Calculating oxygen consumption for Hamilton Medical ventilators

Author: Simon Franz, Reviewer: Bernhard Schmitt, Thomas Reimer, Munir Karjaghli, Sebastian Hollenberg
Last change: 07.07.2020, Revision , Image added

As at June 2020, many hospitals are housing far more ICU beds than normal. Many may also be using new makes or models of ventilators they are unfamiliar with. In order to work out the total amount of oxygen required under these changed circumstances, it is necessary to know how to calculate the oxygen consumption for a particular ventilator.

While the basic principle applies to most makes and models, the calculation depends on several parameters that may differ.

To calculate the estimated oxygen consumption for your Hamilton Medical ventilator, you need to take these parameters into account:

  • Fraction of inspired oxygen (%Oxygen)
  • Expiratory minute volume (ExpMinVol) (x2 for patients < 8 kg)
  • Base flow (see table below)
  • In the case of leaks: leak flow (Mvleak)

The calculation is as follows:

(ExpMinVol + Base flow + MVleak) * ((%Oxygen – 20.9) / 79.1)

Base flow rates for Hamilton Medical ventilators

Adult/pediatric 3 l/min 6 l/min Flow trigger setting ≤ 2 l/min: 4 l/min 
Flow trigger setting > 2 l/min: 2*Flow trigger  
IntelliSync+: variable
Range: 2 to 30 l/min
Neonatal 4 l/min 6 l/min Flow trigger setting ≤ 1 l/min: 2 l/min
Flow trigger setting > 1 l/min: 2*Flow trigger (max. 6 l/min)
Range: 2 to 6 l/min
All Not applicable Not applicable Pressure trigger or trigger off: 1 l/min

Note: This calcuation provides you with an estimate only and the actual consumption may be higher.

Tip: HAMILTON-C1/T1/MR1 ventilators offer oxygen consumption as a measured parameter. When activated, the O2 consumption is displayed in the System > Info window.

Example: Calculation of the estimated oxygen requirement for a HAMILTON-C1 ventilator based on the following parameters:

Expiratory minute volume (ExpMinVol) 8 l/min
Total minute volume leakage (MVleak) 1 l/min
Base flow 3 l/min
Set duration (FiO2) 60%
Planned duration of transport 120 min

O2 consumption (in l/min): (8.0 l/min + 3.0 l/min + 1.0 l/min) * (60.0 – 20.9) / 79.1 = 5.93 l/min

Total oxygen requirement (in liters) for 120 minutes: 5.93 l/min * 120 = 711.6 liters

Therefore, the estimated oxygen consumption for the planned transport duration of 2 hours is approximately 712 liters.

oxygen consumption, transport, oxygen, oxygen requirement, base flow, leaks

Date of Printing: 15.04.2021
The content of this Knowledge Base is intended for informational purposes only. Hamilton Medical AG provides no warranty with respect to the information contained in this Knowledge Base and reliance on any part of this information is solely at your own risk. For detailed instructions on operating your Hamilton Medical device, please refer to the official Hamilton Medical Operator’s Manual for the respective device.