorder like pneumonia, atelectasis, tumor or PE
(problem w oxygenation or CO2 elimination or both)