1. BEDSIDE RESPIRATORY
ASSESSMENT &
SPIROMETRY
Dr. Arjun chhetri
Dpt of Anaesthesiology

2. Lung Volumes and Capacities
PFT tracings have:
 Four Lung volumes:
tidal volume, inspiratory
reserve volume,
expiratory reserve
volume, and residual
volume
 Five capacities:,
inspiratory capacity,
expiratory capacity, vital
capacity, functional
residual capacity, and
total lung capacity

3. Lung Volumes
 Tidal Volume (TV):
volume of air inhaled or
exhaled with each
breath during quiet
breathing (6-8 ml/kg)
 Inspiratory Reserve
Volume (IRV):
maximum volume of air
inhaled from the end-
inspiratory tidal
position.(1900-3300ml)
 Expiratory Reserve
Volume (ERV):
maximum volume of air
that can be exhaled
from resting end-
expiratory tidal

4. Lung Volumes
 Residual Volume
(RV):
 Volume of air
remaining in lungs
after maximium
exhalation (20-25
ml/kg) (1700-
2100ml)
 Indirectly measured
(FRC-ERV)
 It can not be
measured by
spirometry

5. Lung Capacities
 Total Lung Capacity
(TLC): Sum of all volume
compartments or volume
of air in lungs after
maximum inspiration (4-6
L)
 Vital Capacity (VC):
TLC minus RV or
maximum volume of air
exhaled from maximal
inspiratory level. (60-70
ml/kg) (3100-4800ml)
 Inspiratory Capacity
(IC): Sum of IRV and TV
or the maximum volume
of air that can be inhaled
from the end-expiratory
tidal position. (2400-
3800ml).
 Expiratory Capacity
(EC): TV+ ERV

6. Lung Capacities
 Functional Residual
Capacity (FRC):
 Sum of RV and ERV or
the volume of air in the
lungs at end-expiratory
tidal position.(30-35
ml/kg) (2300-3300ml).
 It can not be measured
by spirometry)

7. VOLUMES, CAPACITIES AND
THEIR CLINICAL SIGNIFICANCE
1) TIDAL VOLUME (TV):
 VOLUME OF AIR INHALED/EXHALED IN EACH BREATH
DURING QUIET RESPIRATION.
 N – 6-8 ml/kg.
 TV FALLS WITH DECREASE IN COMPLIANCE,
DECREASED VENTILATORY MUSCLE STRENGTH.
2) INSPIRATORY RESERVE VOLUME (IRV):
 MAX. VOL. OF AIR WHICH CAN BE INSPIRED AFTER A
NORMAL TIDAL INSPIRATION i.e. FROM END
INSPIRATION PT.
 N- 1900 ml- 3300 ml.

8. CONTINUED………
3) EXPIRATORY RESERVE VOLUME (ERV):
 MAX. VOLUME OF AIR WHICH CAN BE EXPIRED
AFTER A NORMAL TIDAL EXPIRATION i.e. FROM
END EXPIRATION PT.
 N- 700 ml – 1000 ml
4) INSPIRATORY CAPACITY (IC) :
 MAX. VOL. OF AIR WHICH CAN BE INSPIRED
AFTER A NORMAL TIDAL EXPIRATION.
 IC = IRV + TV
 N-2400 ml – 3800 ml.

9. CONTINUED………..
4) VITAL CAPACITY:
 MAX. VOL. OF AIR EXPIRED AFTER A MAX.
INSPIRATION .
 MEASURED WITH VITALOGRAPH
 VC= TV+ERV+IRV
 N- 3.1-4.8L. OR 60-70 ml/kg
 VC IS COSIDERED ABNORMAL IF ≤ 80% OF
PREDICTED VALUE

10. FACTORS INFLUENCING VC
 PHYSIOLOGICAL :
 physical dimensions- directly proportional to
ht.
 SEX – more in males : large chest size, more
muscle power.
 AGE – decreases with increasing age
 STRENGTH OF RESPIRATORY MUSCLES
 POSTURE – decreases in supine position
 PREGNANCY- unchanged or increases by
10% ( increase in AP diameter In pregnancy)

11. CONTINUED………
 PATHOLOGICAL:
 DISEASE OF RESPIRATORY MUSCLES
 ABDOMINAL CONDITION : pain, dis. and
splinting

12. FACTORS DECREASING VITAL
CAPACITY
1) Alteration in muscle power- d/t drugs, n-m
dis., cerebral tumours.
2) Pulmonary diseases – pneumonia, chronic
bronchitis, asthma, fibrosis, emphysema,
pulmonary edema,.
3) Space occupying lesions in chest- tumours,
pleural/pericardial effusion, kyphoscoliosis
4) Abdominal tumours, ascites.

13. 5) Depression of respiration : opioids/ volatile
agents
6) Abdominal splinting – abdominal binders,
tight bandages, hip spica.
7)Abdominal pain – decreases by 50% & 75% in
lower & upper abdominal Surgeries
respectively.
8) Posture – by altering pulmonary Blood
volume.

14. DIFFERENT POSTURES
AFFECTING VC
 POSITION
 TRENDELENBERG
 LITHOTOMY
 PRONE
 RT. LATERAL
 LT. LATERAL
 DECREASE IN VC
 14.5%
 18%
 10%
 12%
 10%

15. VC CONTINUED…….
 VC correlates with capability for deep
breathing and effective cough.
 So in post operative period if VC falls below 3
times VC– artificial respiration is needed to
maintain airway clear of secretions.

16. CONTINUED…….
6) TOTAL LUNG CAPACITY :
 Maximum volume of air attained in lungs after
maximal inspiration.
 N- 4-6 l or 80-100 ml/kg
 TLC= VC + RV
7) RESIDUAL VOLUME (RV):
 Volume of air remaining in the lungs after
maximal expiration.
 N- 1570 – 2100 ml OR 20 – 25 ml/kg.

17. CONTINUED……
8) FUNCTIONAL RESIDUAL CAPACITY
(FRC):
 Volume of air remaining in the lungs at
passive end expiration.
 N- 2.3 -3.3 L OR 30-35 ml/kg.
 FRC = RV + ERV
 Decreases under anaesthesia
 with spontaneous Respiration – decreases by
20%
 With paralysis – decreases by 16%

18. FACTORS AFFECTING FRC
 FRC INCREASES WITH
 Increased height
 Erect position (30% more than in supine)
 Decreased lung recoil (e.g. emphysema)
 FRC DECREASES WITH
 Obesity
 Muscle paralysis (especially in supine)
 Supine position
 Restrictive lung disease (e.g. fibrosis, Pregnancy)
 Anaesthesia
 FRC does NOT change with age.

19. Pulmonary Function Tests
 The term encompasses a wide variety of
objective tests to assess lung function
 Provide objective and standardized
measurements for assessing the presence and
severity of respiratory dysfunction.

20. GOALS
 To predict the presence of pulmonary
dysfunction
 To know the functional nature of disease
(obstructive or restrictive. )
 To assess the severity of disease
 To assess the progression of disease
 To assess the response to treatment
 To identify patients at increased risk of
morbidity and mortality, undergoing pulmonary
resection.

21.  To wean patient from ventilator in icu.
 Medicolegal- to assess lung impairment as a
result of occupational hazard.
 Epidemiological surveys- to assess the
hazards to document incidence of disease
 To identify patients at perioperative risk of
pulmonary complications
CONTINUED……..

22. INDICATIONS OF PFT IN PAC
GUIDELINES FOR PREOPERATIVE
SPIROMETRY
 Age > 70 yrs.
 Morbid obesity
 Thoracic surgery
 Upper abdominal surgery
 Smoking history and cough
 Any pulomonary disease

23. INDICATIONS FOR
PREOPERATIVE SPIROMETRY
 ACP GUIDELINES FOR PREOPERATIVE
SPIROMETRY
 Lung resection
 H/o smoking, dyspnoea
 Cardiac surgery
 Upper abdominal surgery
 Lower abdominal surgery
 Uncharacterized pulmonary disease(defined as
history of pulmonary Disease or symptoms and no
PFT in last 60 days)

24. CONTRAINDICATIONS FOR PFT
 1.Myocardial infarction within a month
 2.Unstable angina
 3.Recent thoraco abdominal surgery
 4.Recent ophthalmic surgery
 5.Thoracic or abdominal aneurysm
 6.Pnemothorax

25. BED SIDE PFT
1) Sabrasez breath holding test:
• Ask the patient to take a full but not too deep breath & hold it as long
as possible.
>25 SEC.-NORMAL Cardiopulmonary Reserve (CPR)
15-25 SEC- LIMITED CPR
<15 SEC- VERY POOR CPR (Contraindication for elective
surgery)
25- 30 SEC - 3500 ml VC
20 – 25 SEC - 3000 ml VC
15 - 20 SEC - 2500 ml VC
10 - 15 SEC - 2000 ml VC
5 - 10 SEC - 1500 ml VC

26. BED SIDE PFT
2) Single breath count:
After deep breath, hold it and start counting till
the next breath.
 N- 30-40 COUNT
 Indicates vital capacity

27. BED SIDE PFT
3) SCHNEIDER’S MATCH BLOWING TEST:
MEASURES Maximum Breathing Capacity.
Ask to blow a match stick from a distance of 6”
(15 cms) with-
 Mouth wide open
 Chin rested/supported
 No purse lipping
 No head movement
 No air movement in the room
 Mouth and match at the same level

28. BED SIDE PFT
 Can not blow out a match
 MBC < 60 L/min
 FEV1 < 1.6L
 Able to blow out a match
 MBC > 60 L/min
 FEV1 > 1.6L
 MODIFIED MATCH TEST:
DISTANCE MBC
9” >150 L/MIN.
6” >60 L/MIN.
3” > 40 L/MIN.

29. BED SIDE TEST
4) COUGH TEST: DEEP BREATH F/BY
COUGH
 ABILITY TO COUGH
 STRENGTH
 EFFECTIVENESS
INADEQUATE COUGH IF: FVC<20 ML/KG
FEV1 < 15 ML/KG
PEFR < 200 L/MIN.
VC ~ 3 TIMES TV FOR EFFECTIVE COUGH.
A wet productive cough / self propagated
paraoxysms of coughing – patient susceptible
for pulmonary Complication.

30. Tracheal auscultation/ Forced
expiratory time
 After deep breath, exhale maximally and
forcefully & keep stethoscope over trachea &
listen.
N FET – 3-5 SECS.
OBS.LUNG DIS. - > 6 SEC
RES. LUNG DIS.- < 3 SEC

31. DEBONO WHISTLE
BLOWING TEST
MEASURES PEFR.
Patient blows down a wide bore tube at the
end of which is a whistle, on the side is a hole
with adjustable knob.
As subject blows → whistle blows, leak hole
is gradually increased till the intensity of
whistle disappears.
At the last position at which the whistle can
be blown , the PEFR can be read off the scale.

33. PEFR(peak expiratory flow rate)
 Simple and cheap test.
 Patient ask to take full inspiration to TLC and
then blow out forcefully into peak flow meter.
 Lips must be placed tightly around the
mouthpiece.
 Best three test is recorded.
 Not a good measure of airflow limitation.
 Best used to monitor progression of disease
and Rx.
 Coughing is ineffective if peak flow is

34. SPIROMETRY
 SPIROMETRY : CORNERSTONE OF ALL
PFTs.
 John hutchinson – invented spirometer.
 “Spirometry is a medical test that measures
the volume of air an individual inhales or
exhales as a function of time.”
 Measures VC, FVC, FEV1, PEFR.
 CAN’T MEASURE – FRC, RV, TLC.

35. PREPERATION
 Prior explanation to the patient
 Not to smoke /inhale bronchodilators 6 hrs
prior or oral bronchodilators 12hrs prior.
 Remove any tight clothings/ waist belt/
dentures
 Pt. Seated comfortably
If obese, child < 12 yrs- standing

36.  Nose clip to close nostrils.
 Exp. Effort shld last ≥ 4 secs.
 Should not be interfered by coughing, glottic
closure, mechanical obstruction.
 3 acceptable tracings taken & largest value is
used.

38. RECORDED PARAMETER
 Normally forced vital capacity(FVC) is reported
along with FEV1.
 Ratio of FEV1/FVC (IN %).

39. Measurements Obtained from the
FVC Curve
 FEV1---the volume exhaled during the first
second of the FVC maneuver
 FEF 25-75%---the mean expiratory flow
during the middle half of the FVC maneuver;
reflects flow through the small (<2 mm in
diameter) airways
 FEV1/FVC---the ratio of FEV1 to FVC X 100
(expressed as a percent); an important value
because a reduction of this ratio from
expected values is specific for obstructive
rather than restrictive diseases

40. Spirometry Interpretation:
Obstructive vs. Restrictive Defect
 Obstructive Disorders
 Characterized by a
limitation of expiratory
airflow so that airways
cannot empty as rapidly
compared to normal (such
as through narrowed
airways from
bronchospasm,
inflammation, etc.)
Examples:
 Asthma
 Emphysema
 Cystic Fibrosis
Restrictive Disorders
Characterized by reduced
lung volumes/decreased
lung compliance
Examples:
Interstitial Fibrosis
Scoliosis
Obesity
Lung Resection
Neuromuscular diseases
Cystic Fibrosis

41. Spirometry Interpretation: Obstructive
vs. Restrictive Defect
 Obstructive
Disorders
 FVC nl or↓
 FEV1 ↓
 FEF25-75% ↓
 FEV1/FVC ↓
 TLC nl or ↑
 Restrictive Disorders
 FVC ↓
 FEV1 ↓
 FEF 25-75% nl to ↓
 FEV1/FVC nl to ↑
 TLC ↓

42. Spirometry Interpretation
 FVC
 Interpretation of %
predicted:
 80-120% Normal
 70-79% Mild reduction
 50%-69% Moderate
reduction
 <50% Severe reduction
FEV1
Interpretation of %
predicted:
 >75% Normal
 60%-75% Mild obstruction
 50-59% Moderate
obstruction
 <49% Severe obstruction
 <25 y.o. add 5% and >60
y.o. subtract 5

43. Spirometry Interpretation
 FEF 25-75%
 Interpretation of %
predicted:
 >79% Normal
 60-79%Mild
obstruction
 40-59%Moderate
obstruction
 <40% Severe
obstruction
 FEV1/FVC
 Interpretation of
absolute value:
 80 or higher
Normal
 79 or lower
Abnormal

44. FLOW VOLUME LOOPS
 Measured in respiratory function department.
 Peak flow at different lung vol are recorded.
 Although more complex to interpret, provide
more accurate regarding ventilatory function.
 Provide useful data abt severity of obstructive
& respiratory disease.

46. How is a flow-volume loop
helpful?

47. Methacholine challenge test
 Also known as bronchial challenge test.
 Primarily used to diagnose bronchial hyper-
reactivity.
 Methacholine is an agent that, when inhaled,
causes the airways to spasm and narrow if
asthma is present.
 During this test, patient inhale increasing
amounts of methacholine aerosol mist before
and after spirometry.

48. CONTD….
 Considered positive, meaning asthma is
present, if the lung function drops by at least
20%.
 A bronchodilator is always given at the end of
the test to reverse the effects of the
methacholine.
 Therapeutic uses are limited by its adverse
cardiovascular effects, such as bradycardia
and hypotension.

49. SINGLE BREATH TEST USING
CO
 Pt inspires a dilute mixture of CO and hold the
breath for 10 secs.
 CO taken up is determined by infrared
analysis:
 DlCO = CO ml/min/mmhg
 PACO – PcCO
 N range 17- 25 ml/min./mmhg.
 DLO2 = DLCO x 1.23

50. DLCO decreases in-
 Emphysema, lung resection, pul. Embolism,
anaemia
 Pulmonary fibrosis, sarcoidosis- increased
thickness
 DLCO increases in:
(Cond. Which increase pulm, bld flow)
 Supine position
 Exercise
 Obesity
 L-R shunt

51. CONTINUED………..
2) HELIUM DILUTION METHOD:
Patient breathes in and out of a spirometer filled with 10%
helium and 90% o2, till conc. In spirometer and lung becomes
same (equilibirium).
As no helium is lost; (as he is insoluble in blood)
C1 X V1 = C2 ( V1 + V2)
V2 = V1 ( C1 – C2)
C2
V1= VOL. OF SPIROMETER
V2= FRC
C1= Conc.of He in the spirometer before equilibrium
C2 = Conc, of He in the spirometer after equilibrium

52. TESTS FOR
CARDIOPLULMONARY
INTERACTIONS
 QUALITATIVE- history, exam, ABG, stair
climbing test
 QUANTITATIVE- 6 minute walk test

53. CONTINUED…….
 1) STAIR CLIMBING TEST:
 If able to climb 3 flights of stairs without stopping/dypnoea at his/her
own pace- ↓ed morbidity & mortality
 If not able to climb 2 flights – high risk
 2) 6 MINUTE WALK TEST:
- Gold standard
- C.P. reserve is measured by estimating max. O2 uptake during
exercise
- Modified if pt. can’t walk – bicycle exercises
- If pt. is able to walk for >2000 feet during 6 min pd,
- VO2 max > 15 ml/kg/min
- If 1080 feet in 1 min : VO2 of 12ml/kg/min
- Simultaneously oximetry is done & if Spo2 falls >4%- high risk

54.  Thank you