Static

1
Static Dynamic Lung Volumes

• Lab 6

2
Spirometer

• Classic instrument for measuring air volumes
• Wet- Consists of an air collecting bell inverted
  in a vessel of water

Amount of water displaced gives you estimate of
the air required to displaces it
3
Spirometer

• Useful for static volume measurement
• Vital capacity
• Peak airflow
• Limited usefulness when measuring rapid volume
  changes- speech
• Inertia of the bell
• Sluggish response
• Total volume is not obscured but breath group
  data is!

4
Chest Wall Measurement

• Lung volume can be determined from changes in rib
  cage and abdominal size
• Devices for transducing size changes
• Magnetometers
• Mercury strain gauges
• Inductance plethysmography
• Respitrace

5
Chest Wall Measurement

• Chest walls 2 parts (rib cage abdomen),
  Contribute to the total lung volume change
• Rib cage and abdomen movement are not 11 so
  calibration of abdomen rib cage are completed

6
Normal Adult- 20 year old Male
Vtl
Red LV Green RC Blue AB Yellow Audio
7
Normal Adult- 20 year old Male
Vtl
LV
RC
AB
Audio
8
Multihandicapped Adult- 36 year old Male
Multihandicapped Adult- 36 year old Male
Lt. Blue Orange Pt
Red LV Green RC Blue AB Yellow Audio
9
Multihandicapped Adult- 36 year old Male
Pt
Vtl
LV
RC
AB
Audio
10
Articulatory Phonatory Volumes

• Specific articulatory events phonatory tasks
  can be measured by
• Spirometer- Although not accurate enough
• Poor resolution frequency response
• Respitrace- Also not accurate enough
• Poor time resolution
• Pneumotachograph
• Integration of the flow signal to get volume
• Shows very small volume changes in a fraction of
  a second

11
Pneumotachograph vs. Spirometer

• Greater squareness of
• the corners indicate better
• frequency response

12
Air Volume Measurements

• Volume is calculated by multiplying mean flow by
  the events duration
• .123 (flow) x 20 (duration) 2.46 L (volume)
• Not always the most accurate method for measuring
  articulatory volumes

13
Laboratory

• Purpose
• Measure a patient's forced vital capacity (FVC)
• Evaluate maximum phonation volume
• Derive estimates of mean airflow from a volume
  record
• Estimate lung volume used for each breath group
  during reading of a standard passage (in absolute
  terms and as a age of FVC)

14
Laboratory

• Part I-
• FVC maximum amount of air that can be expired
  after a maximal inspiration- represents the total
  amount of air that is available for use.
• Measure height of patient
• Measure FVC with spirometer or aerophone
• Max. inhalation at REL, then max exhalation
• 3 trials
• Determine patients expected FVC (norms or
  formula in Appendix G

15
Laboratory

• Part II
• Phonation volume (PV) the maximum amount of air
  that is available for a maximally sustained
  phonation
• Use sample (figure A) of sustained /a/ for the
  lab questions
• Is PV normal (Use norms in text)
• Abnormal PV might occur in which pathological
  conditions?
• For the patient exercise do a sustained /a/ on
  the aerophone, mark it and calculate volume.

16
Laboratory

• Part III
• Assessment of lung volume change during a
  speaking task (how a patient manages air for
  speech purposes)
• Duration relative volume of each breath group
  (amount of air expressed as a age of VC)
• Mark speaking record
• Use Figure B

17
Laboratory

• Analysis questions for part III
• Find REL- draw line across bottom of cycle
• Divide into 10 equal segments (10 each)
• Mark each breath group
• The FVC for this sample will be ?
• To calculate age of VC
• Volume (in Liters) x 100 / VC in L
• ex. .64 x 100/ 4.4 14.5

18
Laboratory

• Mean airflow data
• Used to assess more general characteristics of
  ventilatory, laryngeal and/or articulatory
  function
• Mean speech airflow volume of air the speaker
  uses divided by the duration of the utterance

19
Laboratory

• Part IV
• Use Figs. 3 4 of the running speech samples and
  highlight the mean flow rate from your
  calculations
• baseline volume where speech begins
• Finishing volume where speech ends
• Total volume baseline volume-finishing volume
• Speech volume of each breath group expiration
  duration
• Mean airflow rate mean speech volume/mean
  duration