Respiratory pathophysiology 2 Flashcards
A forced vital capacity is the
volume of air that can be exhaled after a maximal inhalation
What are the normal values of forced vital capacity?
male: 4.8 L
female: 3.7 L
What is the forced expiratory volume?
volume of air that can be exhaled after a maximal inhalation in 1 second
Forced expiratory volume depends on
the patient’s effort
Forced expiratory volume declines
with age (predicted values take this into account)
FEV1 to FVC ratio compares
volume of air expired in 1 second and total volume of air expired
FEV1/FVC ratio is useful in diagnosis of
obstructive vs. restrictive disease
FEV1/FVC ratio is __________ with obstructive disease & ________ with restrictive disease
<70% suggest obstructive disease; usually normal
The forced expiratory flow at 25-75% vital capacity is ____________ with obstructive disease & ___________ with restrictive disease
usually reduced; usually normal
The maximum voluntary ventilation is the
maximum volume of air that can be inhaled and exhaled over the course of 1 minute
The best test of endurance is the
maximum voluntary ventilation
Normal maximum voluntary ventilation values for males & females are
male: 140-180 L
female: 80-120 L
Flow-volume loops allow us to
differentiate between obstructive & restrictive respiratory diseases
The patient begins inhalation from
residual volume and stops when they achieve total lung capacity
Inhalation produces a waveform that moves from
right to left with a negative deflection
Exhalation occurs when the patient exhales back to
residual volume
Exhalation produces a waveform that moves from
left to right with a positive deflection
________ is the width of the loop
Vital capacity
All of the following are independent risk factors for postoperative pulmonary complications EXCEPT:
a. age >65 years
b. chronic obstructive pulmonary disease
c. congestive heart failure
d. asthma
d. asthma
Independent risk factors for postoperative pulmonary complications can be categorized as
patient-related
procedure-related
diagnostic testing
Patient examples of risk factors for postoperative pulmonary complications include
old age (>60 years), COPD, CHF, smoking, ASA >2
Procedure examples of risk factors for postoperative pulmonary complications include
surgery >2 hrs, GA, aortic or abdominal surgery
Diagnostic examples of risk factors for postoperative pulmonary complications include
albumin <3.5 g/dL (indicates poor nutritional status)
Short term benefits of smoking cessation include
a reduction in carboxyhemoglobin (improved P50), but this does not reduce the risk of postoperative pulmonary complications
Risk reduction strategies for postoperative pulmonary complications include:
smoking cessation (at least 6 weeks)
consider anesthetic options besides GA
teach patient to use pulmonary recruitment maneuvers
treat active infections (prophylaxis is not indicated)
treat expiratory airflow obstruction with bronchodilators and corticosteroids
employ alveolar recruitment maneuvers (ARMs)+ PEEP
Factors that have NOT been shown to increase risk of postoperative pulmonary complications for non-thoracic surgery include:
mild/moderate asthma
ABG analysis
pulmonary function testing
Short term effects of smoking cessation include
carbon monoxide t1/2= 4-6 hrs
P50 returns to near normal in 12 hours
Return of pulmonary function after smoking takes at least 6 weeks. This includes:
airway function
mucociliary clearance
sputum production
pulmonary immune function
hepatic enzyme induction also subsides after 6 weeks
A peak airway pressure of _______ is required for initial reopening of the atelectatic regions.
30 cm H2O
Increasing the PIP to ________________________ appears to reverse anesthesia-induced atelectasis almost completely
40 cm H2O for 8 seconds
Postoperative strategies to reduce postoperative pulmonary complications include
utilize effective analgesia (intercostal nerve block, neuraxial opioids, PCA)
use pulmonary recruitment maneuvers
A patient with severe kyphoscoliosis is expected to have a reduced: (select 2)
a. FEV1/FVC ratio
b. FRC
c. FEF 25-75%
D. FEV1
B. FRC
D. FEV1
Obstructive disease is characterized by
small airway obstruction and increased resistance to expiratory flow
getting air out is the problem
Restrictive disease is characterized by a
proportionate reduction in all of the lung volumes along with poor compliance
small lung volumes are the problem
Patients with obstructive disease have a decreased
FEV1/FVC
Patients with obstructive disease can have a normal or decreased
FEV1 & FVC
Patients with restrictive disease have a decreased
FEV1 & FVC
Patients with restrictive disease have a ___________ FEV1/FVC & FEF 25-75%
normal
The spirometry waveform of an obstructive disease looks like:
the expiratory limb has a concave shape
The spirometry waveform of a restrictive disease looks like:
the restrictive loop is smaller and right shifted
What does a fixed lesion look like on spirometry?
the inspiratory and expiratory limbs are flat- someone smashed my ice cream cone & it needs to be “fixed”
Examples of a fixed lesion include
tracheal stenosis
Sometimes can upper airway lesion is a problem during inspiration and expiration. Other times the upper airway lesion is
variable and only creates the obstruction during inspiration OR during expiration
A ____________ obstruction has obstruction with inspiration.
extrathoracic
A __________ obstruction has obstruction with expiration
intrathoracic
A patient with asthma experiences bronchospasm immediately following tracheal intubation. This is MOST likely the result of:
a. mast cell degranulation
b. decreased sympathetic tone
c. histamine release
d. vagal stimulation
d. vagal stimulation
