Reliability and limits of transport-ventilators to safely ventilate severe patients in special surge situations.

Background: Intensive Care Units (ICU) have sometimes been overwhelmed by the surge of COVID-19 patients. Extending ICU capacity can be limited by the lack of air and oxygen pressure sources available. Transport ventilators requiring only one O source may be used in such places.

Objective: To evaluate the performances of four transport ventilators and an ICU ventilator in simulated severe respiratory conditions.

Materials And Methods: Two pneumatic transport ventilators, (Oxylog 3000, Draeger; Osiris 3, Air Liquide Medical Systems), two turbine transport ventilators (Elisee 350, ResMed; Monnal T60, Air Liquide Medical Systems) and an ICU ventilator (Engström Carestation-GE Healthcare) were evaluated on a Michigan test lung. We tested each ventilator with different set volumes (Vt = 350, 450, 550 ml) and compliances (20 or 50 ml/cmHO) and a resistance of 15 cmHO/l/s based on values described in COVID-19 Acute Respiratory Distress Syndrome. Volume error (percentage of Vt) with P of 4 cmHO and trigger delay during assist-control ventilation simulating spontaneous breathing activity with P of 4 cmHO and 8 cmHO were measured.

Results: Grouping all conditions, the volume error was 2.9 ± 2.2% for Engström Carestation; 3.6 ± 3.9% for Osiris 3; 2.5 ± 2.1% for Oxylog 3000; 5.4 ± 2.7% for Monnal T60 and 8.8 ± 4.8% for Elisee 350. Grouping all conditions (P of 4 cmHO and 8 cmHO), trigger delay was 50 ± 11 ms, 71 ± 8 ms, 132 ± 22 ms, 60 ± 12 and 67 ± 6 ms for Engström Carestation, Osiris 3, Oxylog 3000, Monnal T60 and Elisee 350, respectively.

Conclusions: In surge situations such as COVID-19 pandemic, transport ventilators may be used to accurately control delivered volumes in locations, where only oxygen pressure supply is available. Performances regarding triggering function are acceptable for three out of the four transport ventilators tested.