Sharing mechanical ventilator: In vitro evaluation of circuit cross-flows and patient interactions

Sebastiano Maria Colombo, Michele Battistin, Eleonora Carlesso, Luigi Vivona, Fabio Carfagna, Carlo Valsecchi, Gaetano Florio, Luca Carenzo, Tommaso Tonetti, Vito Marco Ranieri, Maurizio Cecconi, Antonio Pesenti, Giacomo Grasselli, Alberto Zanella

Research output: Contribution to journalArticlepeer-review


During the COVID-19 pandemic, a shortage of mechanical ventilators was reported and ventilator sharing between patients was proposed as an ultimate solution. Two lung simulators were ventilated by one anesthesia machine connected through two respiratory circuits and T-pieces. Five different combinations of compliances (30–50 mL × cmH2O−1) and resistances (5–20 cmH2O × L−1 × s−1) were tested. The ventilation setting was: pressure-controlled ventilation, positive end-expiratory pressure 15 cmH2O, inspiratory pressure 10 cmH2O, respiratory rate 20 bpm. Pressures and flows from all the circuit sections have been recorded and analyzed. Simulated patients with equal compliance and resistance received similar ventilation. Compliance reduction from 50 to 30 mL × cmH2O−1 decreased the tidal volume (VT) by 32% (418 ± 49 vs. 285 ± 17 mL). The resistance increase from 5 to 20 cmH2O × L−1 × s−1 decreased VT by 22% (425 ± 69 vs. 331 ± 51 mL). The maximal alveolar pressure was lower at higher compliance and resistance values and decreased linearly with the time constant (r2 = 0.80, p < 0.001). The minimum alveolar pressure ranged from 15.5 ± 0.04 to 16.57 ± 0.04 cmH2O. Cross-flows between the simulated patients have been recorded in all the tested combinations, during both the inspiratory and expiratory phases. The simultaneous ventilation of two patients with one ventilator may be unable to match individual patient’s needs and has a high risk of cross-interference.

Original languageEnglish
Article number547
Issue number7
Publication statusPublished - Jul 2021


  • COVID-19
  • Cross-flow dynamics
  • SARS-CoV2 infection
  • Shared ventilation
  • Sharing mechanical ventilator
  • Two patients one ventilator

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Process Chemistry and Technology
  • Filtration and Separation


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