Thanks to the pandemic, the world is short by about a million ventilators, according to one estimate last year. A quick-fix solution has been to multiplex — split the outlet tube so that each ventilator is shared by many patients. However, doctors frown at split ventilation because it brings a host of problems, such as lack of independent control for each patient and cross-contamination of pathogens.

Now, researchers at the Massachusetts Institute of Technology, USA, have designed a way to connect a ventilator to two patients with individualised controls. The ‘Individualised System for Augmenting Ventilator Efficacy’ or iSAVE ventilation circuit enables independent control of volume and pressure for each patient and incorporates safety measures to tackle sudden patient deterioration and cross-contamination, says Shriya Srinivasan, a post-doctoral researcher who is a part of the group. The iSAVE utilises a series of valves and flow regulators in parallel limbs to effectively maintain the desired volume for each patient. Filters prevent cross-contamination between individual patient circuits and also filter the expired gas before release into the room through the pressure release valve, thus limiting pathogen exposure for healthcare workers. The one-way valves prevent backflow and mitigate over-distention in cases of rapid flow change. Srinivasan says these machines are inexpensive and can be produced quickly, but cautions that they should be used only during acute shortage of ventilators.