Mechanics Of Ventilation

Question 1

Why does the absence of surfactant lead to pulmonary edema

Answer 1

The alveoli begin to collapse due to an inward increase in tension. This creates a vacuum that sucks in blood from the capillary

Question 2

Do the small or large areas have the least resistance

Answer 2

Small

Question 3

Obstructive diseases affect the _______ airways

Answer 3

Small

Question 4

Helium is frequently added (in place of some N2 gas) water divers’ tanks because

Answer 4

Helium is less viscous than N2 and reduces therefore the main airway resistance

Question 5

How come breathing helium is not beneficial in asthma

Answer 5

It does not reduce resistance in small airways

Question 6

Forced expiration causes airway constriction and ______ airway resistance

Answer 6

Increase

Question 7

You are in inspiration is the transairway pressure is ___________

Answer 7

Positive

Question 8

The point in the airways where Paw = Ppl

Answer 8

Equal point pressure

Question 9

Airway proximal to EPP can collapse during _____ _________

Answer 9

Forced expiration

Question 10

Which of the following plays a role in the occurrence of expiratory wheezes in patients with COPD with emphysematous changes

Answer 10

Reduced elastic recoil

Question 11

The difference in work for inspiration and expiration is called

Answer 11

Hysteresis

Question 12

Does it cause more work to inflate or deflate the lung

Answer 12

Inflate

Question 13

What does FEV represent

Answer 13

The amount of air that can be pushed out in one second

Question 14

What is a normal FEV/FVC ratio

Answer 14

75-85%

Question 15

What do you suspect if a patients FEV/FVC is 40%

Answer 15

Obstructive pulmonary disease

Question 16

What do you suspect if a patents vital capacity is low

Answer 16

Restrictive lung disease

Question 17

If a low flow is seen on FEF what is suspected

Answer 17

Obstruction

Question 18

If low volume is seen on FEF what is suspected

Answer 18

Restriction

Question 19

collapse of the airways is more likely to occur in forced _________

Answer 19

Expiration (seen in COPD patients)

Question 20

A space where no exchange happens

Answer 20

Dead space

Question 21

What is the equation of alveolar ventilation

Answer 21

Respiratory frequency x (tidal volume-dead space)

Question 22

The amount of air reaching the alveoli over minute

Answer 22

Alveolar ventilation

Question 23

At 30/min, Vt of 9L/min (compared to normal breathing 7.5 L/min, RR14/min) you expect his arterial Co2 (PaCO2) to

Answer 23

Increase above normal
VT =9000 mL/min / 30 RR = 300 tidal volume

Normal = 500
Hyperpnea
This is shallow air/breathing

Question 24

What is the equation for calculating total dead space volume

Answer 24

VD= VT- (Peco2 x VT/ Paco2

Question 25

what is the equation for calculating alveolar ventilation

Answer 25

Va= Vecp2 x 0.863 / PACO2

Question 26

When you hyperventilate, what happens to the alveolar ventilation and PaCO2

Answer 26

VA increases

PACO2 Decreases

Question 27

Does hypoventialtion cases hypocapnia or hypercapnia

Answer 27

Hypercapnia (increase in PaCO2)

Question 28

Does hypernea lead to an increase in PaCO2

Answer 28

No

Question 29

How do you calculate PAO2?

Answer 29

PIO2-PaCO2/RQ