Bed side pulmonary function tests 7

Bed side Pulmonary Function Tests
dr.rajasekharr@gmail.com 1

• Pulmonary function tests have been used traditionally in
the preoperative assessment before any major surgery.
INDICATIONS
 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.

 To identify patients at perioperative risk of pulmonary
complications
 Degree and severity of impairment
 Identify the site of airway obstruction

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
15-25 SEC- LIMITED CardioPulmonary Reserve
<15 SEC- VERY POOR CardioPulmonary Reserve
(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

Breath Holding Test

2) Single breath count:
After deep breath, hold it and start counting till the next
breath.
 Normal- 30-40 COUNT
 Indicates vital capacity

3) SNIDER’SMATCH BLOWING TEST:
Measures Maximum Breathing Capacity.
Should take 6 attempts
Ask to blow a match stick from a distance of 6” (15
cms) with
 Mouth wide open
 Chin rested/supported
 No pursed lips
 No head movement
 No air movement in the room
 Mouth and match stick at the same level

Match Blowing Test

• 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 of Olsen:
DISTANCE MBC
9” >150 L/MIN.
6” >60 L/MIN.
3” > 40 L/MIN.

4) GREENE & BEROWITZ COUGH TEST:
DEEP BREATH F/BY COUGH
 ABILITY TO COUGH
 STRENGTH
 EFFECTIVENESS
INADEQUATE COUGH : 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 paroxysms of
coughing – patient susceptible for pulmonary
Complication.

5) FORCED EXPIRATORY TIME:
After deep breath, exhale maximally and forcefully &
keep stethoscope over trachea & listen.
Normal FET – 3-5 SECS.
Obstructive Lung Disease - > 6 SEC
Restrictive Lung Disease - < 3 SEC

Auscultation over Trachea

6. RESPIRATORY RATE
• Essential yet frequently undervalued component of PFT
• Imp. evaluator in weaning & extubation protocols
• Increase RR ‐ muscle fatigue ‐work load ‐ weaning fails

7) DE BONO’S 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.

DE BONO’S WHISTLE

8)Wright ‘s Respirometer :
measures VT and minute volume
 Simple and rapid
 Instrument- compact, light and portable.
 Disadvantage: It under- reads at low flow rates and over-reads
at high flow rates.
 Can be connected to endo tracheal tube or face mask
 Prior explanation to patient is needed.

Contd…
 Ideally done in sitting position.
 MV- instrument record for 1 min. And read directly
 VT-calculated and dividing MV by counting Respiratory
Rate.
 Accurate measurement in the range of 3.7-20
L/min.(±10%)
 USES: 1)Bedside PFT
2) ICU – Weaning Pts. from Ventilator.

9) MICROSPIROMETERS – MEASURE VC.

10) BED SIDE PULSE OXIMETRY
11) ABG.

References
1) SNIDER,T. H.Simple Bedside Test of Respiratory Function. J. Am. Med. Assoc.
170:1631, 1959.
2) CARILLI, A. D. and J. R. HENDERSON. Estimation of Ventilatory Function by
Blowing Out a Match. Am. Rev. Resp. Dis. 89:680, 1964.
3) OLSEN, C. R. The Match Test: A Measure of Ventilatory Function. Am. Rev. Resp.
Dis. 86:37,1962.
4) WRIGHT, B. M. and C. B. McKERROW. Maximum Forced Expiratory Flow Rate as a
Measure of Ventilatory Capacity. Br. Med. J. 2:1041, 1959.
5) DE BONO, E. F. A Whistle for Testing Lung Function. Lancet 2:1146, 1963.

Bed side pulmonary function tests 7

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Bed side pulmonary function tests 7