volume flow loop

Question 1

flow volume loop

Answer 1

flow volume loop consist of forced expiatory maneuver followed expiratory maneuver followed by forced inspiratory maneuver
volume is on x-axis
flow is on y-axis

Question 2

volume calibration

Answer 2

one cm equal 1 liter

one volt equals 1 liter

Question 3

flow calibration

Answer 3

two cm equals 2 l/sec

one volt equals 2 l/sec

Question 4

FEF max

Answer 4

peak of expiratory curve

Question 5

FIF max

Answer 5

peak of inspiratory curve

Question 6

FEF and FIF fir 25, 50, 75%

Answer 6

at the flow rate measured at 25,50,75 points on expiatory and inspiratory curve

Question 7

FVC

Answer 7

the volume measure from the beginning to end of the expiatory curve

Question 8

Tidal volume

Answer 8

the volume measured from the repeated tracing at one end of FVC curve

Question 9

restrictive changee

Answer 9

the volumes are decreased which result a skinny loop

Question 10

obstructive changes

Answer 10

peak flow maybe decreased or same

the expiratory portion of the curve flattens toward the volume axis this is called scooped appearance

Question 11

fixed large airway obstruction

Answer 11

flow is limited during both expiration and inspiration
this causes the flow volume curve to flatten both the exp. and insp. portion of flow loop
causes: tracheal stenosis
Goiters

Question 12

Variable intrathoracic obstruction

Answer 12

dynamic compression of the airway during expiration and dilation of the airway
the increase intrathoracic pressure during expiration causes airway to collapse and during inspiration the negative intrapleural pressure cause airway to expand
and flow volume curve is flat during expr. and normal during inspr.
causes: tracheomalacia
tumors in the lower trachea

Question 13

variable extrathoracic obstruction

Answer 13

dynamic compr. of the airway during inspr.
neg. intrapleural pressure tend to collapse the airway during insp.
the positive intrapleural press. during force exhalation dilate the airway
the flow volume curve is normal in expiration phase and flattened in inspiratory
causes: croup
vocal cord paralysis
acute epiglottis
adenotonsillar hypertrophy

Question 14

post-bronchodialator change

Answer 14

air flow limitation diminishes and improving the scooped appearance of an obstructive tracing
PEF increase

Question 15

poor effort identification

Answer 15

poor reproducibility
flow rates are lower at high lung volumes
flat expiratory portion of the curve