1. Ventilatory Parameters
AKA weaning parameters

2. Parameters Respiratory Rate Tidal Volume Minute Ventilation
Vital Capacity
NIF (MIP,MIF)
RSBI

3. How to measure You need some type of volume measuring device
Wright Respirometer is a hand held device for this
Measure exhaled tidal volume for one minute, it will accumulate and give you a minute ventilation

4. How to Measure cont.
Take the minute ventilation value and divide by the RR. This gives you the average Vt
Coach the patient to do a Vital Capacity
Take the largest volume you obtain
With another device, a manometer, measure the amount of negative force a patient can generate
Do this by attaching the manometer and occluding all air and watch the manometer

5. How to Measure cont. You should have four values
Respiratory rate
Minute ventilation
Vital capacity
Negative inspiratory force
From these you can calculate
Tidal volume
RSBI

6. Respiratory Rate Normal 12-20 bpm Minimal values Less than 25 bpm
More than 10 bpm

7. Tidal Volume The average size tidal volume
Measure the Minute Ventilation and divide by the rate

8. Tidal Volume Normal about 5ml/kg Minimal values More than 250ml
Minute ventilation and RSBI are more important

9. Minute Ventilation Normal 5-10 lpm Minimal Values Less than 10
More than 5

10. Vital Capacity
The maximum amount of air you can breathe out after inhaling as much as possible.
“take a big breath in and blow it all out”
FVC is the basic test done in a PFT
The patient is not to use force for this test, we are measuring just the volume

11. Vital Capacity
Normal
Minimal values
10 ml/kg
1 liter (1000ml)

12. NIF Negative Inspiratory Force Maximum Inspiratory Pressure (MIP)
Maximum Inspiratory Force (MIF)
The maximum amount of force a patient can generate while breathing in with a closed circuit.

13. NIF
Normal values >100 cmH2O
Minimal Values
Greater than 20 cmH2O

14. RSBI Rapid Shallow Breathing Index
The more rapid and shallow the breathing the less effective it is
Respiratory rate(f) divided by tidal volume(Vt)
Single best indicator of post extubation success

15. RSBI
Normal <105
Use the Vt and RR from the parameters gathered