Respiratory Mecahnics Calculator

DISCLAIMER

This is a website for calculation of lung mechanics during mechanical ventilation. It is intended for educational usage . By using this calculator, you accept the full responsiblity and liability of your patient's care and that there is no responsiblity and/or liability towards the original authours.

This site contains copyrighted information based on publised scientific data on lung mechanics. It is devleoped by Dr. Teddy Tun Win Hla, Dr Francesco Vasques and Dr Luigi Camporota .

This site is currently still being developed and in alpha testing phase. If any queries or feedback, please contact teddyhla@gmail.com.

Please click here for version history and future vision.

Step 1 : Theoretical Normal Values




Estimated Theoretical FRC (FRCtheoretical) is litres.

Estimated Theoretical Respiratory System Compliance is(CRS-Theoretical) ml/cmH2O.

Step 2 : Assessment of Respiratory Mechanics


Perform a 5 second inspiratory hold to measure Peak airway Pressure (Ppeak) and Plateau Pressure (Pplat).


Now, perform a 5 secondary expiratory hold to measure total PEEP pressure (PEEPtot).



For instructions on how to perform inspiratory and expiratory hold, please click the relevant link for your ventilator.
Hamilton Draeger on page 38. Maquet Servo on slide 48

The driving pressure (ΔP) is cmH2O.

Actual respiratory system compliance (CRS-Actual) is ml/cmH2O.

Estimate of an actual FRC is litres.

Calculated PEEP volume is mililitres.

Now, press calculate below for further results on airway resistances and mechanical power.

Calculated airway resistances (Raw) is cmH2O/litres/second.

Calculated dynamic strain (Straindynamic) is .

Calculated total strain (Straintotal) is .

Calculated mecahnical power of the system (MPRS) is Joules/min.

Step 3 : Low Flow PV Loop

Modify pressure and volume alarms on your ventilator to Pressure limit of 45 cmH2O and Volume limit of 1000ml.

Perform a recruitment maneouvre of sustained inflation at 40cmH2O for 10 seconds. Mind the cuff pressure!

Perform a PV loop procedure, with starting pressure 5 to maximum pressure of 40cmH2O, volume limit 12ml/kg, flow 8l/seconds, and run inspiratory and expiratory loops.

⚠Please note this procedure can affect haemodnyamic stability.

For instructions on how to perform PV Loops, please click the relevant link for your ventilator.
Hamilton Draeger

Use cursor to 1 and 2 to find the best (most linear) interval.



VT/Inspiratory Capacity is % .

VT + Peep Volume / Inspiratory Capacity is %.

Step 4 : Potential for Lung Recruitment

Set PEEP to 15 cmH2O, keep ΔP 15 cmH2O and remaining settings unchanged on PC-AC

Link the variation of PEEP and Pins on the ventilator settings, reduce PEEP to 5 but keep ΔP 15 and freeze.

Use the cursor to measure the volume of the last breath at PEEP 15 and first breath at PEEP 5.

⚠ High PEEP can increase right ventricle afterload, and also may worsen gas exchange.

Measure the volume of the last breath at 15 and first breath at 5 PEEP.

in mililitres.
in mililitres.

Calculate Δ PEEP volume, ΔV and ΔVrecruitment.

The Δ PEEP volume is mililitres.

The ΔV volume is mililitres.

The ΔVrecruitment is mililitres.