Open AccessSimultaneous ventilation in the Covid-19 pandemic. A bench study
Author(s) -
Claude Guérin,
Martin Cour,
Neven Stevic,
Florian Degivry,
Erwan L’Her,
Bruno Louis,
Laurent Argaud
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0245578
Subject(s) - medicine , expiration , covid-19 , tidal volume , pulmonary compliance , ventilation (architecture) , peak inspiratory pressure , anesthesia , lung , respiratory system , physics , disease , infectious disease (medical specialty) , thermodynamics
COVID-19 pandemic sets the healthcare system to a shortage of ventilators. We aimed at assessing tidal volume (V T ) delivery and air recirculation during expiration when one ventilator is divided into 2 test-lungs. The study was performed in a research laboratory in a medical ICU of a University hospital. An ICU (V500) and a lower-level ventilator (Elisée 350) were attached to two test-lungs (QuickLung) through a dedicated flow-splitter. A 50 mL/cmH 2 O Compliance (C) and 5 cmH 2 O/L/s Resistance (R) were set in both A and B test-lungs (A C50R5 / B C50R5, step1), A C50-R20 / B C20-R20 (step 2), A C20-R20 / B C10-R20 (step 3), and A C50-R20 / B C20-R5 (step 4). Each ventilator was set in volume and pressure control mode to deliver 800mL V T . We assessed V T from a pneumotachograph placed immediately before each lung, pendelluft air, and expiratory resistance (circuit and valve). Values are median (1 st -3 rd quartiles) and compared between ventilators by non-parametric tests. Between Elisée 350 and V500 in volume control V T in A/B test- lungs were 381/387 vs. 412/433 mL in step 1, 501/270 vs. 492/370 mL in step 2, 509/237 vs. 496/332 mL in step 3, and 496/281 vs. 480/329 mL in step 4. In pressure control the corresponding values were 373/336 vs. 430/414 mL, 416/185 vs. 322/234 mL, 193/108 vs. 176/ 92 mL and 422/201 vs. 481/329mL, respectively (P<0.001 between ventilators at each step for each volume). Pendelluft air volume ranged between 0.7 to 37.8 ml and negatively correlated with expiratory resistance in steps 2 and 3. The lower-level ventilator performed closely to the ICU ventilator. In the clinical setting, these findings suggest that, due to dependence of V T to C, pressure control should be preferred to maintain adequate V T at least in one patient when C and/or R changes abruptly and monitoring of V T should be done carefully. Increasing expiratory resistance should reduce pendelluft volume.