Module 2: Resp Ax (Ventilation)

Question 1

what does ventilation play a critical role in?

Answer 1

CO2 clearance, determining arterial O2 saturation, and O2 supply

Question 2

what is the main respiratory muscle?

Answer 2

diaphragm and then intercostal muscles

Question 3

what is the tissue in the lungs?

Answer 3

elastic tissue. parietal pleura line thoracic wall and upper portion of diaphragm; visceral pleura line outside of each lung

Question 4

type 1 alveolar cells

Answer 4

• comprise 90% of alveolar wall, susceptible to injury, and are main structural cells

Question 5

type 2 alveolar cells

Answer 5

double the number of type 1 cells; produce surfactant; and can divide into type 1 and 2 cells when lung tissue is damaged

Question 6

what is the most sensitive region of the respiratory tract?

Answer 6

carina; triggers cough reflex

Question 7

what is the role of surfactant?

Answer 7

increases lung compliance, prevents alveolar collapse, and decreases alveolar surface tension

Question 8

ventilation assessment

Answer 8

• main determinants = RR and tidal volume which define minute ventilation
• RR and Vt are influenced by WOB
• WOB is influenced by lung compliance, a/w resistance and respiratory muscle function

Question 9

ventilation

Answer 9

movement of air in and out of the lungs

Question 10

what is one way to determine effectiveness of ventilation?

Answer 10

measuring PaCO2

Question 11

what are ax cues that can indicate an increase in PaCO2 levels (hypercapnia/hypercarbia)?

Answer 11

• increased RR
• shallow breaths
• SOB/dyspnea
• headaches, dizziness, confusion, decreased LOC
• respiratory acidosis

Question 12

ax cues for respiratory muscle function

Answer 12

• medical hx, course of illness
• nutrition status
• prolonged ventilator dependence
• neuro conditions
• increased WOB leading to fatigue

Question 13

compliance

Answer 13

measure of distensibility of a tissue

Question 14

what is internal compliance?

Answer 14

how easily the alveoli/lung tissue can be stretched

Question 15

what happens if internal compliance is decreased?

Answer 15

that means lungs are stiff, and trying to inflate poorly compliant lungs require more pressure and physical effort increasing WOB

Question 16

what happens if internal compliance is increased?

Answer 16

lungs are easily stretched and require less pressure, so WOB is decreased

Question 17

what is the effect of resp infections on internal compliance?

Answer 17

they reduce internal compliance b/c accumulation of fluid and thick mucus in alveoli makes it harder for lungs to expand and fill with air

Question 18

ax cues for internal compliance

Answer 18

• medical hx (COPD, pulmonary fibrosis, interstitial lung disease)
• chest xray (consolidation, atelectasis)
• secretions
• crackles on auscultation

Question 19

what is external compliance?

Answer 19

the ability of the lungs to fully inflate and the diaphragm and chest wall to expand and contract

Question 20

ax cues for external compliance

Answer 20

• medical hx (trauma, rib #s, chest burns)
• anything inhibiting diaphragm expansion (obesity, ascites, pregnancy, bowel obstruction, rib or spinal deformities)
• pneumo/hemothorax
• pleural effusion
• pain with breathing/coughing

Question 21

normal WOB is _____ of total body expenditure

Answer 21

<2%

Question 22

what can airway resistance be influenced by?

Answer 22

diameter of airway/artificial airway (the narrower the diameter, the greater the resistance therefore causing increased WOB)

Question 23

ax cues for airway resistance

Answer 23

• wheezes/stridor
• presence of bronchospasm
• medical hx
• a/w obstruction (anaphylaxis, tumors)
• artificial airways
• thick, copious secretions

Question 24

work of breathing

Answer 24

amount of effort required to breathe

Question 25

what three factors impact WOB?

Answer 25

1) force required to expand lungs 2) pressure required to overcome elastic recoil of lungs 3) resistance generated by airways

Question 26

when does WOB increase?

Answer 26

with any condition that impairs resp muscles, decreases lung compliance, or increases a/w resistance

Question 27

ax cues for increased WOB

Answer 27

- nasal flaring - accessory muscle use - chest retractions

Question 28

tidal volume

Answer 28

volume of air that is inhaled and exhaled in a single breath during normal quiet breathing (mL)

Question 29

why is tidal volume important?

Answer 29

its a factor in determining overall efficiency of ventilation

Question 30

what is the equation for minute ventilation

Answer 30

minute ventilation (L/min) = tidal volume (mL) x RR (breaths/min)

Question 31

what is the primary compensatory mechanism in tidal volume?

Answer 31

a change in RR to maintain volume of air moving in and out per minute

Question 32

minute ventilation

Answer 32

amount of air inhaled and exhaled from the lungs in one minute determined by RR and tV

Question 33

what might directly impact tidal volume?

Answer 33

- age, body size - resp muscle strength - resp disease, condition - meds - LOC - mechanical ventilation

Question 34

ax cues for tidal volume

Answer 34

- observed depth of respirations - directly measured volumes through mechanical ventilation

Question 35

vital capacity

Answer 35

max volume (amount) of air that can be expired after a max inhalation (deep breath); reflects max lung capacity

Question 36

why is vital capacity important?

Answer 36

part of criteria used for determining if a pt can be weaned from ventilatory support

Question 37

what is a normal VC measurement? how can you obtain a measurement?

Answer 37

~3-5L. using settings on a ventilator (usually done by RT), or by coughing

Question 38

what is the most accurate way to determine vital capacity?

Answer 38

spirometry

Question 39

what factors directly impact vital capacity

Answer 39

- resp muscle fx - internal/external compliance concerns - age related anatomic changes

Question 40

ax cues for vital capacity

Answer 40

- ability to cough - pulm fx tests/spirometry - measurement via mechanical ventilator

Question 41

functional residual capacity

Answer 41

volume of air left in lungs at the end of normal exhalation; used in determining compliance

Question 42

what does FRC do?

Answer 42

allows air to flow easily into lungs during inhalation; helps prevent collapse of small airways and alveoli at the end of expiration

Question 43

how do conditions like atelectasis and ARDS affect FRC?

Answer 43

lead to alveolar collapse and loss of FRC = decreased compliance, increased WOB and impaired ventilation

Question 44

what factors directly impact FRC?

Answer 44

- age - disease (COPD, asthma) - body position (decreased FRC in supine) - abdominal pressure - alveolar collapse (consolidation, ARDS, atelectasis decrease FRC and vol of air in lungs)