Conserving Oxygen During COVID-19 Pandemic

To conserve oxygen supply during times of potential shortage, alternative use of FD140 and FD140i can be a temporary intervention. Read full details on advice.

31st March 2021

Within the ongoing pandemic, we advise judicious use of oxygen where concerns exist regarding oxygen supply and where Type 1 respiratory failure SARS-CoV-2 patients are being treated with high flow CPAP.

Armstrong Medical product advisory notice:

Product Advisory: Conserving Oxygen During COVID-19 Pandemic

Read the full advisory notice.

Reducing oxygen consumption with the FD140i

With O2 consumption becoming a real challenge here are 4 ways in which the FD140i can assist with optimising flow and reducing oxygen consumption.


Simple transition from HFOT to CPAP

The continuous pressure achieved with CPAP maintains alveoli stability and may enable a reduction in FiO2, helping reduce oxygen consumption.

For example:
HFOT 60L/min, FiO2 0.9 = O2 consumption 54L/min.
CPAP 75L/min, FiO2 0.6 = O2 consumption 45L/min.

HFOT via nasal cannula delivers low levels of PEEP and in the hypoxic patient its main benefit is the washout of nasopharyngeal dead space at flows exceeding 45L/min.

Nasal high flow reduces dead space

Winfried Möller et al.
Read the full paper.

Optimal flow for the patient

Unlike conventional blender flow meter systems, the FD140i provides incremental flow adjustment of 1L/min with enhanced pressure measurement.

Clinicians can clearly observe the patient’s work of breathing and in response to the therapy and adjust accordingly to find the optimal flow.

Low pressure alarms

Low pressure alarms will make users aware of leaks. In addition to increasing oxygen consumption, leaks will increase the risk of virus transmission. As highlighted at #WSM2021 an NIV machine with leak compensation with badly fitted mask can use up to 250L/min.

Dedicated helmet mode

Leaks with face mask CPAP can become more challenging as PEEP levels increase. Helmets have demonstrated better patient compliance at higher PEEP. In addition the increased helmet volume may enable users to deliver lower flow compared to face mask CPAP.

Further Reading

Clinical evidence on high flow oxygen therapy and active humidification in adults

C. Gotera et al. Read the full paper.


FIO2 in an Adult Model Simulating High-Flow Nasal Cannula Therapy

Yusuke Chikata et al. Read the full paper.


Physiologic Effects of High-Flow Nasal Cannula Oxygen in Critical Care Subjects

Frederic Vargas et al. Read the full paper.


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